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Daniel Veillard598bec32003-07-06 10:02:03 +00005 <title>The XML C parser and toolkit of Gnome</title>
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Daniel Veillard598bec32003-07-06 10:02:03 +000011<h1 align="center">The XML C parser and toolkit of Gnome</h1>
Daniel Veillardb05deb71999-08-10 19:04:08 +000012
Daniel Veillard9c466822001-10-25 12:03:39 +000013<h1>Note: this is the flat content of the <a href="index.html">web
14site</a></h1>
15
Daniel Veillardc9484202001-10-24 12:35:52 +000016<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +000017
18<p></p>
Daniel Veillard9c466822001-10-25 12:03:39 +000019
Daniel Veillard7ebac022004-02-25 22:36:35 +000020<p
21style="text-align: right; font-style: italic; font-size: 10pt">"Programming
22with libxml2 is like the thrilling embrace of an exotic stranger." <a
23href="http://diveintomark.org/archives/2004/02/18/libxml2">Mark
24Pilgrim</a></p>
25
Daniel Veillard598bec32003-07-06 10:02:03 +000026<p>Libxml2 is the XML C parser and toolkit developed for the Gnome project
Daniel Veillard23a52c52003-08-18 10:01:18 +000027(but usable outside of the Gnome platform), it is free software available
Daniel Veillardeec1ae92003-09-09 13:11:01 +000028under the <a href="http://www.opensource.org/licenses/mit-license.html">MIT
29License</a>. XML itself is a metalanguage to design markup languages, i.e.
30text language where semantic and structure are added to the content using
31extra "markup" information enclosed between angle brackets. HTML is the most
32well-known markup language. Though the library is written in C <a
33href="python.html">a variety of language bindings</a> make it available in
34other environments.</p>
Daniel Veillard9c466822001-10-25 12:03:39 +000035
Daniel Veillard710823b2003-03-04 10:05:52 +000036<p>Libxml2 is known to be very portable, the library should build and work
37without serious troubles on a variety of systems (Linux, Unix, Windows,
38CygWin, MacOS, MacOS X, RISC Os, OS/2, VMS, QNX, MVS, ...)</p>
39
Daniel Veillard9c466822001-10-25 12:03:39 +000040<p>Libxml2 implements a number of existing standards related to markup
41languages:</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +000042<ul>
Daniel Veillard9c466822001-10-25 12:03:39 +000043 <li>the XML standard: <a
44 href="http://www.w3.org/TR/REC-xml">http://www.w3.org/TR/REC-xml</a></li>
45 <li>Namespaces in XML: <a
46 href="http://www.w3.org/TR/REC-xml-names/">http://www.w3.org/TR/REC-xml-names/</a></li>
47 <li>XML Base: <a
48 href="http://www.w3.org/TR/xmlbase/">http://www.w3.org/TR/xmlbase/</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +000049 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc2396.txt">RFC 2396</a> :
50 Uniform Resource Identifiers <a
Daniel Veillard9c466822001-10-25 12:03:39 +000051 href="http://www.ietf.org/rfc/rfc2396.txt">http://www.ietf.org/rfc/rfc2396.txt</a></li>
52 <li>XML Path Language (XPath) 1.0: <a
53 href="http://www.w3.org/TR/xpath">http://www.w3.org/TR/xpath</a></li>
54 <li>HTML4 parser: <a
55 href="http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</a></li>
Daniel Veillard23a52c52003-08-18 10:01:18 +000056 <li>XML Pointer Language (XPointer) Version 1.0: <a
Daniel Veillard9c466822001-10-25 12:03:39 +000057 href="http://www.w3.org/TR/xptr">http://www.w3.org/TR/xptr</a></li>
58 <li>XML Inclusions (XInclude) Version 1.0: <a
59 href="http://www.w3.org/TR/xinclude/">http://www.w3.org/TR/xinclude/</a></li>
Daniel Veillard23a52c52003-08-18 10:01:18 +000060 <li>ISO-8859-x encodings, as well as <a
Daniel Veillard9c466822001-10-25 12:03:39 +000061 href="http://www.cis.ohio-state.edu/rfc/rfc2044.txt">rfc2044</a> [UTF-8]
62 and <a href="http://www.cis.ohio-state.edu/rfc/rfc2781.txt">rfc2781</a>
Daniel Veillard23a52c52003-08-18 10:01:18 +000063 [UTF-16] Unicode encodings, and more if using iconv support</li>
Daniel Veillard9c466822001-10-25 12:03:39 +000064 <li>part of SGML Open Technical Resolution TR9401:1997</li>
65 <li>XML Catalogs Working Draft 06 August 2001: <a
66 href="http://www.oasis-open.org/committees/entity/spec-2001-08-06.html">http://www.oasis-open.org/committees/entity/spec-2001-08-06.html</a></li>
Daniel Veillard5c396542002-03-15 07:57:50 +000067 <li>Canonical XML Version 1.0: <a
68 href="http://www.w3.org/TR/xml-c14n">http://www.w3.org/TR/xml-c14n</a>
Daniel Veillard2d347fa2002-03-17 10:34:11 +000069 and the Exclusive XML Canonicalization CR draft <a
70 href="http://www.w3.org/TR/xml-exc-c14n">http://www.w3.org/TR/xml-exc-c14n</a></li>
Daniel Veillard758c5312003-12-15 11:51:25 +000071 <li>Relax NG, ISO/IEC 19757-2:2003, <a
Daniel Veillard17bed982003-02-24 20:11:43 +000072 href="http://www.oasis-open.org/committees/relax-ng/spec-20011203.html">http://www.oasis-open.org/committees/relax-ng/spec-20011203.html</a></li>
Daniel Veillardf83a2c72003-04-08 13:48:40 +000073 <li>W3C XML Schemas Part 2: Datatypes <a
74 href="http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/">REC 02 May
Daniel Veillard7ecced52003-12-18 14:22:09 +000075 2001</a></li>
Daniel Veillard96984452000-08-31 13:50:12 +000076</ul>
77
Daniel Veillard560c2a42003-07-06 21:13:49 +000078<p>In most cases libxml2 tries to implement the specifications in a
79relatively strictly compliant way. As of release 2.4.16, libxml2 passes all
801800+ tests from the <a
Daniel Veillarda5393562002-02-20 11:40:49 +000081href="http://www.oasis-open.org/committees/xml-conformance/">OASIS XML Tests
82Suite</a>.</p>
Daniel Veillard5b16f582002-02-20 11:38:46 +000083
Daniel Veillard0b28e882002-07-24 23:47:05 +000084<p>To some extent libxml2 provides support for the following additional
85specifications but doesn't claim to implement them completely:</p>
Daniel Veillard9c466822001-10-25 12:03:39 +000086<ul>
87 <li>Document Object Model (DOM) <a
88 href="http://www.w3.org/TR/DOM-Level-2-Core/">http://www.w3.org/TR/DOM-Level-2-Core/</a>
Daniel Veillard0b28e882002-07-24 23:47:05 +000089 it doesn't implement the API itself, gdome2 does this on top of
Daniel Veillard9c466822001-10-25 12:03:39 +000090 libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +000091 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc959.txt">RFC 959</a> :
Daniel Veillard8a469172003-06-12 16:05:07 +000092 libxml2 implements a basic FTP client code</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +000093 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc1945.txt">RFC 1945</a> :
94 HTTP/1.0, again a basic HTTP client code</li>
Daniel Veillard9c466822001-10-25 12:03:39 +000095 <li>SAX: a minimal SAX implementation compatible with early expat
96 versions</li>
97 <li>DocBook SGML v4: libxml2 includes a hackish parser to transition to
98 XML</li>
99</ul>
100
Daniel Veillardf83a2c72003-04-08 13:48:40 +0000101<p>A partial implementation of <a
102href="http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/">XML Schemas Part
1031: Structure</a> is being worked on but it would be far too early to make any
104conformance statement about it at the moment.</p>
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000105
Daniel Veillard96984452000-08-31 13:50:12 +0000106<p>Separate documents:</p>
107<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000108 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a> providing an
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000109 implementation of XSLT 1.0 and common extensions like EXSLT for
110 libxml2</li>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000111 <li><a href="http://www.cs.unibo.it/~casarini/gdome2/">the gdome2 page</a>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000112 : a standard DOM2 implementation for libxml2</li>
113 <li><a href="http://www.aleksey.com/xmlsec/">the XMLSec page</a>: an
114 implementation of <a href="http://www.w3.org/TR/xmldsig-core/">W3C XML
115 Digital Signature</a> for libxml2</li>
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000116 <li>also check the related links section below for more related and active
117 projects.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000118</ul>
119
Daniel Veillard806cada2003-03-19 21:58:59 +0000120<p>Results of the <a
121href="http://xmlbench.sourceforge.net/results/benchmark/index.html">xmlbench
Daniel Veillard31ae4622004-02-16 07:45:44 +0000122benchmark</a> on sourceforge February 2004 (smaller is better):</p>
Daniel Veillardd8da01c2003-03-24 15:58:23 +0000123
Daniel Veillard31ae4622004-02-16 07:45:44 +0000124<p align="center"><img src="benchmark.png"
Daniel Veillardd8da01c2003-03-24 15:58:23 +0000125alt="benchmark results for Expat Xerces libxml2 Oracle and Sun toolkits"></p>
Daniel Veillard806cada2003-03-19 21:58:59 +0000126
Daniel Veillarde1662542002-08-28 11:50:59 +0000127<p>Logo designed by <a href="mailto:liyanage@access.ch">Marc Liyanage</a>.</p>
128
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000129<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000130
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000131<p>This document describes libxml, the <a
Daniel Veillard560c2a42003-07-06 21:13:49 +0000132href="http://www.w3.org/XML/">XML</a> C parser and toolkit developed for the
133<a href="http://www.gnome.org/">Gnome</a> project. <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000134href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
135structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000136
Daniel Veillard0142b842000-01-14 14:45:24 +0000137<p>Here are some key points about libxml:</p>
138<ul>
Daniel Veillard8a469172003-06-12 16:05:07 +0000139 <li>Libxml2 exports Push (progressive) and Pull (blocking) type parser
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000140 interfaces for both XML and HTML.</li>
Daniel Veillard8a469172003-06-12 16:05:07 +0000141 <li>Libxml2 can do DTD validation at parse time, using a parsed document
Daniel Veillard91e9d582001-02-26 07:31:12 +0000142 instance, or with an arbitrary DTD.</li>
Daniel Veillard8a469172003-06-12 16:05:07 +0000143 <li>Libxml2 includes complete <a
Daniel Veillard8c2ecaf2001-07-10 17:53:07 +0000144 href="http://www.w3.org/TR/xpath">XPath</a>, <a
145 href="http://www.w3.org/TR/xptr">XPointer</a> and <a
146 href="http://www.w3.org/TR/xinclude">XInclude</a> implementations.</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000147 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard189446d2000-10-13 10:23:06 +0000148 sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillardab8500d2000-10-15 21:06:19 +0000149 Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000150 <li>Basic support for HTTP and FTP client allowing applications to fetch
Daniel Veillard0b28e882002-07-24 23:47:05 +0000151 remote resources.</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000152 <li>The design is modular, most of the extensions can be compiled out.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000153 <li>The internal document representation is as close as possible to the <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000154 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
Daniel Veillard560c2a42003-07-06 21:13:49 +0000155 <li>Libxml2 also has a <a
156 href="http://www.megginson.com/SAX/index.html">SAX like interface</a>;
157 the interface is designed to be compatible with <a
Daniel Veillard402e8c82000-02-29 22:57:47 +0000158 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillardc575b992002-02-08 13:28:40 +0000159 <li>This library is released under the <a
160 href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard0b28e882002-07-24 23:47:05 +0000161 License</a>. See the Copyright file in the distribution for the precise
Daniel Veillardc575b992002-02-08 13:28:40 +0000162 wording.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000163</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000164
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000165<p>Warning: unless you are forced to because your application links with a
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000166Gnome-1.X library requiring it, <strong><span
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000167style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use
168libxml2</p>
169
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000170<h2><a name="FAQ">FAQ</a></h2>
171
Daniel Veillard0b28e882002-07-24 23:47:05 +0000172<p>Table of Contents:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000173<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000174 <li><a href="FAQ.html#License">License(s)</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000175 <li><a href="FAQ.html#Installati">Installation</a></li>
176 <li><a href="FAQ.html#Compilatio">Compilation</a></li>
177 <li><a href="FAQ.html#Developer">Developer corner</a></li>
178</ul>
179
Daniel Veillard63d83142002-05-20 06:51:05 +0000180<h3><a name="License">License</a>(s)</h3>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000181<ol>
182 <li><em>Licensing Terms for libxml</em>
Daniel Veillard8a469172003-06-12 16:05:07 +0000183 <p>libxml2 is released under the <a
Daniel Veillardc575b992002-02-08 13:28:40 +0000184 href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard0b28e882002-07-24 23:47:05 +0000185 License</a>; see the file Copyright in the distribution for the precise
Daniel Veillardc575b992002-02-08 13:28:40 +0000186 wording</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000187 </li>
Daniel Veillard8a469172003-06-12 16:05:07 +0000188 <li><em>Can I embed libxml2 in a proprietary application ?</em>
Daniel Veillard42766c02002-08-22 20:52:17 +0000189 <p>Yes. The MIT License allows you to keep proprietary the changes you
190 made to libxml, but it would be graceful to send-back bug fixes and
191 improvements as patches for possible incorporation in the main
Daniel Veillard0b28e882002-07-24 23:47:05 +0000192 development tree.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000193 </li>
194</ol>
195
196<h3><a name="Installati">Installation</a></h3>
197<ol>
Daniel Veillard560c2a42003-07-06 21:13:49 +0000198 <li><strong><span style="background-color: #FF0000">Do Not Use
199 libxml1</span></strong>, use libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000200 <li><em>Where can I get libxml</em> ?
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000201 <p>The original distribution comes from <a
202 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a
Daniel Veillard024f1992003-12-10 16:43:49 +0000203 href="ftp://ftp.gnome.org/pub/GNOME/sources/libxml2/2.6/">gnome.org</a></p>
Daniel Veillard63d83142002-05-20 06:51:05 +0000204 <p>Most Linux and BSD distributions include libxml, this is probably the
Daniel Veillard0b28e882002-07-24 23:47:05 +0000205 safer way for end-users to use libxml.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000206 <p>David Doolin provides precompiled Windows versions at <a
207 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
208 </li>
209 <li><em>I see libxml and libxml2 releases, which one should I install ?</em>
210 <ul>
Daniel Veillard42766c02002-08-22 20:52:17 +0000211 <li>If you are not constrained by backward compatibility issues with
212 existing applications, install libxml2 only</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000213 <li>If you are not doing development, you can safely install both.
Daniel Veillard0b28e882002-07-24 23:47:05 +0000214 Usually the packages <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000215 href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a
216 href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a> are
Daniel Veillard0b28e882002-07-24 23:47:05 +0000217 compatible (this is not the case for development packages).</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000218 <li>If you are a developer and your system provides separate packaging
219 for shared libraries and the development components, it is possible
220 to install libxml and libxml2, and also <a
221 href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>
222 and <a
223 href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>
224 too for libxml2 &gt;= 2.3.0</li>
225 <li>If you are developing a new application, please develop against
226 libxml2(-devel)</li>
227 </ul>
228 </li>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000229 <li><em>I can't install the libxml package, it conflicts with libxml0</em>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000230 <p>You probably have an old libxml0 package used to provide the shared
Daniel Veillard42766c02002-08-22 20:52:17 +0000231 library for libxml.so.0, you can probably safely remove it. The libxml
232 packages provided on <a
Daniel Veillard0b28e882002-07-24 23:47:05 +0000233 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provide
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000234 libxml.so.0</p>
235 </li>
236 <li><em>I can't install the libxml(2) RPM package due to failed
Daniel Veillard63d83142002-05-20 06:51:05 +0000237 dependencies</em>
238 <p>The most generic solution is to re-fetch the latest src.rpm , and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000239 rebuild it locally with</p>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000240 <p><code>rpm --rebuild libxml(2)-xxx.src.rpm</code>.</p>
Daniel Veillard42766c02002-08-22 20:52:17 +0000241 <p>If everything goes well it will generate two binary rpm packages (one
242 providing the shared libs and xmllint, and the other one, the -devel
243 package, providing includes, static libraries and scripts needed to build
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000244 applications with libxml(2)) that you can install locally.</p>
245 </li>
246</ol>
247
248<h3><a name="Compilatio">Compilation</a></h3>
249<ol>
Daniel Veillard8a469172003-06-12 16:05:07 +0000250 <li><em>What is the process to compile libxml2 ?</em>
251 <p>As most UNIX libraries libxml2 follows the "standard":</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000252 <p><code>gunzip -c xxx.tar.gz | tar xvf -</code></p>
253 <p><code>cd libxml-xxxx</code></p>
254 <p><code>./configure --help</code></p>
255 <p>to see the options, then the compilation/installation proper</p>
256 <p><code>./configure [possible options]</code></p>
257 <p><code>make</code></p>
258 <p><code>make install</code></p>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000259 <p>At that point you may have to rerun ldconfig or a similar utility to
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000260 update your list of installed shared libs.</p>
261 </li>
Daniel Veillard8a469172003-06-12 16:05:07 +0000262 <li><em>What other libraries are needed to compile/install libxml2 ?</em>
263 <p>Libxml2 does not require any other library, the normal C ANSI API
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000264 should be sufficient (please report any violation to this rule you may
265 find).</p>
Daniel Veillard8a469172003-06-12 16:05:07 +0000266 <p>However if found at configuration time libxml2 will detect and use the
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000267 following libs:</p>
268 <ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000269 <li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a> : a
Daniel Veillard0b28e882002-07-24 23:47:05 +0000270 highly portable and available widely compression library.</li>
271 <li>iconv: a powerful character encoding conversion library. It is
272 included by default in recent glibc libraries, so it doesn't need to
273 be installed specifically on Linux. It now seems a <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000274 href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part
275 of the official UNIX</a> specification. Here is one <a
Daniel Veillarddad3f682002-11-17 16:47:27 +0000276 href="http://www.gnu.org/software/libiconv/">implementation of the
277 library</a> which source can be found <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000278 href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>.</li>
279 </ul>
280 </li>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000281 <li><em>Make check fails on some platforms</em>
Daniel Veillard42766c02002-08-22 20:52:17 +0000282 <p>Sometimes the regression tests' results don't completely match the
283 value produced by the parser, and the makefile uses diff to print the
284 delta. On some platforms the diff return breaks the compilation process;
285 if the diff is small this is probably not a serious problem.</p>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000286 <p>Sometimes (especially on Solaris) make checks fail due to limitations
Daniel Veillarde46182c2002-02-12 14:29:11 +0000287 in make. Try using GNU-make instead.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000288 </li>
289 <li><em>I use the CVS version and there is no configure script</em>
Daniel Veillard42766c02002-08-22 20:52:17 +0000290 <p>The configure script (and other Makefiles) are generated. Use the
291 autogen.sh script to regenerate the configure script and Makefiles,
292 like:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000293 <p><code>./autogen.sh --prefix=/usr --disable-shared</code></p>
294 </li>
295 <li><em>I have troubles when running make tests with gcc-3.0</em>
296 <p>It seems the initial release of gcc-3.0 has a problem with the
297 optimizer which miscompiles the URI module. Please use another
Daniel Veillard0b28e882002-07-24 23:47:05 +0000298 compiler.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000299 </li>
300</ol>
301
302<h3><a name="Developer">Developer</a> corner</h3>
303<ol>
Daniel Veillard93d95252003-04-29 20:25:40 +0000304 <li><em>Troubles compiling or linking programs using libxml2</em>
305 <p>Usually the problem comes from the fact that the compiler doesn't get
306 the right compilation or linking flags. There is a small shell script
307 <code>xml2-config</code> which is installed as part of libxml2 usual
Daniel Veillard560c2a42003-07-06 21:13:49 +0000308 install process which provides those flags. Use</p>
Daniel Veillard93d95252003-04-29 20:25:40 +0000309 <p><code>xml2-config --cflags</code></p>
310 <p>to get the compilation flags and</p>
311 <p><code>xml2-config --libs</code></p>
312 <p>to get the linker flags. Usually this is done directly from the
313 Makefile as:</p>
314 <p><code>CFLAGS=`xml2-config --cflags`</code></p>
315 <p><code>LIBS=`xml2-config --libs`</code></p>
316 </li>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000317 <li><em>xmlDocDump() generates output on one line.</em>
Daniel Veillard8a469172003-06-12 16:05:07 +0000318 <p>Libxml2 will not <strong>invent</strong> spaces in the content of a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000319 document since <strong>all spaces in the content of a document are
320 significant</strong>. If you build a tree from the API and want
321 indentation:</p>
322 <ol>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000323 <li>the correct way is to generate those yourself too.</li>
Daniel Veillard8a469172003-06-12 16:05:07 +0000324 <li>the dangerous way is to ask libxml2 to add those blanks to your
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000325 content <strong>modifying the content of your document in the
326 process</strong>. The result may not be what you expect. There is
327 <strong>NO</strong> way to guarantee that such a modification won't
Daniel Veillard0b28e882002-07-24 23:47:05 +0000328 affect other parts of the content of your document. See <a
Daniel Veillard5373ea12003-07-24 13:09:13 +0000329 href="http://xmlsoft.org/html/libxml-parser.html#xmlKeepBlanksDefault">xmlKeepBlanksDefault
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000330 ()</a> and <a
Daniel Veillard5373ea12003-07-24 13:09:13 +0000331 href="http://xmlsoft.org/html/libxml-tree.html#xmlSaveFormatFile">xmlSaveFormatFile
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000332 ()</a></li>
333 </ol>
334 </li>
335 <li>Extra nodes in the document:
336 <p><em>For a XML file as below:</em></p>
337 <pre>&lt;?xml version="1.0"?&gt;
338&lt;PLAN xmlns="http://www.argus.ca/autotest/1.0/"&gt;
339&lt;NODE CommFlag="0"/&gt;
340&lt;NODE CommFlag="1"/&gt;
341&lt;/PLAN&gt;</pre>
342 <p><em>after parsing it with the function
343 pxmlDoc=xmlParseFile(...);</em></p>
344 <p><em>I want to the get the content of the first node (node with the
345 CommFlag="0")</em></p>
346 <p><em>so I did it as following;</em></p>
Daniel Veillard63d83142002-05-20 06:51:05 +0000347 <pre>xmlNodePtr pnode;
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000348pnode=pxmlDoc-&gt;children-&gt;children;</pre>
349 <p><em>but it does not work. If I change it to</em></p>
350 <pre>pnode=pxmlDoc-&gt;children-&gt;children-&gt;next;</pre>
351 <p><em>then it works. Can someone explain it to me.</em></p>
352 <p></p>
353 <p>In XML all characters in the content of the document are significant
354 <strong>including blanks and formatting line breaks</strong>.</p>
355 <p>The extra nodes you are wondering about are just that, text nodes with
Daniel Veillard63d83142002-05-20 06:51:05 +0000356 the formatting spaces which are part of the document but that people tend
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000357 to forget. There is a function <a
358 href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault
359 ()</a> to remove those at parse time, but that's an heuristic, and its
Daniel Veillard0b28e882002-07-24 23:47:05 +0000360 use should be limited to cases where you are certain there is no
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000361 mixed-content in the document.</p>
362 </li>
363 <li><em>I get compilation errors of existing code like when accessing
Daniel Veillard0b28e882002-07-24 23:47:05 +0000364 <strong>root</strong> or <strong>child fields</strong> of nodes.</em>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000365 <p>You are compiling code developed for libxml version 1 and using a
366 libxml2 development environment. Either switch back to libxml v1 devel or
367 even better fix the code to compile with libxml2 (or both) by <a
368 href="upgrade.html">following the instructions</a>.</p>
369 </li>
370 <li><em>I get compilation errors about non existing
371 <strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000372 fields.</em>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000373 <p>The source code you are using has been <a
374 href="upgrade.html">upgraded</a> to be able to compile with both libxml
375 and libxml2, but you need to install a more recent version:
376 libxml(-devel) &gt;= 1.8.8 or libxml2(-devel) &gt;= 2.1.0</p>
377 </li>
378 <li><em>XPath implementation looks seriously broken</em>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000379 <p>XPath implementation prior to 2.3.0 was really incomplete. Upgrade to
380 a recent version, there are no known bugs in the current version.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000381 </li>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000382 <li><em>The example provided in the web page does not compile.</em>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000383 <p>It's hard to maintain the documentation in sync with the code
384 &lt;grin/&gt; ...</p>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000385 <p>Check the previous points 1/ and 2/ raised before, and please send
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000386 patches.</p>
387 </li>
Daniel Veillard8d7b5c72003-11-15 18:24:36 +0000388 <li><em>Where can I get more examples and information than provided on the
Daniel Veillard42766c02002-08-22 20:52:17 +0000389 web page?</em>
Daniel Veillard8a469172003-06-12 16:05:07 +0000390 <p>Ideally a libxml2 book would be nice. I have no such plan ... But you
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000391 can:</p>
392 <ul>
393 <li>check more deeply the <a href="html/libxml-lib.html">existing
394 generated doc</a></li>
Daniel Veillardc480c4e2003-12-10 13:24:38 +0000395 <li>have a look at <a href="examples/index.html">the set of
396 examples</a>.</li>
Daniel Veillard8a469172003-06-12 16:05:07 +0000397 <li>look for examples of use for libxml2 function using the Gnome code.
Daniel Veillard0b28e882002-07-24 23:47:05 +0000398 For example the following will query the full Gnome CVS base for the
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000399 use of the <strong>xmlAddChild()</strong> function:
400 <p><a
401 href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p>
402 <p>This may be slow, a large hardware donation to the gnome project
403 could cure this :-)</p>
404 </li>
405 <li><a
Daniel Veillardc480c4e2003-12-10 13:24:38 +0000406 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Browse
407 the libxml2 source</a> , I try to write code as clean and documented
Daniel Veillard42766c02002-08-22 20:52:17 +0000408 as possible, so looking at it may be helpful. In particular the code
409 of xmllint.c and of the various testXXX.c test programs should
410 provide good examples of how to do things with the library.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000411 </ul>
412 </li>
413 <li>What about C++ ?
Daniel Veillard8a469172003-06-12 16:05:07 +0000414 <p>libxml2 is written in pure C in order to allow easy reuse on a number
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000415 of platforms, including embedded systems. I don't intend to convert to
416 C++.</p>
Daniel Veillard91e69c52003-08-04 01:43:07 +0000417 <p>There is however a C++ wrapper which may fulfill your needs:</p>
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000418 <ul>
419 <li>by Ari Johnson &lt;ari@btigate.com&gt;:
420 <p>Website: <a
Daniel Veillard91e69c52003-08-04 01:43:07 +0000421 href="http://libxmlplusplus.sourceforge.net/">http://libxmlplusplus.sourceforge.net/</a></p>
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000422 <p>Download: <a
Daniel Veillard91e69c52003-08-04 01:43:07 +0000423 href="http://sourceforge.net/project/showfiles.php?group_id=12999">http://sourceforge.net/project/showfiles.php?group_id=12999</a></p>
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000424 </li>
Daniel Veillard83ee40d2003-08-09 22:24:09 +0000425 <!-- Website is currently unavailable as of 2003-08-02
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000426 <li>by Peter Jones &lt;pjones@pmade.org&gt;
Daniel Veillard83ee40d2003-08-09 22:24:09 +0000427 <p>Website: <a
428 href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000429 </li>
Daniel Veillard83ee40d2003-08-09 22:24:09 +0000430 -->
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000431 </ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000432 </li>
433 <li>How to validate a document a posteriori ?
434 <p>It is possible to validate documents which had not been validated at
Daniel Veillard42766c02002-08-22 20:52:17 +0000435 initial parsing time or documents which have been built from scratch
436 using the API. Use the <a
Daniel Veillard5373ea12003-07-24 13:09:13 +0000437 href="http://xmlsoft.org/html/libxml-valid.html#xmlValidateDtd">xmlValidateDtd()</a>
Daniel Veillard63d83142002-05-20 06:51:05 +0000438 function. It is also possible to simply add a DTD to an existing
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000439 document:</p>
440 <pre>xmlDocPtr doc; /* your existing document */
Daniel Veillard0b28e882002-07-24 23:47:05 +0000441xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */
442
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000443 dtd-&gt;name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */
444
445 doc-&gt;intSubset = dtd;
446 if (doc-&gt;children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
447 else xmlAddPrevSibling(doc-&gt;children, (xmlNodePtr)dtd);
448 </pre>
449 </li>
Daniel Veillarddad3f682002-11-17 16:47:27 +0000450 <li>So what is this funky "xmlChar" used all the time?
451 <p>It is a null terminated sequence of utf-8 characters. And only utf-8!
452 You need to convert strings encoded in different ways to utf-8 before
453 passing them to the API. This can be accomplished with the iconv library
454 for instance.</p>
John Fleck61f6fb62002-10-31 15:23:29 +0000455 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000456 <li>etc ...</li>
457</ol>
458
459<p></p>
460
Daniel Veillard66f68e72003-08-18 16:39:51 +0000461<h2><a name="Documentat">Developer Menu</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000462
Daniel Veillard0b28e882002-07-24 23:47:05 +0000463<p>There are several on-line resources related to using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000464<ol>
MST 2003 John Fleck2b7142a2003-11-22 03:55:27 +0000465 <li>Use the <a href="search.php">search engine</a> to look up
466 information.</li>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000467 <li>Check the <a href="FAQ.html">FAQ.</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000468 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
MST 2003 John Fleck2b7142a2003-11-22 03:55:27 +0000469 documentation</a> automatically extracted from code comments.</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000470 <li>Look at the documentation about <a href="encoding.html">libxml
Daniel Veillard0b28e882002-07-24 23:47:05 +0000471 internationalization support</a>.</li>
Daniel Veillardbc66f852002-01-14 09:49:20 +0000472 <li>This page provides a global overview and <a href="example.html">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000473 examples</a> on how to use libxml.</li>
Daniel Veillardc480c4e2003-12-10 13:24:38 +0000474 <li><a href="examples/index.html">Code examples</a></li>
Daniel Veillard560c2a42003-07-06 21:13:49 +0000475 <li>John Fleck's libxml2 tutorial: <a href="tutorial/index.html">html</a>
476 or <a href="tutorial/xmltutorial.pdf">pdf</a>.</li>
Daniel Veillard1177ca42003-04-26 22:29:54 +0000477 <li>If you need to parse large files, check the <a
478 href="xmlreader.html">xmlReader</a> API tutorial</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000479 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
Daniel Veillard402e8c82000-02-29 22:57:47 +0000480 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
481 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillardc480c4e2003-12-10 13:24:38 +0000482 <li>George Lebl wrote <a
MST 2003 John Fleck2b7142a2003-11-22 03:55:27 +0000483 href="http://www-106.ibm.com/developerworks/library/l-gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000484 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000485 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
Daniel Veillard0b28e882002-07-24 23:47:05 +0000486 file</a>.</li>
Daniel Veillard42766c02002-08-22 20:52:17 +0000487 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>
488 description. If you are starting a new project using libxml you should
489 really use the 2.x version.</li>
Daniel Veillard845cce42002-01-09 11:51:37 +0000490 <li>And don't forget to look at the <a
491 href="http://mail.gnome.org/archives/xml/">mailing-list archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000492</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000493
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000494<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000495
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000496<p>Well, bugs or missing features are always possible, and I will make a
497point of fixing them in a timely fashion. The best way to report a bug is to
Daniel Veillardccf996f2003-08-14 10:48:38 +0000498use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Gnome
Daniel Veillard42766c02002-08-22 20:52:17 +0000499bug tracking database</a> (make sure to use the "libxml2" module name). I
500look at reports there regularly and it's good to have a reminder when a bug
501is still open. Be sure to specify that the bug is for the package libxml2.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000502
Daniel Veillard4ac494b2003-09-18 15:08:00 +0000503<p>For small problems you can try to get help on IRC, the #xml channel on
504irc.gnome.org (port 6667) usually have a few person subscribed which may help
505(but there is no garantee and if a real issue is raised it should go on the
506mailing-list for archival).</p>
Daniel Veillard9582d6c2003-09-16 11:40:04 +0000507
Daniel Veillard0142b842000-01-14 14:45:24 +0000508<p>There is also a mailing-list <a
Daniel Veillard3197f162001-04-04 00:40:08 +0000509href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a
510href="http://mail.gnome.org/archives/xml/">on-line archive</a> (<a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000511href="http://xmlsoft.org/messages">old</a>). To subscribe to this list,
512please visit the <a
513href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and
514follow the instructions. <strong>Do not send code, I won't debug it</strong>
515(but patches are really appreciated!).</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000516
Daniel Veillard008186f2001-09-13 14:24:44 +0000517<p>Check the following <strong><span style="color: #FF0000">before
518posting</span></strong>:</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000519<ul>
Daniel Veillard321be0c2002-10-08 21:26:42 +0000520 <li>Read the <a href="FAQ.html">FAQ</a> and <a href="search.php">use the
Daniel Veillarda37aab82003-06-09 09:10:36 +0000521 search engine</a> to get information related to your problem.</li>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000522 <li>Make sure you are <a href="ftp://xmlsoft.org/">using a recent
523 version</a>, and that the problem still shows up in a recent version.</li>
524 <li>Check the <a href="http://mail.gnome.org/archives/xml/">list
525 archives</a> to see if the problem was reported already. In this case
Daniel Veillard63d83142002-05-20 06:51:05 +0000526 there is probably a fix available, similarly check the <a
Daniel Veillardccf996f2003-08-14 10:48:38 +0000527 href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">registered
Daniel Veillard0b28e882002-07-24 23:47:05 +0000528 open bugs</a>.</li>
529 <li>Make sure you can reproduce the bug with xmllint or one of the test
530 programs found in source in the distribution.</li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000531 <li>Please send the command showing the error as well as the input (as an
Daniel Veillard63d83142002-05-20 06:51:05 +0000532 attachment)</li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000533</ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000534
Daniel Veillarda37aab82003-06-09 09:10:36 +0000535<p>Then send the bug with associated information to reproduce it to the <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000536href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml
Daniel Veillard98d071d2003-01-10 09:22:44 +0000537related I will approve it. Please do not send mail to me directly, it makes
Daniel Veillard0b28e882002-07-24 23:47:05 +0000538things really hard to track and in some cases I am not the best person to
Daniel Veillard98d071d2003-01-10 09:22:44 +0000539answer a given question, ask on the list.</p>
540
541<p>To <span style="color: #E50000">be really clear about support</span>:</p>
542<ul>
Daniel Veillarda37aab82003-06-09 09:10:36 +0000543 <li>Support or help <span style="color: #E50000">requests MUST be sent to
Daniel Veillard98d071d2003-01-10 09:22:44 +0000544 the list or on bugzilla</span> in case of problems, so that the Question
545 and Answers can be shared publicly. Failing to do so carries the implicit
546 message "I want free support but I don't want to share the benefits with
Daniel Veillard831e8fd2003-01-25 11:45:34 +0000547 others" and is not welcome. I will automatically Carbon-Copy the
548 xml@gnome.org mailing list for any technical reply made about libxml2 or
549 libxslt.</li>
Daniel Veillard560c2a42003-07-06 21:13:49 +0000550 <li>There is <span style="color: #E50000">no garantee of support</span>, if
551 your question remains unanswered after a week, repost it, making sure you
552 gave all the detail needed and the information requested.</li>
Daniel Veillarda37aab82003-06-09 09:10:36 +0000553 <li>Failing to provide information as requested or double checking first
Daniel Veillard98d071d2003-01-10 09:22:44 +0000554 for prior feedback also carries the implicit message "the time of the
555 library maintainers is less valuable than my time" and might not be
556 welcome.</li>
557</ul>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000558
Daniel Veillard91e9d582001-02-26 07:31:12 +0000559<p>Of course, bugs reported with a suggested patch for fixing them will
Daniel Veillard0b28e882002-07-24 23:47:05 +0000560probably be processed faster than those without.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000561
562<p>If you're looking for help, a quick look at <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000563href="http://mail.gnome.org/archives/xml/">the list archive</a> may actually
Daniel Veillard560c2a42003-07-06 21:13:49 +0000564provide the answer. I usually send source samples when answering libxml2
565usage questions. The <a
566href="http://xmlsoft.org/html/book1.html">auto-generated documentation</a> is
567not as polished as I would like (i need to learn more about DocBook), but
568it's a good starting point.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000569
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000570<h2><a name="help">How to help</a></h2>
571
572<p>You can help the project in various ways, the best thing to do first is to
573subscribe to the mailing-list as explained before, check the <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000574href="http://mail.gnome.org/archives/xml/">archives </a>and the <a
Daniel Veillardccf996f2003-08-14 10:48:38 +0000575href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Gnome bug
Daniel Veillard0b28e882002-07-24 23:47:05 +0000576database</a>:</p>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000577<ol>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000578 <li>Provide patches when you find problems.</li>
Daniel Veillard8a469172003-06-12 16:05:07 +0000579 <li>Provide the diffs when you port libxml2 to a new platform. They may not
Daniel Veillardab8500d2000-10-15 21:06:19 +0000580 be integrated in all cases but help pinpointing portability problems
581 and</li>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000582 <li>Provide documentation fixes (either as patches to the code comments or
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000583 as HTML diffs).</li>
Daniel Veillard42766c02002-08-22 20:52:17 +0000584 <li>Provide new documentations pieces (translations, examples, etc
585 ...).</li>
Daniel Veillard0b28e882002-07-24 23:47:05 +0000586 <li>Check the TODO file and try to close one of the items.</li>
587 <li>Take one of the points raised in the archive or the bug database and
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000588 provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me
589 </a>before to avoid synchronization problems and check that the suggested
590 fix will fit in nicely :-)</li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000591</ol>
592
Daniel Veillard10a2c651999-12-12 13:03:50 +0000593<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000594
Daniel Veillard8a469172003-06-12 16:05:07 +0000595<p>The latest versions of libxml2 can be found on <a
Daniel Veillard20c8cf22001-06-26 22:47:36 +0000596href="ftp://xmlsoft.org/">xmlsoft.org</a> (<a
597href="ftp://speakeasy.rpmfind.net/pub/libxml/">Seattle</a>, <a
598href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000599href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard024f1992003-12-10 16:43:49 +0000600as a <a href="ftp://ftp.gnome.org/pub/GNOME/sources/libxml2/2.6/">source
MDT 2002 John Fleck30c70542002-09-24 14:24:54 +0000601archive</a><!-- commenting this out because they seem to have disappeared or <a
Daniel Veillarda41123c2001-04-22 19:31:20 +0000602href="ftp://ftp.gnome.org/pub/GNOME/stable/redhat/i386/libxml/">RPM
Daniel Veillarde16b5742002-09-26 17:50:03 +0000603packages</a> -->
Daniel Veillard321be0c2002-10-08 21:26:42 +0000604 , Antonin Sprinzl also provide <a href="ftp://gd.tuwien.ac.at/pub/libxml/">a
Daniel Veillarde16b5742002-09-26 17:50:03 +0000605mirror in Austria</a>. (NOTE that you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000606href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
607href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillardb46a5732003-04-08 13:35:48 +0000608packages installed to compile applications using libxml.)</p>
609
610<p>Binary ports:</p>
611<ul>
612 <li>Red Hat RPMs for i386 are available directly on <a
613 href="ftp://xmlsoft.org/">xmlsoft.org</a>, the source RPM will compile on
614 any architecture supported by Red Hat.</li>
Daniel Veillardf83a2c72003-04-08 13:48:40 +0000615 <li><p><a href="mailto:igor@zlatkovic.com">Igor Zlatkovic</a></p>
Daniel Veillardce192eb2003-04-16 15:58:05 +0000616 is now the maintainer of the Windows port, <a
Daniel Veillardb46a5732003-04-08 13:35:48 +0000617 href="http://www.zlatkovic.com/projects/libxml/index.html">he provides
618 binaries</a>.</li>
619 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides
620 <a href="http://garypennington.net/libxml2/">Solaris binaries</a>.</li>
621 <li><a href="mailto:Steve.Ball@zveno.com">Steve Ball</a> provides <a
622 href="http://www.zveno.com/open_source/libxml2xslt.html">Mac Os X
623 binaries</a>.</li>
624 <li>The HP-UX porting center provides <a
625 href="http://hpux.connect.org.uk/hppd/hpux/Gnome/">HP-UX binaries</a></li>
626</ul>
627
628<p>If you know other supported binary ports, please <a
629href="http://veillard.com/">contact me</a>.</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000630
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000631<p><a name="Snapshot">Snapshot:</a></p>
632<ul>
Daniel Veillard8a469172003-06-12 16:05:07 +0000633 <li>Code from the W3C cvs base gnome-xml <a
Daniel Veillard0b28e882002-07-24 23:47:05 +0000634 href="ftp://xmlsoft.org/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a>.</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000635 <li>Docs, content of the web site, the list archive included <a
Daniel Veillard0b28e882002-07-24 23:47:05 +0000636 href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a>.</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000637</ul>
638
Daniel Veillardc6271d22001-10-27 07:50:58 +0000639<p><a name="Contribs">Contributions:</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000640
641<p>I do accept external contributions, especially if compiling on another
Daniel Veillardc6271d22001-10-27 07:50:58 +0000642platform, get in touch with me to upload the package, wrappers for various
Daniel Veillard51095312001-10-28 18:51:57 +0000643languages have been provided, and can be found in the <a
644href="contribs.html">contrib section</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000645
Daniel Veillard8a469172003-06-12 16:05:07 +0000646<p>Libxml2 is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000647<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000648 <li><p>The <a
649 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Gnome
Daniel Veillard402e8c82000-02-29 22:57:47 +0000650 CVS base</a>. Check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000651 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a>
652 page; the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000653 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000654 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000655</ul>
656
657<h2><a name="News">News</a></h2>
658
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000659<h3>CVS only : check the <a
660href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000661for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000662
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000663<p>Items not finished and worked on, get in touch with the list if you want
664to test those</p>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000665<ul>
Daniel Veillard72fef162003-02-05 14:31:19 +0000666 <li>More testing on RelaxNG</li>
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000667 <li>Finishing up <a href="http://www.w3.org/TR/xmlschema-1/">XML
Daniel Veillard72fef162003-02-05 14:31:19 +0000668 Schemas</a></li>
669</ul>
670
Daniel Veillard92914492004-02-23 16:33:21 +0000671<h3>2.6.7: Feb 23 2004</h3>
672<ul>
673 <li>documentation: tutorial updates (John Fleck), benchmark results</li>
674 <li>xmlWriter: updates and fixes (Alfred Mickautsch, Lucas Brasilino)</li>
675 <li>XPath optimization (Petr Pajas)</li>
676 <li>DTD ID handling optimization</li>
677 <li>bugfixes: xpath number with &gt; 19 fractional (William Brack), push
678 mode with unescaped '&gt;' characters, fix xmllint --stream --timing, fix
679 xmllint --memory --stream memory usage, xmlAttrSerializeTxtContent
680 handling NULL, trying to fix Relax-NG/Perl interface.</li>
681 <li>python: 2.3 compatibility, whitespace fixes (Malcolm Tredinnick)</li>
682 <li>Added relaxng option to xmllint --shell</li>
683</ul>
684
Daniel Veillard5c9547e2004-02-12 15:31:49 +0000685<h3>2.6.6: Feb 12 2004</h3>
686<ul>
687 <li>nanohttp and nanoftp: buffer overflow error on URI parsing (Igor and
688 William) reported by Yuuichi Teranishi</li>
689 <li>bugfixes: make test and path issues, xmlWriter attribute serialization
690 (William Brack), xmlWriter indentation (William), schemas validation
691 (Eric Haszlakiewicz), XInclude dictionnaries issues (William and Oleg
692 Paraschenko), XInclude empty fallback (William), HTML warnings (William),
693 XPointer in XInclude (William), Python namespace serialization,
694 isolat1ToUTF8 bound error (Alfred Mickautsch), output of parameter
695 entities in internal subset (William), internal subset bug in push mode,
696 &lt;xs:all&gt; fix (Alexey Sarytchev)</li>
697 <li>Build: fix for automake-1.8 (Alexander Winston), warnings removal
698 (Philip Ludlam), SOCKLEN_T detection fixes (Daniel Richard), fix
699 --with-minimum configuration.</li>
700 <li>XInclude: allow the 2001 namespace without warning.</li>
701 <li>Documentation: missing example/index.html (John Fleck), version
702 dependancies (John Fleck)</li>
703 <li>reader API: structured error reporting (Steve Ball)</li>
704 <li>Windows compilation: mingw, msys (Mikhail Grushinskiy), function
705 prototype (Cameron Johnson), MSVC6 compiler warnings, _WINSOCKAPI_
706 patch</li>
707 <li>Parsers: added xmlByteConsumed(ctxt) API to get the byte offest in
708 input.</li>
709</ul>
710
Daniel Veillard189f46b2004-01-25 21:03:04 +0000711<h3>2.6.5: Jan 25 2004</h3>
712<ul>
713 <li>Bugfixes: dictionnaries for schemas (William Brack), regexp segfault
714 (William), xs:all problem (William), a number of XPointer bugfixes
715 (William), xmllint error go to stderr, DTD validation problem with
716 namespace, memory leak (William), SAX1 cleanup and minimal options fixes
717 (Mark Vadoc), parser context reset on error (Shaun McCance), XPath union
718 evaluation problem (William) , xmlReallocLoc with NULL (Aleksey Sanin),
719 XML Schemas double free (Steve Ball), XInclude with no href, argument
720 callbacks order for XPath callbacks (Frederic Peters)</li>
721 <li>Documentation: python scripts (William Brack), xslt stylesheets (John
722 Fleck), doc (Sven Zimmerman), I/O example.</li>
723 <li>Python bindings: fixes (William), enum support (Stéphane Bidoul),
724 structured error reporting (Stéphane Bidoul)</li>
725 <li>XInclude: various fixes for conformance, problem related to dictionnary
726 references (William &amp; me), recursion (William)</li>
727 <li>xmlWriter: indentation (Lucas Brasilino), memory leaks (Alfred
Daniel Veillard5c9547e2004-02-12 15:31:49 +0000728 Mickautsch),</li>
Daniel Veillard189f46b2004-01-25 21:03:04 +0000729 <li>xmlSchemas: normalizedString datatype (John Belmonte)</li>
730 <li>code cleanup for strings functions (William)</li>
731 <li>Windows: compiler patches (Mark Vakoc)</li>
732 <li>Parser optimizations, a few new XPath and dictionnary APIs for future
733 XSLT optimizations.</li>
734</ul>
735
Daniel Veillarde6e59cd2003-12-24 11:56:44 +0000736<h3>2.6.4: Dec 24 2003</h3>
737<ul>
738 <li>Windows build fixes (Igor Zlatkovic)</li>
Daniel Veillard189f46b2004-01-25 21:03:04 +0000739 <li>Some serious XInclude problems reported by Oleg Paraschenko and</li>
740 <li>Unix and Makefile packaging fixes (me, William Brack,</li>
Daniel Veillarde6e59cd2003-12-24 11:56:44 +0000741 <li>Documentation improvements (John Fleck, William Brack), example fix
742 (Lucas Brasilino)</li>
743 <li>bugfixes: xmlTextReaderExpand() with xmlReaderWalker, XPath handling of
744 NULL strings (William Brack) , API building reader or parser from
745 filedescriptor should not close it, changed XPath sorting to be stable
746 again (William Brack), xmlGetNodePath() generating '(null)' (William
747 Brack), DTD validation and namespace bug (William Brack), XML Schemas
748 double inclusion behaviour</li>
749</ul>
750
Daniel Veillardc480c4e2003-12-10 13:24:38 +0000751<h3>2.6.3: Dec 10 2003</h3>
752<ul>
753 <li>documentation updates and cleanup (DV, William Brack, John Fleck)</li>
754 <li>added a repository of examples, examples from Aleksey Sanin, Dodji
Daniel Veillarde6e59cd2003-12-24 11:56:44 +0000755 Seketeli, Alfred Mickautsch</li>
Daniel Veillardc480c4e2003-12-10 13:24:38 +0000756 <li>Windows updates: Mark Vakoc, Igor Zlatkovic, Eric Zurcher, Mingw
757 (Kenneth Haley)</li>
758 <li>Unicode range checking (William Brack)</li>
759 <li>code cleanup (William Brack)</li>
760 <li>Python bindings: doc (John Fleck), bug fixes</li>
761 <li>UTF-16 cleanup and BOM issues (William Brack)</li>
762 <li>bug fixes: ID and xmlReader validation, XPath (William Brack),
763 xmlWriter (Alfred Mickautsch), hash.h inclusion problem, HTML parser
764 (James Bursa), attribute defaulting and validation, some serialization
765 cleanups, XML_GET_LINE macro, memory debug when using threads (William
766 Brack), serialization of attributes and entities content, xmlWriter
767 (Daniel Schulman)</li>
768 <li>XInclude bugfix, new APIs and update to the last version including the
769 namespace change.</li>
770 <li>XML Schemas improvements: include (Robert Stepanek), import and
771 namespace handling, fixed the regression tests troubles, added examples
Daniel Veillarde6e59cd2003-12-24 11:56:44 +0000772 based on Eric van der Vlist book, regexp fixes</li>
Daniel Veillardc480c4e2003-12-10 13:24:38 +0000773 <li>preliminary pattern support for streaming (needed for schemas
774 constraints), added xmlTextReaderPreservePattern() to collect subdocument
775 when streaming.</li>
776 <li>various fixes in the structured error handling</li>
777</ul>
778
Daniel Veillard6d373a22003-11-04 10:26:43 +0000779<h3>2.6.2: Nov 4 2003</h3>
780<ul>
781 <li>XPath context unregistration fixes</li>
782 <li>text node coalescing fixes (Mark Lilback)</li>
783 <li>API to screate a W3C Schemas from an existing document (Steve Ball)</li>
784 <li>BeOS patches (Marcin 'Shard' Konicki)</li>
785 <li>xmlStrVPrintf function added (Aleksey Sanin)</li>
786 <li>compilation fixes (Mark Vakoc)</li>
787 <li>stdin parsing fix (William Brack)</li>
788 <li>a posteriori DTD validation fixes</li>
Daniel Veillardc480c4e2003-12-10 13:24:38 +0000789 <li>xmlReader bug fixes: Walker fixes, python bindings</li>
Daniel Veillard6d373a22003-11-04 10:26:43 +0000790 <li>fixed xmlStopParser() to really stop the parser and errors</li>
791 <li>always generate line numbers when using the new xmlReadxxx
792 functions</li>
793 <li>added XInclude support to the xmlReader interface</li>
794 <li>implemented XML_PARSE_NONET parser option</li>
795 <li>DocBook XSLT processing bug fixed</li>
796 <li>HTML serialization for &lt;p&gt; elements (William Brack and me)</li>
797 <li>XPointer failure in XInclude are now handled as resource errors</li>
798 <li>fixed xmllint --html to use the HTML serializer on output (added
799 --xmlout to implement the previous behaviour of saving it using the XML
800 serializer)</li>
801</ul>
802
Daniel Veillarde4e3f5d2003-10-28 23:06:32 +0000803<h3>2.6.1: Oct 28 2003</h3>
804<ul>
805 <li>Mostly bugfixes after the big 2.6.0 changes</li>
806 <li>Unix compilation patches: libxml.m4 (Patrick Welche), warnings cleanup
807 (William Brack)</li>
808 <li>Windows compilation patches (Joachim Bauch, Stephane Bidoul, Igor
809 Zlatkovic)</li>
810 <li>xmlWriter bugfix (Alfred Mickautsch)</li>
811 <li>chvalid.[ch]: couple of fixes from Stephane Bidoul</li>
Daniel Veillard6d373a22003-11-04 10:26:43 +0000812 <li>context reset: error state reset, push parser reset (Graham
813 Bennett)</li>
Daniel Veillarde4e3f5d2003-10-28 23:06:32 +0000814 <li>context reuse: generate errors if file is not readable</li>
815 <li>defaulted attributes for element coming from internal entities
816 (Stephane Bidoul)</li>
817 <li>Python: tab and spaces mix (William Brack)</li>
818 <li>Error handler could crash in DTD validation in 2.6.0</li>
819 <li>xmlReader: do not use the document or element _private field</li>
820 <li>testSAX.c: avoid a problem with some PIs (Massimo Morara)</li>
821 <li>general bug fixes: mandatory encoding in text decl, serializing
822 Document Fragment nodes, xmlSearchNs 2.6.0 problem (Kasimier Buchcik),
823 XPath errors not reported, slow HTML parsing of large documents.</li>
824</ul>
825
Daniel Veillard3e35f8e2003-10-21 00:05:38 +0000826<h3>2.6.0: Oct 20 2003</h3>
827<ul>
828 <li>Major revision release: should be API and ABI compatible but got a lot
829 of change</li>
830 <li>Increased the library modularity, far more options can be stripped out,
831 a --with-minimum configuration will weight around 160KBytes</li>
832 <li>Use per parser and per document dictionnary, allocate names and small
833 text nodes from the dictionnary</li>
834 <li>Switch to a SAX2 like parser rewrote most of the XML parser core,
835 provides namespace resolution and defaulted attributes, minimize memory
836 allocations and copies, namespace checking and specific error handling,
837 immutable buffers, make predefined entities static structures, etc...</li>
838 <li>rewrote all the error handling in the library, all errors can be
839 intercepted at a structured level, with precise information
840 available.</li>
841 <li>New simpler and more generic XML and HTML parser APIs, allowing to
842 easilly modify the parsing options and reuse parser context for multiple
843 consecutive documents.</li>
844 <li>Similar new APIs for the xmlReader, for options and reuse, provided new
845 functions to access content as const strings, use them for Python
846 bindings</li>
847 <li>a lot of other smaller API improvements: xmlStrPrintf (Aleksey Sanin),
848 Walker i.e. reader on a document tree based on Alfred Mickautsch code,
849 make room in nodes for line numbers, reference counting and future PSVI
850 extensions, generation of character ranges to be checked with faster
851 algorithm (William), xmlParserMaxDepth (Crutcher Dunnavant), buffer
852 access</li>
853 <li>New xmlWriter API provided by Alfred Mickautsch</li>
854 <li>Schemas: base64 support by Anthony Carrico</li>
855 <li>Parser&lt;-&gt;HTTP integration fix, proper processing of the Mime-Type
856 and charset informations if available.</li>
857 <li>Relax-NG: bug fixes including the one reported by Martijn Faassen and
858 zeroOrMore, better error reporting.</li>
859 <li>Python bindings (Stéphane Bidoul), never use stdout for errors
860 output</li>
861 <li>Portability: all the headers have macros for export and calling
862 convention definitions (Igor Zlatkovic), VMS update (Craig A. Berry),
863 Windows: threads (Jesse Pelton), Borland compiler (Eric Zurcher, Igor),
864 Mingw (Igor), typos (Mark Vakoc), beta version (Stephane Bidoul),
865 warning cleanups on AIX and MIPS compilers (William Brack), BeOS (Marcin
866 'Shard' Konicki)</li>
867 <li>Documentation fixes and README (William Brack), search fix (William),
868 tutorial updates (John Fleck), namespace docs (Stefan Kost)</li>
869 <li>Bug fixes: xmlCleanupParser (Dave Beckett), threading uninitialized
870 mutexes, HTML doctype lowercase, SAX/IO (William), compression detection
871 and restore (William), attribute declaration in DTDs (William), namespace
872 on attribute in HTML output (William), input filename (Rob Richards),
873 namespace DTD validation, xmlReplaceNode (Chris Ryland), I/O callbacks
874 (Markus Keim), CDATA serialization (Shaun McCance), xmlReader (Peter
875 Derr), high codepoint charref like &amp;#x10FFFF;, buffer access in push
876 mode (Justin Fletcher), TLS threads on Windows (Jesse Pelton), XPath bug
877 (William), xmlCleanupParser (Marc Liyanage), CDATA output (William), HTTP
878 error handling.</li>
879 <li>xmllint options: --dtdvalidfpi for Tobias Reif, --sax1 for compat
880 testing, --nodict for building without tree dictionnary, --nocdata to
881 replace CDATA by text, --nsclean to remove surperfluous namespace
882 declarations</li>
883 <li>added xml2-config --libtool-libs option from Kevin P. Fleming</li>
884 <li>a lot of profiling and tuning of the code, speedup patch for
885 xmlSearchNs() by Luca Padovani. The xmlReader should do far less
886 allocation and it speed should get closer to SAX. Chris Anderson worked
887 on speeding and cleaning up repetitive checking code.</li>
888 <li>cleanup of "make tests"</li>
889 <li>libxml-2.0-uninstalled.pc from Malcolm Tredinnick</li>
890 <li>deactivated the broken docBook SGML parser code and plugged the XML
891 parser instead.</li>
892</ul>
893
Daniel Veillardeec1ae92003-09-09 13:11:01 +0000894<h3>2.5.11: Sep 9 2003</h3>
895
896<p>A bugfix only release:</p>
897<ul>
898 <li>risk of crash in Relax-NG</li>
899 <li>risk of crash when using multithreaded programs</li>
900</ul>
901
Daniel Veillardcfba2fe2003-08-15 00:33:43 +0000902<h3>2.5.10: Aug 15 2003</h3>
903
904<p>A bugfixes only release</p>
905<ul>
906 <li>Windows Makefiles (William Brack)</li>
907 <li>UTF-16 support fixes (Mark Itzcovitz)</li>
908 <li>Makefile and portability (William Brack) automake, Linux alpha, Mingw
Daniel Veillardeec1ae92003-09-09 13:11:01 +0000909 on Windows (Mikhail Grushinskiy)</li>
Daniel Veillardcfba2fe2003-08-15 00:33:43 +0000910 <li>HTML parser (Oliver Stoeneberg)</li>
911 <li>XInclude performance problem reported by Kevin Ruscoe</li>
912 <li>XML parser performance problem reported by Grant Goodale</li>
913 <li>xmlSAXParseDTD() bug fix from Malcolm Tredinnick</li>
Daniel Veillardeec1ae92003-09-09 13:11:01 +0000914 <li>and a couple other cleanup</li>
Daniel Veillardcfba2fe2003-08-15 00:33:43 +0000915</ul>
916
Daniel Veillard83ee40d2003-08-09 22:24:09 +0000917<h3>2.5.9: Aug 9 2003</h3>
918<ul>
919 <li>bugfixes: IPv6 portability, xmlHasNsProp (Markus Keim), Windows build
920 (Wiliam Brake, Jesse Pelton, Igor), Schemas (Peter Sobisch), threading
921 (Rob Richards), hexBinary type (), UTF-16 BOM (Dodji Seketeli),
922 xmlReader, Relax-NG schemas compilation, namespace handling, EXSLT (Sean
923 Griffin), HTML parsing problem (William Brack), DTD validation for mixed
924 content + namespaces, HTML serialization, library initialization,
925 progressive HTML parser</li>
926 <li>better interfaces for Relax-NG error handling (Joachim Bauch, )</li>
927 <li>adding xmlXIncludeProcessTree() for XInclud'ing in a subtree</li>
928 <li>doc fixes and improvements (John Fleck)</li>
929 <li>configure flag for -with-fexceptions when embedding in C++</li>
930 <li>couple of new UTF-8 helper functions (William Brack)</li>
931 <li>general encoding cleanup + ISO-8859-x without iconv (Peter Jacobi)</li>
932 <li>xmlTextReader cleanup + enum for node types (Bjorn Reese)</li>
933 <li>general compilation/warning cleanup Solaris/HP-UX/... (William
934 Brack)</li>
935</ul>
936
Daniel Veillard560c2a42003-07-06 21:13:49 +0000937<h3>2.5.8: Jul 6 2003</h3>
938<ul>
939 <li>bugfixes: XPath, XInclude, file/URI mapping, UTF-16 save (Mark
940 Itzcovitz), UTF-8 checking, URI saving, error printing (William Brack),
941 PI related memleak, compilation without schemas or without xpath (Joerg
942 Schmitz-Linneweber/Garry Pennington), xmlUnlinkNode problem with DTDs,
943 rpm problem on , i86_64, removed a few compilation problems from 2.5.7,
944 xmlIOParseDTD, and xmlSAXParseDTD (Malcolm Tredinnick)</li>
945 <li>portability: DJGPP (MsDos) , OpenVMS (Craig A. Berry)</li>
946 <li>William Brack fixed multithreading lock problems</li>
947 <li>IPv6 patch for FTP and HTTP accesses (Archana Shah/Wipro)</li>
948 <li>Windows fixes (Igor Zlatkovic, Eric Zurcher), threading (Stéphane
949 Bidoul)</li>
950 <li>A few W3C Schemas Structure improvements</li>
951 <li>W3C Schemas Datatype improvements (Charlie Bozeman)</li>
952 <li>Python bindings for thread globals (Stéphane Bidoul), and method/class
Daniel Veillard83ee40d2003-08-09 22:24:09 +0000953 generator</li>
954 <li>added --nonet option to xmllint</li>
Daniel Veillard560c2a42003-07-06 21:13:49 +0000955 <li>documentation improvements (John Fleck)</li>
956</ul>
957
Daniel Veillard92fc02c2003-04-24 23:12:35 +0000958<h3>2.5.7: Apr 25 2003</h3>
959<ul>
960 <li>Relax-NG: Compiling to regexp and streaming validation on top of the
961 xmlReader interface, added to xmllint --stream</li>
962 <li>xmlReader: Expand(), Next() and DOM access glue, bug fixes</li>
963 <li>Support for large files: RGN validated a 4.5GB instance</li>
964 <li>Thread support is now configured in by default</li>
965 <li>Fixes: update of the Trio code (Bjorn), WXS Date and Duration fixes
966 (Charles Bozeman), DTD and namespaces (Brent Hendricks), HTML push parser
967 and zero bytes handling, some missing Windows file path conversions,
968 behaviour of the parser and validator in the presence of "out of memory"
Daniel Veillard93d95252003-04-29 20:25:40 +0000969 error conditions</li>
Daniel Veillard92fc02c2003-04-24 23:12:35 +0000970 <li>extended the API to be able to plug a garbage collecting memory
971 allocator, added xmlMallocAtomic() and modified the allocations
972 accordingly.</li>
973 <li>Performances: removed excessive malloc() calls, speedup of the push and
974 xmlReader interfaces, removed excessive thread locking</li>
975 <li>Documentation: man page (John Fleck), xmlReader documentation</li>
976 <li>Python: adding binding for xmlCatalogAddLocal (Brent M Hendricks)</li>
977</ul>
978
Daniel Veillardc2d4a932003-04-01 11:13:05 +0000979<h3>2.5.6: Apr 1 2003</h3>
980<ul>
981 <li>Fixed W3C XML Schemas datatype, should be compliant now except for
982 binHex and base64 which are not supported yet.</li>
983 <li>bug fixes: non-ASCII IDs, HTML output, XInclude on large docs and
984 XInclude entities handling, encoding detection on external subsets, XML
985 Schemas bugs and memory leaks, HTML parser (James Bursa)</li>
986 <li>portability: python/trio (Albert Chin), Sun compiler warnings</li>
987 <li>documentation: added --relaxng option to xmllint man page (John)</li>
988 <li>improved error reporting: xml:space, start/end tag mismatches, Relax NG
989 errors</li>
990</ul>
991
992<h3>2.5.5: Mar 24 2003</h3>
Daniel Veillardd8da01c2003-03-24 15:58:23 +0000993<ul>
994 <li>Lot of fixes on the Relax NG implementation. More testing including
995 DocBook and TEI examples.</li>
996 <li>Increased the support for W3C XML Schemas datatype</li>
997 <li>Several bug fixes in the URI handling layer</li>
998 <li>Bug fixes: HTML parser, xmlReader, DTD validation, XPath, encoding
999 conversion, line counting in the parser.</li>
1000 <li>Added support for $XMLLINT_INDENT environment variable, FTP delete</li>
1001 <li>Fixed the RPM spec file name</li>
1002</ul>
1003
Daniel Veillard17bed982003-02-24 20:11:43 +00001004<h3>2.5.4: Feb 20 2003</h3>
1005<ul>
1006 <li>Conformance testing and lot of fixes on Relax NG and XInclude
1007 implementation</li>
1008 <li>Implementation of XPointer element() scheme</li>
1009 <li>Bug fixes: XML parser, XInclude entities merge, validity checking on
1010 namespaces,
1011 <p>2 serialization bugs, node info generation problems, a DTD regexp
1012 generation problem.</p>
1013 </li>
1014 <li>Portability: windows updates and path canonicalization (Igor)</li>
1015 <li>A few typo fixes (Kjartan Maraas)</li>
1016 <li>Python bindings generator fixes (Stephane Bidoul)</li>
1017</ul>
1018
Daniel Veillard1d788d22003-02-10 16:21:58 +00001019<h3>2.5.3: Feb 10 2003</h3>
1020<ul>
1021 <li>RelaxNG and XML Schemas datatypes improvements, and added a first
1022 version of RelaxNG Python bindings</li>
1023 <li>Fixes: XLink (Sean Chittenden), XInclude (Sean Chittenden), API fix for
1024 serializing namespace nodes, encoding conversion bug, XHTML1
1025 serialization</li>
1026 <li>Portability fixes: Windows (Igor), AMD 64bits RPM spec file</li>
1027</ul>
1028
Daniel Veillard72fef162003-02-05 14:31:19 +00001029<h3>2.5.2: Feb 5 2003</h3>
1030<ul>
1031 <li>First implementation of RelaxNG, added --relaxng flag to xmllint</li>
1032 <li>Schemas support now compiled in by default.</li>
1033 <li>Bug fixes: DTD validation, namespace checking, XInclude and entities,
1034 delegateURI in XML Catalogs, HTML parser, XML reader (Stéphane Bidoul),
1035 XPath parser and evaluation, UTF8ToUTF8 serialization, XML reader memory
1036 consumption, HTML parser, HTML serialization in the presence of
1037 namespaces</li>
1038 <li>added an HTML API to check elements and attributes.</li>
1039 <li>Documentation improvement, PDF for the tutorial (John Fleck), doc
1040 patches (Stefan Kost)</li>
1041 <li>Portability fixes: NetBSD (Julio Merino), Windows (Igor Zlatkovic)</li>
1042 <li>Added python bindings for XPointer, contextual error reporting
1043 (Stéphane Bidoul)</li>
1044 <li>URI/file escaping problems (Stefano Zacchiroli)</li>
Daniel Veillardcf27f7c2002-04-30 07:12:39 +00001045</ul>
1046
Daniel Veillarde2830f12003-01-08 17:47:49 +00001047<h3>2.5.1: Jan 8 2003</h3>
1048<ul>
1049 <li>Fixes a memory leak and configuration/compilation problems in 2.5.0</li>
1050 <li>documentation updates (John)</li>
1051 <li>a couple of XmlTextReader fixes</li>
1052</ul>
1053
Daniel Veillard7b4b2f92003-01-06 13:11:20 +00001054<h3>2.5.0: Jan 6 2003</h3>
1055<ul>
1056 <li>New <a href="xmlreader.html">XmltextReader interface</a> based on C#
1057 API (with help of Stéphane Bidoul)</li>
1058 <li>Windows: more exports, including the new API (Igor)</li>
1059 <li>XInclude fallback fix</li>
1060 <li>Python: bindings for the new API, packaging (Stéphane Bidoul),
1061 drv_libxml2.py Python xml.sax driver (Stéphane Bidoul), fixes, speedup
1062 and iterators for Python-2.2 (Hannu Krosing)</li>
1063 <li>Tutorial fixes (john Fleck and Niraj Tolia) xmllint man update
1064 (John)</li>
1065 <li>Fix an XML parser bug raised by Vyacheslav Pindyura</li>
1066 <li>Fix for VMS serialization (Nigel Hall) and config (Craig A. Berry)</li>
1067 <li>Entities handling fixes</li>
1068 <li>new API to optionally track node creation and deletion (Lukas
1069 Schroeder)</li>
1070 <li>Added documentation for the XmltextReader interface and some <a
1071 href="guidelines.html">XML guidelines</a></li>
1072</ul>
1073
Daniel Veillardc1eed322002-12-12 11:01:32 +00001074<h3>2.4.30: Dec 12 2002</h3>
1075<ul>
1076 <li>2.4.29 broke the python bindings, rereleasing</li>
1077 <li>Improvement/fixes of the XML API generator, and couple of minor code
1078 fixes.</li>
1079</ul>
1080
Daniel Veillard9b4bb4d2002-12-11 19:28:47 +00001081<h3>2.4.29: Dec 11 2002</h3>
1082<ul>
1083 <li>Windows fixes (Igor): Windows CE port, pthread linking, python bindings
1084 (Stéphane Bidoul), Mingw (Magnus Henoch), and export list updates</li>
1085 <li>Fix for prev in python bindings (ERDI Gergo)</li>
1086 <li>Fix for entities handling (Marcus Clarke)</li>
1087 <li>Refactored the XML and HTML dumps to a single code path, fixed XHTML1
1088 dump</li>
1089 <li>Fix for URI parsing when handling URNs with fragment identifiers</li>
1090 <li>Fix for HTTP URL escaping problem</li>
1091 <li>added an TextXmlReader (C#) like API (work in progress)</li>
1092 <li>Rewrote the API in XML generation script, includes a C parser and saves
1093 more informations needed for C# bindings</li>
1094</ul>
1095
Daniel Veillardf9c4cad2002-11-22 15:57:07 +00001096<h3>2.4.28: Nov 22 2002</h3>
1097<ul>
1098 <li>a couple of python binding fixes</li>
1099 <li>2 bug fixes in the XML push parser</li>
1100 <li>potential memory leak removed (Martin Stoilov)</li>
1101 <li>fix to the configure script for Unix (Dimitri Papadopoulos)</li>
1102 <li>added encoding support for XInclude parse="text"</li>
1103 <li>autodetection of XHTML1 and specific serialization rules added</li>
Daniel Veillard9b4bb4d2002-12-11 19:28:47 +00001104 <li>nasty threading bug fixed (William Brack)</li>
Daniel Veillardf9c4cad2002-11-22 15:57:07 +00001105</ul>
1106
Daniel Veillarddad3f682002-11-17 16:47:27 +00001107<h3>2.4.27: Nov 17 2002</h3>
1108<ul>
1109 <li>fixes for the Python bindings</li>
1110 <li>a number of bug fixes: SGML catalogs, xmlParseBalancedChunkMemory(),
1111 HTML parser, Schemas (Charles Bozeman), document fragment support
1112 (Christian Glahn), xmlReconciliateNs (Brian Stafford), XPointer,
1113 xmlFreeNode(), xmlSAXParseMemory (Peter Jones), xmlGetNodePath (Petr
1114 Pajas), entities processing</li>
1115 <li>added grep to xmllint --shell</li>
1116 <li>VMS update patch from Craig A. Berry</li>
1117 <li>cleanup of the Windows build with support for more compilers (Igor),
1118 better thread support on Windows</li>
1119 <li>cleanup of Unix Makefiles and spec file</li>
1120 <li>Improvements to the documentation (John Fleck)</li>
1121</ul>
1122
Daniel Veillard48267432002-10-18 11:21:38 +00001123<h3>2.4.26: Oct 18 2002</h3>
1124<ul>
1125 <li>Patches for Windows CE port, improvements on Windows paths handling</li>
1126 <li>Fixes to the validation code (DTD and Schemas), xmlNodeGetPath() ,
1127 HTML serialization, Namespace compliance, and a number of small
1128 problems</li>
1129</ul>
1130
Daniel Veillarde16b5742002-09-26 17:50:03 +00001131<h3>2.4.25: Sep 26 2002</h3>
1132<ul>
1133 <li>A number of bug fixes: XPath, validation, Python bindings, DOM and
1134 tree, xmlI/O, Html</li>
1135 <li>Serious rewrite of XInclude</li>
1136 <li>Made XML Schemas regexp part of the default build and APIs, small fix
1137 and improvement of the regexp core</li>
1138 <li>Changed the validation code to reuse XML Schemas regexp APIs</li>
1139 <li>Better handling of Windows file paths, improvement of Makefiles (Igor,
1140 Daniel Gehriger, Mark Vakoc)</li>
1141 <li>Improved the python I/O bindings, the tests, added resolver and regexp
Daniel Veillard321be0c2002-10-08 21:26:42 +00001142 APIs</li>
Daniel Veillarde16b5742002-09-26 17:50:03 +00001143 <li>New logos from Marc Liyanage</li>
1144 <li>Tutorial improvements: John Fleck, Christopher Harris</li>
1145 <li>Makefile: Fixes for AMD x86_64 (Mandrake), DESTDIR (Christophe
1146 Merlet)</li>
1147 <li>removal of all stderr/perror use for error reporting</li>
1148 <li>Better error reporting: XPath and DTD validation</li>
1149 <li>update of the trio portability layer (Bjorn Reese)</li>
1150</ul>
1151
Daniel Veillard42766c02002-08-22 20:52:17 +00001152<p><strong>2.4.24: Aug 22 2002</strong></p>
1153<ul>
1154 <li>XPath fixes (William), xf:escape-uri() (Wesley Terpstra)</li>
1155 <li>Python binding fixes: makefiles (William), generator, rpm build, x86-64
1156 (fcrozat)</li>
1157 <li>HTML &lt;style&gt; and boolean attributes serializer fixes</li>
1158 <li>C14N improvements by Aleksey</li>
Daniel Veillarde1662542002-08-28 11:50:59 +00001159 <li>doc cleanups: Rick Jones</li>
Daniel Veillard42766c02002-08-22 20:52:17 +00001160 <li>Windows compiler makefile updates: Igor and Elizabeth Barham</li>
1161 <li>XInclude: implementation of fallback and xml:base fixup added</li>
1162</ul>
1163
Daniel Veillard782afda2002-07-08 15:12:49 +00001164<h3>2.4.23: July 6 2002</h3>
1165<ul>
1166 <li>performances patches: Peter Jacobi</li>
1167 <li>c14n fixes, testsuite and performances: Aleksey Sanin</li>
1168 <li>added xmlDocFormatDump: Chema Celorio</li>
1169 <li>new tutorial: John Fleck</li>
1170 <li>new hash functions and performances: Sander Vesik, portability fix from
1171 Peter Jacobi</li>
1172 <li>a number of bug fixes: XPath (William Brack, Richard Jinks), XML and
1173 HTML parsers, ID lookup function</li>
1174 <li>removal of all remaining sprintf: Aleksey Sanin</li>
1175</ul>
1176
Daniel Veillardc0801af2002-05-28 16:28:42 +00001177<h3>2.4.22: May 27 2002</h3>
1178<ul>
1179 <li>a number of bug fixes: configure scripts, base handling, parser, memory
1180 usage, HTML parser, XPath, documentation (Christian Cornelssen),
Daniel Veillard21473672002-06-17 07:29:22 +00001181 indentation, URI parsing</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +00001182 <li>Optimizations for XMLSec, fixing and making public some of the network
1183 protocol handlers (Aleksey)</li>
1184 <li>performance patch from Gary Pennington</li>
1185 <li>Charles Bozeman provided date and time support for XML Schemas
1186 datatypes</li>
1187</ul>
1188
Daniel Veillardcf27f7c2002-04-30 07:12:39 +00001189<h3>2.4.21: Apr 29 2002</h3>
1190
1191<p>This release is both a bug fix release and also contains the early XML
1192Schemas <a href="http://www.w3.org/TR/xmlschema-1/">structures</a> and <a
1193href="http://www.w3.org/TR/xmlschema-2/">datatypes</a> code, beware, all
1194interfaces are likely to change, there is huge holes, it is clearly a work in
1195progress and don't even think of putting this code in a production system,
Daniel Veillarde6d8e202002-05-02 06:11:10 +00001196it's actually not compiled in by default. The real fixes are:</p>
Daniel Veillardcf27f7c2002-04-30 07:12:39 +00001197<ul>
1198 <li>a couple of bugs or limitations introduced in 2.4.20</li>
1199 <li>patches for Borland C++ and MSC by Igor</li>
1200 <li>some fixes on XPath strings and conformance patches by Richard
1201 Jinks</li>
1202 <li>patch from Aleksey for the ExcC14N specification</li>
1203 <li>OSF/1 bug fix by Bjorn</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001204</ul>
1205
Daniel Veillarda7084cd2002-04-15 17:12:47 +00001206<h3>2.4.20: Apr 15 2002</h3>
1207<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +00001208 <li>bug fixes: file descriptor leak, XPath, HTML output, DTD validation</li>
Daniel Veillarda7084cd2002-04-15 17:12:47 +00001209 <li>XPath conformance testing by Richard Jinks</li>
1210 <li>Portability fixes: Solaris, MPE/iX, Windows, OSF/1, python bindings,
1211 libxml.m4</li>
1212</ul>
1213
Daniel Veillard19274092002-03-25 16:48:03 +00001214<h3>2.4.19: Mar 25 2002</h3>
1215<ul>
1216 <li>bug fixes: half a dozen XPath bugs, Validation, ISO-Latin to UTF8
1217 encoder</li>
1218 <li>portability fixes in the HTTP code</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +00001219 <li>memory allocation checks using valgrind, and profiling tests</li>
Daniel Veillard19274092002-03-25 16:48:03 +00001220 <li>revamp of the Windows build and Makefiles</li>
1221</ul>
1222
Daniel Veillard34ce8be2002-03-18 19:37:11 +00001223<h3>2.4.18: Mar 18 2002</h3>
1224<ul>
1225 <li>bug fixes: tree, SAX, canonicalization, validation, portability,
Daniel Veillard63d83142002-05-20 06:51:05 +00001226 XPath</li>
Daniel Veillard34ce8be2002-03-18 19:37:11 +00001227 <li>removed the --with-buffer option it was becoming unmaintainable</li>
1228 <li>serious cleanup of the Python makefiles</li>
1229 <li>speedup patch to XPath very effective for DocBook stylesheets</li>
1230 <li>Fixes for Windows build, cleanup of the documentation</li>
1231</ul>
1232
Daniel Veillardaf43f632002-03-08 15:05:20 +00001233<h3>2.4.17: Mar 8 2002</h3>
1234<ul>
1235 <li>a lot of bug fixes, including "namespace nodes have no parents in
1236 XPath"</li>
1237 <li>fixed/improved the Python wrappers, added more examples and more
1238 regression tests, XPath extension functions can now return node-sets</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001239 <li>added the XML Canonicalization support from Aleksey Sanin</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001240</ul>
1241
Daniel Veillard5f4b5992002-02-20 10:22:49 +00001242<h3>2.4.16: Feb 20 2002</h3>
1243<ul>
1244 <li>a lot of bug fixes, most of them were triggered by the XML Testsuite
1245 from OASIS and W3C. Compliance has been significantly improved.</li>
1246 <li>a couple of portability fixes too.</li>
1247</ul>
1248
Daniel Veillard397ff112002-02-11 18:27:20 +00001249<h3>2.4.15: Feb 11 2002</h3>
1250<ul>
1251 <li>Fixed the Makefiles, especially the python module ones</li>
1252 <li>A few bug fixes and cleanup</li>
1253 <li>Includes cleanup</li>
1254</ul>
1255
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +00001256<h3>2.4.14: Feb 8 2002</h3>
1257<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +00001258 <li>Change of License to the <a
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +00001259 href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard63d83142002-05-20 06:51:05 +00001260 License</a> basically for integration in XFree86 codebase, and removing
1261 confusion around the previous dual-licensing</li>
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +00001262 <li>added Python bindings, beta software but should already be quite
1263 complete</li>
1264 <li>a large number of fixes and cleanups, especially for all tree
1265 manipulations</li>
1266 <li>cleanup of the headers, generation of a reference API definition in
1267 XML</li>
1268</ul>
1269
1270<h3>2.4.13: Jan 14 2002</h3>
Daniel Veillard744683d2002-01-14 17:30:20 +00001271<ul>
1272 <li>update of the documentation: John Fleck and Charlie Bozeman</li>
1273 <li>cleanup of timing code from Justin Fletcher</li>
1274 <li>fixes for Windows and initial thread support on Win32: Igor and Serguei
1275 Narojnyi</li>
1276 <li>Cygwin patch from Robert Collins</li>
1277 <li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li>
1278</ul>
1279
Daniel Veillardef90ba72001-12-07 14:24:22 +00001280<h3>2.4.12: Dec 7 2001</h3>
1281<ul>
1282 <li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman),
1283 XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups
1284 (robert)</li>
1285 <li>Eric Lavigne contributed project files for MacOS</li>
1286 <li>some makefiles cleanups</li>
1287</ul>
1288
Daniel Veillarda4871052001-11-26 13:19:48 +00001289<h3>2.4.11: Nov 26 2001</h3>
1290<ul>
1291 <li>fixed a couple of errors in the includes, fixed a few bugs, some code
1292 cleanups</li>
1293 <li>xmllint man pages improvement by Heiko Rupp</li>
1294 <li>updated VMS build instructions from John A Fotheringham</li>
1295 <li>Windows Makefiles updates from Igor</li>
1296</ul>
1297
Daniel Veillard43d3f612001-11-10 11:57:23 +00001298<h3>2.4.10: Nov 10 2001</h3>
1299<ul>
1300 <li>URI escaping fix (Joel Young)</li>
1301 <li>added xmlGetNodePath() (for paths or XPointers generation)</li>
1302 <li>Fixes namespace handling problems when using DTD and validation</li>
1303 <li>improvements on xmllint: Morus Walter patches for --format and
1304 --encode, Stefan Kost and Heiko Rupp improvements on the --shell</li>
1305 <li>fixes for xmlcatalog linking pointed by Weiqi Gao</li>
1306 <li>fixes to the HTML parser</li>
1307</ul>
1308
1309<h3>2.4.9: Nov 6 2001</h3>
1310<ul>
1311 <li>fixes more catalog bugs</li>
1312 <li>avoid a compilation problem, improve xmlGetLineNo()</li>
1313</ul>
1314
Daniel Veillarded421aa2001-11-04 21:22:45 +00001315<h3>2.4.8: Nov 4 2001</h3>
1316<ul>
1317 <li>fixed SGML catalogs broken in previous release, updated xmlcatalog
1318 tool</li>
1319 <li>fixed a compile errors and some includes troubles.</li>
1320</ul>
1321
Daniel Veillard52dcab32001-10-30 12:51:17 +00001322<h3>2.4.7: Oct 30 2001</h3>
1323<ul>
1324 <li>exported some debugging interfaces</li>
1325 <li>serious rewrite of the catalog code</li>
1326 <li>integrated Gary Pennington thread safety patch, added configure option
1327 and regression tests</li>
1328 <li>removed an HTML parser bug</li>
1329 <li>fixed a couple of potentially serious validation bugs</li>
1330 <li>integrated the SGML DocBook support in xmllint</li>
1331 <li>changed the nanoftp anonymous login passwd</li>
1332 <li>some I/O cleanup and a couple of interfaces for Perl wrapper</li>
1333 <li>general bug fixes</li>
1334 <li>updated xmllint man page by John Fleck</li>
1335 <li>some VMS and Windows updates</li>
1336</ul>
1337
Daniel Veillard60087f32001-10-10 09:45:09 +00001338<h3>2.4.6: Oct 10 2001</h3>
1339<ul>
Daniel Veillard52dcab32001-10-30 12:51:17 +00001340 <li>added an updated man pages by John Fleck</li>
Daniel Veillard60087f32001-10-10 09:45:09 +00001341 <li>portability and configure fixes</li>
1342 <li>an infinite loop on the HTML parser was removed (William)</li>
1343 <li>Windows makefile patches from Igor</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001344 <li>fixed half a dozen bugs reported for libxml or libxslt</li>
Daniel Veillard60087f32001-10-10 09:45:09 +00001345 <li>updated xmlcatalog to be able to modify SGML super catalogs</li>
1346</ul>
1347
Daniel Veillarddadd0872001-09-15 09:21:44 +00001348<h3>2.4.5: Sep 14 2001</h3>
1349<ul>
1350 <li>Remove a few annoying bugs in 2.4.4</li>
1351 <li>forces the HTML serializer to output decimal charrefs since some
1352 version of Netscape can't handle hexadecimal ones</li>
1353</ul>
1354
1355<h3>1.8.16: Sep 14 2001</h3>
1356<ul>
1357 <li>maintenance release of the old libxml1 branch, couple of bug and
1358 portability fixes</li>
1359</ul>
1360
Daniel Veillard04382ae2001-09-12 18:51:30 +00001361<h3>2.4.4: Sep 12 2001</h3>
1362<ul>
1363 <li>added --convert to xmlcatalog, bug fixes and cleanups of XML
1364 Catalog</li>
1365 <li>a few bug fixes and some portability changes</li>
1366 <li>some documentation cleanups</li>
1367</ul>
1368
Daniel Veillard39936902001-08-24 00:49:01 +00001369<h3>2.4.3: Aug 23 2001</h3>
1370<ul>
1371 <li>XML Catalog support see the doc</li>
1372 <li>New NaN/Infinity floating point code</li>
1373 <li>A few bug fixes</li>
1374</ul>
1375
1376<h3>2.4.2: Aug 15 2001</h3>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001377<ul>
1378 <li>adds xmlLineNumbersDefault() to control line number generation</li>
1379 <li>lot of bug fixes</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001380 <li>the Microsoft MSC projects files should now be up to date</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001381 <li>inheritance of namespaces from DTD defaulted attributes</li>
1382 <li>fixes a serious potential security bug</li>
1383 <li>added a --format option to xmllint</li>
1384</ul>
1385
1386<h3>2.4.1: July 24 2001</h3>
1387<ul>
1388 <li>possibility to keep line numbers in the tree</li>
1389 <li>some computation NaN fixes</li>
1390 <li>extension of the XPath API</li>
1391 <li>cleanup for alpha and ia64 targets</li>
1392 <li>patch to allow saving through HTTP PUT or POST</li>
Daniel Veillard09ab7e12001-07-10 15:49:44 +00001393</ul>
1394
1395<h3>2.4.0: July 10 2001</h3>
1396<ul>
1397 <li>Fixed a few bugs in XPath, validation, and tree handling.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001398 <li>Fixed XML Base implementation, added a couple of examples to the
Daniel Veillard09ab7e12001-07-10 15:49:44 +00001399 regression tests</li>
1400 <li>A bit of cleanup</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +00001401</ul>
1402
Daniel Veillard5b43fde2001-07-05 23:31:40 +00001403<h3>2.3.14: July 5 2001</h3>
1404<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +00001405 <li>fixed some entities problems and reduce memory requirement when
1406 substituting them</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +00001407 <li>lots of improvements in the XPath queries interpreter can be
Daniel Veillard63d83142002-05-20 06:51:05 +00001408 substantially faster</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +00001409 <li>Makefiles and configure cleanups</li>
1410 <li>Fixes to XPath variable eval, and compare on empty node set</li>
1411 <li>HTML tag closing bug fixed</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001412 <li>Fixed an URI reference computation problem when validating</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +00001413</ul>
1414
Daniel Veillard2adbb512001-06-28 16:20:36 +00001415<h3>2.3.13: June 28 2001</h3>
1416<ul>
1417 <li>2.3.12 configure.in was broken as well as the push mode XML parser</li>
1418 <li>a few more fixes for compilation on Windows MSC by Yon Derek</li>
1419</ul>
1420
1421<h3>1.8.14: June 28 2001</h3>
1422<ul>
1423 <li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li>
1424 <li>Small Makefile fix</li>
1425</ul>
1426
Daniel Veillard11648102001-06-26 16:08:24 +00001427<h3>2.3.12: June 26 2001</h3>
1428<ul>
1429 <li>lots of cleanup</li>
1430 <li>a couple of validation fix</li>
1431 <li>fixed line number counting</li>
1432 <li>fixed serious problems in the XInclude processing</li>
1433 <li>added support for UTF8 BOM at beginning of entities</li>
1434 <li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0
1435 miscompile uri.c (William), Thomas Leitner provided a fix for the
1436 optimizer on Tru64</li>
1437 <li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for
1438 compilation on Windows MSC</li>
1439 <li>update of libxml-doc.el (Felix Natter)</li>
1440 <li>fixed 2 bugs in URI normalization code</li>
1441</ul>
1442
Daniel Veillarde3c81b52001-06-17 14:50:34 +00001443<h3>2.3.11: June 17 2001</h3>
1444<ul>
1445 <li>updates to trio, Makefiles and configure should fix some portability
1446 problems (alpha)</li>
1447 <li>fixed some HTML serialization problems (pre, script, and block/inline
1448 handling), added encoding aware APIs, cleanup of this code</li>
1449 <li>added xmlHasNsProp()</li>
1450 <li>implemented a specific PI for encoding support in the DocBook SGML
1451 parser</li>
1452 <li>some XPath fixes (-Infinity, / as a function parameter and namespaces
1453 node selection)</li>
1454 <li>fixed a performance problem and an error in the validation code</li>
1455 <li>fixed XInclude routine to implement the recursive behaviour</li>
1456 <li>fixed xmlFreeNode problem when libxml is included statically twice</li>
1457 <li>added --version to xmllint for bug reports</li>
1458</ul>
1459
Daniel Veillard2e4f1882001-06-01 10:11:57 +00001460<h3>2.3.10: June 1 2001</h3>
1461<ul>
1462 <li>fixed the SGML catalog support</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001463 <li>a number of reported bugs got fixed, in XPath, iconv detection,
1464 XInclude processing</li>
Daniel Veillard2e4f1882001-06-01 10:11:57 +00001465 <li>XPath string function should now handle unicode correctly</li>
1466</ul>
1467
Daniel Veillard4623acd2001-05-19 15:13:15 +00001468<h3>2.3.9: May 19 2001</h3>
1469
1470<p>Lots of bugfixes, and added a basic SGML catalog support:</p>
1471<ul>
1472 <li>HTML push bugfix #54891 and another patch from Jonas Borgström</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001473 <li>some serious speed optimization again</li>
Daniel Veillard4623acd2001-05-19 15:13:15 +00001474 <li>some documentation cleanups</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001475 <li>trying to get better linking on Solaris (-R)</li>
Daniel Veillard4623acd2001-05-19 15:13:15 +00001476 <li>XPath API cleanup from Thomas Broyer</li>
1477 <li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed
1478 xmlValidGetValidElements()</li>
1479 <li>Added an INSTALL file</li>
1480 <li>Attribute removal added to API: #54433</li>
1481 <li>added a basic support for SGML catalogs</li>
1482 <li>fixed xmlKeepBlanksDefault(0) API</li>
1483 <li>bugfix in xmlNodeGetLang()</li>
1484 <li>fixed a small configure portability problem</li>
1485 <li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li>
1486</ul>
1487
Daniel Veillarda265af72001-05-14 11:13:58 +00001488<h3>1.8.13: May 14 2001</h3>
1489<ul>
1490 <li>bugfixes release of the old libxml1 branch used by Gnome</li>
1491</ul>
1492
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +00001493<h3>2.3.8: May 3 2001</h3>
1494<ul>
1495 <li>Integrated an SGML DocBook parser for the Gnome project</li>
1496 <li>Fixed a few things in the HTML parser</li>
1497 <li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating
1498 point portability issue</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001499 <li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for
1500 DOM+validation using the XML REC as input and a 700MHz celeron).</li>
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +00001501 <li>incorporated more Windows cleanup</li>
1502 <li>added xmlSaveFormatFile()</li>
1503 <li>fixed problems in copying nodes with entities references (gdome)</li>
1504 <li>removed some troubles surrounding the new validation module</li>
1505</ul>
1506
Daniel Veillarda41123c2001-04-22 19:31:20 +00001507<h3>2.3.7: April 22 2001</h3>
1508<ul>
1509 <li>lots of small bug fixes, corrected XPointer</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001510 <li>Non deterministic content model validation support</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +00001511 <li>added xmlDocCopyNode for gdome2</li>
1512 <li>revamped the way the HTML parser handles end of tags</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001513 <li>XPath: corrections of namespaces support and number formatting</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +00001514 <li>Windows: Igor Zlatkovic patches for MSC compilation</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001515 <li>HTML output fixes from P C Chow and William M. Brack</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +00001516 <li>Improved validation speed sensible for DocBook</li>
1517 <li>fixed a big bug with ID declared in external parsed entities</li>
1518 <li>portability fixes, update of Trio from Bjorn Reese</li>
1519</ul>
1520
Daniel Veillardafc73112001-04-11 11:51:41 +00001521<h3>2.3.6: April 8 2001</h3>
1522<ul>
1523 <li>Code cleanup using extreme gcc compiler warning options, found and
1524 cleared half a dozen potential problem</li>
1525 <li>the Eazel team found an XML parser bug</li>
1526 <li>cleaned up the user of some of the string formatting function. used the
1527 trio library code to provide the one needed when the platform is missing
1528 them</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001529 <li>xpath: removed a memory leak and fixed the predicate evaluation
1530 problem, extended the testsuite and cleaned up the result. XPointer seems
1531 broken ...</li>
Daniel Veillardafc73112001-04-11 11:51:41 +00001532</ul>
1533
Daniel Veillard56a4cb82001-03-24 17:00:36 +00001534<h3>2.3.5: Mar 23 2001</h3>
1535<ul>
1536 <li>Biggest change is separate parsing and evaluation of XPath expressions,
1537 there is some new APIs for this too</li>
1538 <li>included a number of bug fixes(XML push parser, 51876, notations,
1539 52299)</li>
1540 <li>Fixed some portability issues</li>
1541</ul>
1542
Daniel Veillarde356c282001-03-10 12:32:04 +00001543<h3>2.3.4: Mar 10 2001</h3>
1544<ul>
1545 <li>Fixed bugs #51860 and #51861</li>
1546 <li>Added a global variable xmlDefaultBufferSize to allow default buffer
1547 size to be application tunable.</li>
1548 <li>Some cleanup in the validation code, still a bug left and this part
1549 should probably be rewritten to support ambiguous content model :-\</li>
1550 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3
1551 parser</li>
1552 <li>Fixed another bug in xmlNodeGetContent()</li>
1553 <li>Bjorn fixed XPath node collection and Number formatting</li>
1554 <li>Fixed a loop reported in the HTML parsing</li>
1555 <li>blank space are reported even if the Dtd content model proves that they
Daniel Veillard63d83142002-05-20 06:51:05 +00001556 are formatting spaces, this is for XML conformance</li>
Daniel Veillarde356c282001-03-10 12:32:04 +00001557</ul>
1558
Daniel Veillardb402c072001-03-01 17:28:58 +00001559<h3>2.3.3: Mar 1 2001</h3>
1560<ul>
1561 <li>small change in XPath for XSLT</li>
1562 <li>documentation cleanups</li>
1563 <li>fix in validation by Gary Pennington</li>
1564 <li>serious parsing performances improvements</li>
1565</ul>
1566
Daniel Veillardec70e912001-02-26 20:10:45 +00001567<h3>2.3.2: Feb 24 2001</h3>
Daniel Veillard71681102001-02-24 17:48:53 +00001568<ul>
1569 <li>chasing XPath bugs, found a bunch, completed some TODO</li>
1570 <li>fixed a Dtd parsing bug</li>
1571 <li>fixed a bug in xmlNodeGetContent</li>
1572 <li>ID/IDREF support partly rewritten by Gary Pennington</li>
1573</ul>
1574
Daniel Veillardec70e912001-02-26 20:10:45 +00001575<h3>2.3.1: Feb 15 2001</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +00001576<ul>
1577 <li>some XPath and HTML bug fixes for XSLT</li>
1578 <li>small extension of the hash table interfaces for DOM gdome2
1579 implementation</li>
1580 <li>A few bug fixes</li>
1581</ul>
1582
Daniel Veillardec70e912001-02-26 20:10:45 +00001583<h3>2.3.0: Feb 8 2001 (2.2.12 was on 25 Jan but I didn't kept track)</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +00001584<ul>
1585 <li>Lots of XPath bug fixes</li>
1586 <li>Add a mode with Dtd lookup but without validation error reporting for
1587 XSLT</li>
1588 <li>Add support for text node without escaping (XSLT)</li>
1589 <li>bug fixes for xmlCheckFilename</li>
1590 <li>validation code bug fixes from Gary Pennington</li>
1591 <li>Patch from Paul D. Smith correcting URI path normalization</li>
1592 <li>Patch to allow simultaneous install of libxml-devel and
1593 libxml2-devel</li>
1594 <li>the example Makefile is now fixed</li>
1595 <li>added HTML to the RPM packages</li>
1596 <li>tree copying bugfixes</li>
1597 <li>updates to Windows makefiles</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001598 <li>optimization patch from Bjorn Reese</li>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +00001599</ul>
1600
Daniel Veillardec70e912001-02-26 20:10:45 +00001601<h3>2.2.11: Jan 4 2001</h3>
Daniel Veillard503b8932001-01-05 06:36:31 +00001602<ul>
1603 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
1604 <li>added htmlHandleOmittedElem()</li>
1605 <li>Applied Bjorn Reese's IPV6 first patch</li>
1606 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +00001607 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +00001608</ul>
1609
Daniel Veillard2ddd23d2000-11-25 10:42:19 +00001610<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +00001611<ul>
1612 <li>Fix the Windows problems of 2.2.8</li>
1613 <li>integrate OpenVMS patches</li>
1614 <li>better handling of some nasty HTML input</li>
1615 <li>Improved the XPointer implementation</li>
1616 <li>integrate a number of provided patches</li>
1617</ul>
1618
Daniel Veillard2ddd23d2000-11-25 10:42:19 +00001619<h3>2.2.9: Nov 25 2000</h3>
1620<ul>
1621 <li>erroneous release :-(</li>
1622</ul>
1623
Daniel Veillard28929b22000-11-13 18:22:49 +00001624<h3>2.2.8: Nov 13 2000</h3>
1625<ul>
1626 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
1627 support</li>
1628 <li>Patch in conditional section handling</li>
1629 <li>updated MS compiler project</li>
1630 <li>fixed some XPath problems</li>
1631 <li>added an URI escaping function</li>
1632 <li>some other bug fixes</li>
1633</ul>
1634
1635<h3>2.2.7: Oct 31 2000</h3>
1636<ul>
1637 <li>added message redirection</li>
1638 <li>XPath improvements (thanks TOM !)</li>
1639 <li>xmlIOParseDTD() added</li>
1640 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
1641 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
1642</ul>
1643
Daniel Veillard29a11cc2000-10-25 13:32:39 +00001644<h3>2.2.6: Oct 25 2000:</h3>
1645<ul>
1646 <li>Added an hash table module, migrated a number of internal structure to
1647 those</li>
1648 <li>Fixed a posteriori validation problems</li>
1649 <li>HTTP module cleanups</li>
1650 <li>HTML parser improvements (tag errors, script/style handling, attribute
1651 normalization)</li>
1652 <li>coalescing of adjacent text nodes</li>
1653 <li>couple of XPath bug fixes, exported the internal API</li>
1654</ul>
1655
Daniel Veillardab8500d2000-10-15 21:06:19 +00001656<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +00001657<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +00001658 <li>XPointer implementation and testsuite</li>
1659 <li>Lot of XPath fixes, added variable and functions registration, more
1660 tests</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001661 <li>Portability fixes, lots of enhancements toward an easy Windows build
1662 and release</li>
Daniel Veillard189446d2000-10-13 10:23:06 +00001663 <li>Late validation fixes</li>
1664 <li>Integrated a lot of contributed patches</li>
1665 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +00001666 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +00001667</ul>
1668
1669<h3>2.2.4: Oct 1 2000:</h3>
1670<ul>
1671 <li>main XPath problem fixed</li>
1672 <li>Integrated portability patches for Windows</li>
1673 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +00001674</ul>
1675
Daniel Veillardd5f97f82000-09-17 16:38:14 +00001676<h3>2.2.3: Sep 17 2000</h3>
1677<ul>
1678 <li>bug fixes</li>
1679 <li>cleanup of entity handling code</li>
1680 <li>overall review of all loops in the parsers, all sprintf usage has been
1681 checked too</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001682 <li>Far better handling of larges Dtd. Validating against DocBook XML Dtd
Daniel Veillardd5f97f82000-09-17 16:38:14 +00001683 works smoothly now.</li>
1684</ul>
1685
1686<h3>1.8.10: Sep 6 2000</h3>
1687<ul>
1688 <li>bug fix release for some Gnome projects</li>
1689</ul>
1690
1691<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +00001692<ul>
1693 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +00001694 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +00001695</ul>
1696
Daniel Veillardd5f97f82000-09-17 16:38:14 +00001697<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +00001698<ul>
1699 <li>a purely bug fixes release</li>
1700 <li>fixed an encoding support problem when parsing from a memory block</li>
1701 <li>fixed a DOCTYPE parsing problem</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001702 <li>removed a bug in the function allowing to override the memory
1703 allocation routines</li>
Daniel Veillarda2679fa2000-07-22 02:38:15 +00001704</ul>
1705
Daniel Veillardd5f97f82000-09-17 16:38:14 +00001706<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +00001707<ul>
1708 <li>applied a lot of portability fixes</li>
1709 <li>better encoding support/cleanup and saving (content is now always
1710 encoded in UTF-8)</li>
1711 <li>the HTML parser now correctly handles encodings</li>
1712 <li>added xmlHasProp()</li>
1713 <li>fixed a serious problem with &amp;#38;</li>
1714 <li>propagated the fix to FTP client</li>
1715 <li>cleanup, bugfixes, etc ...</li>
1716 <li>Added a page about <a href="encoding.html">libxml Internationalization
1717 support</a></li>
1718</ul>
1719
Daniel Veillard60979bd2000-07-10 12:17:33 +00001720<h3>1.8.9: July 9 2000</h3>
1721<ul>
1722 <li>fixed the spec the RPMs should be better</li>
1723 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
1724 rpmfind users problem</li>
1725</ul>
1726
Daniel Veillard6388e172000-07-03 16:07:19 +00001727<h3>2.1.1: July 1 2000</h3>
1728<ul>
1729 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
1730 <li>improvements on the HTML parser</li>
1731</ul>
1732
Daniel Veillard3f6f7f62000-06-30 17:58:25 +00001733<h3>2.1.0 and 1.8.8: June 29 2000</h3>
1734<ul>
Daniel Veillardc0801af2002-05-28 16:28:42 +00001735 <li>1.8.8 is mostly a commodity package for upgrading to libxml2 according
1736 to <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
Daniel Veillard3f6f7f62000-06-30 17:58:25 +00001737 about &amp;#38; charref parsing</li>
1738 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
1739 also contains numerous fixes and enhancements:
1740 <ul>
1741 <li>added xmlStopParser() to stop parsing</li>
1742 <li>improved a lot parsing speed when there is large CDATA blocs</li>
1743 <li>includes XPath patches provided by Picdar Technology</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001744 <li>tried to fix as much as possible DTD validation and namespace
Daniel Veillard3f6f7f62000-06-30 17:58:25 +00001745 related problems</li>
1746 <li>output to a given encoding has been added/tested</li>
1747 <li>lot of various fixes</li>
1748 </ul>
1749 </li>
1750</ul>
1751
Daniel Veillarde0aed302000-04-16 08:52:20 +00001752<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +00001753<ul>
1754 <li>First public release of libxml2. If you are using libxml, it's a good
Daniel Veillard63d83142002-05-20 06:51:05 +00001755 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initially
1756 scheduled for Apr 3 the release occurred only on Apr 12 due to massive
Daniel Veillarde0aed302000-04-16 08:52:20 +00001757 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +00001758 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +00001759 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +00001760 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +00001761 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +00001762 <pre>#include "xxx.h"</pre>
1763 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +00001764 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
1765 <li>the memory allocation routines used by libxml can now be overloaded
1766 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +00001767 <li>The previously CVS only tool tester has been renamed
1768 <strong>xmllint</strong> and is now installed as part of the libxml2
1769 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +00001770 <li>The I/O interface has been revamped. There is now ways to plug in
1771 specific I/O modules, either at the URI scheme detection level using
1772 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
1773 parser context using xmlCreateIOParserCtxt()</li>
1774 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
1775 number of the libxml module in use</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001776 <li>a number of optional features of libxml can now be excluded at
1777 configure time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001778</ul>
1779
1780<h3>2.0.0beta: Mar 14 2000</h3>
1781<ul>
1782 <li>This is a first Beta release of libxml version 2</li>
Daniel Veillarde356c282001-03-10 12:32:04 +00001783 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org
1784 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and
1785 RPMs</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001786 <li>This version is now the head in the Gnome CVS base, the old one is
1787 available under the tag LIB_XML_1_X</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +00001788 <li>This includes a very large set of changes. From a programmatic point
1789 of view applications should not have to be modified too much, check the
1790 <a href="upgrade.html">upgrade page</a></li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001791 <li>Some interfaces may changes (especially a bit about encoding).</li>
1792 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +00001793 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001794 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
1795 handled now</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001796 <li>Better handling of entities, especially well-formedness checking
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001797 and proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +00001798 <li>DTD conditional sections</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001799 <li>Validation now correctly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +00001800 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
Daniel Veillard63d83142002-05-20 06:51:05 +00001801 structures to accommodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +00001802 </ul>
1803 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001804 <li>Serious progress were made toward compliance, <a
1805 href="conf/result.html">here are the result of the test</a> against the
Daniel Veillard63d83142002-05-20 06:51:05 +00001806 OASIS testsuite (except the Japanese tests since I don't support that
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001807 encoding yet). This URL is rebuilt every couple of hours using the CVS
1808 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +00001809</ul>
1810
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001811<h3>1.8.7: Mar 6 2000</h3>
1812<ul>
1813 <li>This is a bug fix release:</li>
1814 <li>It is possible to disable the ignorable blanks heuristic used by
1815 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001816 that for adherence to XML spec, this behaviour will be disabled by
1817 default in 2.x . The same function will allow to keep compatibility for
1818 old code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +00001819 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
1820 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001821 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
1822 compilation on some platforms has been fixed</li>
1823 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
1824 URIs</li>
1825</ul>
1826
Daniel Veillarde41f2b72000-01-30 20:00:07 +00001827<h3>1.8.6: Jan 31 2000</h3>
1828<ul>
1829 <li>added a nanoFTP transport module, debugged until the new version of <a
1830 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
1831 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +00001832</ul>
1833
1834<h3>1.8.5: Jan 21 2000</h3>
1835<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +00001836 <li>adding APIs to parse a well balanced chunk of XML (production <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001837 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the
1838 XML spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +00001839 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +00001840 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
1841 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +00001842 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
1843 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +00001844</ul>
1845
1846<h3>1.8.4: Jan 13 2000</h3>
1847<ul>
1848 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
1849 <li>all exit() call should have been removed from libxml</li>
1850 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
1851 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +00001852</ul>
1853
1854<h3>1.8.3: Jan 5 2000</h3>
1855<ul>
1856 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001857 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001858 <li>lots of bug fixes and improvement added over XMas holidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +00001859 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +00001860 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
1861 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +00001862 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +00001863 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +00001864 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +00001865</ul>
1866
1867<h3>1.8.2: Dec 21 1999</h3>
1868<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +00001869 <li>I got another problem with includes and C++, I hope this issue is fixed
1870 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +00001871 <li>Added a few tree modification functions: xmlReplaceNode,
1872 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
1873 xmlDocSetRootElement</li>
1874 <li>Tried to improve the HTML output with help from <a
1875 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +00001876</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +00001877
Daniel Veillarde4e51311999-12-18 15:32:46 +00001878<h3>1.8.1: Dec 18 1999</h3>
1879<ul>
1880 <li>various patches to avoid troubles when using libxml with C++ compilers
1881 the "namespace" keyword and C escaping in include files</li>
1882 <li>a problem in one of the core macros IS_CHAR was corrected</li>
1883 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
1884 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +00001885 <li>fixed a posteriori validation (validation after parsing, or by using a
1886 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +00001887 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +00001888</ul>
1889
1890<h3>1.8.0: Dec 12 1999</h3>
1891<ul>
1892 <li>cleanup, especially memory wise</li>
1893 <li>the parser should be more reliable, especially the HTML one, it should
1894 not crash, whatever the input !</li>
1895 <li>Integrated various patches, especially a speedup improvement for large
1896 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
1897 configure with --with-buffers to enable them.</li>
1898 <li>attribute normalization, oops should have been added long ago !</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001899 <li>attributes defaulted from DTDs should be available, xmlSetProp() now
1900 does entities escaping by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +00001901</ul>
Daniel Veillard35008381999-10-25 13:15:52 +00001902
1903<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001904<ul>
Daniel Veillard35008381999-10-25 13:15:52 +00001905 <li>Lots of HTML improvement</li>
1906 <li>Fixed some errors when saving both XML and HTML</li>
1907 <li>More examples, the regression tests should now look clean</li>
1908 <li>Fixed a bug with contiguous charref</li>
1909</ul>
1910
1911<h3>1.7.3: Sep 29 1999</h3>
1912<ul>
1913 <li>portability problems fixed</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00001914 <li>snprintf was used unconditionally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +00001915 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001916</ul>
1917
1918<h3>1.7.1: Sep 24 1999</h3>
1919<ul>
1920 <li>The basic type for strings manipulated by libxml has been renamed in
1921 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001922 is that CHAR was conflicting with a predefined type on Windows. However
1923 on non WIN32 environment, compatibility is provided by the way of a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001924 <strong>#define </strong>.</li>
1925 <li>Changed another error : the use of a structure field called errno, and
1926 leading to troubles on platforms where it's a macro</li>
1927</ul>
1928
Daniel Veillard63d83142002-05-20 06:51:05 +00001929<h3>1.7.0: Sep 23 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001930<ul>
1931 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00001932 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001933 <li>Added an errno to report errors by another mean than a simple printf
1934 like callback</li>
1935 <li>Finished ID/IDREF support and checking when validation</li>
1936 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00001937 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001938 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
1939 implementation</li>
1940 <li>Added an HTML parser front-end</li>
1941</ul>
1942
1943<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001944
Daniel Veillard402e8c82000-02-29 22:57:47 +00001945<p><a href="http://www.w3.org/TR/REC-xml">XML is a standard</a> for
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001946markup-based structured documents. Here is <a name="example">an example XML
1947document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00001948<pre>&lt;?xml version="1.0"?&gt;
1949&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
1950 &lt;head&gt;
1951 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
1952 &lt;/head&gt;
1953 &lt;chapter&gt;
1954 &lt;title&gt;The Linux adventure&lt;/title&gt;
1955 &lt;p&gt;bla bla bla ...&lt;/p&gt;
1956 &lt;image href="linus.gif"/&gt;
1957 &lt;p&gt;...&lt;/p&gt;
1958 &lt;/chapter&gt;
1959&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00001960
Daniel Veillard0b28e882002-07-24 23:47:05 +00001961<p>The first line specifies that it is an XML document and gives useful
Daniel Veillard42766c02002-08-22 20:52:17 +00001962information about its encoding. Then the rest of the document is a text
1963format whose structure is specified by tags between brackets. <strong>Each
1964tag opened has to be closed</strong>. XML is pedantic about this. However, if
1965a tag is empty (no content), a single tag can serve as both the opening and
1966closing tag if it ends with <code>/&gt;</code> rather than with
1967<code>&gt;</code>. Note that, for example, the image tag has no content (just
1968an attribute) and is closed by ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +00001969
Daniel Veillard42766c02002-08-22 20:52:17 +00001970<p>XML can be applied successfully to a wide range of tasks, ranging from
1971long term structured document maintenance (where it follows the steps of
1972SGML) to simple data encoding mechanisms like configuration file formatting
1973(glade), spreadsheets (gnumeric), or even shorter lived documents such as
1974WebDAV where it is used to encode remote calls between a client and a
1975server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001976
Daniel Veillard82687162001-01-22 15:32:01 +00001977<h2><a name="XSLT">XSLT</a></h2>
1978
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +00001979<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
1980
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001981<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a
1982language for transforming XML documents into other XML documents (or
1983HTML/textual output).</p>
Daniel Veillard82687162001-01-22 15:32:01 +00001984
Daniel Veillard560c2a42003-07-06 21:13:49 +00001985<p>A separate library called libxslt is available implementing XSLT-1.0 for
1986libxml2. This module "libxslt" too can be found in the Gnome CVS base.</p>
Daniel Veillard82687162001-01-22 15:32:01 +00001987
Daniel Veillard383b1472001-01-23 11:39:52 +00001988<p>You can check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001989href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a>
1990supported and the progresses on the <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001991href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog"
Daniel Veillard0b28e882002-07-24 23:47:05 +00001992name="Changelog">Changelog</a>.</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001993
1994<h2><a name="Python">Python and bindings</a></h2>
1995
Daniel Veillard42766c02002-08-22 20:52:17 +00001996<p>There are a number of language bindings and wrappers available for
1997libxml2, the list below is not exhaustive. Please contact the <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001998href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a>
1999(<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in
2000order to get updates to this list or to discuss the specific topic of libxml2
2001or libxslt wrappers or bindings:</p>
2002<ul>
Daniel Veillardc14401e2002-11-20 14:28:17 +00002003 <li><a href="http://libxmlplusplus.sourceforge.net/">Libxml++</a> seems the
2004 most up-to-date C++ bindings for libxml2, check the <a
2005 href="http://libxmlplusplus.sourceforge.net/reference/html/hierarchy.html">documentation</a>
2006 and the <a
2007 href="http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/libxmlplusplus/libxml%2b%2b/examples/">examples</a>.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002008 <li>There is another <a href="http://libgdome-cpp.berlios.de/">C++ wrapper
Daniel Veillard0b28e882002-07-24 23:47:05 +00002009 based on the gdome2 bindings</a> maintained by Tobias Peters.</li>
Daniel Veillard9b6fd302002-05-13 12:06:47 +00002010 <li>and a third C++ wrapper by Peter Jones &lt;pjones@pmade.org&gt;
2011 <p>Website: <a
2012 href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
2013 </li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002014 <li><a
2015 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard63d83142002-05-20 06:51:05 +00002016 Sergeant</a> developed <a
2017 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for
Daniel Veillardaf43f632002-03-08 15:05:20 +00002018 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
Daniel Veillard0b28e882002-07-24 23:47:05 +00002019 application server</a>.</li>
Daniel Veillard4ac494b2003-09-18 15:08:00 +00002020 <li>If you're interested into scripting XML processing, have a look at <a
2021 href="http://xsh.sourceforge.net/">XSH</a> an XML editing shell based on
2022 Libxml2 Perl bindings.</li>
Daniel Veillard21473672002-06-17 07:29:22 +00002023 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides an
Daniel Veillardaf43f632002-03-08 15:05:20 +00002024 earlier version of the libxml/libxslt <a
Daniel Veillard0b28e882002-07-24 23:47:05 +00002025 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a>.</li>
Daniel Veillard21473672002-06-17 07:29:22 +00002026 <li>Gopal.V and Peter Minten develop <a
2027 href="http://savannah.gnu.org/projects/libxmlsharp">libxml#</a>, a set of
Daniel Veillard0b28e882002-07-24 23:47:05 +00002028 C# libxml2 bindings.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002029 <li>Petr Kozelka provides <a
2030 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
Daniel Veillard0b28e882002-07-24 23:47:05 +00002031 libxml2</a> with Kylix, Delphi and other Pascal compilers.</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +00002032 <li>Uwe Fechner also provides <a
2033 href="http://sourceforge.net/projects/idom2-pas/">idom2</a>, a DOM2
Daniel Veillard0b28e882002-07-24 23:47:05 +00002034 implementation for Kylix2/D5/D6 from Borland.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002035 <li>Wai-Sun "Squidster" Chia provides <a
2036 href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
2037 libxml2 bindings are also available in Ruby through the <a
2038 href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
2039 maintained by Tobias Peters.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002040 <li>Steve Ball and contributors maintains <a
2041 href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
Daniel Veillard0b28e882002-07-24 23:47:05 +00002042 Tcl</a>.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002043 <li>There is support for libxml2 in the DOM module of PHP.</li>
Daniel Veillard41b01a82003-02-27 11:09:06 +00002044 <li><a href="http://savannah.gnu.org/projects/classpathx/">LibxmlJ</a> is
Daniel Veillard806cada2003-03-19 21:58:59 +00002045 an effort to create a 100% JAXP-compatible Java wrapper for libxml2 and
2046 libxslt as part of GNU ClasspathX project.</li>
Daniel Veillard6d373a22003-11-04 10:26:43 +00002047 <li>Patrick McPhee provides Rexx bindings fof libxml2 and libxslt, look for
2048 <a href="http://www.interlog.com/~ptjm/software.html">RexxXML</a>.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002049</ul>
2050
Daniel Veillardc0801af2002-05-28 16:28:42 +00002051<p>The distribution includes a set of Python bindings, which are guaranteed
2052to be maintained as part of the library in the future, though the Python
Daniel Veillard41b01a82003-02-27 11:09:06 +00002053interface have not yet reached the completeness of the C API.</p>
Daniel Veillard7b4b2f92003-01-06 13:11:20 +00002054
Daniel Veillard27907c72002-12-16 16:05:58 +00002055<p><a href="mailto:stephane.bidoul@softwareag.com">Stéphane Bidoul</a>
Daniel Veillard7b4b2f92003-01-06 13:11:20 +00002056maintains <a href="http://users.skynet.be/sbi/libxml-python/">a Windows port
2057of the Python bindings</a>.</p>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002058
Daniel Veillard7ef0fcb2002-12-14 10:38:55 +00002059<p>Note to people interested in building bindings, the API is formalized as
2060<a href="libxml2-api.xml">an XML API description file</a> which allows to
2061automate a large part of the Python bindings, this includes function
Daniel Veillard7b4b2f92003-01-06 13:11:20 +00002062descriptions, enums, structures, typedefs, etc... The Python script used to
2063build the bindings is python/generator.py in the source distribution.</p>
Daniel Veillard7ef0fcb2002-12-14 10:38:55 +00002064
Daniel Veillardaf43f632002-03-08 15:05:20 +00002065<p>To install the Python bindings there are 2 options:</p>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +00002066<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002067 <li>If you use an RPM based distribution, simply install the <a
2068 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python
2069 RPM</a> (and if needed the <a
2070 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
2071 RPM</a>).</li>
2072 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python
2073 module distribution</a> corresponding to your installed version of
2074 libxml2 and libxslt. Note that to install it you will need both libxml2
2075 and libxslt installed and run "python setup.py build install" in the
2076 module tree.</li>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +00002077</ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002078
2079<p>The distribution includes a set of examples and regression tests for the
2080python bindings in the <code>python/tests</code> directory. Here are some
Daniel Veillard0b28e882002-07-24 23:47:05 +00002081excerpts from those tests:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002082
2083<h3>tst.py:</h3>
2084
2085<p>This is a basic test of the file interface and DOM navigation:</p>
MST 2003 John Fleck2dffb762003-11-29 04:41:24 +00002086<pre>import libxml2, sys
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002087
2088doc = libxml2.parseFile("tst.xml")
2089if doc.name != "tst.xml":
2090 print "doc.name failed"
2091 sys.exit(1)
2092root = doc.children
2093if root.name != "doc":
2094 print "root.name failed"
2095 sys.exit(1)
2096child = root.children
2097if child.name != "foo":
2098 print "child.name failed"
2099 sys.exit(1)
2100doc.freeDoc()</pre>
2101
Daniel Veillard0b28e882002-07-24 23:47:05 +00002102<p>The Python module is called libxml2; parseFile is the equivalent of
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002103xmlParseFile (most of the bindings are automatically generated, and the xml
2104prefix is removed and the casing convention are kept). All node seen at the
Daniel Veillard63d83142002-05-20 06:51:05 +00002105binding level share the same subset of accessors:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002106<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002107 <li><code>name</code> : returns the node name</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +00002108 <li><code>type</code> : returns a string indicating the node type</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002109 <li><code>content</code> : returns the content of the node, it is based on
2110 xmlNodeGetContent() and hence is recursive.</li>
2111 <li><code>parent</code> , <code>children</code>, <code>last</code>,
2112 <code>next</code>, <code>prev</code>, <code>doc</code>,
2113 <code>properties</code>: pointing to the associated element in the tree,
2114 those may return None in case no such link exists.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002115</ul>
2116
Daniel Veillard63d83142002-05-20 06:51:05 +00002117<p>Also note the need to explicitly deallocate documents with freeDoc() .
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002118Reference counting for libxml2 trees would need quite a lot of work to
2119function properly, and rather than risk memory leaks if not implemented
2120correctly it sounds safer to have an explicit function to free a tree. The
2121wrapper python objects like doc, root or child are them automatically garbage
2122collected.</p>
2123
2124<h3>validate.py:</h3>
2125
2126<p>This test check the validation interfaces and redirection of error
2127messages:</p>
2128<pre>import libxml2
2129
Daniel Veillard63d83142002-05-20 06:51:05 +00002130#deactivate error messages from the validation
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002131def noerr(ctx, str):
2132 pass
2133
2134libxml2.registerErrorHandler(noerr, None)
2135
2136ctxt = libxml2.createFileParserCtxt("invalid.xml")
2137ctxt.validate(1)
2138ctxt.parseDocument()
2139doc = ctxt.doc()
2140valid = ctxt.isValid()
2141doc.freeDoc()
2142if valid != 0:
Daniel Veillard63d83142002-05-20 06:51:05 +00002143 print "validity check failed"</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002144
2145<p>The first thing to notice is the call to registerErrorHandler(), it
2146defines a new error handler global to the library. It is used to avoid seeing
2147the error messages when trying to validate the invalid document.</p>
2148
2149<p>The main interest of that test is the creation of a parser context with
2150createFileParserCtxt() and how the behaviour can be changed before calling
Daniel Veillard63d83142002-05-20 06:51:05 +00002151parseDocument() . Similarly the informations resulting from the parsing phase
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002152are also available using context methods.</p>
2153
2154<p>Contexts like nodes are defined as class and the libxml2 wrappers maps the
2155C function interfaces in terms of objects method as much as possible. The
2156best to get a complete view of what methods are supported is to look at the
2157libxml2.py module containing all the wrappers.</p>
2158
2159<h3>push.py:</h3>
2160
2161<p>This test show how to activate the push parser interface:</p>
2162<pre>import libxml2
2163
2164ctxt = libxml2.createPushParser(None, "&lt;foo", 4, "test.xml")
2165ctxt.parseChunk("/&gt;", 2, 1)
2166doc = ctxt.doc()
2167
2168doc.freeDoc()</pre>
2169
Daniel Veillard63d83142002-05-20 06:51:05 +00002170<p>The context is created with a special call based on the
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002171xmlCreatePushParser() from the C library. The first argument is an optional
Daniel Veillard63d83142002-05-20 06:51:05 +00002172SAX callback object, then the initial set of data, the length and the name of
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002173the resource in case URI-References need to be computed by the parser.</p>
2174
2175<p>Then the data are pushed using the parseChunk() method, the last call
Daniel Veillard63d83142002-05-20 06:51:05 +00002176setting the third argument terminate to 1.</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002177
2178<h3>pushSAX.py:</h3>
2179
2180<p>this test show the use of the event based parsing interfaces. In this case
2181the parser does not build a document, but provides callback information as
2182the parser makes progresses analyzing the data being provided:</p>
2183<pre>import libxml2
2184log = ""
2185
2186class callback:
2187 def startDocument(self):
2188 global log
2189 log = log + "startDocument:"
2190
2191 def endDocument(self):
2192 global log
2193 log = log + "endDocument:"
2194
2195 def startElement(self, tag, attrs):
2196 global log
2197 log = log + "startElement %s %s:" % (tag, attrs)
2198
2199 def endElement(self, tag):
2200 global log
2201 log = log + "endElement %s:" % (tag)
2202
2203 def characters(self, data):
2204 global log
2205 log = log + "characters: %s:" % (data)
2206
2207 def warning(self, msg):
2208 global log
2209 log = log + "warning: %s:" % (msg)
2210
2211 def error(self, msg):
2212 global log
2213 log = log + "error: %s:" % (msg)
2214
2215 def fatalError(self, msg):
2216 global log
2217 log = log + "fatalError: %s:" % (msg)
2218
2219handler = callback()
2220
2221ctxt = libxml2.createPushParser(handler, "&lt;foo", 4, "test.xml")
2222chunk = " url='tst'&gt;b"
2223ctxt.parseChunk(chunk, len(chunk), 0)
2224chunk = "ar&lt;/foo&gt;"
2225ctxt.parseChunk(chunk, len(chunk), 1)
2226
Daniel Veillardfcbfa2d2002-02-21 17:54:27 +00002227reference = "startDocument:startElement foo {'url': 'tst'}:" + \
2228 "characters: bar:endElement foo:endDocument:"
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002229if log != reference:
2230 print "Error got: %s" % log
Daniel Veillard63d83142002-05-20 06:51:05 +00002231 print "Expected: %s" % reference</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002232
2233<p>The key object in that test is the handler, it provides a number of entry
2234points which can be called by the parser as it makes progresses to indicate
2235the information set obtained. The full set of callback is larger than what
2236the callback class in that specific example implements (see the SAX
2237definition for a complete list). The wrapper will only call those supplied by
2238the object when activated. The startElement receives the names of the element
Daniel Veillard63d83142002-05-20 06:51:05 +00002239and a dictionary containing the attributes carried by this element.</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002240
2241<p>Also note that the reference string generated from the callback shows a
2242single character call even though the string "bar" is passed to the parser
2243from 2 different call to parseChunk()</p>
2244
2245<h3>xpath.py:</h3>
2246
Daniel Veillard63d83142002-05-20 06:51:05 +00002247<p>This is a basic test of XPath wrappers support</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002248<pre>import libxml2
2249
2250doc = libxml2.parseFile("tst.xml")
2251ctxt = doc.xpathNewContext()
2252res = ctxt.xpathEval("//*")
2253if len(res) != 2:
2254 print "xpath query: wrong node set size"
2255 sys.exit(1)
2256if res[0].name != "doc" or res[1].name != "foo":
2257 print "xpath query: wrong node set value"
2258 sys.exit(1)
2259doc.freeDoc()
2260ctxt.xpathFreeContext()</pre>
2261
2262<p>This test parses a file, then create an XPath context to evaluate XPath
2263expression on it. The xpathEval() method execute an XPath query and returns
2264the result mapped in a Python way. String and numbers are natively converted,
2265and node sets are returned as a tuple of libxml2 Python nodes wrappers. Like
Daniel Veillard63d83142002-05-20 06:51:05 +00002266the document, the XPath context need to be freed explicitly, also not that
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002267the result of the XPath query may point back to the document tree and hence
2268the document must be freed after the result of the query is used.</p>
2269
2270<h3>xpathext.py:</h3>
2271
2272<p>This test shows how to extend the XPath engine with functions written in
2273python:</p>
2274<pre>import libxml2
2275
2276def foo(ctx, x):
2277 return x + 1
2278
2279doc = libxml2.parseFile("tst.xml")
2280ctxt = doc.xpathNewContext()
2281libxml2.registerXPathFunction(ctxt._o, "foo", None, foo)
2282res = ctxt.xpathEval("foo(1)")
2283if res != 2:
2284 print "xpath extension failure"
2285doc.freeDoc()
2286ctxt.xpathFreeContext()</pre>
2287
2288<p>Note how the extension function is registered with the context (but that
Daniel Veillard63d83142002-05-20 06:51:05 +00002289part is not yet finalized, this may change slightly in the future).</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002290
2291<h3>tstxpath.py:</h3>
2292
Daniel Veillard63d83142002-05-20 06:51:05 +00002293<p>This test is similar to the previous one but shows how the extension
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002294function can access the XPath evaluation context:</p>
2295<pre>def foo(ctx, x):
2296 global called
2297
2298 #
2299 # test that access to the XPath evaluation contexts
2300 #
2301 pctxt = libxml2.xpathParserContext(_obj=ctx)
2302 ctxt = pctxt.context()
2303 called = ctxt.function()
2304 return x + 1</pre>
2305
2306<p>All the interfaces around the XPath parser(or rather evaluation) context
2307are not finalized, but it should be sufficient to do contextual work at the
2308evaluation point.</p>
2309
2310<h3>Memory debugging:</h3>
2311
2312<p>last but not least, all tests starts with the following prologue:</p>
2313<pre>#memory debug specific
Daniel Veillardaf43f632002-03-08 15:05:20 +00002314libxml2.debugMemory(1)</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002315
2316<p>and ends with the following epilogue:</p>
2317<pre>#memory debug specific
2318libxml2.cleanupParser()
2319if libxml2.debugMemory(1) == 0:
2320 print "OK"
2321else:
2322 print "Memory leak %d bytes" % (libxml2.debugMemory(1))
2323 libxml2.dumpMemory()</pre>
2324
2325<p>Those activate the memory debugging interface of libxml2 where all
Daniel Veillard63d83142002-05-20 06:51:05 +00002326allocated block in the library are tracked. The prologue then cleans up the
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002327library state and checks that all allocated memory has been freed. If not it
2328calls dumpMemory() which saves that list in a <code>.memdump</code> file.</p>
Daniel Veillard82687162001-01-22 15:32:01 +00002329
Daniel Veillard8a469172003-06-12 16:05:07 +00002330<h2><a name="architecture">libxml2 architecture</a></h2>
Daniel Veillard4540be42000-08-19 16:40:28 +00002331
Daniel Veillard560c2a42003-07-06 21:13:49 +00002332<p>Libxml2 is made of multiple components; some of them are optional, and
2333most of the block interfaces are public. The main components are:</p>
Daniel Veillard4540be42000-08-19 16:40:28 +00002334<ul>
2335 <li>an Input/Output layer</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +00002336 <li>FTP and HTTP client layers (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00002337 <li>an Internationalization layer managing the encodings support</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +00002338 <li>a URI module</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00002339 <li>the XML parser and its basic SAX interface</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +00002340 <li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00002341 <li>a SAX tree module to build an in-memory DOM representation</li>
2342 <li>a tree module to manipulate the DOM representation</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +00002343 <li>a validation module using the DOM representation (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00002344 <li>an XPath module for global lookup in a DOM representation
Daniel Veillard91e9d582001-02-26 07:31:12 +00002345 (optional)</li>
2346 <li>a debug module (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00002347</ul>
2348
2349<p>Graphically this gives the following:</p>
2350
2351<p><img src="libxml.gif" alt="a graphical view of the various"></p>
2352
2353<p></p>
2354
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00002355<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002356
2357<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +00002358returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00002359<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +00002360as the file name, the document type, and a <strong>children</strong> pointer
2361which is the root of the document (or more exactly the first child under the
2362root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard91e9d582001-02-26 07:31:12 +00002363chained in double-linked lists of siblings and with a children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +00002364relationship. An xmlNode can also carry properties (a chain of xmlAttr
2365structures). An attribute may have a value which is a list of TEXT or
2366ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002367
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002368<p>Here is an example (erroneous with respect to the XML spec since there
2369should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002370
2371<p><img src="structure.gif" alt=" structure.gif "></p>
2372
2373<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +00002374called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00002375prints them back as parsed. This is useful for detecting errors both in XML
2376code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard91e9d582001-02-26 07:31:12 +00002377which prints the actual in-memory structure of the document; here is the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00002378result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002379<pre>DOCUMENT
2380version=1.0
2381standalone=true
2382 ELEMENT EXAMPLE
2383 ATTRIBUTE prop1
2384 TEXT
2385 content=gnome is great
2386 ATTRIBUTE prop2
2387 ENTITY_REF
2388 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +00002389 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +00002390 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002391 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +00002392 TEXT
2393 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002394 ELEMENT chapter
2395 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +00002396 TEXT
2397 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002398 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +00002399 TEXT
2400 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002401 ELEMENT image
2402 ATTRIBUTE href
2403 TEXT
2404 content=linus.gif
2405 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +00002406 TEXT
2407 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002408
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002409<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +00002410
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00002411<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00002412
Daniel Veillard402e8c82000-02-29 22:57:47 +00002413<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002414memory. In that case (and if you don't expect to save back the XML document
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00002415loaded using libxml), it's better to use the SAX interface of libxml. SAX is
2416a <strong>callback-based interface</strong> to the parser. Before parsing,
2417the application layer registers a customized set of callbacks which are
2418called by the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00002419
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002420<p>To get more detailed step-by-step guidance on using the SAX interface of
Daniel Veillard4540be42000-08-19 16:40:28 +00002421libxml, see the <a
2422href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
2423documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002424Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00002425
2426<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
2427program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002428binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +00002429distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002430testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00002431<pre>SAX.setDocumentLocator()
2432SAX.startDocument()
2433SAX.getEntity(amp)
2434SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
2435SAX.characters( , 3)
2436SAX.startElement(head)
2437SAX.characters( , 4)
2438SAX.startElement(title)
2439SAX.characters(Welcome to Gnome, 16)
2440SAX.endElement(title)
2441SAX.characters( , 3)
2442SAX.endElement(head)
2443SAX.characters( , 3)
2444SAX.startElement(chapter)
2445SAX.characters( , 4)
2446SAX.startElement(title)
2447SAX.characters(The Linux adventure, 19)
2448SAX.endElement(title)
2449SAX.characters( , 4)
2450SAX.startElement(p)
2451SAX.characters(bla bla bla ..., 15)
2452SAX.endElement(p)
2453SAX.characters( , 4)
2454SAX.startElement(image, href='linus.gif')
2455SAX.endElement(image)
2456SAX.characters( , 4)
2457SAX.startElement(p)
2458SAX.characters(..., 3)
2459SAX.endElement(p)
2460SAX.characters( , 3)
2461SAX.endElement(chapter)
2462SAX.characters( , 1)
2463SAX.endElement(EXAMPLE)
2464SAX.endDocument()</pre>
2465
Daniel Veillard8a469172003-06-12 16:05:07 +00002466<p>Most of the other interfaces of libxml2 are based on the DOM tree-building
Daniel Veillardec70e912001-02-26 20:10:45 +00002467facility, so nearly everything up to the end of this document presupposes the
2468use of the standard DOM tree build. Note that the DOM tree itself is built by
2469a set of registered default callbacks, without internal specific
2470interface.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00002471
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002472<h2><a name="Validation">Validation &amp; DTDs</a></h2>
2473
2474<p>Table of Content:</p>
2475<ol>
2476 <li><a href="#General5">General overview</a></li>
2477 <li><a href="#definition">The definition</a></li>
2478 <li><a href="#Simple">Simple rules</a>
2479 <ol>
Daniel Veillard9c466822001-10-25 12:03:39 +00002480 <li><a href="#reference">How to reference a DTD from a document</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002481 <li><a href="#Declaring">Declaring elements</a></li>
2482 <li><a href="#Declaring1">Declaring attributes</a></li>
2483 </ol>
2484 </li>
2485 <li><a href="#Some">Some examples</a></li>
2486 <li><a href="#validate">How to validate</a></li>
2487 <li><a href="#Other">Other resources</a></li>
2488</ol>
2489
2490<h3><a name="General5">General overview</a></h3>
2491
2492<p>Well what is validation and what is a DTD ?</p>
2493
2494<p>DTD is the acronym for Document Type Definition. This is a description of
Daniel Veillard63d83142002-05-20 06:51:05 +00002495the content for a family of XML files. This is part of the XML 1.0
Daniel Veillard0b28e882002-07-24 23:47:05 +00002496specification, and allows one to describe and verify that a given document
2497instance conforms to the set of rules detailing its structure and content.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002498
2499<p>Validation is the process of checking a document against a DTD (more
2500generally against a set of construction rules).</p>
2501
2502<p>The validation process and building DTDs are the two most difficult parts
Daniel Veillard0b28e882002-07-24 23:47:05 +00002503of the XML life cycle. Briefly a DTD defines all the possible elements to be
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002504found within your document, what is the formal shape of your document tree
Daniel Veillard0b28e882002-07-24 23:47:05 +00002505(by defining the allowed content of an element; either text, a regular
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002506expression for the allowed list of children, or mixed content i.e. both text
Daniel Veillard42766c02002-08-22 20:52:17 +00002507and children). The DTD also defines the valid attributes for all elements and
2508the types of those attributes.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002509
2510<h3><a name="definition1">The definition</a></h3>
2511
2512<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a
2513href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of
2514Rev1</a>):</p>
2515<ul>
2516 <li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring
2517 elements</a></li>
2518 <li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring
2519 attributes</a></li>
2520</ul>
2521
2522<p>(unfortunately) all this is inherited from the SGML world, the syntax is
2523ancient...</p>
2524
2525<h3><a name="Simple1">Simple rules</a></h3>
2526
Daniel Veillard42766c02002-08-22 20:52:17 +00002527<p>Writing DTDs can be done in many ways. The rules to build them if you need
2528something permanent or something which can evolve over time can be radically
2529different. Really complex DTDs like DocBook ones are flexible but quite
2530harder to design. I will just focus on DTDs for a formats with a fixed simple
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002531structure. It is just a set of basic rules, and definitely not exhaustive nor
Daniel Veillard63d83142002-05-20 06:51:05 +00002532usable for complex DTD design.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002533
2534<h4><a name="reference1">How to reference a DTD from a document</a>:</h4>
2535
2536<p>Assuming the top element of the document is <code>spec</code> and the dtd
2537is placed in the file <code>mydtd</code> in the subdirectory
2538<code>dtds</code> of the directory from where the document were loaded:</p>
2539
2540<p><code>&lt;!DOCTYPE spec SYSTEM "dtds/mydtd"&gt;</code></p>
2541
2542<p>Notes:</p>
2543<ul>
Daniel Veillard0b28e882002-07-24 23:47:05 +00002544 <li>The system string is actually an URI-Reference (as defined in <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002545 href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a
Daniel Veillard0b28e882002-07-24 23:47:05 +00002546 full URL string indicating the location of your DTD on the Web. This is a
2547 really good thing to do if you want others to validate your document.</li>
2548 <li>It is also possible to associate a <code>PUBLIC</code> identifier (a
Daniel Veillard63d83142002-05-20 06:51:05 +00002549 magic string) so that the DTD is looked up in catalogs on the client side
Daniel Veillard0b28e882002-07-24 23:47:05 +00002550 without having to locate it on the web.</li>
2551 <li>A DTD contains a set of element and attribute declarations, but they
Daniel Veillard63d83142002-05-20 06:51:05 +00002552 don't define what the root of the document should be. This is explicitly
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002553 told to the parser/validator as the first element of the
2554 <code>DOCTYPE</code> declaration.</li>
2555</ul>
2556
2557<h4><a name="Declaring2">Declaring elements</a>:</h4>
2558
2559<p>The following declares an element <code>spec</code>:</p>
2560
2561<p><code>&lt;!ELEMENT spec (front, body, back?)&gt;</code></p>
2562
Daniel Veillard0b28e882002-07-24 23:47:05 +00002563<p>It also expresses that the spec element contains one <code>front</code>,
Daniel Veillardc0801af2002-05-28 16:28:42 +00002564one <code>body</code> and one optional <code>back</code> children elements in
2565this order. The declaration of one element of the structure and its content
2566are done in a single declaration. Similarly the following declares
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002567<code>div1</code> elements:</p>
2568
Daniel Veillard51737272002-01-23 23:10:38 +00002569<p><code>&lt;!ELEMENT div1 (head, (p | list | note)*, div2?)&gt;</code></p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002570
Daniel Veillard0b28e882002-07-24 23:47:05 +00002571<p>which means div1 contains one <code>head</code> then a series of optional
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002572<code>p</code>, <code>list</code>s and <code>note</code>s and then an
2573optional <code>div2</code>. And last but not least an element can contain
2574text:</p>
2575
2576<p><code>&lt;!ELEMENT b (#PCDATA)&gt;</code></p>
2577
2578<p><code>b</code> contains text or being of mixed content (text and elements
2579in no particular order):</p>
2580
2581<p><code>&lt;!ELEMENT p (#PCDATA|a|ul|b|i|em)*&gt;</code></p>
2582
2583<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>,
2584<code>b</code>, <code>i </code>or <code>em</code> elements in no particular
2585order.</p>
2586
2587<h4><a name="Declaring1">Declaring attributes</a>:</h4>
2588
Daniel Veillard0b28e882002-07-24 23:47:05 +00002589<p>Again the attributes declaration includes their content definition:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002590
2591<p><code>&lt;!ATTLIST termdef name CDATA #IMPLIED&gt;</code></p>
2592
2593<p>means that the element <code>termdef</code> can have a <code>name</code>
Daniel Veillard63d83142002-05-20 06:51:05 +00002594attribute containing text (<code>CDATA</code>) and which is optional
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002595(<code>#IMPLIED</code>). The attribute value can also be defined within a
2596set:</p>
2597
2598<p><code>&lt;!ATTLIST list type (bullets|ordered|glossary)
2599"ordered"&gt;</code></p>
2600
2601<p>means <code>list</code> element have a <code>type</code> attribute with 3
2602allowed values "bullets", "ordered" or "glossary" and which default to
Daniel Veillard63d83142002-05-20 06:51:05 +00002603"ordered" if the attribute is not explicitly specified.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002604
2605<p>The content type of an attribute can be text (<code>CDATA</code>),
2606anchor/reference/references
2607(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies)
2608(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s)
2609(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a
2610<code>chapter</code> element can have an optional <code>id</code> attribute
2611of type <code>ID</code>, usable for reference from attribute of type
2612IDREF:</p>
2613
2614<p><code>&lt;!ATTLIST chapter id ID #IMPLIED&gt;</code></p>
2615
2616<p>The last value of an attribute definition can be <code>#REQUIRED
2617</code>meaning that the attribute has to be given, <code>#IMPLIED</code>
2618meaning that it is optional, or the default value (possibly prefixed by
2619<code>#FIXED</code> if it is the only allowed).</p>
2620
2621<p>Notes:</p>
2622<ul>
Daniel Veillard0b28e882002-07-24 23:47:05 +00002623 <li>Usually the attributes pertaining to a given element are declared in a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002624 single expression, but it is just a convention adopted by a lot of DTD
2625 writers:
2626 <pre>&lt;!ATTLIST termdef
2627 id ID #REQUIRED
2628 name CDATA #IMPLIED&gt;</pre>
2629 <p>The previous construct defines both <code>id</code> and
Daniel Veillard0b28e882002-07-24 23:47:05 +00002630 <code>name</code> attributes for the element <code>termdef</code>.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002631 </li>
2632</ul>
2633
2634<h3><a name="Some1">Some examples</a></h3>
2635
Daniel Veillard8a469172003-06-12 16:05:07 +00002636<p>The directory <code>test/valid/dtds/</code> in the libxml2 distribution
Daniel Veillard42766c02002-08-22 20:52:17 +00002637contains some complex DTD examples. The example in the file
2638<code>test/valid/dia.xml</code> shows an XML file where the simple DTD is
2639directly included within the document.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002640
2641<h3><a name="validate1">How to validate</a></h3>
2642
Daniel Veillard0b28e882002-07-24 23:47:05 +00002643<p>The simplest way is to use the xmllint program included with libxml. The
2644<code>--valid</code> option turns-on validation of the files given as input.
2645For example the following validates a copy of the first revision of the XML
Daniel Veillardb8cfbd12001-10-25 10:53:28 +000026461.0 specification:</p>
2647
2648<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p>
2649
Daniel Veillard0b28e882002-07-24 23:47:05 +00002650<p>the -- noout is used to disable output of the resulting tree.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002651
Daniel Veillard42766c02002-08-22 20:52:17 +00002652<p>The <code>--dtdvalid dtd</code> allows validation of the document(s)
2653against a given DTD.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002654
Daniel Veillard8a469172003-06-12 16:05:07 +00002655<p>Libxml2 exports an API to handle DTDs and validation, check the <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002656href="http://xmlsoft.org/html/libxml-valid.html">associated
2657description</a>.</p>
2658
2659<h3><a name="Other1">Other resources</a></h3>
2660
2661<p>DTDs are as old as SGML. So there may be a number of examples on-line, I
2662will just list one for now, others pointers welcome:</p>
2663<ul>
2664 <li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li>
2665</ul>
2666
2667<p>I suggest looking at the examples found under test/valid/dtd and any of
2668the large number of books available on XML. The dia example in test/valid
2669should be both simple and complete enough to allow you to build your own.</p>
2670
2671<p></p>
2672
2673<h2><a name="Memory">Memory Management</a></h2>
2674
2675<p>Table of Content:</p>
2676<ol>
2677 <li><a href="#General3">General overview</a></li>
Daniel Veillard8a469172003-06-12 16:05:07 +00002678 <li><a href="#setting">Setting libxml2 set of memory routines</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002679 <li><a href="#cleanup">Cleaning up after parsing</a></li>
2680 <li><a href="#Debugging">Debugging routines</a></li>
2681 <li><a href="#General4">General memory requirements</a></li>
2682</ol>
2683
2684<h3><a name="General3">General overview</a></h3>
2685
2686<p>The module <code><a
2687href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
Daniel Veillard8a469172003-06-12 16:05:07 +00002688provides the interfaces to the libxml2 memory system:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002689<ul>
Daniel Veillard8a469172003-06-12 16:05:07 +00002690 <li>libxml2 does not use the libc memory allocator directly but xmlFree(),
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002691 xmlMalloc() and xmlRealloc()</li>
2692 <li>those routines can be reallocated to a specific set of routine, by
2693 default the libc ones i.e. free(), malloc() and realloc()</li>
2694 <li>the xmlmemory.c module includes a set of debugging routine</li>
2695</ul>
2696
Daniel Veillard8a469172003-06-12 16:05:07 +00002697<h3><a name="setting">Setting libxml2 set of memory routines</a></h3>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002698
2699<p>It is sometimes useful to not use the default memory allocator, either for
2700debugging, analysis or to implement a specific behaviour on memory management
2701(like on embedded systems). Two function calls are available to do so:</p>
2702<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002703 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet
2704 ()</a> which return the current set of functions in use by the parser</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002705 <li><a
2706 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002707 which allow to set up a new set of memory allocation functions</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002708</ul>
2709
2710<p>Of course a call to xmlMemSetup() should probably be done before calling
Daniel Veillard8a469172003-06-12 16:05:07 +00002711any other libxml2 routines (unless you are sure your allocations routines are
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002712compatibles).</p>
2713
2714<h3><a name="cleanup">Cleaning up after parsing</a></h3>
2715
Daniel Veillard8a469172003-06-12 16:05:07 +00002716<p>Libxml2 is not stateless, there is a few set of memory structures needing
Daniel Veillard63d83142002-05-20 06:51:05 +00002717allocation before the parser is fully functional (some encoding structures
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002718for example). This also mean that once parsing is finished there is a tiny
2719amount of memory (a few hundred bytes) which can be recollected if you don't
2720reuse the parser immediately:</p>
2721<ul>
2722 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser
Daniel Veillardaf43f632002-03-08 15:05:20 +00002723 ()</a> is a centralized routine to free the parsing states. Note that it
2724 won't deallocate any produced tree if any (use the xmlFreeDoc() and
2725 related routines for this).</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002726 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser
Daniel Veillardaf43f632002-03-08 15:05:20 +00002727 ()</a> is the dual routine allowing to preallocate the parsing state
2728 which can be useful for example to avoid initialization reentrancy
Daniel Veillard8a469172003-06-12 16:05:07 +00002729 problems when using libxml2 in multithreaded applications</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002730</ul>
2731
2732<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild
2733at the next invocation of parser routines, but be careful of the consequences
2734in multithreaded applications.</p>
2735
2736<h3><a name="Debugging">Debugging routines</a></h3>
2737
Daniel Veillard8a469172003-06-12 16:05:07 +00002738<p>When configured using --with-mem-debug flag (off by default), libxml2 uses
Daniel Veillard63d83142002-05-20 06:51:05 +00002739a set of memory allocation debugging routines keeping track of all allocated
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002740blocks and the location in the code where the routine was called. A couple of
2741other debugging routines allow to dump the memory allocated infos to a file
2742or call a specific routine when a given block number is allocated:</p>
2743<ul>
2744 <li><a
2745 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002746 <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002747 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>
2748 and <a
2749 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>
2750 are the memory debugging replacement allocation routines</li>
2751 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump
Daniel Veillardaf43f632002-03-08 15:05:20 +00002752 ()</a> dumps all the informations about the allocated memory block lefts
2753 in the <code>.memdump</code> file</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002754</ul>
2755
Daniel Veillard8a469172003-06-12 16:05:07 +00002756<p>When developing libxml2 memory debug is enabled, the tests programs call
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002757xmlMemoryDump () and the "make test" regression tests will check for any
2758memory leak during the full regression test sequence, this helps a lot
Daniel Veillard8a469172003-06-12 16:05:07 +00002759ensuring that libxml2 does not leak memory and bullet proof memory
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002760allocations use (some libc implementations are known to be far too permissive
2761resulting in major portability problems!).</p>
2762
2763<p>If the .memdump reports a leak, it displays the allocation function and
2764also tries to give some informations about the content and structure of the
2765allocated blocks left. This is sufficient in most cases to find the culprit,
Daniel Veillard63d83142002-05-20 06:51:05 +00002766but not always. Assuming the allocation problem is reproducible, it is
2767possible to find more easily:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002768<ol>
2769 <li>write down the block number xxxx not allocated</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00002770 <li>export the environment variable XML_MEM_BREAKPOINT=xxxx , the easiest
Daniel Veillard75794822002-04-11 16:24:32 +00002771 when using GDB is to simply give the command
2772 <p><code>set environment XML_MEM_BREAKPOINT xxxx</code></p>
2773 <p>before running the program.</p>
2774 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002775 <li>run the program under a debugger and set a breakpoint on
2776 xmlMallocBreakpoint() a specific function called when this precise block
2777 is allocated</li>
2778 <li>when the breakpoint is reached you can then do a fine analysis of the
2779 allocation an step to see the condition resulting in the missing
2780 deallocation.</li>
2781</ol>
2782
Daniel Veillard8a469172003-06-12 16:05:07 +00002783<p>I used to use a commercial tool to debug libxml2 memory problems but after
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002784noticing that it was not detecting memory leaks that simple mechanism was
Daniel Veillard75794822002-04-11 16:24:32 +00002785used and proved extremely efficient until now. Lately I have also used <a
2786href="http://developer.kde.org/~sewardj/">valgrind</a> with quite some
2787success, it is tied to the i386 architecture since it works by emulating the
2788processor and instruction set, it is slow but extremely efficient, i.e. it
2789spot memory usage errors in a very precise way.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002790
2791<h3><a name="General4">General memory requirements</a></h3>
2792
Daniel Veillard8a469172003-06-12 16:05:07 +00002793<p>How much libxml2 memory require ? It's hard to tell in average it depends
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002794of a number of things:</p>
2795<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +00002796 <li>the parser itself should work in a fixed amount of memory, except for
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002797 information maintained about the stacks of names and entities locations.
2798 The I/O and encoding handlers will probably account for a few KBytes.
2799 This is true for both the XML and HTML parser (though the HTML parser
2800 need more state).</li>
2801 <li>If you are generating the DOM tree then memory requirements will grow
Daniel Veillard63d83142002-05-20 06:51:05 +00002802 nearly linear with the size of the data. In general for a balanced
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002803 textual document the internal memory requirement is about 4 times the
Daniel Veillard63d83142002-05-20 06:51:05 +00002804 size of the UTF8 serialization of this document (example the XML-1.0
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002805 recommendation is a bit more of 150KBytes and takes 650KBytes of main
2806 memory when parsed). Validation will add a amount of memory required for
2807 maintaining the external Dtd state which should be linear with the
2808 complexity of the content model defined by the Dtd</li>
Daniel Veillardce192eb2003-04-16 15:58:05 +00002809 <li>If you need to work with fixed memory requirements or don't need the
2810 full DOM tree then using the <a href="xmlreader.html">xmlReader
2811 interface</a> is probably the best way to proceed, it still allows to
2812 validate or operate on subset of the tree if needed.</li>
Daniel Veillard8a469172003-06-12 16:05:07 +00002813 <li>If you don't care about the advanced features of libxml2 like
Daniel Veillardce192eb2003-04-16 15:58:05 +00002814 validation, DOM, XPath or XPointer, don't use entities, need to work with
2815 fixed memory requirements, and try to get the fastest parsing possible
2816 then the SAX interface should be used, but it has known restrictions.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002817</ul>
2818
2819<p></p>
2820
2821<h2><a name="Encodings">Encodings support</a></h2>
2822
2823<p>Table of Content:</p>
2824<ol>
2825 <li><a href="encoding.html#What">What does internationalization support
2826 mean ?</a></li>
2827 <li><a href="encoding.html#internal">The internal encoding, how and
2828 why</a></li>
2829 <li><a href="encoding.html#implemente">How is it implemented ?</a></li>
2830 <li><a href="encoding.html#Default">Default supported encodings</a></li>
2831 <li><a href="encoding.html#extend">How to extend the existing
2832 support</a></li>
2833</ol>
2834
2835<h3><a name="What">What does internationalization support mean ?</a></h3>
2836
Daniel Veillarde6e59cd2003-12-24 11:56:44 +00002837<p>If you are not really familiar with Internationalization (usual shortcut
2838is I18N) , Unicode, characters and glyphs, I suggest you read a <a
Daniel Veillard238836e2003-04-07 22:57:29 +00002839href="http://www.tbray.org/ongoing/When/200x/2003/04/06/Unicode">presentation</a>
2840by Tim Bray on Unicode and why you should care about it.</p>
2841
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002842<p>XML was designed from the start to allow the support of any character set
2843by using Unicode. Any conformant XML parser has to support the UTF-8 and
2844UTF-16 default encodings which can both express the full unicode ranges. UTF8
Daniel Veillard63d83142002-05-20 06:51:05 +00002845is a variable length encoding whose greatest points are to reuse the same
2846encoding for ASCII and to save space for Western encodings, but it is a bit
Daniel Veillardabfca612004-01-07 23:38:02 +00002847more complex to handle in practice. UTF-16 use 2 bytes per character (and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002848sometimes combines two pairs), it makes implementation easier, but looks a
2849bit overkill for Western languages encoding. Moreover the XML specification
Daniel Veillard189f46b2004-01-25 21:03:04 +00002850allows the document to be encoded in other encodings at the condition that
2851they are clearly labeled as such. For example the following is a wellformed
2852XML document encoded in ISO-8859-1 and using accentuated letters that we
2853French like for both markup and content:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002854<pre>&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2855&lt;très&gt;là&lt;/très&gt;</pre>
2856
Daniel Veillard8a469172003-06-12 16:05:07 +00002857<p>Having internationalization support in libxml2 means the following:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002858<ul>
2859 <li>the document is properly parsed</li>
2860 <li>informations about it's encoding are saved</li>
2861 <li>it can be modified</li>
2862 <li>it can be saved in its original encoding</li>
Daniel Veillard8a469172003-06-12 16:05:07 +00002863 <li>it can also be saved in another encoding supported by libxml2 (for
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002864 example straight UTF8 or even an ASCII form)</li>
2865</ul>
2866
Daniel Veillard8a469172003-06-12 16:05:07 +00002867<p>Another very important point is that the whole libxml2 API, with the
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002868exception of a few routines to read with a specific encoding or save to a
2869specific encoding, is completely agnostic about the original encoding of the
2870document.</p>
2871
Daniel Veillard8a469172003-06-12 16:05:07 +00002872<p>It should be noted too that the HTML parser embedded in libxml2 now obey
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002873the same rules too, the following document will be (as of 2.2.2) handled in
Daniel Veillard8a469172003-06-12 16:05:07 +00002874an internationalized fashion by libxml2 too:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002875<pre>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
2876 "http://www.w3.org/TR/REC-html40/loose.dtd"&gt;
2877&lt;html lang="fr"&gt;
2878&lt;head&gt;
2879 &lt;META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"&gt;
2880&lt;/head&gt;
2881&lt;body&gt;
2882&lt;p&gt;W3C crée des standards pour le Web.&lt;/body&gt;
2883&lt;/html&gt;</pre>
2884
2885<h3><a name="internal">The internal encoding, how and why</a></h3>
2886
Daniel Veillardabfca612004-01-07 23:38:02 +00002887<p>One of the core decisions was to force all documents to be converted to a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002888default internal encoding, and that encoding to be UTF-8, here are the
Daniel Veillardabfca612004-01-07 23:38:02 +00002889rationales for those choices:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002890<ul>
2891 <li>keeping the native encoding in the internal form would force the libxml
2892 users (or the code associated) to be fully aware of the encoding of the
2893 original document, for examples when adding a text node to a document,
2894 the content would have to be provided in the document encoding, i.e. the
2895 client code would have to check it before hand, make sure it's conformant
2896 to the encoding, etc ... Very hard in practice, though in some specific
2897 cases this may make sense.</li>
2898 <li>the second decision was which encoding. From the XML spec only UTF8 and
2899 UTF16 really makes sense as being the two only encodings for which there
Daniel Veillard63d83142002-05-20 06:51:05 +00002900 is mandatory support. UCS-4 (32 bits fixed size encoding) could be
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002901 considered an intelligent choice too since it's a direct Unicode mapping
2902 support. I selected UTF-8 on the basis of efficiency and compatibility
2903 with surrounding software:
2904 <ul>
2905 <li>UTF-8 while a bit more complex to convert from/to (i.e. slightly
2906 more costly to import and export CPU wise) is also far more compact
2907 than UTF-16 (and UCS-4) for a majority of the documents I see it used
2908 for right now (RPM RDF catalogs, advogato data, various configuration
2909 file formats, etc.) and the key point for today's computer
2910 architecture is efficient uses of caches. If one nearly double the
2911 memory requirement to store the same amount of data, this will trash
2912 caches (main memory/external caches/internal caches) and my take is
2913 that this harms the system far more than the CPU requirements needed
2914 for the conversion to UTF-8</li>
Daniel Veillard8a469172003-06-12 16:05:07 +00002915 <li>Most of libxml2 version 1 users were using it with straight ASCII
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002916 most of the time, doing the conversion with an internal encoding
2917 requiring all their code to be rewritten was a serious show-stopper
2918 for using UTF-16 or UCS-4.</li>
2919 <li>UTF-8 is being used as the de-facto internal encoding standard for
2920 related code like the <a href="http://www.pango.org/">pango</a>
Daniel Veillardabfca612004-01-07 23:38:02 +00002921 upcoming Gnome text widget, and a lot of Unix code (yet another place
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002922 where Unix programmer base takes a different approach from Microsoft
2923 - they are using UTF-16)</li>
2924 </ul>
2925 </li>
2926</ul>
2927
Daniel Veillard8a469172003-06-12 16:05:07 +00002928<p>What does this mean in practice for the libxml2 user:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002929<ul>
Daniel Veillard8a469172003-06-12 16:05:07 +00002930 <li>xmlChar, the libxml2 data type is a byte, those bytes must be assembled
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002931 as UTF-8 valid strings. The proper way to terminate an xmlChar * string
2932 is simply to append 0 byte, as usual.</li>
2933 <li>One just need to make sure that when using chars outside the ASCII set,
2934 the values has been properly converted to UTF-8</li>
2935</ul>
2936
2937<h3><a name="implemente">How is it implemented ?</a></h3>
2938
2939<p>Let's describe how all this works within libxml, basically the I18N
2940(internationalization) support get triggered only during I/O operation, i.e.
2941when reading a document or saving one. Let's look first at the reading
2942sequence:</p>
2943<ol>
2944 <li>when a document is processed, we usually don't know the encoding, a
Daniel Veillard189f46b2004-01-25 21:03:04 +00002945 simple heuristic allows to detect UTF-16 and UCS-4 from encodings where
2946 the ASCII range (0-0x7F) maps with ASCII</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002947 <li>the xml declaration if available is parsed, including the encoding
2948 declaration. At that point, if the autodetected encoding is different
2949 from the one declared a call to xmlSwitchEncoding() is issued.</li>
2950 <li>If there is no encoding declaration, then the input has to be in either
2951 UTF-8 or UTF-16, if it is not then at some point when processing the
2952 input, the converter/checker of UTF-8 form will raise an encoding error.
2953 You may end-up with a garbled document, or no document at all ! Example:
2954 <pre>~/XML -&gt; ./xmllint err.xml
2955err.xml:1: error: Input is not proper UTF-8, indicate encoding !
2956&lt;très&gt;là&lt;/très&gt;
2957 ^
2958err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C
2959&lt;très&gt;là&lt;/très&gt;
2960 ^</pre>
2961 </li>
Daniel Veillard63d83142002-05-20 06:51:05 +00002962 <li>xmlSwitchEncoding() does an encoding name lookup, canonicalize it, and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002963 then search the default registered encoding converters for that encoding.
2964 If it's not within the default set and iconv() support has been compiled
2965 it, it will ask iconv for such an encoder. If this fails then the parser
2966 will report an error and stops processing:
2967 <pre>~/XML -&gt; ./xmllint err2.xml
2968err2.xml:1: error: Unsupported encoding UnsupportedEnc
2969&lt;?xml version="1.0" encoding="UnsupportedEnc"?&gt;
2970 ^</pre>
2971 </li>
Daniel Veillard46c5c1d2002-05-20 07:15:54 +00002972 <li>From that point the encoder processes progressively the input (it is
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002973 plugged as a front-end to the I/O module) for that entity. It captures
Daniel Veillardabfca612004-01-07 23:38:02 +00002974 and converts on-the-fly the document to be parsed to UTF-8. The parser
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002975 itself just does UTF-8 checking of this input and process it
2976 transparently. The only difference is that the encoding information has
2977 been added to the parsing context (more precisely to the input
2978 corresponding to this entity).</li>
2979 <li>The result (when using DOM) is an internal form completely in UTF-8
2980 with just an encoding information on the document node.</li>
2981</ol>
2982
Daniel Veillard63d83142002-05-20 06:51:05 +00002983<p>Ok then what happens when saving the document (assuming you
2984collected/built an xmlDoc DOM like structure) ? It depends on the function
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002985called, xmlSaveFile() will just try to save in the original encoding, while
2986xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given
2987encoding:</p>
2988<ol>
Daniel Veillard8a469172003-06-12 16:05:07 +00002989 <li>if no encoding is given, libxml2 will look for an encoding value
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002990 associated to the document and if it exists will try to save to that
2991 encoding,
2992 <p>otherwise everything is written in the internal form, i.e. UTF-8</p>
2993 </li>
2994 <li>so if an encoding was specified, either at the API level or on the
Daniel Veillard8a469172003-06-12 16:05:07 +00002995 document, libxml2 will again canonicalize the encoding name, lookup for a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002996 converter in the registered set or through iconv. If not found the
2997 function will return an error code</li>
2998 <li>the converter is placed before the I/O buffer layer, as another kind of
Daniel Veillard8a469172003-06-12 16:05:07 +00002999 buffer, then libxml2 will simply push the UTF-8 serialization to through
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003000 that buffer, which will then progressively be converted and pushed onto
3001 the I/O layer.</li>
3002 <li>It is possible that the converter code fails on some input, for example
Daniel Veillard63d83142002-05-20 06:51:05 +00003003 trying to push an UTF-8 encoded Chinese character through the UTF-8 to
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003004 ISO-8859-1 converter won't work. Since the encoders are progressive they
3005 will just report the error and the number of bytes converted, at that
Daniel Veillard8a469172003-06-12 16:05:07 +00003006 point libxml2 will decode the offending character, remove it from the
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003007 buffer and replace it with the associated charRef encoding &amp;#123; and
Daniel Veillard63d83142002-05-20 06:51:05 +00003008 resume the conversion. This guarantees that any document will be saved
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003009 without losses (except for markup names where this is not legal, this is
Daniel Veillard63d83142002-05-20 06:51:05 +00003010 a problem in the current version, in practice avoid using non-ascii
Daniel Veillard189f46b2004-01-25 21:03:04 +00003011 characters for tag or attribute names). A special "ascii" encoding name
3012 is used to save documents to a pure ascii form can be used when
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003013 portability is really crucial</li>
3014</ol>
3015
Daniel Veillardabfca612004-01-07 23:38:02 +00003016<p>Here are a few examples based on the same test document:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003017<pre>~/XML -&gt; ./xmllint isolat1
3018&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
3019&lt;très&gt;là&lt;/très&gt;
3020~/XML -&gt; ./xmllint --encode UTF-8 isolat1
3021&lt;?xml version="1.0" encoding="UTF-8"?&gt;
3022&lt;très&gt;là  &lt;/très&gt;
3023~/XML -&gt; </pre>
3024
3025<p>The same processing is applied (and reuse most of the code) for HTML I18N
3026processing. Looking up and modifying the content encoding is a bit more
3027difficult since it is located in a &lt;meta&gt; tag under the &lt;head&gt;,
3028so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have
3029been provided. The parser also attempts to switch encoding on the fly when
3030detecting such a tag on input. Except for that the processing is the same
3031(and again reuses the same code).</p>
3032
3033<h3><a name="Default">Default supported encodings</a></h3>
3034
Daniel Veillard8a469172003-06-12 16:05:07 +00003035<p>libxml2 has a set of default converters for the following encodings
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003036(located in encoding.c):</p>
3037<ol>
3038 <li>UTF-8 is supported by default (null handlers)</li>
3039 <li>UTF-16, both little and big endian</li>
3040 <li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li>
3041 <li>ASCII, useful mostly for saving</li>
3042 <li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML
3043 predefined entities like &amp;copy; for the Copyright sign.</li>
3044</ol>
3045
Daniel Veillardc0801af2002-05-28 16:28:42 +00003046<p>More over when compiled on an Unix platform with iconv support the full
3047set of encodings supported by iconv can be instantly be used by libxml. On a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003048linux machine with glibc-2.1 the list of supported encodings and aliases fill
30493 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the
3050various Japanese ones.</p>
3051
3052<h4>Encoding aliases</h4>
3053
Daniel Veillard8a469172003-06-12 16:05:07 +00003054<p>From 2.2.3, libxml2 has support to register encoding names aliases. The
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003055goal is to be able to parse document whose encoding is supported but where
3056the name differs (for example from the default set of names accepted by
3057iconv). The following functions allow to register and handle new aliases for
Daniel Veillard8a469172003-06-12 16:05:07 +00003058existing encodings. Once registered libxml2 will automatically lookup the
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003059aliases when handling a document:</p>
3060<ul>
3061 <li>int xmlAddEncodingAlias(const char *name, const char *alias);</li>
3062 <li>int xmlDelEncodingAlias(const char *alias);</li>
3063 <li>const char * xmlGetEncodingAlias(const char *alias);</li>
3064 <li>void xmlCleanupEncodingAliases(void);</li>
3065</ul>
3066
3067<h3><a name="extend">How to extend the existing support</a></h3>
3068
3069<p>Well adding support for new encoding, or overriding one of the encoders
Daniel Veillardabfca612004-01-07 23:38:02 +00003070(assuming it is buggy) should not be hard, just write input and output
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003071conversion routines to/from UTF-8, and register them using
3072xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be
3073called automatically if the parser(s) encounter such an encoding name
3074(register it uppercase, this will help). The description of the encoders,
3075their arguments and expected return values are described in the encoding.h
3076header.</p>
3077
3078<p>A quick note on the topic of subverting the parser to use a different
3079internal encoding than UTF-8, in some case people will absolutely want to
3080keep the internal encoding different, I think it's still possible (but the
3081encoding must be compliant with ASCII on the same subrange) though I didn't
3082tried it. The key is to override the default conversion routines (by
3083registering null encoders/decoders for your charsets), and bypass the UTF-8
3084checking of the parser by setting the parser context charset
3085(ctxt-&gt;charset) to something different than XML_CHAR_ENCODING_UTF8, but
Daniel Veillard63d83142002-05-20 06:51:05 +00003086there is no guarantee that this will work. You may also have some troubles
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003087saving back.</p>
3088
3089<p>Basically proper I18N support is important, this requires at least
3090libxml-2.0.0, but a lot of features and corrections are really available only
3091starting 2.2.</p>
3092
3093<h2><a name="IO">I/O Interfaces</a></h2>
3094
3095<p>Table of Content:</p>
3096<ol>
3097 <li><a href="#General1">General overview</a></li>
3098 <li><a href="#basic">The basic buffer type</a></li>
3099 <li><a href="#Input">Input I/O handlers</a></li>
3100 <li><a href="#Output">Output I/O handlers</a></li>
3101 <li><a href="#entities">The entities loader</a></li>
3102 <li><a href="#Example2">Example of customized I/O</a></li>
3103</ol>
3104
3105<h3><a name="General1">General overview</a></h3>
3106
3107<p>The module <code><a
3108href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides
Daniel Veillard8a469172003-06-12 16:05:07 +00003109the interfaces to the libxml2 I/O system. This consists of 4 main parts:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003110<ul>
3111 <li>Entities loader, this is a routine which tries to fetch the entities
3112 (files) based on their PUBLIC and SYSTEM identifiers. The default loader
Daniel Veillard8a469172003-06-12 16:05:07 +00003113 don't look at the public identifier since libxml2 do not maintain a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003114 catalog. You can redefine you own entity loader by using
3115 <code>xmlGetExternalEntityLoader()</code> and
Daniel Veillard9c466822001-10-25 12:03:39 +00003116 <code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the
3117 example</a>.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003118 <li>Input I/O buffers which are a commodity structure used by the parser(s)
3119 input layer to handle fetching the informations to feed the parser. This
3120 provides buffering and is also a placeholder where the encoding
Daniel Veillard63d83142002-05-20 06:51:05 +00003121 converters to UTF8 are piggy-backed.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003122 <li>Output I/O buffers are similar to the Input ones and fulfill similar
3123 task but when generating a serialization from a tree.</li>
3124 <li>A mechanism to register sets of I/O callbacks and associate them with
3125 specific naming schemes like the protocol part of the URIs.
3126 <p>This affect the default I/O operations and allows to use specific I/O
3127 handlers for certain names.</p>
3128 </li>
3129</ul>
3130
3131<p>The general mechanism used when loading http://rpmfind.net/xml.html for
3132example in the HTML parser is the following:</p>
3133<ol>
3134 <li>The default entity loader calls <code>xmlNewInputFromFile()</code> with
3135 the parsing context and the URI string.</li>
3136 <li>the URI string is checked against the existing registered handlers
3137 using their match() callback function, if the HTTP module was compiled
3138 in, it is registered and its match() function will succeeds</li>
3139 <li>the open() function of the handler is called and if successful will
3140 return an I/O Input buffer</li>
3141 <li>the parser will the start reading from this buffer and progressively
3142 fetch information from the resource, calling the read() function of the
3143 handler until the resource is exhausted</li>
3144 <li>if an encoding change is detected it will be installed on the input
3145 buffer, providing buffering and efficient use of the conversion
3146 routines</li>
3147 <li>once the parser has finished, the close() function of the handler is
Daniel Veillard63d83142002-05-20 06:51:05 +00003148 called once and the Input buffer and associated resources are
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003149 deallocated.</li>
3150</ol>
3151
3152<p>The user defined callbacks are checked first to allow overriding of the
Daniel Veillard8a469172003-06-12 16:05:07 +00003153default libxml2 I/O routines.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003154
3155<h3><a name="basic">The basic buffer type</a></h3>
3156
3157<p>All the buffer manipulation handling is done using the
3158<code>xmlBuffer</code> type define in <code><a
3159href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a
3160resizable memory buffer. The buffer allocation strategy can be selected to be
3161either best-fit or use an exponential doubling one (CPU vs. memory use
Daniel Veillard63d83142002-05-20 06:51:05 +00003162trade-off). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003163<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a
3164system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number
3165of functions allows to manipulate buffers with names starting with the
3166<code>xmlBuffer...</code> prefix.</p>
3167
3168<h3><a name="Input">Input I/O handlers</a></h3>
3169
3170<p>An Input I/O handler is a simple structure
3171<code>xmlParserInputBuffer</code> containing a context associated to the
3172resource (file descriptor, or pointer to a protocol handler), the read() and
3173close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset
3174encoding handler are also present to support charset conversion when
3175needed.</p>
3176
3177<h3><a name="Output">Output I/O handlers</a></h3>
3178
3179<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an
3180Input one except the callbacks are write() and close().</p>
3181
3182<h3><a name="entities">The entities loader</a></h3>
3183
3184<p>The entity loader resolves requests for new entities and create inputs for
3185the parser. Creating an input from a filename or an URI string is done
3186through the xmlNewInputFromFile() routine. The default entity loader do not
3187handle the PUBLIC identifier associated with an entity (if any). So it just
3188calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in
3189XML).</p>
3190
3191<p>If you want to hook up a catalog mechanism then you simply need to
3192override the default entity loader, here is an example:</p>
3193<pre>#include &lt;libxml/xmlIO.h&gt;
3194
3195xmlExternalEntityLoader defaultLoader = NULL;
3196
3197xmlParserInputPtr
3198xmlMyExternalEntityLoader(const char *URL, const char *ID,
3199 xmlParserCtxtPtr ctxt) {
3200 xmlParserInputPtr ret;
3201 const char *fileID = NULL;
3202 /* lookup for the fileID depending on ID */
3203
3204 ret = xmlNewInputFromFile(ctxt, fileID);
3205 if (ret != NULL)
3206 return(ret);
3207 if (defaultLoader != NULL)
3208 ret = defaultLoader(URL, ID, ctxt);
3209 return(ret);
3210}
3211
3212int main(..) {
3213 ...
3214
3215 /*
3216 * Install our own entity loader
3217 */
3218 defaultLoader = xmlGetExternalEntityLoader();
3219 xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
3220
3221 ...
3222}</pre>
3223
3224<h3><a name="Example2">Example of customized I/O</a></h3>
3225
3226<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a
3227real use case</a>, xmlDocDump() closes the FILE * passed by the application
3228and this was a problem. The <a
3229href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a
3230new output handler with the closing call deactivated:</p>
3231<ol>
Daniel Veillardc0801af2002-05-28 16:28:42 +00003232 <li>First define a new I/O output allocator where the output don't close
3233 the file:
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003234 <pre>xmlOutputBufferPtr
3235xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) {
3236    xmlOutputBufferPtr ret;
3237    
3238    if (xmlOutputCallbackInitialized == 0)
3239        xmlRegisterDefaultOutputCallbacks();
3240
3241    if (file == NULL) return(NULL);
3242    ret = xmlAllocOutputBuffer(encoder);
3243    if (ret != NULL) {
3244        ret-&gt;context = file;
3245        ret-&gt;writecallback = xmlFileWrite;
3246        ret-&gt;closecallback = NULL; /* No close callback */
3247    }
Daniel Veillardf83a2c72003-04-08 13:48:40 +00003248    return(ret);
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003249} </pre>
3250 </li>
3251 <li>And then use it to save the document:
3252 <pre>FILE *f;
3253xmlOutputBufferPtr output;
3254xmlDocPtr doc;
3255int res;
3256
3257f = ...
3258doc = ....
3259
3260output = xmlOutputBufferCreateOwn(f, NULL);
3261res = xmlSaveFileTo(output, doc, NULL);
3262 </pre>
3263 </li>
3264</ol>
3265
3266<h2><a name="Catalog">Catalog support</a></h2>
3267
3268<p>Table of Content:</p>
3269<ol>
3270 <li><a href="General2">General overview</a></li>
3271 <li><a href="#definition">The definition</a></li>
3272 <li><a href="#Simple">Using catalogs</a></li>
3273 <li><a href="#Some">Some examples</a></li>
3274 <li><a href="#reference">How to tune catalog usage</a></li>
3275 <li><a href="#validate">How to debug catalog processing</a></li>
3276 <li><a href="#Declaring">How to create and maintain catalogs</a></li>
3277 <li><a href="#implemento">The implementor corner quick review of the
3278 API</a></li>
3279 <li><a href="#Other">Other resources</a></li>
3280</ol>
3281
3282<h3><a name="General2">General overview</a></h3>
3283
3284<p>What is a catalog? Basically it's a lookup mechanism used when an entity
3285(a file or a remote resource) references another entity. The catalog lookup
3286is inserted between the moment the reference is recognized by the software
3287(XML parser, stylesheet processing, or even images referenced for inclusion
3288in a rendering) and the time where loading that resource is actually
3289started.</p>
3290
3291<p>It is basically used for 3 things:</p>
3292<ul>
3293 <li>mapping from "logical" names, the public identifiers and a more
3294 concrete name usable for download (and URI). For example it can associate
3295 the logical name
3296 <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
3297 <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be
3298 downloaded</p>
3299 <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
3300 </li>
3301 <li>remapping from a given URL to another one, like an HTTP indirection
3302 saying that
3303 <p>"http://www.oasis-open.org/committes/tr.xsl"</p>
3304 <p>should really be looked at</p>
3305 <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
3306 </li>
3307 <li>providing a local cache mechanism allowing to load the entities
3308 associated to public identifiers or remote resources, this is a really
3309 important feature for any significant deployment of XML or SGML since it
3310 allows to avoid the aleas and delays associated to fetching remote
3311 resources.</li>
3312</ul>
3313
3314<h3><a name="definition">The definitions</a></h3>
3315
3316<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p>
3317<ul>
3318 <li>the older SGML catalogs, the official spec is SGML Open Technical
3319 Resolution TR9401:1997, but is better understood by reading <a
3320 href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from
3321 James Clark. This is relatively old and not the preferred mode of
3322 operation of libxml.</li>
3323 <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML
Daniel Veillardaf43f632002-03-08 15:05:20 +00003324 Catalogs</a> is far more flexible, more recent, uses an XML syntax and
3325 should scale quite better. This is the default option of libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003326</ul>
3327
3328<p></p>
3329
3330<h3><a name="Simple">Using catalog</a></h3>
3331
Daniel Veillard8a469172003-06-12 16:05:07 +00003332<p>In a normal environment libxml2 will by default check the presence of a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003333catalog in /etc/xml/catalog, and assuming it has been correctly populated,
3334the processing is completely transparent to the document user. To take a
3335concrete example, suppose you are authoring a DocBook document, this one
3336starts with the following DOCTYPE definition:</p>
3337<pre>&lt;?xml version='1.0'?&gt;
3338&lt;!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
3339 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"&gt;</pre>
3340
3341<p>When validating the document with libxml, the catalog will be
3342automatically consulted to lookup the public identifier "-//Norman Walsh//DTD
3343DocBk XML V3.1.4//EN" and the system identifier
3344"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have
3345been installed on your system and the catalogs actually point to them, libxml
3346will fetch them from the local disk.</p>
3347
3348<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this
3349DOCTYPE example it's a really old version, but is fine as an example.</p>
3350
Daniel Veillard8a469172003-06-12 16:05:07 +00003351<p>Libxml2 will check the catalog each time that it is requested to load an
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003352entity, this includes DTD, external parsed entities, stylesheets, etc ... If
3353your system is correctly configured all the authoring phase and processing
3354should use only local files, even if your document stays portable because it
3355uses the canonical public and system ID, referencing the remote document.</p>
3356
3357<h3><a name="Some">Some examples:</a></h3>
3358
Daniel Veillard8a469172003-06-12 16:05:07 +00003359<p>Here is a couple of fragments from XML Catalogs used in libxml2 early
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003360regression tests in <code>test/catalogs</code> :</p>
3361<pre>&lt;?xml version="1.0"?&gt;
3362&lt;!DOCTYPE catalog PUBLIC
3363 "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
3364 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
3365&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
3366 &lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
3367 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
3368...</pre>
3369
3370<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are
3371written in XML, there is a specific namespace for catalog elements
3372"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this
3373catalog is a <code>public</code> mapping it allows to associate a Public
3374Identifier with an URI.</p>
3375<pre>...
3376 &lt;rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
3377 rewritePrefix="file:///usr/share/xml/docbook/"/&gt;
3378...</pre>
3379
3380<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that
3381any URI starting with a given prefix should be looked at another URI
3382constructed by replacing the prefix with an new one. In effect this acts like
3383a cache system for a full area of the Web. In practice it is extremely useful
3384with a file prefix if you have installed a copy of those resources on your
3385local system.</p>
3386<pre>...
3387&lt;delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
3388 catalog="file:///usr/share/xml/docbook.xml"/&gt;
3389&lt;delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
3390 catalog="file:///usr/share/xml/docbook.xml"/&gt;
3391&lt;delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
3392 catalog="file:///usr/share/xml/docbook.xml"/&gt;
3393&lt;delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
3394 catalog="file:///usr/share/xml/docbook.xml"/&gt;
3395&lt;delegateURI uriStartString="http://www.oasis-open.org/docbook/"
3396 catalog="file:///usr/share/xml/docbook.xml"/&gt;
3397...</pre>
3398
3399<p>Delegation is the core features which allows to build a tree of catalogs,
3400easier to maintain than a single catalog, based on Public Identifier, System
3401Identifier or URI prefixes it instructs the catalog software to look up
3402entries in another resource. This feature allow to build hierarchies of
3403catalogs, the set of entries presented should be sufficient to redirect the
3404resolution of all DocBook references to the specific catalog in
3405<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all
3406references for DocBook 4.2.1 to a specific catalog installed at the same time
3407as the DocBook resources on the local machine.</p>
3408
3409<h3><a name="reference">How to tune catalog usage:</a></h3>
3410
3411<p>The user can change the default catalog behaviour by redirecting queries
3412to its own set of catalogs, this can be done by setting the
3413<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an
3414empty one should deactivate loading the default <code>/etc/xml/catalog</code>
3415default catalog</p>
3416
3417<h3><a name="validate">How to debug catalog processing:</a></h3>
3418
3419<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will
Daniel Veillard8a469172003-06-12 16:05:07 +00003420make libxml2 output debugging informations for each catalog operations, for
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003421example:</p>
3422<pre>orchis:~/XML -&gt; xmllint --memory --noout test/ent2
3423warning: failed to load external entity "title.xml"
3424orchis:~/XML -&gt; export XML_DEBUG_CATALOG=
3425orchis:~/XML -&gt; xmllint --memory --noout test/ent2
3426Failed to parse catalog /etc/xml/catalog
3427Failed to parse catalog /etc/xml/catalog
3428warning: failed to load external entity "title.xml"
3429Catalogs cleanup
3430orchis:~/XML -&gt; </pre>
3431
3432<p>The test/ent2 references an entity, running the parser from memory makes
3433the base URI unavailable and the the "title.xml" entity cannot be loaded.
3434Setting up the debug environment variable allows to detect that an attempt is
3435made to load the <code>/etc/xml/catalog</code> but since it's not present the
3436resolution fails.</p>
3437
3438<p>But the most advanced way to debug XML catalog processing is to use the
3439<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load
3440catalogs and make resolution queries to see what is going on. This is also
3441used for the regression tests:</p>
3442<pre>orchis:~/XML -&gt; ./xmlcatalog test/catalogs/docbook.xml \
3443 "-//OASIS//DTD DocBook XML V4.1.2//EN"
3444http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
3445orchis:~/XML -&gt; </pre>
3446
3447<p>For debugging what is going on, adding one -v flags increase the verbosity
3448level to indicate the processing done (adding a second flag also indicate
3449what elements are recognized at parsing):</p>
3450<pre>orchis:~/XML -&gt; ./xmlcatalog -v test/catalogs/docbook.xml \
3451 "-//OASIS//DTD DocBook XML V4.1.2//EN"
3452Parsing catalog test/catalogs/docbook.xml's content
3453Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
3454http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
3455Catalogs cleanup
3456orchis:~/XML -&gt; </pre>
3457
3458<p>A shell interface is also available to debug and process multiple queries
3459(and for regression tests):</p>
3460<pre>orchis:~/XML -&gt; ./xmlcatalog -shell test/catalogs/docbook.xml \
3461 "-//OASIS//DTD DocBook XML V4.1.2//EN"
3462&gt; help
3463Commands available:
3464public PublicID: make a PUBLIC identifier lookup
3465system SystemID: make a SYSTEM identifier lookup
3466resolve PublicID SystemID: do a full resolver lookup
3467add 'type' 'orig' 'replace' : add an entry
3468del 'values' : remove values
3469dump: print the current catalog state
3470debug: increase the verbosity level
3471quiet: decrease the verbosity level
3472exit: quit the shell
3473&gt; public "-//OASIS//DTD DocBook XML V4.1.2//EN"
3474http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
3475&gt; quit
3476orchis:~/XML -&gt; </pre>
3477
3478<p>This should be sufficient for most debugging purpose, this was actually
3479used heavily to debug the XML Catalog implementation itself.</p>
3480
3481<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3>
3482
3483<p>Basically XML Catalogs are XML files, you can either use XML tools to
3484manage them or use <strong>xmlcatalog</strong> for this. The basic step is
3485to create a catalog the -create option provide this facility:</p>
3486<pre>orchis:~/XML -&gt; ./xmlcatalog --create tst.xml
3487&lt;?xml version="1.0"?&gt;
3488&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
3489 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
3490&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
3491orchis:~/XML -&gt; </pre>
3492
3493<p>By default xmlcatalog does not overwrite the original catalog and save the
3494result on the standard output, this can be overridden using the -noout
3495option. The <code>-add</code> command allows to add entries in the
3496catalog:</p>
3497<pre>orchis:~/XML -&gt; ./xmlcatalog --noout --create --add "public" \
3498 "-//OASIS//DTD DocBook XML V4.1.2//EN" \
3499 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
3500orchis:~/XML -&gt; cat tst.xml
3501&lt;?xml version="1.0"?&gt;
3502&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
3503 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
3504&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
3505&lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
3506 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
3507&lt;/catalog&gt;
3508orchis:~/XML -&gt; </pre>
3509
3510<p>The <code>-add</code> option will always take 3 parameters even if some of
3511the XML Catalog constructs (like nextCatalog) will have only a single
3512argument, just pass a third empty string, it will be ignored.</p>
3513
3514<p>Similarly the <code>-del</code> option remove matching entries from the
3515catalog:</p>
3516<pre>orchis:~/XML -&gt; ./xmlcatalog --del \
3517 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
3518&lt;?xml version="1.0"?&gt;
3519&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
3520 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
3521&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
3522orchis:~/XML -&gt; </pre>
3523
3524<p>The catalog is now empty. Note that the matching of <code>-del</code> is
3525exact and would have worked in a similar fashion with the Public ID
3526string.</p>
3527
3528<p>This is rudimentary but should be sufficient to manage a not too complex
3529catalog tree of resources.</p>
3530
3531<h3><a name="implemento">The implementor corner quick review of the
3532API:</a></h3>
3533
3534<p>First, and like for every other module of libxml, there is an
3535automatically generated <a href="html/libxml-catalog.html">API page for
3536catalog support</a>.</p>
3537
3538<p>The header for the catalog interfaces should be included as:</p>
3539<pre>#include &lt;libxml/catalog.h&gt;</pre>
3540
3541<p>The API is voluntarily kept very simple. First it is not obvious that
3542applications really need access to it since it is the default behaviour of
Daniel Veillard560c2a42003-07-06 21:13:49 +00003543libxml2 (Note: it is possible to completely override libxml2 default catalog
3544by using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003545plug an application specific resolver).</p>
3546
Daniel Veillard8a469172003-06-12 16:05:07 +00003547<p>Basically libxml2 support 2 catalog lists:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003548<ul>
3549 <li>the default one, global shared by all the application</li>
3550 <li>a per-document catalog, this one is built if the document uses the
3551 <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is
3552 associated to the parser context and destroyed when the parsing context
3553 is destroyed.</li>
3554</ul>
3555
3556<p>the document one will be used first if it exists.</p>
3557
3558<h4>Initialization routines:</h4>
3559
3560<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be
3561used at startup to initialize the catalog, if the catalog should be
3562initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs()
3563should be called before xmlInitializeCatalog() which would otherwise do a
3564default initialization first.</p>
3565
3566<p>The xmlCatalogAddLocal() call is used by the parser to grow the document
3567own catalog list if needed.</p>
3568
3569<h4>Preferences setup:</h4>
3570
3571<p>The XML Catalog spec requires the possibility to select default
3572preferences between public and system delegation,
3573xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and
3574xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should
3575be forbidden, allowed for global catalog, for document catalog or both, the
3576default is to allow both.</p>
3577
3578<p>And of course xmlCatalogSetDebug() allows to generate debug messages
3579(through the xmlGenericError() mechanism).</p>
3580
3581<h4>Querying routines:</h4>
3582
3583<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic()
3584and xmlCatalogResolveURI() are relatively explicit if you read the XML
3585Catalog specification they correspond to section 7 algorithms, they should
3586also work if you have loaded an SGML catalog with a simplified semantic.</p>
3587
3588<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but
3589operate on the document catalog list</p>
3590
3591<h4>Cleanup and Miscellaneous:</h4>
3592
3593<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is
3594the per-document equivalent.</p>
3595
3596<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the
3597first catalog in the global list, and xmlCatalogDump() allows to dump a
3598catalog state, those routines are primarily designed for xmlcatalog, I'm not
3599sure that exposing more complex interfaces (like navigation ones) would be
3600really useful.</p>
3601
3602<p>The xmlParseCatalogFile() is a function used to load XML Catalog files,
3603it's similar as xmlParseFile() except it bypass all catalog lookups, it's
3604provided because this functionality may be useful for client tools.</p>
3605
3606<h4>threaded environments:</h4>
3607
3608<p>Since the catalog tree is built progressively, some care has been taken to
3609try to avoid troubles in multithreaded environments. The code is now thread
Daniel Veillard8a469172003-06-12 16:05:07 +00003610safe assuming that the libxml2 library has been compiled with threads
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003611support.</p>
3612
3613<p></p>
3614
3615<h3><a name="Other">Other resources</a></h3>
3616
3617<p>The XML Catalog specification is relatively recent so there isn't much
3618literature to point at:</p>
3619<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +00003620 <li>You can find a good rant from Norm Walsh about <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003621 href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the
3622 need for catalogs</a>, it provides a lot of context informations even if
Daniel Veillard93d3a472002-04-26 14:04:55 +00003623 I don't agree with everything presented. Norm also wrote a more recent
3624 article <a
3625 href="http://wwws.sun.com/software/xml/developers/resolver/article/">XML
3626 entities and URI resolvers</a> describing them.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003627 <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML
3628 catalog proposal</a> from John Cowan</li>
3629 <li>The <a href="http://www.rddl.org/">Resource Directory Description
3630 Language</a> (RDDL) another catalog system but more oriented toward
3631 providing metadata for XML namespaces.</li>
3632 <li>the page from the OASIS Technical <a
3633 href="http://www.oasis-open.org/committees/entity/">Committee on Entity
3634 Resolution</a> who maintains XML Catalog, you will find pointers to the
3635 specification update, some background and pointers to others tools
3636 providing XML Catalog support</li>
Daniel Veillardabfca612004-01-07 23:38:02 +00003637 <li>There is a <a href="buildDocBookCatalog">shell script</a> to generate
Daniel Veillard35e937a2002-01-19 22:21:54 +00003638 XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/
3639 directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on
3640 the resources found on the system. Otherwise it will just create
3641 ~/xmlcatalog and ~/dbkxmlcatalog and doing:
Daniel Veillard8594de92003-04-25 10:08:44 +00003642 <p><code>export XML_CATALOG_FILES=$HOME/xmlcatalog</code></p>
Daniel Veillard35e937a2002-01-19 22:21:54 +00003643 <p>should allow to process DocBook documentations without requiring
Daniel Veillard63d83142002-05-20 06:51:05 +00003644 network accesses for the DTD or stylesheets</p>
Daniel Veillard35e937a2002-01-19 22:21:54 +00003645 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003646 <li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a
Daniel Veillard35e937a2002-01-19 22:21:54 +00003647 small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems
3648 to work fine for me too</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003649 <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog
3650 manual page</a></li>
3651</ul>
3652
3653<p>If you have suggestions for corrections or additions, simply contact
3654me:</p>
3655
3656<h2><a name="library">The parser interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003657
3658<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard8a469172003-06-12 16:05:07 +00003659using the XML tollkit from the C language. It is not intended to be
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003660extensive. I hope the automatically generated documents will provide the
3661completeness required, but as a separate set of documents. The interfaces of
Daniel Veillard560c2a42003-07-06 21:13:49 +00003662the XML parser are by principle low level, Those interested in a higher level
3663API should <a href="#DOM">look at DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +00003664
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00003665<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
3666separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003667interfaces</a>. Let's have a look at how the XML parser can be called:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +00003668
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003669<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003670
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003671<p>Usually, the first thing to do is to read an XML input. The parser accepts
3672documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +00003673defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003674<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003675 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003676 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003677 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003678</dl>
3679<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003680 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003681 <dd><p>Parse an XML document contained in a (possibly compressed)
3682 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003683 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003684</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003685
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003686<p>The parser returns a pointer to the document structure (or NULL in case of
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003687failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003688
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003689<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +00003690
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003691<p>In order for the application to keep the control when the document is
Daniel Veillard560c2a42003-07-06 21:13:49 +00003692being fetched (which is common for GUI based programs) libxml2 provides a
3693push interface, too, as of version 1.8.3. Here are the interface
3694functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +00003695<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
3696 void *user_data,
3697 const char *chunk,
3698 int size,
3699 const char *filename);
3700int xmlParseChunk (xmlParserCtxtPtr ctxt,
3701 const char *chunk,
3702 int size,
3703 int terminate);</pre>
3704
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003705<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +00003706<pre> FILE *f;
3707
3708 f = fopen(filename, "r");
3709 if (f != NULL) {
3710 int res, size = 1024;
3711 char chars[1024];
3712 xmlParserCtxtPtr ctxt;
3713
3714 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +00003715 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +00003716 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
3717 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +00003718 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +00003719 xmlParseChunk(ctxt, chars, res, 0);
3720 }
3721 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +00003722 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +00003723 xmlFreeParserCtxt(ctxt);
3724 }
3725 }</pre>
3726
Daniel Veillard8a469172003-06-12 16:05:07 +00003727<p>The HTML parser embedded into libxml2 also has a push interface; the
Daniel Veillardec70e912001-02-26 20:10:45 +00003728functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard0142b842000-01-14 14:45:24 +00003729
3730<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
3731
Daniel Veillardec70e912001-02-26 20:10:45 +00003732<p>The tree-building interface makes the parser memory-hungry, first loading
3733the document in memory and then building the tree itself. Reading a document
3734without building the tree is possible using the SAX interfaces (see SAX.h and
3735<a href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003736Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard91e9d582001-02-26 07:31:12 +00003737limited to SAX: just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +00003738<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +00003739
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003740<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003741
3742<p>The other way to get an XML tree in memory is by building it. Basically
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003743there is a set of functions dedicated to building new elements. (These are
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003744also described in &lt;libxml/tree.h&gt;.) For example, here is a piece of
3745code that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003746<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +00003747 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +00003748 xmlNodePtr tree, subtree;
3749
3750 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +00003751 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
3752 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
3753 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
3754 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +00003755 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +00003756 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +00003757 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
3758 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
3759 subtree = xmlNewChild(tree, NULL, "image", NULL);
3760 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003761
3762<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003763
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003764<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003765
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00003766<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003767code has access to the internal structure of all the elements of the tree.
3768The names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +00003769<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003770<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +00003771example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003772<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003773
3774<p>points to the title element,</p>
Daniel Veillard91e9d582001-02-26 07:31:12 +00003775<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003776
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003777<p>points to the text node containing the chapter title "The Linux
3778adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003779
Daniel Veillardb24054a1999-12-18 15:32:46 +00003780<p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em> to be
Daniel Veillard60979bd2000-07-10 12:17:33 +00003781present before the document root, so <code>doc-&gt;children</code> may point
Daniel Veillard91e9d582001-02-26 07:31:12 +00003782to an element which is not the document Root Element; a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +00003783<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +00003784
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003785<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003786
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003787<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00003788is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003789<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003790 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
3791 xmlChar *value);</code></dt>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003792 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node.
3793 The value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003794 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003795</dl>
3796<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003797 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +00003798 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +00003799 <dd><p>This function returns a pointer to new copy of the property
3800 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003801 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003802</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003803
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003804<p>Two functions are provided for reading and writing the text associated
3805with elements:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003806<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003807 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +00003808 *value);</code></dt>
Daniel Veillardec70e912001-02-26 20:10:45 +00003809 <dd><p>This function takes an "external" string and converts it to one
3810 text node or possibly to a list of entity and text nodes. All
3811 non-predefined entity references like &amp;Gnome; will be stored
3812 internally as entity nodes, hence the result of the function may not be
3813 a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003814 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003815</dl>
3816<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003817 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +00003818 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003819 <dd><p>This function is the inverse of
3820 <code>xmlStringGetNodeList()</code>. It generates a new string
3821 containing the content of the text and entity nodes. Note the extra
3822 argument inLine. If this argument is set to 1, the function will expand
3823 entity references. For example, instead of returning the &amp;Gnome;
3824 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard91e9d582001-02-26 07:31:12 +00003825 "GNU Network Object Model Environment").</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003826 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003827</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003828
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003829<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003830
3831<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003832<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003833 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +00003834 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003835 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003836 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003837</dl>
3838<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003839 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003840 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003841 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003842</dl>
3843<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003844 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003845 <dd><p>Saves the document to a file. In this case, the compression
3846 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003847 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003848</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003849
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003850<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003851
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003852<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003853accesses. The level of compression on saves can be turned on either globally
3854or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003855<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003856 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003857 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003858 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003859</dl>
3860<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003861 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003862 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003863 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003864</dl>
3865<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003866 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003867 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003868 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003869</dl>
3870<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003871 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003872 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003873 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003874</dl>
3875
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003876<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003877
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003878<p>Entities in principle are similar to simple C macros. An entity defines an
3879abbreviation for a given string that you can reuse many times throughout the
3880content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003881may occur frequently within a document, or to confine the change needed to a
3882document to a restricted area in the internal subset of the document (at the
3883beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003884<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +000038852 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +000038863 &lt;!ENTITY xml "Extensible Markup Language"&gt;
38874 ]&gt;
38885 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +000038896 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +000038907 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003891
3892<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing
Daniel Veillard91e9d582001-02-26 07:31:12 +00003893its name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard8a469172003-06-12 16:05:07 +00003894are 5 predefined entities in libxml2 allowing you to escape characters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003895predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003896<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003897for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003898<strong>&amp;quot;</strong> for the character '"', and
3899<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003900
3901<p>One of the problems related to entities is that you may want the parser to
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003902substitute an entity's content so that you can see the replacement text in
3903your application. Or you may prefer to keep entity references as such in the
3904content to be able to save the document back without losing this usually
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003905precious information (if the user went through the pain of explicitly
3906defining entities, he may have a a rather negative attitude if you blindly
Daniel Veillard63d83142002-05-20 06:51:05 +00003907substitute them as saving time). The <a
Daniel Veillard5373ea12003-07-24 13:09:13 +00003908href="html/libxml-parser.html#xmlSubstituteEntitiesDefault">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003909function allows you to check and change the behaviour, which is to not
3910substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003911
Daniel Veillard8a469172003-06-12 16:05:07 +00003912<p>Here is the DOM tree built by libxml2 for the previous document in the
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003913default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003914<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003915DOCUMENT
3916version=1.0
3917 ELEMENT EXAMPLE
3918 TEXT
3919 content=
3920 ENTITY_REF
3921 INTERNAL_GENERAL_ENTITY xml
3922 content=Extensible Markup Language
3923 TEXT
3924 content=</pre>
3925
3926<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003927<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003928DOCUMENT
3929version=1.0
3930 ELEMENT EXAMPLE
3931 TEXT
3932 content= Extensible Markup Language</pre>
3933
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003934<p>So, entities or no entities? Basically, it depends on your use case. I
3935suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003936entities in your XML document or data if you are not willing to handle the
3937entity references elements in the DOM tree.</p>
3938
Daniel Veillard8a469172003-06-12 16:05:07 +00003939<p>Note that at save time libxml2 enforces the conversion of the predefined
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003940entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard91e9d582001-02-26 07:31:12 +00003941transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003942reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003943finding them in the input).</p>
3944
Daniel Veillard7b9c4b72000-08-25 16:26:50 +00003945<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard8a469172003-06-12 16:05:07 +00003946on top of the libxml2 SAX interface is difficult!!! If you plan to use
Daniel Veillard63d83142002-05-20 06:51:05 +00003947non-predefined entities in your documents, then the learning curve to handle
Daniel Veillard91e9d582001-02-26 07:31:12 +00003948then using the SAX API may be long. If you plan to use complex documents, I
Daniel Veillard7b9c4b72000-08-25 16:26:50 +00003949strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +00003950deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +00003951
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003952<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003953
Daniel Veillard8a469172003-06-12 16:05:07 +00003954<p>The libxml2 library implements <a
Daniel Veillardec303412000-03-24 13:41:54 +00003955href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
Daniel Veillard63d83142002-05-20 06:51:05 +00003956recognizing namespace constructs in the input, and does namespace lookup
Daniel Veillardec303412000-03-24 13:41:54 +00003957automatically when building the DOM tree. A namespace declaration is
3958associated with an in-memory structure and all elements or attributes within
3959that namespace point to it. Hence testing the namespace is a simple and fast
3960equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003961
Daniel Veillard8a469172003-06-12 16:05:07 +00003962<p>I suggest that people using libxml2 use a namespace, and declare it in the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003963root element of their document as the default namespace. Then they don't need
3964to use the prefix in the content but we will have a basis for future semantic
Daniel Veillard91e9d582001-02-26 07:31:12 +00003965refinement and merging of data from different sources. This doesn't increase
Daniel Veillardec70e912001-02-26 20:10:45 +00003966the size of the XML output significantly, but significantly increases its
3967value in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003968<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
3969 &lt;elem1&gt;...&lt;/elem1&gt;
3970 &lt;elem2&gt;...&lt;/elem2&gt;
3971&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003972
Daniel Veillardec70e912001-02-26 20:10:45 +00003973<p>The namespace value has to be an absolute URL, but the URL doesn't have to
3974point to any existing resource on the Web. It will bind all the element and
Daniel Veillardc0801af2002-05-28 16:28:42 +00003975attributes with that URL. I suggest to use an URL within a domain you
3976control, and that the URL should contain some kind of version information if
3977possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a
3978good namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +00003979
3980<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003981version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003982and if the version information don't match something you know, warn the user
3983and be liberal in what you accept as the input. Also do *not* try to base
Daniel Veillard60979bd2000-07-10 12:17:33 +00003984namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
Daniel Veillard91e9d582001-02-26 07:31:12 +00003985same as &lt;bar:text&gt; in another document. What really matters is the URI
Daniel Veillard60979bd2000-07-10 12:17:33 +00003986associated with the element or the attribute, not the prefix string (which is
Daniel Veillard91e9d582001-02-26 07:31:12 +00003987just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillardec303412000-03-24 13:41:54 +00003988<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard91e9d582001-02-26 07:31:12 +00003989prefix and its URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003990
3991<p>@@Interfaces@@</p>
Daniel Veillard3e35f8e2003-10-21 00:05:38 +00003992<pre>xmlNodePtr node;
Daniel Veillardfc8dc352003-10-18 09:07:46 +00003993if(!strncmp(node-&gt;name,"mytag",5)
3994 &amp;&amp; node-&gt;ns
3995 &amp;&amp; !strcmp(node-&gt;ns-&gt;href,"http://www.mysite.com/myns/1.0")) {
3996 ...
Daniel Veillard3e35f8e2003-10-21 00:05:38 +00003997}</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003998
Daniel Veillard91e9d582001-02-26 07:31:12 +00003999<p>Usually people object to using namespaces together with validity checking.
4000I will try to make sure that using namespaces won't break validity checking,
4001so even if you plan to use or currently are using validation I strongly
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00004002suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004003<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard91e9d582001-02-26 07:31:12 +00004004flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard3e35f8e2003-10-21 00:05:38 +00004005from multiple DTDs will certainly break current validation schemes. To check
4006such documents one needs to use schema-validation, which is supported in
4007libxml2 as well. See <a href="http://www.relaxng.org/">relagx-ng</a> and <a
4008href="http://www.w3c.org/XML/Schema">w3c-schema</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004009
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004010<h2><a name="Upgrading">Upgrading 1.x code</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004011
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004012<p>Incompatible changes:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004013
Daniel Veillard8a469172003-06-12 16:05:07 +00004014<p>Version 2 of libxml2 is the first version introducing serious backward
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004015incompatible changes. The main goals were:</p>
4016<ul>
4017 <li>a general cleanup. A number of mistakes inherited from the very early
4018 versions couldn't be changed due to compatibility constraints. Example
4019 the "childs" element in the nodes.</li>
4020 <li>Uniformization of the various nodes, at least for their header and link
4021 parts (doc, parent, children, prev, next), the goal is a simpler
4022 programming model and simplifying the task of the DOM implementors.</li>
4023 <li>better conformances to the XML specification, for example version 1.x
4024 had an heuristic to try to detect ignorable white spaces. As a result the
4025 SAX event generated were ignorableWhitespace() while the spec requires
4026 character() in that case. This also mean that a number of DOM node
4027 containing blank text may populate the DOM tree which were not present
4028 before.</li>
4029</ul>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004030
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004031<h3>How to fix libxml-1.x code:</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004032
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004033<p>So client code of libxml designed to run with version 1.x may have to be
4034changed to compile against version 2.x of libxml. Here is a list of changes
4035that I have collected, they may not be sufficient, so in case you find other
Daniel Veillardfc8dc352003-10-18 09:07:46 +00004036change which are required, <a href="mailto:Daniel.Veillard@w3.org">drop me a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004037mail</a>:</p>
4038<ol>
4039 <li>The package name have changed from libxml to libxml2, the library name
4040 is now -lxml2 . There is a new xml2-config script which should be used to
4041 select the right parameters libxml2</li>
4042 <li>Node <strong>childs</strong> field has been renamed
4043 <strong>children</strong> so s/childs/children/g should be applied
Daniel Veillard63d83142002-05-20 06:51:05 +00004044 (probability of having "childs" anywhere else is close to 0+</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004045 <li>The document don't have anymore a <strong>root</strong> element it has
4046 been replaced by <strong>children</strong> and usually you will get a
4047 list of element here. For example a Dtd element for the internal subset
4048 and it's declaration may be found in that list, as well as processing
4049 instructions or comments found before or after the document root element.
4050 Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of
Daniel Veillard63d83142002-05-20 06:51:05 +00004051 a document. Alternatively if you are sure to not reference DTDs nor have
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004052 PIs or comments before or after the root element
4053 s/-&gt;root/-&gt;children/g will probably do it.</li>
4054 <li>The white space issue, this one is more complex, unless special case of
4055 validating parsing, the line breaks and spaces usually used for indenting
4056 and formatting the document content becomes significant. So they are
4057 reported by SAX and if your using the DOM tree, corresponding nodes are
4058 generated. Too approach can be taken:
4059 <ol>
4060 <li>lazy one, use the compatibility call
4061 <strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are
4062 relying on a special (and possibly broken) set of heuristics of
4063 libxml to detect ignorable blanks. Don't complain if it breaks or
4064 make your application not 100% clean w.r.t. to it's input.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00004065 <li>the Right Way: change you code to accept possibly insignificant
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004066 blanks characters, or have your tree populated with weird blank text
Daniel Veillard63d83142002-05-20 06:51:05 +00004067 nodes. You can spot them using the commodity function
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004068 <strong>xmlIsBlankNode(node)</strong> returning 1 for such blank
4069 nodes.</li>
4070 </ol>
4071 <p>Note also that with the new default the output functions don't add any
4072 extra indentation when saving a tree in order to be able to round trip
4073 (read and save) without inflating the document with extra formatting
4074 chars.</p>
4075 </li>
4076 <li>The include path has changed to $prefix/libxml/ and the includes
4077 themselves uses this new prefix in includes instructions... If you are
4078 using (as expected) the
4079 <pre>xml2-config --cflags</pre>
4080 <p>output to generate you compile commands this will probably work out of
4081 the box</p>
4082 </li>
Daniel Veillard63d83142002-05-20 06:51:05 +00004083 <li>xmlDetectCharEncoding takes an extra argument indicating the length in
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004084 byte of the head of the document available for character detection.</li>
4085</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004086
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004087<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004088
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004089<p>Two new version of libxml (1.8.11) and libxml2 (2.3.4) have been released
Daniel Veillard63d83142002-05-20 06:51:05 +00004090to allow smooth upgrade of existing libxml v1code while retaining
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004091compatibility. They offers the following:</p>
4092<ol>
4093 <li>similar include naming, one should use
4094 <strong>#include&lt;libxml/...&gt;</strong> in both cases.</li>
4095 <li>similar identifiers defined via macros for the child and root fields:
4096 respectively <strong>xmlChildrenNode</strong> and
4097 <strong>xmlRootNode</strong></li>
4098 <li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be
4099 inserted once in the client code</li>
4100</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004101
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004102<p>So the roadmap to upgrade your existing libxml applications is the
4103following:</p>
4104<ol>
4105 <li>install the libxml-1.8.8 (and libxml-devel-1.8.8) packages</li>
Daniel Veillard63d83142002-05-20 06:51:05 +00004106 <li>find all occurrences where the xmlDoc <strong>root</strong> field is
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004107 used and change it to <strong>xmlRootNode</strong></li>
Daniel Veillardc0801af2002-05-28 16:28:42 +00004108 <li>similarly find all occurrences where the xmlNode
4109 <strong>childs</strong> field is used and change it to
4110 <strong>xmlChildrenNode</strong></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004111 <li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your
4112 <strong>main()</strong> or in the library init entry point</li>
4113 <li>Recompile, check compatibility, it should still work</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +00004114 <li>Change your configure script to look first for xml2-config and fall
4115 back using xml-config . Use the --cflags and --libs output of the command
4116 as the Include and Linking parameters needed to use libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004117 <li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and
4118 libxml-devel-1.8.y can be kept simultaneously)</li>
4119 <li>remove your config.cache, relaunch your configuration mechanism, and
4120 recompile, if steps 2 and 3 were done right it should compile as-is</li>
4121 <li>Test that your application is still running correctly, if not this may
4122 be due to extra empty nodes due to formating spaces being kept in libxml2
4123 contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your
4124 code before calling the parser (next to
4125 <strong>LIBXML_TEST_VERSION</strong> is a fine place).</li>
4126</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004127
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004128<p>Following those steps should work. It worked for some of my own code.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004129
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004130<p>Let me put some emphasis on the fact that there is far more changes from
4131libxml 1.x to 2.x than the ones you may have to patch for. The overall code
4132has been considerably cleaned up and the conformance to the XML specification
4133has been drastically improved too. Don't take those changes as an excuse to
4134not upgrade, it may cost a lot on the long term ...</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004135
Daniel Veillard52dcab32001-10-30 12:51:17 +00004136<h2><a name="Thread">Thread safety</a></h2>
4137
Daniel Veillard8a469172003-06-12 16:05:07 +00004138<p>Starting with 2.4.7, libxml2 makes provisions to ensure that concurrent
Daniel Veillard52dcab32001-10-30 12:51:17 +00004139threads can safely work in parallel parsing different documents. There is
4140however a couple of things to do to ensure it:</p>
4141<ul>
4142 <li>configure the library accordingly using the --with-threads options</li>
4143 <li>call xmlInitParser() in the "main" thread before using any of the
Daniel Veillard8a469172003-06-12 16:05:07 +00004144 libxml2 API (except possibly selecting a different memory allocator)</li>
Daniel Veillard52dcab32001-10-30 12:51:17 +00004145</ul>
4146
4147<p>Note that the thread safety cannot be ensured for multiple threads sharing
4148the same document, the locking must be done at the application level, libxml
4149exports a basic mutex and reentrant mutexes API in &lt;libxml/threads.h&gt;.
4150The parts of the library checked for thread safety are:</p>
4151<ul>
4152 <li>concurrent loading</li>
4153 <li>file access resolution</li>
4154 <li>catalog access</li>
4155 <li>catalog building</li>
4156 <li>entities lookup/accesses</li>
4157 <li>validation</li>
4158 <li>global variables per-thread override</li>
4159 <li>memory handling</li>
4160</ul>
4161
4162<p>XPath is supposed to be thread safe now, but this wasn't tested
4163seriously.</p>
4164
Daniel Veillard35008381999-10-25 13:15:52 +00004165<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +00004166
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00004167<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document
4168Object Model</em>; this is an API for accessing XML or HTML structured
4169documents. Native support for DOM in Gnome is on the way (module gnome-dom),
4170and will be based on gnome-xml. This will be a far cleaner interface to
4171manipulate XML files within Gnome since it won't expose the internal
4172structure.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +00004173
Daniel Veillard8a469172003-06-12 16:05:07 +00004174<p>The current DOM implementation on top of libxml2 is the <a
Daniel Veillarda47fb3d2001-03-25 17:23:49 +00004175href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this
4176is a full DOM interface, thanks to Paolo Casarini, check the <a
4177href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more
4178informations.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004179
Daniel Veillard35008381999-10-25 13:15:52 +00004180<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +00004181
4182<p>Here is a real size example, where the actual content of the application
4183data is not kept in the DOM tree but uses internal structures. It is based on
Daniel Veillard14fff061999-06-22 21:49:07 +00004184a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +00004185storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
4186base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00004187<pre>&lt;?xml version="1.0"?&gt;
4188&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
4189 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00004190
Daniel Veillard60979bd2000-07-10 12:17:33 +00004191 &lt;gjob:Job&gt;
4192 &lt;gjob:Project ID="3"/&gt;
4193 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
4194 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00004195
Daniel Veillard60979bd2000-07-10 12:17:33 +00004196 &lt;gjob:Update&gt;
4197 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
4198 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
4199 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
4200 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00004201
Daniel Veillard60979bd2000-07-10 12:17:33 +00004202 &lt;gjob:Developers&gt;
4203 &lt;gjob:Developer&gt;
4204 &lt;/gjob:Developer&gt;
4205 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00004206
Daniel Veillard60979bd2000-07-10 12:17:33 +00004207 &lt;gjob:Contact&gt;
4208 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
4209 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
4210 &lt;gjob:Company&gt;
4211 &lt;/gjob:Company&gt;
4212 &lt;gjob:Organisation&gt;
4213 &lt;/gjob:Organisation&gt;
4214 &lt;gjob:Webpage&gt;
4215 &lt;/gjob:Webpage&gt;
4216 &lt;gjob:Snailmail&gt;
4217 &lt;/gjob:Snailmail&gt;
4218 &lt;gjob:Phone&gt;
4219 &lt;/gjob:Phone&gt;
4220 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00004221
Daniel Veillard60979bd2000-07-10 12:17:33 +00004222 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00004223 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +00004224 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00004225
Daniel Veillard60979bd2000-07-10 12:17:33 +00004226 &lt;gjob:Skills&gt;
4227 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00004228
Daniel Veillard60979bd2000-07-10 12:17:33 +00004229 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00004230 A GNOME based system that will allow a superuser to configure
4231 compressed and uncompressed files and/or file systems to be backed
4232 up with a supported media in the system. This should be able to
4233 perform via find commands generating a list of files that are passed
4234 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
4235 or via operations performed on the filesystem itself. Email
4236 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +00004237 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00004238
Daniel Veillard60979bd2000-07-10 12:17:33 +00004239 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00004240
Daniel Veillard60979bd2000-07-10 12:17:33 +00004241 &lt;/gjob:Jobs&gt;
4242&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00004243
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00004244<p>While loading the XML file into an internal DOM tree is a matter of
Daniel Veillard63d83142002-05-20 06:51:05 +00004245calling only a couple of functions, browsing the tree to gather the data and
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00004246generate the internal structures is harder, and more error prone.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00004247
4248<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00004249structure. For example, the ordering of the attributes is not significant,
4250the XML specification is clear about it. It's also usually a good idea not to
Daniel Veillardec70e912001-02-26 20:10:45 +00004251depend on the order of the children of a given node, unless it really makes
4252things harder. Here is some code to parse the information for a person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00004253<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +00004254 * A person record
4255 */
4256typedef struct person {
4257 char *name;
4258 char *email;
4259 char *company;
4260 char *organisation;
4261 char *smail;
4262 char *webPage;
4263 char *phone;
4264} person, *personPtr;
4265
4266/*
4267 * And the code needed to parse it
4268 */
4269personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
4270 personPtr ret = NULL;
4271
4272DEBUG("parsePerson\n");
4273 /*
4274 * allocate the struct
4275 */
4276 ret = (personPtr) malloc(sizeof(person));
4277 if (ret == NULL) {
4278 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +00004279 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +00004280 }
4281 memset(ret, 0, sizeof(person));
4282
4283 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +00004284 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +00004285 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +00004286 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
4287 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
4288 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
4289 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
4290 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +00004291 }
4292
4293 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +00004294}</pre>
4295
Daniel Veillard91e9d582001-02-26 07:31:12 +00004296<p>Here are a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +00004297<ul>
Daniel Veillard91e9d582001-02-26 07:31:12 +00004298 <li>Usually a recursive parsing style is the more convenient one: XML data
Daniel Veillard63d83142002-05-20 06:51:05 +00004299 is by nature subject to repetitive constructs and usually exhibits highly
4300 structured patterns.</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00004301 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>,
4302 i.e. the pointer to the global XML document and the namespace reserved to
4303 the application. Document wide information are needed for example to
4304 decode entities and it's a good coding practice to define a namespace for
4305 your application set of data and test that the element and attributes
4306 you're analyzing actually pertains to your application space. This is
4307 done by a simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardec70e912001-02-26 20:10:45 +00004308 <li>To retrieve text and attributes value, you can use the function
4309 <em>xmlNodeListGetString</em> to gather all the text and entity reference
4310 nodes generated by the DOM output and produce an single text string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +00004311</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +00004312
4313<p>Here is another piece of code used to parse another level of the
4314structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00004315<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +00004316/*
Daniel Veillard14fff061999-06-22 21:49:07 +00004317 * a Description for a Job
4318 */
4319typedef struct job {
4320 char *projectID;
4321 char *application;
4322 char *category;
4323 personPtr contact;
4324 int nbDevelopers;
4325 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
4326} job, *jobPtr;
4327
4328/*
4329 * And the code needed to parse it
4330 */
4331jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
4332 jobPtr ret = NULL;
4333
4334DEBUG("parseJob\n");
4335 /*
4336 * allocate the struct
4337 */
4338 ret = (jobPtr) malloc(sizeof(job));
4339 if (ret == NULL) {
4340 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +00004341 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +00004342 }
4343 memset(ret, 0, sizeof(job));
4344
4345 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +00004346 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +00004347 while (cur != NULL) {
4348
Daniel Veillard60979bd2000-07-10 12:17:33 +00004349 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
4350 ret-&gt;projectID = xmlGetProp(cur, "ID");
4351 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +00004352 fprintf(stderr, "Project has no ID\n");
4353 }
4354 }
Daniel Veillard60979bd2000-07-10 12:17:33 +00004355 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
4356 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
4357 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
4358 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
4359 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
4360 ret-&gt;contact = parsePerson(doc, ns, cur);
4361 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +00004362 }
4363
4364 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +00004365}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +00004366
Daniel Veillardec70e912001-02-26 20:10:45 +00004367<p>Once you are used to it, writing this kind of code is quite simple, but
Daniel Veillard63d83142002-05-20 06:51:05 +00004368boring. Ultimately, it could be possible to write stubbers taking either C
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00004369data structure definitions, a set of XML examples or an XML DTD and produce
4370the code needed to import and export the content between C data and XML
4371storage. This is left as an exercise to the reader :-)</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00004372
Daniel Veillard6f0adb52000-07-03 11:41:26 +00004373<p>Feel free to use <a href="example/gjobread.c">the code for the full C
4374parsing example</a> as a template, it is also available with Makefile in the
4375Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00004376
Daniel Veillardc310d562000-06-23 18:32:15 +00004377<h2><a name="Contributi">Contributions</a></h2>
4378<ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00004379 <li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of
4380 patches, Gary Pennington worked on the validation API, threading support
4381 and Solaris port.</li>
4382 <li>John Fleck helps maintaining the documentation and man pages.</li>
Daniel Veillard7b4b2f92003-01-06 13:11:20 +00004383 <li><a href="mailto:igor@zlatkovic.com">Igor Zlatkovic</a> is now the
4384 maintainer of the Windows port, <a
4385 href="http://www.zlatkovic.com/projects/libxml/index.html">he provides
4386 binaries</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00004387 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides
4388 <a href="http://garypennington.net/libxml2/">Solaris binaries</a></li>
Daniel Veillarde356c282001-03-10 12:32:04 +00004389 <li><a
4390 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard63d83142002-05-20 06:51:05 +00004391 Sergeant</a> developed <a
4392 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for
Daniel Veillardaf43f632002-03-08 15:05:20 +00004393 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
4394 application server</a></li>
4395 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> and <a
4396 href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a
Daniel Veillardca989762001-06-23 17:39:29 +00004397 href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions
Daniel Veillard3f6f7f62000-06-30 17:58:25 +00004398 documentation</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00004399 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
4400 href="http://xmlsoft.org/messages/0488.html">man pages</a></li>
Daniel Veillard5168dbf2001-07-07 00:18:23 +00004401 <li>there is a module for <a
4402 href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support
4403 in OpenNSD/AOLServer</a></li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +00004404 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provided the
4405 first version of libxml/libxslt <a
4406 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
Daniel Veillard1aadc442001-11-28 13:10:32 +00004407 <li>Petr Kozelka provides <a
4408 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
4409 libxml2</a> with Kylix and Delphi and other Pascal compilers</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +00004410 <li><a href="mailto:aleksey@aleksey.com">Aleksey Sanin</a> implemented the
4411 <a href="http://www.w3.org/Signature/">XML Canonicalization and XML
4412 Digital Signature</a> <a
4413 href="http://www.aleksey.com/xmlsec/">implementations for libxml2</a></li>
Daniel Veillard17bed982003-02-24 20:11:43 +00004414 <li><a href="mailto:Steve.Ball@zveno.com">Steve Ball</a>, <a
4415 href="http://www.zveno.com/">Zveno</a> and contributors maintain <a
4416 href="http://tclxml.sourceforge.net/">tcl bindings for libxml2 and
4417 libxslt</a>, as well as <a
4418 href="http://tclxml.sf.net/tkxmllint.html">tkxmllint</a> a GUI for
4419 xmllint and <a href="http://tclxml.sf.net/tkxsltproc.html">tkxsltproc</a>
4420 a GUI for xsltproc.</li>
Daniel Veillardc310d562000-06-23 18:32:15 +00004421</ul>
4422
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00004423<p></p>
Daniel Veillardccb09631998-10-27 06:21:04 +00004424</body>
4425</html>