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Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
2 "http://www.w3.org/TR/html4/loose.dtd">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3<html>
4<head>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]5 <title>The XML C library for Gnome</title>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]6 <meta name="GENERATOR" content="amaya 5.1">
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]7 <meta http-equiv="Content-Type" content="text/html">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]8</head>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]9
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]10<body bgcolor="#ffffff">
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]11<h1 align="center">The XML C library for Gnome</h1>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]12
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]13<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 +0000[diff] [blame]16<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]17
18<p></p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]19
20<p>Libxml is the XML C library developped for the Gnome project. XML itself
21is a metalanguage to design markup languages, i.e. text language where
22semantic and structure are added to the content using extra "markup"
23information enclosed between angle bracket. HTML is the most well-known
Daniel Veillard1eb24242002-03-18 11:33:03 +0000[diff] [blame]24markup language. Though the library is written in C <a href="python.html">a
25variety of language binding</a> makes it available in other environments.</p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]26
27<p>Libxml2 implements a number of existing standards related to markup
28languages:</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]29<ul>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]30 <li>the XML standard: <a
31 href="http://www.w3.org/TR/REC-xml">http://www.w3.org/TR/REC-xml</a></li>
32 <li>Namespaces in XML: <a
33 href="http://www.w3.org/TR/REC-xml-names/">http://www.w3.org/TR/REC-xml-names/</a></li>
34 <li>XML Base: <a
35 href="http://www.w3.org/TR/xmlbase/">http://www.w3.org/TR/xmlbase/</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]36 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc2396.txt">RFC 2396</a> :
37 Uniform Resource Identifiers <a
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]38 href="http://www.ietf.org/rfc/rfc2396.txt">http://www.ietf.org/rfc/rfc2396.txt</a></li>
39 <li>XML Path Language (XPath) 1.0: <a
40 href="http://www.w3.org/TR/xpath">http://www.w3.org/TR/xpath</a></li>
41 <li>HTML4 parser: <a
42 href="http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</a></li>
43 <li>most of XML Pointer Language (XPointer) Version 1.0: <a
44 href="http://www.w3.org/TR/xptr">http://www.w3.org/TR/xptr</a></li>
45 <li>XML Inclusions (XInclude) Version 1.0: <a
46 href="http://www.w3.org/TR/xinclude/">http://www.w3.org/TR/xinclude/</a></li>
47 <li>[ISO-8859-1], <a
48 href="http://www.cis.ohio-state.edu/rfc/rfc2044.txt">rfc2044</a> [UTF-8]
49 and <a href="http://www.cis.ohio-state.edu/rfc/rfc2781.txt">rfc2781</a>
50 [UTF-16] core encodings</li>
51 <li>part of SGML Open Technical Resolution TR9401:1997</li>
52 <li>XML Catalogs Working Draft 06 August 2001: <a
53 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 +0000[diff] [blame]54 <li>Canonical XML Version 1.0: <a
55 href="http://www.w3.org/TR/xml-c14n">http://www.w3.org/TR/xml-c14n</a>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]56 and the Exclusive XML Canonicalization CR draft <a
57 href="http://www.w3.org/TR/xml-exc-c14n">http://www.w3.org/TR/xml-exc-c14n</a></li>
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]58</ul>
59
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]60<p>In most cases libxml tries to implement the specifications in a relatively
Daniel Veillarda5393562002-02-20 11:40:49 +0000[diff] [blame]61strict way. As of release 2.4.16, libxml2 passes all 1800+ tests from the <a
62href="http://www.oasis-open.org/committees/xml-conformance/">OASIS XML Tests
63Suite</a>.</p>
Daniel Veillard5b16f582002-02-20 11:38:46 +0000[diff] [blame]64
65<p>To some extent libxml2 provide some support for the following other
66specification but don't claim to implement them:</p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]67<ul>
68 <li>Document Object Model (DOM) <a
69 href="http://www.w3.org/TR/DOM-Level-2-Core/">http://www.w3.org/TR/DOM-Level-2-Core/</a>
70 it doesn't implement the API itself, gdome2 does this in top of
71 libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]72 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc959.txt">RFC 959</a> :
73 libxml implements a basic FTP client code</li>
74 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc1945.txt">RFC 1945</a> :
75 HTTP/1.0, again a basic HTTP client code</li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]76 <li>SAX: a minimal SAX implementation compatible with early expat
77 versions</li>
78 <li>DocBook SGML v4: libxml2 includes a hackish parser to transition to
79 XML</li>
80</ul>
81
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]82<p>Libxml2 is known to be very portable, the library should build and work
83without serious troubles on a variety of systems (Linux, Unix, Windows,
84CygWin, MacOs, MacOsX, RISC Os, OS/2, VMS, QNX, MVS, ...)</p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]85
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]86<p>Separate documents:</p>
87<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]88 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a> providing an
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]89 implementation of XSLT 1.0 and common extensions like EXSLT for
90 libxml2</li>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]91 <li><a href="http://www.cs.unibo.it/~casarini/gdome2/">the gdome2 page</a>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]92 : a standard DOM2 implementation for libxml2</li>
93 <li><a href="http://www.aleksey.com/xmlsec/">the XMLSec page</a>: an
94 implementation of <a href="http://www.w3.org/TR/xmldsig-core/">W3C XML
95 Digital Signature</a> for libxml2</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]96</ul>
97
98<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]99
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]100<p>This document describes libxml, the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]101href="http://www.w3.org/XML/">XML</a> C library developped for the <a
102href="http://www.gnome.org/">Gnome</a> project. <a
103href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
104structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]105
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]106<p>Here are some key points about libxml:</p>
107<ul>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]108 <li>Libxml exports Push (progressive) and Pull (blocking) type parser
109 interfaces for both XML and HTML.</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]110 <li>Libxml can do DTD validation at parse time, using a parsed document
111 instance, or with an arbitrary DTD.</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]112 <li>Libxml includes complete <a
Daniel Veillard8c2ecaf2001-07-10 17:53:07 +0000[diff] [blame]113 href="http://www.w3.org/TR/xpath">XPath</a>, <a
114 href="http://www.w3.org/TR/xptr">XPointer</a> and <a
115 href="http://www.w3.org/TR/xinclude">XInclude</a> implementations.</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]116 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]117 sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]118 Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]119 <li>Basic support for HTTP and FTP client allowing aplications to fetch
120 remote resources</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]121 <li>The design is modular, most of the extensions can be compiled out.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]122 <li>The internal document repesentation is as close as possible to the <a
123 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
124 <li>Libxml also has a <a href="http://www.megginson.com/SAX/index.html">SAX
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]125 like interface</a>; the interface is designed to be compatible with <a
126 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]127 <li>This library is released under the <a
128 href="http://www.opensource.org/licenses/mit-license.html">MIT
129 Licence</a> see the Copyright file in the distribution for the precise
130 wording.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]131</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]132
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000[diff] [blame]133<p>Warning: unless you are forced to because your application links with a
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]134Gnome-1.X library requiring it, <strong><span
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000[diff] [blame]135style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use
136libxml2</p>
137
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]138<h2><a name="FAQ">FAQ</a></h2>
139
140<p>Table of Content:</p>
141<ul>
142 <li><a href="FAQ.html#Licence">Licence(s)</a></li>
143 <li><a href="FAQ.html#Installati">Installation</a></li>
144 <li><a href="FAQ.html#Compilatio">Compilation</a></li>
145 <li><a href="FAQ.html#Developer">Developer corner</a></li>
146</ul>
147
148<h3><a name="Licence">Licence</a>(s)</h3>
149<ol>
150 <li><em>Licensing Terms for libxml</em>
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]151 <p>libxml is released under the <a
152 href="http://www.opensource.org/licenses/mit-license.html">MIT
153 Licence</a>, see the file Copyright in the distribution for the precise
154 wording</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]155 </li>
156 <li><em>Can I embed libxml in a proprietary application ?</em>
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]157 <p>Yes. The MIT Licence allows you to also keep proprietary the changes
158 you made to libxml, but it would be graceful to provide back bugfixes and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]159 improvements as patches for possible incorporation in the main
160 development tree</p>
161 </li>
162</ol>
163
164<h3><a name="Installati">Installation</a></h3>
165<ol>
166 <li>Unless you are forced to because your application links with a Gnome
167 library requiring it, <strong><span style="background-color: #FF0000">Do
168 Not Use libxml1</span></strong>, use libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]169 <li><em>Where can I get libxml</em> ?
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]170 <p>The original distribution comes from <a
171 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a
172 href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">gnome.org</a></p>
173 <p>Most linux and Bsd distribution includes libxml, this is probably the
174 safer way for end-users</p>
175 <p>David Doolin provides precompiled Windows versions at <a
176 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
177 </li>
178 <li><em>I see libxml and libxml2 releases, which one should I install ?</em>
179 <ul>
180 <li>If you are not concerned by any existing backward compatibility
181 with existing application, install libxml2 only</li>
182 <li>If you are not doing development, you can safely install both.
183 usually the packages <a
184 href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a
185 href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a> are
186 compatible (this is not the case for development packages)</li>
187 <li>If you are a developer and your system provides separate packaging
188 for shared libraries and the development components, it is possible
189 to install libxml and libxml2, and also <a
190 href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>
191 and <a
192 href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>
193 too for libxml2 &gt;= 2.3.0</li>
194 <li>If you are developing a new application, please develop against
195 libxml2(-devel)</li>
196 </ul>
197 </li>
198 <li><em>I can't install the libxml package it conflicts with libxml0</em>
199 <p>You probably have an old libxml0 package used to provide the shared
200 library for libxml.so.0, you can probably safely remove it. Anyway the
201 libxml packages provided on <a
202 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provides
203 libxml.so.0</p>
204 </li>
205 <li><em>I can't install the libxml(2) RPM package due to failed
206 dependancies</em>
207 <p>The most generic solution is to refetch the latest src.rpm , and
208 rebuild it locally with</p>
209 <p><code>rpm --rebuild libxml(2)-xxx.src.rpm</code></p>
210 <p>if everything goes well it will generate two binary rpm (one providing
211 the shared libs and xmllint, and the other one, the -devel package
212 providing includes, static libraries and scripts needed to build
213 applications with libxml(2)) that you can install locally.</p>
214 </li>
215</ol>
216
217<h3><a name="Compilatio">Compilation</a></h3>
218<ol>
219 <li><em>What is the process to compile libxml ?</em>
220 <p>As most UNIX libraries libxml follows the "standard":</p>
221 <p><code>gunzip -c xxx.tar.gz | tar xvf -</code></p>
222 <p><code>cd libxml-xxxx</code></p>
223 <p><code>./configure --help</code></p>
224 <p>to see the options, then the compilation/installation proper</p>
225 <p><code>./configure [possible options]</code></p>
226 <p><code>make</code></p>
227 <p><code>make install</code></p>
228 <p>At that point you may have to rerun ldconfig or similar utility to
229 update your list of installed shared libs.</p>
230 </li>
231 <li><em>What other libraries are needed to compile/install libxml ?</em>
232 <p>Libxml does not requires any other library, the normal C ANSI API
233 should be sufficient (please report any violation to this rule you may
234 find).</p>
235 <p>However if found at configuration time libxml will detect and use the
236 following libs:</p>
237 <ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]238 <li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a> : a
239 highly portable and available widely compression library</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]240 <li>iconv: a powerful character encoding conversion library. It's
241 included by default on recent glibc libraries, so it doesn't need to
242 be installed specifically on linux. It seems it's now <a
243 href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part
244 of the official UNIX</a> specification. Here is one <a
245 href="http://clisp.cons.org/~haible/packages-libiconv.html">implementation
246 of the library</a> which source can be found <a
247 href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>.</li>
248 </ul>
249 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]250 <li><em>make check fails on some platforms</em>
251 <p>Sometime the regression tests results don't completely match the value
252 produced by the parser, and the makefile uses diff to print the delta. On
253 some platforms the diff return breaks the compilation process, if the
Daniel Veillarde46182c2002-02-12 14:29:11 +0000[diff] [blame]254 diff is small this is probably not a serious problem.</p>
255 <p>Sometimes (especially on Solaris) make checks fails due to limitations
256 in make. Try using GNU-make instead.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]257 </li>
258 <li><em>I use the CVS version and there is no configure script</em>
259 <p>The configure (and other Makefiles) are generated. Use the autogen.sh
260 script to regenerate the configure and Makefiles, like:</p>
261 <p><code>./autogen.sh --prefix=/usr --disable-shared</code></p>
262 </li>
263 <li><em>I have troubles when running make tests with gcc-3.0</em>
264 <p>It seems the initial release of gcc-3.0 has a problem with the
265 optimizer which miscompiles the URI module. Please use another
266 compiler</p>
267 </li>
268</ol>
269
270<h3><a name="Developer">Developer</a> corner</h3>
271<ol>
272 <li><em>xmlDocDump() generates output on one line</em>
273 <p>libxml will not <strong>invent</strong> spaces in the content of a
274 document since <strong>all spaces in the content of a document are
275 significant</strong>. If you build a tree from the API and want
276 indentation:</p>
277 <ol>
278 <li>the correct way is to generate those yourself too</li>
279 <li>the dangerous way is to ask libxml to add those blanks to your
280 content <strong>modifying the content of your document in the
281 process</strong>. The result may not be what you expect. There is
282 <strong>NO</strong> way to guarantee that such a modification won't
283 impact other part of the content of your document. See <a
284 href="http://xmlsoft.org/html/libxml-parser.html#XMLKEEPBLANKSDEFAULT">xmlKeepBlanksDefault
285 ()</a> and <a
286 href="http://xmlsoft.org/html/libxml-tree.html#XMLSAVEFORMATFILE">xmlSaveFormatFile
287 ()</a></li>
288 </ol>
289 </li>
290 <li>Extra nodes in the document:
291 <p><em>For a XML file as below:</em></p>
292 <pre>&lt;?xml version="1.0"?&gt;
293&lt;PLAN xmlns="http://www.argus.ca/autotest/1.0/"&gt;
294&lt;NODE CommFlag="0"/&gt;
295&lt;NODE CommFlag="1"/&gt;
296&lt;/PLAN&gt;</pre>
297 <p><em>after parsing it with the function
298 pxmlDoc=xmlParseFile(...);</em></p>
299 <p><em>I want to the get the content of the first node (node with the
300 CommFlag="0")</em></p>
301 <p><em>so I did it as following;</em></p>
302 <pre>xmlNodePtr pode;
303pnode=pxmlDoc-&gt;children-&gt;children;</pre>
304 <p><em>but it does not work. If I change it to</em></p>
305 <pre>pnode=pxmlDoc-&gt;children-&gt;children-&gt;next;</pre>
306 <p><em>then it works. Can someone explain it to me.</em></p>
307 <p></p>
308 <p>In XML all characters in the content of the document are significant
309 <strong>including blanks and formatting line breaks</strong>.</p>
310 <p>The extra nodes you are wondering about are just that, text nodes with
311 the formatting spaces wich are part of the document but that people tend
312 to forget. There is a function <a
313 href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault
314 ()</a> to remove those at parse time, but that's an heuristic, and its
315 use should be limited to case where you are sure there is no
316 mixed-content in the document.</p>
317 </li>
318 <li><em>I get compilation errors of existing code like when accessing
319 <strong>root</strong> or <strong>childs fields</strong> of nodes</em>
320 <p>You are compiling code developed for libxml version 1 and using a
321 libxml2 development environment. Either switch back to libxml v1 devel or
322 even better fix the code to compile with libxml2 (or both) by <a
323 href="upgrade.html">following the instructions</a>.</p>
324 </li>
325 <li><em>I get compilation errors about non existing
326 <strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong>
327 fields</em>
328 <p>The source code you are using has been <a
329 href="upgrade.html">upgraded</a> to be able to compile with both libxml
330 and libxml2, but you need to install a more recent version:
331 libxml(-devel) &gt;= 1.8.8 or libxml2(-devel) &gt;= 2.1.0</p>
332 </li>
333 <li><em>XPath implementation looks seriously broken</em>
334 <p>XPath implementation prior to 2.3.0 was really incomplete, upgrade to
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]335 a recent version, there is no known bug in the current version.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]336 </li>
337 <li><em>The example provided in the web page does not compile</em>
338 <p>It's hard to maintain the documentation in sync with the code
339 &lt;grin/&gt; ...</p>
340 <p>Check the previous points 1/ and 2/ raised before, and send
341 patches.</p>
342 </li>
343 <li><em>Where can I get more examples and informations than in the web
344 page</em>
345 <p>Ideally a libxml book would be nice. I have no such plan ... But you
346 can:</p>
347 <ul>
348 <li>check more deeply the <a href="html/libxml-lib.html">existing
349 generated doc</a></li>
350 <li>looks for examples of use for libxml function using the Gnome code
351 for example the following will query the full Gnome CVs base for the
352 use of the <strong>xmlAddChild()</strong> function:
353 <p><a
354 href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p>
355 <p>This may be slow, a large hardware donation to the gnome project
356 could cure this :-)</p>
357 </li>
358 <li><a
359 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Browse
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]360 the libxml source</a> , I try to write code as clean and documented
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]361 as possible, so looking at it may be helpful. Especially the code of
362 xmllint.c and of the various testXXX.c tests programs should provide
363 good example on how to do things with the library.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]364 </ul>
365 </li>
366 <li>What about C++ ?
367 <p>libxml is written in pure C in order to allow easy reuse on a number
368 of platforms, including embedded systems. I don't intend to convert to
369 C++.</p>
370 <p>There is however a C++ wrapper provided by Ari Johnson
371 &lt;ari@btigate.com&gt; which may fullfill your needs:</p>
372 <p>Website: <a
373 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
374 <p>Download: <a
375 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
376 </li>
377 <li>How to validate a document a posteriori ?
378 <p>It is possible to validate documents which had not been validated at
379 initial parsing time or documents who have been built from scratch using
380 the API. Use the <a
381 href="http://xmlsoft.org/html/libxml-valid.html#XMLVALIDATEDTD">xmlValidateDtd()</a>
382 function. It is also possible to simply add a Dtd to an existing
383 document:</p>
384 <pre>xmlDocPtr doc; /* your existing document */
385 xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */
386 dtd-&gt;name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */
387
388 doc-&gt;intSubset = dtd;
389 if (doc-&gt;children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
390 else xmlAddPrevSibling(doc-&gt;children, (xmlNodePtr)dtd);
391 </pre>
392 </li>
393 <li>etc ...</li>
394</ol>
395
396<p></p>
397
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]398<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]399
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]400<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]401<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]402 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]403 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]404 documentation</a> automatically extracted from code comments (using <a
405 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
406 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000[diff] [blame]407 <li>Look at the documentation about <a href="encoding.html">libxml
408 internationalization support</a></li>
Daniel Veillardbc66f852002-01-14 09:49:20 +0000[diff] [blame]409 <li>This page provides a global overview and <a href="example.html">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]410 examples</a> on how to use libxml.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]411 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]412 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
413 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]414 <li>George Lebl wrote <a
415 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]416 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]417 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
418 file</a></li>
419 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
420 starting a new project using libxml you should really use the 2.x
421 version.</li>
Daniel Veillard845cce42002-01-09 11:51:37 +0000[diff] [blame]422 <li>And don't forget to look at the <a
423 href="http://mail.gnome.org/archives/xml/">mailing-list archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]424</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]425
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]426<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]427
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]428<p>Well, bugs or missing features are always possible, and I will make a
429point of fixing them in a timely fashion. The best way to report a bug is to
430use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome
431bug tracking database</a> (make sure to use the "libxml" module name). I look
432at reports there regularly and it's good to have a reminder when a bug is
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]433still open. Be sure to specify that the bug is for the package libxml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]434
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]435<p>There is also a mailing-list <a
Daniel Veillard3197f162001-04-04 00:40:08 +0000[diff] [blame]436href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a
437href="http://mail.gnome.org/archives/xml/">on-line archive</a> (<a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]438href="http://xmlsoft.org/messages">old</a>). To subscribe to this list,
439please visit the <a
440href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and
441follow the instructions. <strong>Do not send code, I won't debug it</strong>
442(but patches are really appreciated!).</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]443
Daniel Veillard008186f2001-09-13 14:24:44 +0000[diff] [blame]444<p>Check the following <strong><span style="color: #FF0000">before
445posting</span></strong>:</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]446<ul>
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]447 <li>read the <a href="FAQ.html">FAQ</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]448 <li>make sure you are <a href="ftp://xmlsoft.org/">using a recent
449 version</a>, and that the problem still shows up in those</li>
450 <li>check the <a href="http://mail.gnome.org/archives/xml/">list
451 archives</a> to see if the problem was reported already, in this case
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000[diff] [blame]452 there is probably a fix available, similary check the <a
453 href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">registered
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]454 open bugs</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]455 <li>make sure you can reproduce the bug with xmllint or one of the test
456 programs found in source in the distribution</li>
457 <li>Please send the command showing the error as well as the input (as an
458 attachement)</li>
459</ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]460
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]461<p>Then send the bug with associated informations to reproduce it to the <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]462href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml
Daniel Veillard008186f2001-09-13 14:24:44 +0000[diff] [blame]463related I will approve it.. Please do not send me mail directly, it makes
464things really harder to track and in some cases I'm not the best person to
465answer a given question, ask the list instead.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]466
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]467<p>Of course, bugs reported with a suggested patch for fixing them will
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]468probably be processed faster.</p>
469
470<p>If you're looking for help, a quick look at <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000[diff] [blame]471href="http://mail.gnome.org/archives/xml/">the list archive</a> may actually
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]472provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]473questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]474documentantion</a> is not as polished as I would like (i need to learn more
475about Docbook), but it's a good starting point.</p>
476
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]477<h2><a name="help">How to help</a></h2>
478
479<p>You can help the project in various ways, the best thing to do first is to
480subscribe to the mailing-list as explained before, check the <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000[diff] [blame]481href="http://mail.gnome.org/archives/xml/">archives </a>and the <a
482href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome bug
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]483database:</a>:</p>
484<ol>
485 <li>provide patches when you find problems</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]486 <li>provide the diffs when you port libxml to a new platform. They may not
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]487 be integrated in all cases but help pinpointing portability problems
488 and</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]489 <li>provide documentation fixes (either as patches to the code comments or
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]490 as HTML diffs).</li>
491 <li>provide new documentations pieces (translations, examples, etc ...)</li>
492 <li>Check the TODO file and try to close one of the items</li>
493 <li>take one of the points raised in the archive or the bug database and
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000[diff] [blame]494 provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me
495 </a>before to avoid synchronization problems and check that the suggested
496 fix will fit in nicely :-)</li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]497</ol>
498
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]499<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]500
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]501<p>The latest versions of libxml can be found on <a
Daniel Veillard20c8cf22001-06-26 22:47:36 +0000[diff] [blame]502href="ftp://xmlsoft.org/">xmlsoft.org</a> (<a
503href="ftp://speakeasy.rpmfind.net/pub/libxml/">Seattle</a>, <a
504href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]505href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]506as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]507archive</a> or <a
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]508href="ftp://ftp.gnome.org/pub/GNOME/stable/redhat/i386/libxml/">RPM
509packages</a>. (NOTE that you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]510href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
511href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]512packages installed to compile applications using libxml.) <a
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]513href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now the
514maintainer of the Windows port, <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]515href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]516provides binaries</a>. <a href="mailto:Gary.Pennington@sun.com">Gary
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]517Pennington</a> provides <a href="http://garypennington.net/libxml2/">Solaris
518binaries</a>.</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]519
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]520<p><a name="Snapshot">Snapshot:</a></p>
521<ul>
522 <li>Code from the W3C cvs base libxml <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]523 href="ftp://xmlsoft.org/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]524 <li>Docs, content of the web site, the list archive included <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]525 href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]526</ul>
527
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]528<p><a name="Contribs">Contributions:</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]529
530<p>I do accept external contributions, especially if compiling on another
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]531platform, get in touch with me to upload the package, wrappers for various
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]532languages have been provided, and can be found in the <a
533href="contribs.html">contrib section</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]534
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]535<p>Libxml is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]536<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]537 <li><p>The <a
538 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Gnome
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]539 CVS base</a>. Check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]540 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a>
541 page; the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]542 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]543 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]544</ul>
545
546<h2><a name="News">News</a></h2>
547
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]548<h3>CVS only : check the <a
549href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]550for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]551
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]552<p>Items floating around but not actively worked on, get in touch with me if
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]553you want to test those</p>
554<ul>
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]555 <li>Finishing up <a href="http://www.w3.org/TR/xptr">XPointer</a> and <a
556 href="http://www.w3.org/TR/xinclude">XInclude</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]557</ul>
558
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]559<h3>2.4.19: Mar 25 2002</h3>
560<ul>
561 <li>bug fixes: half a dozen XPath bugs, Validation, ISO-Latin to UTF8
562 encoder</li>
563 <li>portability fixes in the HTTP code</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]564 <li>memory allocation checks using valgrind, and profiling tests</li>
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]565 <li>revamp of the Windows build and Makefiles</li>
566</ul>
567
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]568<h3>2.4.18: Mar 18 2002</h3>
569<ul>
570 <li>bug fixes: tree, SAX, canonicalization, validation, portability,
571 xpath</li>
572 <li>removed the --with-buffer option it was becoming unmaintainable</li>
573 <li>serious cleanup of the Python makefiles</li>
574 <li>speedup patch to XPath very effective for DocBook stylesheets</li>
575 <li>Fixes for Windows build, cleanup of the documentation</li>
576</ul>
577
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]578<h3>2.4.17: Mar 8 2002</h3>
579<ul>
580 <li>a lot of bug fixes, including "namespace nodes have no parents in
581 XPath"</li>
582 <li>fixed/improved the Python wrappers, added more examples and more
583 regression tests, XPath extension functions can now return node-sets</li>
584 <li>added the XML Canonalization support from Aleksey Sanin</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]585</ul>
586
Daniel Veillard5f4b5992002-02-20 10:22:49 +0000[diff] [blame]587<h3>2.4.16: Feb 20 2002</h3>
588<ul>
589 <li>a lot of bug fixes, most of them were triggered by the XML Testsuite
590 from OASIS and W3C. Compliance has been significantly improved.</li>
591 <li>a couple of portability fixes too.</li>
592</ul>
593
Daniel Veillard397ff112002-02-11 18:27:20 +0000[diff] [blame]594<h3>2.4.15: Feb 11 2002</h3>
595<ul>
596 <li>Fixed the Makefiles, especially the python module ones</li>
597 <li>A few bug fixes and cleanup</li>
598 <li>Includes cleanup</li>
599</ul>
600
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]601<h3>2.4.14: Feb 8 2002</h3>
602<ul>
603 <li>Change of Licence to the <a
604 href="http://www.opensource.org/licenses/mit-license.html">MIT
605 Licence</a> basisally for integration in XFree86 codebase, and removing
606 confusion around the previous dual-licencing</li>
607 <li>added Python bindings, beta software but should already be quite
608 complete</li>
609 <li>a large number of fixes and cleanups, especially for all tree
610 manipulations</li>
611 <li>cleanup of the headers, generation of a reference API definition in
612 XML</li>
613</ul>
614
615<h3>2.4.13: Jan 14 2002</h3>
Daniel Veillard744683d2002-01-14 17:30:20 +0000[diff] [blame]616<ul>
617 <li>update of the documentation: John Fleck and Charlie Bozeman</li>
618 <li>cleanup of timing code from Justin Fletcher</li>
619 <li>fixes for Windows and initial thread support on Win32: Igor and Serguei
620 Narojnyi</li>
621 <li>Cygwin patch from Robert Collins</li>
622 <li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li>
623</ul>
624
Daniel Veillardef90ba72001-12-07 14:24:22 +0000[diff] [blame]625<h3>2.4.12: Dec 7 2001</h3>
626<ul>
627 <li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman),
628 XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups
629 (robert)</li>
630 <li>Eric Lavigne contributed project files for MacOS</li>
631 <li>some makefiles cleanups</li>
632</ul>
633
Daniel Veillarda4871052001-11-26 13:19:48 +0000[diff] [blame]634<h3>2.4.11: Nov 26 2001</h3>
635<ul>
636 <li>fixed a couple of errors in the includes, fixed a few bugs, some code
637 cleanups</li>
638 <li>xmllint man pages improvement by Heiko Rupp</li>
639 <li>updated VMS build instructions from John A Fotheringham</li>
640 <li>Windows Makefiles updates from Igor</li>
641</ul>
642
Daniel Veillard43d3f612001-11-10 11:57:23 +0000[diff] [blame]643<h3>2.4.10: Nov 10 2001</h3>
644<ul>
645 <li>URI escaping fix (Joel Young)</li>
646 <li>added xmlGetNodePath() (for paths or XPointers generation)</li>
647 <li>Fixes namespace handling problems when using DTD and validation</li>
648 <li>improvements on xmllint: Morus Walter patches for --format and
649 --encode, Stefan Kost and Heiko Rupp improvements on the --shell</li>
650 <li>fixes for xmlcatalog linking pointed by Weiqi Gao</li>
651 <li>fixes to the HTML parser</li>
652</ul>
653
654<h3>2.4.9: Nov 6 2001</h3>
655<ul>
656 <li>fixes more catalog bugs</li>
657 <li>avoid a compilation problem, improve xmlGetLineNo()</li>
658</ul>
659
Daniel Veillarded421aa2001-11-04 21:22:45 +0000[diff] [blame]660<h3>2.4.8: Nov 4 2001</h3>
661<ul>
662 <li>fixed SGML catalogs broken in previous release, updated xmlcatalog
663 tool</li>
664 <li>fixed a compile errors and some includes troubles.</li>
665</ul>
666
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]667<h3>2.4.7: Oct 30 2001</h3>
668<ul>
669 <li>exported some debugging interfaces</li>
670 <li>serious rewrite of the catalog code</li>
671 <li>integrated Gary Pennington thread safety patch, added configure option
672 and regression tests</li>
673 <li>removed an HTML parser bug</li>
674 <li>fixed a couple of potentially serious validation bugs</li>
675 <li>integrated the SGML DocBook support in xmllint</li>
676 <li>changed the nanoftp anonymous login passwd</li>
677 <li>some I/O cleanup and a couple of interfaces for Perl wrapper</li>
678 <li>general bug fixes</li>
679 <li>updated xmllint man page by John Fleck</li>
680 <li>some VMS and Windows updates</li>
681</ul>
682
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]683<h3>2.4.6: Oct 10 2001</h3>
684<ul>
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]685 <li>added an updated man pages by John Fleck</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]686 <li>portability and configure fixes</li>
687 <li>an infinite loop on the HTML parser was removed (William)</li>
688 <li>Windows makefile patches from Igor</li>
689 <li>fixed half a dozen bugs reported fof libxml or libxslt</li>
690 <li>updated xmlcatalog to be able to modify SGML super catalogs</li>
691</ul>
692
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]693<h3>2.4.5: Sep 14 2001</h3>
694<ul>
695 <li>Remove a few annoying bugs in 2.4.4</li>
696 <li>forces the HTML serializer to output decimal charrefs since some
697 version of Netscape can't handle hexadecimal ones</li>
698</ul>
699
700<h3>1.8.16: Sep 14 2001</h3>
701<ul>
702 <li>maintenance release of the old libxml1 branch, couple of bug and
703 portability fixes</li>
704</ul>
705
Daniel Veillard04382ae2001-09-12 18:51:30 +0000[diff] [blame]706<h3>2.4.4: Sep 12 2001</h3>
707<ul>
708 <li>added --convert to xmlcatalog, bug fixes and cleanups of XML
709 Catalog</li>
710 <li>a few bug fixes and some portability changes</li>
711 <li>some documentation cleanups</li>
712</ul>
713
Daniel Veillard39936902001-08-24 00:49:01 +0000[diff] [blame]714<h3>2.4.3: Aug 23 2001</h3>
715<ul>
716 <li>XML Catalog support see the doc</li>
717 <li>New NaN/Infinity floating point code</li>
718 <li>A few bug fixes</li>
719</ul>
720
721<h3>2.4.2: Aug 15 2001</h3>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]722<ul>
723 <li>adds xmlLineNumbersDefault() to control line number generation</li>
724 <li>lot of bug fixes</li>
725 <li>the Microsoft MSC projects files shuld now be up to date</li>
726 <li>inheritance of namespaces from DTD defaulted attributes</li>
727 <li>fixes a serious potential security bug</li>
728 <li>added a --format option to xmllint</li>
729</ul>
730
731<h3>2.4.1: July 24 2001</h3>
732<ul>
733 <li>possibility to keep line numbers in the tree</li>
734 <li>some computation NaN fixes</li>
735 <li>extension of the XPath API</li>
736 <li>cleanup for alpha and ia64 targets</li>
737 <li>patch to allow saving through HTTP PUT or POST</li>
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]738</ul>
739
740<h3>2.4.0: July 10 2001</h3>
741<ul>
742 <li>Fixed a few bugs in XPath, validation, and tree handling.</li>
743 <li>Fixed XML Base implementation, added a coupel of examples to the
744 regression tests</li>
745 <li>A bit of cleanup</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]746</ul>
747
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]748<h3>2.3.14: July 5 2001</h3>
749<ul>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]750 <li>fixed some entities problems and reduce mem requirement when
751 substituing them</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]752 <li>lots of improvements in the XPath queries interpreter can be
753 substancially faster</li>
754 <li>Makefiles and configure cleanups</li>
755 <li>Fixes to XPath variable eval, and compare on empty node set</li>
756 <li>HTML tag closing bug fixed</li>
757 <li>Fixed an URI reference computating problem when validating</li>
758</ul>
759
Daniel Veillard2adbb512001-06-28 16:20:36 +0000[diff] [blame]760<h3>2.3.13: June 28 2001</h3>
761<ul>
762 <li>2.3.12 configure.in was broken as well as the push mode XML parser</li>
763 <li>a few more fixes for compilation on Windows MSC by Yon Derek</li>
764</ul>
765
766<h3>1.8.14: June 28 2001</h3>
767<ul>
768 <li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li>
769 <li>Small Makefile fix</li>
770</ul>
771
Daniel Veillard11648102001-06-26 16:08:24 +0000[diff] [blame]772<h3>2.3.12: June 26 2001</h3>
773<ul>
774 <li>lots of cleanup</li>
775 <li>a couple of validation fix</li>
776 <li>fixed line number counting</li>
777 <li>fixed serious problems in the XInclude processing</li>
778 <li>added support for UTF8 BOM at beginning of entities</li>
779 <li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0
780 miscompile uri.c (William), Thomas Leitner provided a fix for the
781 optimizer on Tru64</li>
782 <li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for
783 compilation on Windows MSC</li>
784 <li>update of libxml-doc.el (Felix Natter)</li>
785 <li>fixed 2 bugs in URI normalization code</li>
786</ul>
787
Daniel Veillarde3c81b52001-06-17 14:50:34 +0000[diff] [blame]788<h3>2.3.11: June 17 2001</h3>
789<ul>
790 <li>updates to trio, Makefiles and configure should fix some portability
791 problems (alpha)</li>
792 <li>fixed some HTML serialization problems (pre, script, and block/inline
793 handling), added encoding aware APIs, cleanup of this code</li>
794 <li>added xmlHasNsProp()</li>
795 <li>implemented a specific PI for encoding support in the DocBook SGML
796 parser</li>
797 <li>some XPath fixes (-Infinity, / as a function parameter and namespaces
798 node selection)</li>
799 <li>fixed a performance problem and an error in the validation code</li>
800 <li>fixed XInclude routine to implement the recursive behaviour</li>
801 <li>fixed xmlFreeNode problem when libxml is included statically twice</li>
802 <li>added --version to xmllint for bug reports</li>
803</ul>
804
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]805<h3>2.3.10: June 1 2001</h3>
806<ul>
807 <li>fixed the SGML catalog support</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]808 <li>a number of reported bugs got fixed, in XPath, iconv detection,
809 XInclude processing</li>
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]810 <li>XPath string function should now handle unicode correctly</li>
811</ul>
812
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]813<h3>2.3.9: May 19 2001</h3>
814
815<p>Lots of bugfixes, and added a basic SGML catalog support:</p>
816<ul>
817 <li>HTML push bugfix #54891 and another patch from Jonas Borgström</li>
818 <li>some serious speed optimisation again</li>
819 <li>some documentation cleanups</li>
820 <li>trying to get better linking on solaris (-R)</li>
821 <li>XPath API cleanup from Thomas Broyer</li>
822 <li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed
823 xmlValidGetValidElements()</li>
824 <li>Added an INSTALL file</li>
825 <li>Attribute removal added to API: #54433</li>
826 <li>added a basic support for SGML catalogs</li>
827 <li>fixed xmlKeepBlanksDefault(0) API</li>
828 <li>bugfix in xmlNodeGetLang()</li>
829 <li>fixed a small configure portability problem</li>
830 <li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li>
831</ul>
832
Daniel Veillarda265af72001-05-14 11:13:58 +0000[diff] [blame]833<h3>1.8.13: May 14 2001</h3>
834<ul>
835 <li>bugfixes release of the old libxml1 branch used by Gnome</li>
836</ul>
837
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]838<h3>2.3.8: May 3 2001</h3>
839<ul>
840 <li>Integrated an SGML DocBook parser for the Gnome project</li>
841 <li>Fixed a few things in the HTML parser</li>
842 <li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating
843 point portability issue</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]844 <li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for
845 DOM+validation using the XML REC as input and a 700MHz celeron).</li>
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]846 <li>incorporated more Windows cleanup</li>
847 <li>added xmlSaveFormatFile()</li>
848 <li>fixed problems in copying nodes with entities references (gdome)</li>
849 <li>removed some troubles surrounding the new validation module</li>
850</ul>
851
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]852<h3>2.3.7: April 22 2001</h3>
853<ul>
854 <li>lots of small bug fixes, corrected XPointer</li>
855 <li>Non determinist content model validation support</li>
856 <li>added xmlDocCopyNode for gdome2</li>
857 <li>revamped the way the HTML parser handles end of tags</li>
858 <li>XPath: corrctions of namespacessupport and number formatting</li>
859 <li>Windows: Igor Zlatkovic patches for MSC compilation</li>
860 <li>HTML ouput fixes from P C Chow and William M. Brack</li>
861 <li>Improved validation speed sensible for DocBook</li>
862 <li>fixed a big bug with ID declared in external parsed entities</li>
863 <li>portability fixes, update of Trio from Bjorn Reese</li>
864</ul>
865
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]866<h3>2.3.6: April 8 2001</h3>
867<ul>
868 <li>Code cleanup using extreme gcc compiler warning options, found and
869 cleared half a dozen potential problem</li>
870 <li>the Eazel team found an XML parser bug</li>
871 <li>cleaned up the user of some of the string formatting function. used the
872 trio library code to provide the one needed when the platform is missing
873 them</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]874 <li>xpath: removed a memory leak and fixed the predicate evaluation
875 problem, extended the testsuite and cleaned up the result. XPointer seems
876 broken ...</li>
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]877</ul>
878
Daniel Veillard56a4cb82001-03-24 17:00:36 +0000[diff] [blame]879<h3>2.3.5: Mar 23 2001</h3>
880<ul>
881 <li>Biggest change is separate parsing and evaluation of XPath expressions,
882 there is some new APIs for this too</li>
883 <li>included a number of bug fixes(XML push parser, 51876, notations,
884 52299)</li>
885 <li>Fixed some portability issues</li>
886</ul>
887
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]888<h3>2.3.4: Mar 10 2001</h3>
889<ul>
890 <li>Fixed bugs #51860 and #51861</li>
891 <li>Added a global variable xmlDefaultBufferSize to allow default buffer
892 size to be application tunable.</li>
893 <li>Some cleanup in the validation code, still a bug left and this part
894 should probably be rewritten to support ambiguous content model :-\</li>
895 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3
896 parser</li>
897 <li>Fixed another bug in xmlNodeGetContent()</li>
898 <li>Bjorn fixed XPath node collection and Number formatting</li>
899 <li>Fixed a loop reported in the HTML parsing</li>
900 <li>blank space are reported even if the Dtd content model proves that they
901 are formatting spaces, this is for XmL conformance</li>
902</ul>
903
Daniel Veillardb402c072001-03-01 17:28:58 +0000[diff] [blame]904<h3>2.3.3: Mar 1 2001</h3>
905<ul>
906 <li>small change in XPath for XSLT</li>
907 <li>documentation cleanups</li>
908 <li>fix in validation by Gary Pennington</li>
909 <li>serious parsing performances improvements</li>
910</ul>
911
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]912<h3>2.3.2: Feb 24 2001</h3>
Daniel Veillard71681102001-02-24 17:48:53 +0000[diff] [blame]913<ul>
914 <li>chasing XPath bugs, found a bunch, completed some TODO</li>
915 <li>fixed a Dtd parsing bug</li>
916 <li>fixed a bug in xmlNodeGetContent</li>
917 <li>ID/IDREF support partly rewritten by Gary Pennington</li>
918</ul>
919
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]920<h3>2.3.1: Feb 15 2001</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]921<ul>
922 <li>some XPath and HTML bug fixes for XSLT</li>
923 <li>small extension of the hash table interfaces for DOM gdome2
924 implementation</li>
925 <li>A few bug fixes</li>
926</ul>
927
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]928<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 +0000[diff] [blame]929<ul>
930 <li>Lots of XPath bug fixes</li>
931 <li>Add a mode with Dtd lookup but without validation error reporting for
932 XSLT</li>
933 <li>Add support for text node without escaping (XSLT)</li>
934 <li>bug fixes for xmlCheckFilename</li>
935 <li>validation code bug fixes from Gary Pennington</li>
936 <li>Patch from Paul D. Smith correcting URI path normalization</li>
937 <li>Patch to allow simultaneous install of libxml-devel and
938 libxml2-devel</li>
939 <li>the example Makefile is now fixed</li>
940 <li>added HTML to the RPM packages</li>
941 <li>tree copying bugfixes</li>
942 <li>updates to Windows makefiles</li>
943 <li>optimisation patch from Bjorn Reese</li>
944</ul>
945
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]946<h3>2.2.11: Jan 4 2001</h3>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]947<ul>
948 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
949 <li>added htmlHandleOmittedElem()</li>
950 <li>Applied Bjorn Reese's IPV6 first patch</li>
951 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]952 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]953</ul>
954
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]955<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000[diff] [blame]956<ul>
957 <li>Fix the Windows problems of 2.2.8</li>
958 <li>integrate OpenVMS patches</li>
959 <li>better handling of some nasty HTML input</li>
960 <li>Improved the XPointer implementation</li>
961 <li>integrate a number of provided patches</li>
962</ul>
963
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]964<h3>2.2.9: Nov 25 2000</h3>
965<ul>
966 <li>erroneous release :-(</li>
967</ul>
968
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]969<h3>2.2.8: Nov 13 2000</h3>
970<ul>
971 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
972 support</li>
973 <li>Patch in conditional section handling</li>
974 <li>updated MS compiler project</li>
975 <li>fixed some XPath problems</li>
976 <li>added an URI escaping function</li>
977 <li>some other bug fixes</li>
978</ul>
979
980<h3>2.2.7: Oct 31 2000</h3>
981<ul>
982 <li>added message redirection</li>
983 <li>XPath improvements (thanks TOM !)</li>
984 <li>xmlIOParseDTD() added</li>
985 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
986 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
987</ul>
988
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000[diff] [blame]989<h3>2.2.6: Oct 25 2000:</h3>
990<ul>
991 <li>Added an hash table module, migrated a number of internal structure to
992 those</li>
993 <li>Fixed a posteriori validation problems</li>
994 <li>HTTP module cleanups</li>
995 <li>HTML parser improvements (tag errors, script/style handling, attribute
996 normalization)</li>
997 <li>coalescing of adjacent text nodes</li>
998 <li>couple of XPath bug fixes, exported the internal API</li>
999</ul>
1000
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]1001<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1002<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1003 <li>XPointer implementation and testsuite</li>
1004 <li>Lot of XPath fixes, added variable and functions registration, more
1005 tests</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1006 <li>Portability fixes, lots of enhancements toward an easy Windows build
1007 and release</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1008 <li>Late validation fixes</li>
1009 <li>Integrated a lot of contributed patches</li>
1010 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]1011 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1012</ul>
1013
1014<h3>2.2.4: Oct 1 2000:</h3>
1015<ul>
1016 <li>main XPath problem fixed</li>
1017 <li>Integrated portability patches for Windows</li>
1018 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1019</ul>
1020
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1021<h3>2.2.3: Sep 17 2000</h3>
1022<ul>
1023 <li>bug fixes</li>
1024 <li>cleanup of entity handling code</li>
1025 <li>overall review of all loops in the parsers, all sprintf usage has been
1026 checked too</li>
1027 <li>Far better handling of larges Dtd. Validating against Docbook XML Dtd
1028 works smoothly now.</li>
1029</ul>
1030
1031<h3>1.8.10: Sep 6 2000</h3>
1032<ul>
1033 <li>bug fix release for some Gnome projects</li>
1034</ul>
1035
1036<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]1037<ul>
1038 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]1039 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]1040</ul>
1041
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1042<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]1043<ul>
1044 <li>a purely bug fixes release</li>
1045 <li>fixed an encoding support problem when parsing from a memory block</li>
1046 <li>fixed a DOCTYPE parsing problem</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1047 <li>removed a bug in the function allowing to override the memory
1048 allocation routines</li>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]1049</ul>
1050
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1051<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]1052<ul>
1053 <li>applied a lot of portability fixes</li>
1054 <li>better encoding support/cleanup and saving (content is now always
1055 encoded in UTF-8)</li>
1056 <li>the HTML parser now correctly handles encodings</li>
1057 <li>added xmlHasProp()</li>
1058 <li>fixed a serious problem with &amp;#38;</li>
1059 <li>propagated the fix to FTP client</li>
1060 <li>cleanup, bugfixes, etc ...</li>
1061 <li>Added a page about <a href="encoding.html">libxml Internationalization
1062 support</a></li>
1063</ul>
1064
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1065<h3>1.8.9: July 9 2000</h3>
1066<ul>
1067 <li>fixed the spec the RPMs should be better</li>
1068 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
1069 rpmfind users problem</li>
1070</ul>
1071
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]1072<h3>2.1.1: July 1 2000</h3>
1073<ul>
1074 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
1075 <li>improvements on the HTML parser</li>
1076</ul>
1077
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1078<h3>2.1.0 and 1.8.8: June 29 2000</h3>
1079<ul>
1080 <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to
1081 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
1082 about &amp;#38; charref parsing</li>
1083 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
1084 also contains numerous fixes and enhancements:
1085 <ul>
1086 <li>added xmlStopParser() to stop parsing</li>
1087 <li>improved a lot parsing speed when there is large CDATA blocs</li>
1088 <li>includes XPath patches provided by Picdar Technology</li>
1089 <li>tried to fix as much as possible DtD validation and namespace
1090 related problems</li>
1091 <li>output to a given encoding has been added/tested</li>
1092 <li>lot of various fixes</li>
1093 </ul>
1094 </li>
1095</ul>
1096
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1097<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1098<ul>
1099 <li>First public release of libxml2. If you are using libxml, it's a good
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1100 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally
1101 scheduled for Apr 3 the relase occured only on Apr 12 due to massive
1102 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1103 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1104 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1105 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1106 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1107 <pre>#include "xxx.h"</pre>
1108 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]1109 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
1110 <li>the memory allocation routines used by libxml can now be overloaded
1111 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1112 <li>The previously CVS only tool tester has been renamed
1113 <strong>xmllint</strong> and is now installed as part of the libxml2
1114 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1115 <li>The I/O interface has been revamped. There is now ways to plug in
1116 specific I/O modules, either at the URI scheme detection level using
1117 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
1118 parser context using xmlCreateIOParserCtxt()</li>
1119 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
1120 number of the libxml module in use</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1121 <li>a number of optional features of libxml can now be excluded at
1122 configure time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1123</ul>
1124
1125<h3>2.0.0beta: Mar 14 2000</h3>
1126<ul>
1127 <li>This is a first Beta release of libxml version 2</li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]1128 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org
1129 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and
1130 RPMs</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1131 <li>This version is now the head in the Gnome CVS base, the old one is
1132 available under the tag LIB_XML_1_X</li>
1133 <li>This includes a very large set of changes. Froma programmatic point of
1134 view applications should not have to be modified too much, check the <a
1135 href="upgrade.html">upgrade page</a></li>
1136 <li>Some interfaces may changes (especially a bit about encoding).</li>
1137 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1138 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1139 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
1140 handled now</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1141 <li>Better handling of entities, especially well formedness checking
1142 and proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1143 <li>DTD conditional sections</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1144 <li>Validation now correcly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1145 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
1146 structures to accomodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1147 </ul>
1148 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1149 <li>Serious progress were made toward compliance, <a
1150 href="conf/result.html">here are the result of the test</a> against the
1151 OASIS testsuite (except the japanese tests since I don't support that
1152 encoding yet). This URL is rebuilt every couple of hours using the CVS
1153 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1154</ul>
1155
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1156<h3>1.8.7: Mar 6 2000</h3>
1157<ul>
1158 <li>This is a bug fix release:</li>
1159 <li>It is possible to disable the ignorable blanks heuristic used by
1160 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1161 that for adherence to XML spec, this behaviour will be disabled by
1162 default in 2.x . The same function will allow to keep compatibility for
1163 old code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1164 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
1165 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1166 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
1167 compilation on some platforms has been fixed</li>
1168 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
1169 URIs</li>
1170</ul>
1171
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1172<h3>1.8.6: Jan 31 2000</h3>
1173<ul>
1174 <li>added a nanoFTP transport module, debugged until the new version of <a
1175 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
1176 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]1177</ul>
1178
1179<h3>1.8.5: Jan 21 2000</h3>
1180<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1181 <li>adding APIs to parse a well balanced chunk of XML (production <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1182 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the
1183 XML spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1184 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1185 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
1186 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1187 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
1188 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1189</ul>
1190
1191<h3>1.8.4: Jan 13 2000</h3>
1192<ul>
1193 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
1194 <li>all exit() call should have been removed from libxml</li>
1195 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
1196 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1197</ul>
1198
1199<h3>1.8.3: Jan 5 2000</h3>
1200<ul>
1201 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1202 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillarddbfd6411999-12-28 16:35:14 +0000[diff] [blame]1203 <li>lots of bug fixes and improvement added over XMas hollidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1204 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1205 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
1206 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1207 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1208 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1209 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1210</ul>
1211
1212<h3>1.8.2: Dec 21 1999</h3>
1213<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1214 <li>I got another problem with includes and C++, I hope this issue is fixed
1215 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1216 <li>Added a few tree modification functions: xmlReplaceNode,
1217 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
1218 xmlDocSetRootElement</li>
1219 <li>Tried to improve the HTML output with help from <a
1220 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1221</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1222
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1223<h3>1.8.1: Dec 18 1999</h3>
1224<ul>
1225 <li>various patches to avoid troubles when using libxml with C++ compilers
1226 the "namespace" keyword and C escaping in include files</li>
1227 <li>a problem in one of the core macros IS_CHAR was corrected</li>
1228 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
1229 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]1230 <li>fixed a posteriori validation (validation after parsing, or by using a
1231 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1232 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]1233</ul>
1234
1235<h3>1.8.0: Dec 12 1999</h3>
1236<ul>
1237 <li>cleanup, especially memory wise</li>
1238 <li>the parser should be more reliable, especially the HTML one, it should
1239 not crash, whatever the input !</li>
1240 <li>Integrated various patches, especially a speedup improvement for large
1241 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
1242 configure with --with-buffers to enable them.</li>
1243 <li>attribute normalization, oops should have been added long ago !</li>
1244 <li>attributes defaulted from Dtds should be available, xmlSetProp() now
1245 does entities escapting by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1246</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1247
1248<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1249<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1250 <li>Lots of HTML improvement</li>
1251 <li>Fixed some errors when saving both XML and HTML</li>
1252 <li>More examples, the regression tests should now look clean</li>
1253 <li>Fixed a bug with contiguous charref</li>
1254</ul>
1255
1256<h3>1.7.3: Sep 29 1999</h3>
1257<ul>
1258 <li>portability problems fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1259 <li>snprintf was used unconditionnally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1260 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1261</ul>
1262
1263<h3>1.7.1: Sep 24 1999</h3>
1264<ul>
1265 <li>The basic type for strings manipulated by libxml has been renamed in
1266 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1267 is that CHAR was conflicting with a predefined type on Windows. However
1268 on non WIN32 environment, compatibility is provided by the way of a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1269 <strong>#define </strong>.</li>
1270 <li>Changed another error : the use of a structure field called errno, and
1271 leading to troubles on platforms where it's a macro</li>
1272</ul>
1273
1274<h3>1.7.0: sep 23 1999</h3>
1275<ul>
1276 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1277 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1278 <li>Added an errno to report errors by another mean than a simple printf
1279 like callback</li>
1280 <li>Finished ID/IDREF support and checking when validation</li>
1281 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1282 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1283 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
1284 implementation</li>
1285 <li>Added an HTML parser front-end</li>
1286</ul>
1287
1288<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1289
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1290<p><a href="http://www.w3.org/TR/REC-xml">XML is a standard</a> for
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1291markup-based structured documents. Here is <a name="example">an example XML
1292document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1293<pre>&lt;?xml version="1.0"?&gt;
1294&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
1295 &lt;head&gt;
1296 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
1297 &lt;/head&gt;
1298 &lt;chapter&gt;
1299 &lt;title&gt;The Linux adventure&lt;/title&gt;
1300 &lt;p&gt;bla bla bla ...&lt;/p&gt;
1301 &lt;image href="linus.gif"/&gt;
1302 &lt;p&gt;...&lt;/p&gt;
1303 &lt;/chapter&gt;
1304&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1305
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1306<p>The first line specifies that it's an XML document and gives useful
1307information about its encoding. Then the document is a text format whose
1308structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1309to be closed</strong>. XML is pedantic about this. However, if a tag is empty
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1310(no content), a single tag can serve as both the opening and closing tag if
1311it ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note
1312that, for example, the image tag has no content (just an attribute) and is
1313closed by ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1314
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1315<p>XML can be applied sucessfully to a wide range of uses, from long term
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1316structured document maintenance (where it follows the steps of SGML) to
1317simple data encoding mechanisms like configuration file formatting (glade),
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1318spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
1319it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1320
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1321<h2><a name="XSLT">XSLT</a></h2>
1322
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]1323<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
1324
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1325<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a
1326language for transforming XML documents into other XML documents (or
1327HTML/textual output).</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1328
1329<p>A separate library called libxslt is being built on top of libxml2. This
1330module "libxslt" can be found in the Gnome CVS base too.</p>
1331
Daniel Veillard383b1472001-01-23 11:39:52 +0000[diff] [blame]1332<p>You can check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1333href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a>
1334supported and the progresses on the <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1335href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog"
1336name="Changelog">Changelog</a></p>
1337
1338<h2><a name="Python">Python and bindings</a></h2>
1339
1340<p>There is a number of language bindings and wrappers available for libxml2,
1341the list below is not exhaustive. Please contact the <a
1342href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a>
1343(<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in
1344order to get updates to this list or to discuss the specific topic of libxml2
1345or libxslt wrappers or bindings:</p>
1346<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1347 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
1348 for libxml:<br>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1349 Website: <a
1350 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
1351 Download: <a
1352 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
1353 <li>There is another <a href="http://libgdome-cpp.berlios.de/">C++ wrapper
1354 based on the gdome2 </a>bindings maintained by Tobias Peters.</li>
1355 <li><a
1356 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1357 Sergeant</a> developped <a
1358 href="http://axkit.org/download/">XML::LibXSLT</a>, a perl wrapper for
1359 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
1360 application server</a></li>
1361 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides and
1362 earlier version of the libxml/libxslt <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1363 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
1364 <li>Petr Kozelka provides <a
1365 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
1366 libxml2</a> with Kylix, Delphi and other Pascal compilers</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]1367 <li>Uwe Fechner also provides <a
1368 href="http://sourceforge.net/projects/idom2-pas/">idom2</a>, a DOM2
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame^]1369 implementation for Kylix2/D5/D6 from Borland</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1370 <li>Wai-Sun "Squidster" Chia provides <a
1371 href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
1372 libxml2 bindings are also available in Ruby through the <a
1373 href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
1374 maintained by Tobias Peters.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1375 <li>Steve Ball and contributors maintains <a
1376 href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
1377 Tcl</a></li>
1378 <li>There is support for libxml2 in the DOM module of PHP.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1379</ul>
1380
1381<p>The distribution includes a set of Python bindings, which are garanteed to
1382be maintained as part of the library in the future, though the Python
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1383interface have not yet reached the maturity of the C API.</p>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1384
1385<p>To install the Python bindings there are 2 options:</p>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1386<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1387 <li>If you use an RPM based distribution, simply install the <a
1388 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python
1389 RPM</a> (and if needed the <a
1390 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
1391 RPM</a>).</li>
1392 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python
1393 module distribution</a> corresponding to your installed version of
1394 libxml2 and libxslt. Note that to install it you will need both libxml2
1395 and libxslt installed and run "python setup.py build install" in the
1396 module tree.</li>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1397</ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1398
1399<p>The distribution includes a set of examples and regression tests for the
1400python bindings in the <code>python/tests</code> directory. Here are some
1401excepts from those tests:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1402
1403<h3>tst.py:</h3>
1404
1405<p>This is a basic test of the file interface and DOM navigation:</p>
1406<pre>import libxml2
1407
1408doc = libxml2.parseFile("tst.xml")
1409if doc.name != "tst.xml":
1410 print "doc.name failed"
1411 sys.exit(1)
1412root = doc.children
1413if root.name != "doc":
1414 print "root.name failed"
1415 sys.exit(1)
1416child = root.children
1417if child.name != "foo":
1418 print "child.name failed"
1419 sys.exit(1)
1420doc.freeDoc()</pre>
1421
1422<p>The Python module is called libxml2, parseFile is the equivalent of
1423xmlParseFile (most of the bindings are automatically generated, and the xml
1424prefix is removed and the casing convention are kept). All node seen at the
1425binding level share the same subset of accesors:</p>
1426<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1427 <li><code>name</code> : returns the node name</li>
1428 <li><code>type</code> : returns a string indicating the node
1429 typ<code>e</code></li>
1430 <li><code>content</code> : returns the content of the node, it is based on
1431 xmlNodeGetContent() and hence is recursive.</li>
1432 <li><code>parent</code> , <code>children</code>, <code>last</code>,
1433 <code>next</code>, <code>prev</code>, <code>doc</code>,
1434 <code>properties</code>: pointing to the associated element in the tree,
1435 those may return None in case no such link exists.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1436</ul>
1437
1438<p>Also note the need to explicitely deallocate documents with freeDoc() .
1439Reference counting for libxml2 trees would need quite a lot of work to
1440function properly, and rather than risk memory leaks if not implemented
1441correctly it sounds safer to have an explicit function to free a tree. The
1442wrapper python objects like doc, root or child are them automatically garbage
1443collected.</p>
1444
1445<h3>validate.py:</h3>
1446
1447<p>This test check the validation interfaces and redirection of error
1448messages:</p>
1449<pre>import libxml2
1450
1451#desactivate error messages from the validation
1452def noerr(ctx, str):
1453 pass
1454
1455libxml2.registerErrorHandler(noerr, None)
1456
1457ctxt = libxml2.createFileParserCtxt("invalid.xml")
1458ctxt.validate(1)
1459ctxt.parseDocument()
1460doc = ctxt.doc()
1461valid = ctxt.isValid()
1462doc.freeDoc()
1463if valid != 0:
1464 print "validity chec failed"</pre>
1465
1466<p>The first thing to notice is the call to registerErrorHandler(), it
1467defines a new error handler global to the library. It is used to avoid seeing
1468the error messages when trying to validate the invalid document.</p>
1469
1470<p>The main interest of that test is the creation of a parser context with
1471createFileParserCtxt() and how the behaviour can be changed before calling
1472parseDocument() . Similary the informations resulting from the parsing phase
1473are also available using context methods.</p>
1474
1475<p>Contexts like nodes are defined as class and the libxml2 wrappers maps the
1476C function interfaces in terms of objects method as much as possible. The
1477best to get a complete view of what methods are supported is to look at the
1478libxml2.py module containing all the wrappers.</p>
1479
1480<h3>push.py:</h3>
1481
1482<p>This test show how to activate the push parser interface:</p>
1483<pre>import libxml2
1484
1485ctxt = libxml2.createPushParser(None, "&lt;foo", 4, "test.xml")
1486ctxt.parseChunk("/&gt;", 2, 1)
1487doc = ctxt.doc()
1488
1489doc.freeDoc()</pre>
1490
1491<p>The context is created with a speciall call based on the
1492xmlCreatePushParser() from the C library. The first argument is an optional
1493SAX callback object, then the initial set of data, the lenght and the name of
1494the resource in case URI-References need to be computed by the parser.</p>
1495
1496<p>Then the data are pushed using the parseChunk() method, the last call
1497setting the thrird argument terminate to 1.</p>
1498
1499<h3>pushSAX.py:</h3>
1500
1501<p>this test show the use of the event based parsing interfaces. In this case
1502the parser does not build a document, but provides callback information as
1503the parser makes progresses analyzing the data being provided:</p>
1504<pre>import libxml2
1505log = ""
1506
1507class callback:
1508 def startDocument(self):
1509 global log
1510 log = log + "startDocument:"
1511
1512 def endDocument(self):
1513 global log
1514 log = log + "endDocument:"
1515
1516 def startElement(self, tag, attrs):
1517 global log
1518 log = log + "startElement %s %s:" % (tag, attrs)
1519
1520 def endElement(self, tag):
1521 global log
1522 log = log + "endElement %s:" % (tag)
1523
1524 def characters(self, data):
1525 global log
1526 log = log + "characters: %s:" % (data)
1527
1528 def warning(self, msg):
1529 global log
1530 log = log + "warning: %s:" % (msg)
1531
1532 def error(self, msg):
1533 global log
1534 log = log + "error: %s:" % (msg)
1535
1536 def fatalError(self, msg):
1537 global log
1538 log = log + "fatalError: %s:" % (msg)
1539
1540handler = callback()
1541
1542ctxt = libxml2.createPushParser(handler, "&lt;foo", 4, "test.xml")
1543chunk = " url='tst'&gt;b"
1544ctxt.parseChunk(chunk, len(chunk), 0)
1545chunk = "ar&lt;/foo&gt;"
1546ctxt.parseChunk(chunk, len(chunk), 1)
1547
Daniel Veillardfcbfa2d2002-02-21 17:54:27 +0000[diff] [blame]1548reference = "startDocument:startElement foo {'url': 'tst'}:" + \
1549 "characters: bar:endElement foo:endDocument:"
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1550if log != reference:
1551 print "Error got: %s" % log
1552 print "Exprected: %s" % reference</pre>
1553
1554<p>The key object in that test is the handler, it provides a number of entry
1555points which can be called by the parser as it makes progresses to indicate
1556the information set obtained. The full set of callback is larger than what
1557the callback class in that specific example implements (see the SAX
1558definition for a complete list). The wrapper will only call those supplied by
1559the object when activated. The startElement receives the names of the element
1560and a dictionnary containing the attributes carried by this element.</p>
1561
1562<p>Also note that the reference string generated from the callback shows a
1563single character call even though the string "bar" is passed to the parser
1564from 2 different call to parseChunk()</p>
1565
1566<h3>xpath.py:</h3>
1567
1568<p>This is a basic test of XPath warppers support</p>
1569<pre>import libxml2
1570
1571doc = libxml2.parseFile("tst.xml")
1572ctxt = doc.xpathNewContext()
1573res = ctxt.xpathEval("//*")
1574if len(res) != 2:
1575 print "xpath query: wrong node set size"
1576 sys.exit(1)
1577if res[0].name != "doc" or res[1].name != "foo":
1578 print "xpath query: wrong node set value"
1579 sys.exit(1)
1580doc.freeDoc()
1581ctxt.xpathFreeContext()</pre>
1582
1583<p>This test parses a file, then create an XPath context to evaluate XPath
1584expression on it. The xpathEval() method execute an XPath query and returns
1585the result mapped in a Python way. String and numbers are natively converted,
1586and node sets are returned as a tuple of libxml2 Python nodes wrappers. Like
1587the document, the XPath context need to be freed explicitely, also not that
1588the result of the XPath query may point back to the document tree and hence
1589the document must be freed after the result of the query is used.</p>
1590
1591<h3>xpathext.py:</h3>
1592
1593<p>This test shows how to extend the XPath engine with functions written in
1594python:</p>
1595<pre>import libxml2
1596
1597def foo(ctx, x):
1598 return x + 1
1599
1600doc = libxml2.parseFile("tst.xml")
1601ctxt = doc.xpathNewContext()
1602libxml2.registerXPathFunction(ctxt._o, "foo", None, foo)
1603res = ctxt.xpathEval("foo(1)")
1604if res != 2:
1605 print "xpath extension failure"
1606doc.freeDoc()
1607ctxt.xpathFreeContext()</pre>
1608
1609<p>Note how the extension function is registered with the context (but that
1610part is not yet finalized, ths may change slightly in the future).</p>
1611
1612<h3>tstxpath.py:</h3>
1613
1614<p>This test is similar to the previousone but shows how the extension
1615function can access the XPath evaluation context:</p>
1616<pre>def foo(ctx, x):
1617 global called
1618
1619 #
1620 # test that access to the XPath evaluation contexts
1621 #
1622 pctxt = libxml2.xpathParserContext(_obj=ctx)
1623 ctxt = pctxt.context()
1624 called = ctxt.function()
1625 return x + 1</pre>
1626
1627<p>All the interfaces around the XPath parser(or rather evaluation) context
1628are not finalized, but it should be sufficient to do contextual work at the
1629evaluation point.</p>
1630
1631<h3>Memory debugging:</h3>
1632
1633<p>last but not least, all tests starts with the following prologue:</p>
1634<pre>#memory debug specific
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1635libxml2.debugMemory(1)</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1636
1637<p>and ends with the following epilogue:</p>
1638<pre>#memory debug specific
1639libxml2.cleanupParser()
1640if libxml2.debugMemory(1) == 0:
1641 print "OK"
1642else:
1643 print "Memory leak %d bytes" % (libxml2.debugMemory(1))
1644 libxml2.dumpMemory()</pre>
1645
1646<p>Those activate the memory debugging interface of libxml2 where all
1647alloacted block in the library are tracked. The prologue then cleans up the
1648library state and checks that all allocated memory has been freed. If not it
1649calls dumpMemory() which saves that list in a <code>.memdump</code> file.</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1650
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1651<h2><a name="architecture">libxml architecture</a></h2>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1652
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1653<p>Libxml is made of multiple components; some of them are optional, and most
1654of the block interfaces are public. The main components are:</p>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1655<ul>
1656 <li>an Input/Output layer</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1657 <li>FTP and HTTP client layers (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1658 <li>an Internationalization layer managing the encodings support</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1659 <li>a URI module</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1660 <li>the XML parser and its basic SAX interface</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1661 <li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1662 <li>a SAX tree module to build an in-memory DOM representation</li>
1663 <li>a tree module to manipulate the DOM representation</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1664 <li>a validation module using the DOM representation (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1665 <li>an XPath module for global lookup in a DOM representation
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1666 (optional)</li>
1667 <li>a debug module (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1668</ul>
1669
1670<p>Graphically this gives the following:</p>
1671
1672<p><img src="libxml.gif" alt="a graphical view of the various"></p>
1673
1674<p></p>
1675
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1676<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1677
1678<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1679returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1680<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1681as the file name, the document type, and a <strong>children</strong> pointer
1682which is the root of the document (or more exactly the first child under the
1683root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1684chained in double-linked lists of siblings and with a children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1685relationship. An xmlNode can also carry properties (a chain of xmlAttr
1686structures). An attribute may have a value which is a list of TEXT or
1687ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1688
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1689<p>Here is an example (erroneous with respect to the XML spec since there
1690should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1691
1692<p><img src="structure.gif" alt=" structure.gif "></p>
1693
1694<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1695called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1696prints them back as parsed. This is useful for detecting errors both in XML
1697code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1698which prints the actual in-memory structure of the document; here is the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1699result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1700<pre>DOCUMENT
1701version=1.0
1702standalone=true
1703 ELEMENT EXAMPLE
1704 ATTRIBUTE prop1
1705 TEXT
1706 content=gnome is great
1707 ATTRIBUTE prop2
1708 ENTITY_REF
1709 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1710 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1711 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1712 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1713 TEXT
1714 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1715 ELEMENT chapter
1716 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1717 TEXT
1718 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1719 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1720 TEXT
1721 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1722 ELEMENT image
1723 ATTRIBUTE href
1724 TEXT
1725 content=linus.gif
1726 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1727 TEXT
1728 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1729
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1730<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1731
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1732<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1733
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1734<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1735memory. In that case (and if you don't expect to save back the XML document
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1736loaded using libxml), it's better to use the SAX interface of libxml. SAX is
1737a <strong>callback-based interface</strong> to the parser. Before parsing,
1738the application layer registers a customized set of callbacks which are
1739called by the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1740
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1741<p>To get more detailed step-by-step guidance on using the SAX interface of
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1742libxml, see the <a
1743href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
1744documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1745Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1746
1747<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
1748program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1749binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1750distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1751testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1752<pre>SAX.setDocumentLocator()
1753SAX.startDocument()
1754SAX.getEntity(amp)
1755SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
1756SAX.characters( , 3)
1757SAX.startElement(head)
1758SAX.characters( , 4)
1759SAX.startElement(title)
1760SAX.characters(Welcome to Gnome, 16)
1761SAX.endElement(title)
1762SAX.characters( , 3)
1763SAX.endElement(head)
1764SAX.characters( , 3)
1765SAX.startElement(chapter)
1766SAX.characters( , 4)
1767SAX.startElement(title)
1768SAX.characters(The Linux adventure, 19)
1769SAX.endElement(title)
1770SAX.characters( , 4)
1771SAX.startElement(p)
1772SAX.characters(bla bla bla ..., 15)
1773SAX.endElement(p)
1774SAX.characters( , 4)
1775SAX.startElement(image, href='linus.gif')
1776SAX.endElement(image)
1777SAX.characters( , 4)
1778SAX.startElement(p)
1779SAX.characters(..., 3)
1780SAX.endElement(p)
1781SAX.characters( , 3)
1782SAX.endElement(chapter)
1783SAX.characters( , 1)
1784SAX.endElement(EXAMPLE)
1785SAX.endDocument()</pre>
1786
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1787<p>Most of the other interfaces of libxml are based on the DOM tree-building
1788facility, so nearly everything up to the end of this document presupposes the
1789use of the standard DOM tree build. Note that the DOM tree itself is built by
1790a set of registered default callbacks, without internal specific
1791interface.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1792
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1793<h2><a name="Validation">Validation &amp; DTDs</a></h2>
1794
1795<p>Table of Content:</p>
1796<ol>
1797 <li><a href="#General5">General overview</a></li>
1798 <li><a href="#definition">The definition</a></li>
1799 <li><a href="#Simple">Simple rules</a>
1800 <ol>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]1801 <li><a href="#reference">How to reference a DTD from a document</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1802 <li><a href="#Declaring">Declaring elements</a></li>
1803 <li><a href="#Declaring1">Declaring attributes</a></li>
1804 </ol>
1805 </li>
1806 <li><a href="#Some">Some examples</a></li>
1807 <li><a href="#validate">How to validate</a></li>
1808 <li><a href="#Other">Other resources</a></li>
1809</ol>
1810
1811<h3><a name="General5">General overview</a></h3>
1812
1813<p>Well what is validation and what is a DTD ?</p>
1814
1815<p>DTD is the acronym for Document Type Definition. This is a description of
1816the content for a familly of XML files. This is part of the XML 1.0
1817specification, and alows to describe and check that a given document instance
1818conforms to a set of rules detailing its structure and content.</p>
1819
1820<p>Validation is the process of checking a document against a DTD (more
1821generally against a set of construction rules).</p>
1822
1823<p>The validation process and building DTDs are the two most difficult parts
1824of the XML life cycle. Briefly a DTD defines all the possibles element to be
1825found within your document, what is the formal shape of your document tree
1826(by defining the allowed content of an element, either text, a regular
1827expression for the allowed list of children, or mixed content i.e. both text
1828and children). The DTD also defines the allowed attributes for all elements
1829and the types of the attributes.</p>
1830
1831<h3><a name="definition1">The definition</a></h3>
1832
1833<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a
1834href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of
1835Rev1</a>):</p>
1836<ul>
1837 <li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring
1838 elements</a></li>
1839 <li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring
1840 attributes</a></li>
1841</ul>
1842
1843<p>(unfortunately) all this is inherited from the SGML world, the syntax is
1844ancient...</p>
1845
1846<h3><a name="Simple1">Simple rules</a></h3>
1847
1848<p>Writing DTD can be done in multiple ways, the rules to build them if you
1849need something fixed or something which can evolve over time can be radically
1850different. Really complex DTD like Docbook ones are flexible but quite harder
1851to design. I will just focuse on DTDs for a formats with a fixed simple
1852structure. It is just a set of basic rules, and definitely not exhaustive nor
1853useable for complex DTD design.</p>
1854
1855<h4><a name="reference1">How to reference a DTD from a document</a>:</h4>
1856
1857<p>Assuming the top element of the document is <code>spec</code> and the dtd
1858is placed in the file <code>mydtd</code> in the subdirectory
1859<code>dtds</code> of the directory from where the document were loaded:</p>
1860
1861<p><code>&lt;!DOCTYPE spec SYSTEM "dtds/mydtd"&gt;</code></p>
1862
1863<p>Notes:</p>
1864<ul>
1865 <li>the system string is actually an URI-Reference (as defined in <a
1866 href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a
1867 full URL string indicating the location of your DTD on the Web, this is a
1868 really good thing to do if you want others to validate your document</li>
1869 <li>it is also possible to associate a <code>PUBLIC</code> identifier (a
1870 magic string) so that the DTd is looked up in catalogs on the client side
1871 without having to locate it on the web</li>
1872 <li>a dtd contains a set of elements and attributes declarations, but they
1873 don't define what the root of the document should be. This is explicitely
1874 told to the parser/validator as the first element of the
1875 <code>DOCTYPE</code> declaration.</li>
1876</ul>
1877
1878<h4><a name="Declaring2">Declaring elements</a>:</h4>
1879
1880<p>The following declares an element <code>spec</code>:</p>
1881
1882<p><code>&lt;!ELEMENT spec (front, body, back?)&gt;</code></p>
1883
1884<p>it also expresses that the spec element contains one <code>front</code>,
1885one <code>body</code> and one optionnal <code>back</code> children elements
1886in this order. The declaration of one element of the structure and its
1887content are done in a single declaration. Similary the following declares
1888<code>div1</code> elements:</p>
1889
Daniel Veillard51737272002-01-23 23:10:38 +0000[diff] [blame]1890<p><code>&lt;!ELEMENT div1 (head, (p | list | note)*, div2?)&gt;</code></p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1891
1892<p>means div1 contains one <code>head</code> then a series of optional
1893<code>p</code>, <code>list</code>s and <code>note</code>s and then an
1894optional <code>div2</code>. And last but not least an element can contain
1895text:</p>
1896
1897<p><code>&lt;!ELEMENT b (#PCDATA)&gt;</code></p>
1898
1899<p><code>b</code> contains text or being of mixed content (text and elements
1900in no particular order):</p>
1901
1902<p><code>&lt;!ELEMENT p (#PCDATA|a|ul|b|i|em)*&gt;</code></p>
1903
1904<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>,
1905<code>b</code>, <code>i </code>or <code>em</code> elements in no particular
1906order.</p>
1907
1908<h4><a name="Declaring1">Declaring attributes</a>:</h4>
1909
1910<p>again the attributes declaration includes their content definition:</p>
1911
1912<p><code>&lt;!ATTLIST termdef name CDATA #IMPLIED&gt;</code></p>
1913
1914<p>means that the element <code>termdef</code> can have a <code>name</code>
1915attribute containing text (<code>CDATA</code>) and which is optionnal
1916(<code>#IMPLIED</code>). The attribute value can also be defined within a
1917set:</p>
1918
1919<p><code>&lt;!ATTLIST list type (bullets|ordered|glossary)
1920"ordered"&gt;</code></p>
1921
1922<p>means <code>list</code> element have a <code>type</code> attribute with 3
1923allowed values "bullets", "ordered" or "glossary" and which default to
1924"ordered" if the attribute is not explicitely specified.</p>
1925
1926<p>The content type of an attribute can be text (<code>CDATA</code>),
1927anchor/reference/references
1928(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies)
1929(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s)
1930(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a
1931<code>chapter</code> element can have an optional <code>id</code> attribute
1932of type <code>ID</code>, usable for reference from attribute of type
1933IDREF:</p>
1934
1935<p><code>&lt;!ATTLIST chapter id ID #IMPLIED&gt;</code></p>
1936
1937<p>The last value of an attribute definition can be <code>#REQUIRED
1938</code>meaning that the attribute has to be given, <code>#IMPLIED</code>
1939meaning that it is optional, or the default value (possibly prefixed by
1940<code>#FIXED</code> if it is the only allowed).</p>
1941
1942<p>Notes:</p>
1943<ul>
1944 <li>usually the attributes pertaining to a given element are declared in a
1945 single expression, but it is just a convention adopted by a lot of DTD
1946 writers:
1947 <pre>&lt;!ATTLIST termdef
1948 id ID #REQUIRED
1949 name CDATA #IMPLIED&gt;</pre>
1950 <p>The previous construct defines both <code>id</code> and
1951 <code>name</code> attributes for the element <code>termdef</code></p>
1952 </li>
1953</ul>
1954
1955<h3><a name="Some1">Some examples</a></h3>
1956
1957<p>The directory <code>test/valid/dtds/</code> in the libxml distribution
1958contains some complex DTD examples. The <code>test/valid/dia.xml</code>
1959example shows an XML file where the simple DTD is directly included within
1960the document.</p>
1961
1962<h3><a name="validate1">How to validate</a></h3>
1963
1964<p>The simplest is to use the xmllint program comming with libxml. The
1965<code>--valid</code> option turn on validation of the files given as input,
1966for example the following validates a copy of the first revision of the XML
19671.0 specification:</p>
1968
1969<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p>
1970
1971<p>the -- noout is used to not output the resulting tree.</p>
1972
1973<p>The <code>--dtdvalid dtd</code> allows to validate the document(s) against
1974a given DTD.</p>
1975
1976<p>Libxml exports an API to handle DTDs and validation, check the <a
1977href="http://xmlsoft.org/html/libxml-valid.html">associated
1978description</a>.</p>
1979
1980<h3><a name="Other1">Other resources</a></h3>
1981
1982<p>DTDs are as old as SGML. So there may be a number of examples on-line, I
1983will just list one for now, others pointers welcome:</p>
1984<ul>
1985 <li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li>
1986</ul>
1987
1988<p>I suggest looking at the examples found under test/valid/dtd and any of
1989the large number of books available on XML. The dia example in test/valid
1990should be both simple and complete enough to allow you to build your own.</p>
1991
1992<p></p>
1993
1994<h2><a name="Memory">Memory Management</a></h2>
1995
1996<p>Table of Content:</p>
1997<ol>
1998 <li><a href="#General3">General overview</a></li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]1999 <li><a href="#setting">Setting libxml set of memory routines</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2000 <li><a href="#cleanup">Cleaning up after parsing</a></li>
2001 <li><a href="#Debugging">Debugging routines</a></li>
2002 <li><a href="#General4">General memory requirements</a></li>
2003</ol>
2004
2005<h3><a name="General3">General overview</a></h3>
2006
2007<p>The module <code><a
2008href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
2009provides the interfaces to the libxml memory system:</p>
2010<ul>
2011 <li>libxml does not use the libc memory allocator directly but xmlFree(),
2012 xmlMalloc() and xmlRealloc()</li>
2013 <li>those routines can be reallocated to a specific set of routine, by
2014 default the libc ones i.e. free(), malloc() and realloc()</li>
2015 <li>the xmlmemory.c module includes a set of debugging routine</li>
2016</ul>
2017
2018<h3><a name="setting">Setting libxml set of memory routines</a></h3>
2019
2020<p>It is sometimes useful to not use the default memory allocator, either for
2021debugging, analysis or to implement a specific behaviour on memory management
2022(like on embedded systems). Two function calls are available to do so:</p>
2023<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2024 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet
2025 ()</a> which return the current set of functions in use by the parser</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2026 <li><a
2027 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2028 which allow to set up a new set of memory allocation functions</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2029</ul>
2030
2031<p>Of course a call to xmlMemSetup() should probably be done before calling
2032any other libxml routines (unless you are sure your allocations routines are
2033compatibles).</p>
2034
2035<h3><a name="cleanup">Cleaning up after parsing</a></h3>
2036
2037<p>Libxml is not stateless, there is a few set of memory structures needing
2038allocation before the parser is fully functionnal (some encoding structures
2039for example). This also mean that once parsing is finished there is a tiny
2040amount of memory (a few hundred bytes) which can be recollected if you don't
2041reuse the parser immediately:</p>
2042<ul>
2043 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2044 ()</a> is a centralized routine to free the parsing states. Note that it
2045 won't deallocate any produced tree if any (use the xmlFreeDoc() and
2046 related routines for this).</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2047 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2048 ()</a> is the dual routine allowing to preallocate the parsing state
2049 which can be useful for example to avoid initialization reentrancy
2050 problems when using libxml in multithreaded applications</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2051</ul>
2052
2053<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild
2054at the next invocation of parser routines, but be careful of the consequences
2055in multithreaded applications.</p>
2056
2057<h3><a name="Debugging">Debugging routines</a></h3>
2058
2059<p>When configured using --with-mem-debug flag (off by default), libxml uses
2060a set of memory allocation debugging routineskeeping track of all allocated
2061blocks and the location in the code where the routine was called. A couple of
2062other debugging routines allow to dump the memory allocated infos to a file
2063or call a specific routine when a given block number is allocated:</p>
2064<ul>
2065 <li><a
2066 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2067 <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2068 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>
2069 and <a
2070 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>
2071 are the memory debugging replacement allocation routines</li>
2072 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2073 ()</a> dumps all the informations about the allocated memory block lefts
2074 in the <code>.memdump</code> file</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2075</ul>
2076
2077<p>When developping libxml memory debug is enabled, the tests programs call
2078xmlMemoryDump () and the "make test" regression tests will check for any
2079memory leak during the full regression test sequence, this helps a lot
2080ensuring that libxml does not leak memory and bullet proof memory
2081allocations use (some libc implementations are known to be far too permissive
2082resulting in major portability problems!).</p>
2083
2084<p>If the .memdump reports a leak, it displays the allocation function and
2085also tries to give some informations about the content and structure of the
2086allocated blocks left. This is sufficient in most cases to find the culprit,
2087but not always. Assuming the allocation problem is reproductible, it is
2088possible to find more easilly:</p>
2089<ol>
2090 <li>write down the block number xxxx not allocated</li>
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame^]2091 <li>export the environement variable XML_MEM_BREAKPOINT=xxxx , the easiest
2092 when using GDB is to simply give the command
2093 <p><code>set environment XML_MEM_BREAKPOINT xxxx</code></p>
2094 <p>before running the program.</p>
2095 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2096 <li>run the program under a debugger and set a breakpoint on
2097 xmlMallocBreakpoint() a specific function called when this precise block
2098 is allocated</li>
2099 <li>when the breakpoint is reached you can then do a fine analysis of the
2100 allocation an step to see the condition resulting in the missing
2101 deallocation.</li>
2102</ol>
2103
2104<p>I used to use a commercial tool to debug libxml memory problems but after
2105noticing that it was not detecting memory leaks that simple mechanism was
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame^]2106used and proved extremely efficient until now. Lately I have also used <a
2107href="http://developer.kde.org/~sewardj/">valgrind</a> with quite some
2108success, it is tied to the i386 architecture since it works by emulating the
2109processor and instruction set, it is slow but extremely efficient, i.e. it
2110spot memory usage errors in a very precise way.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2111
2112<h3><a name="General4">General memory requirements</a></h3>
2113
2114<p>How much libxml memory require ? It's hard to tell in average it depends
2115of a number of things:</p>
2116<ul>
2117 <li>the parser itself should work in a fixed amout of memory, except for
2118 information maintained about the stacks of names and entities locations.
2119 The I/O and encoding handlers will probably account for a few KBytes.
2120 This is true for both the XML and HTML parser (though the HTML parser
2121 need more state).</li>
2122 <li>If you are generating the DOM tree then memory requirements will grow
2123 nearly lineary with the size of the data. In general for a balanced
2124 textual document the internal memory requirement is about 4 times the
2125 size of the UTF8 serialization of this document (exmple the XML-1.0
2126 recommendation is a bit more of 150KBytes and takes 650KBytes of main
2127 memory when parsed). Validation will add a amount of memory required for
2128 maintaining the external Dtd state which should be linear with the
2129 complexity of the content model defined by the Dtd</li>
2130 <li>If you don't care about the advanced features of libxml like
2131 validation, DOM, XPath or XPointer, but really need to work fixed memory
2132 requirements, then the SAX interface should be used.</li>
2133</ul>
2134
2135<p></p>
2136
2137<h2><a name="Encodings">Encodings support</a></h2>
2138
2139<p>Table of Content:</p>
2140<ol>
2141 <li><a href="encoding.html#What">What does internationalization support
2142 mean ?</a></li>
2143 <li><a href="encoding.html#internal">The internal encoding, how and
2144 why</a></li>
2145 <li><a href="encoding.html#implemente">How is it implemented ?</a></li>
2146 <li><a href="encoding.html#Default">Default supported encodings</a></li>
2147 <li><a href="encoding.html#extend">How to extend the existing
2148 support</a></li>
2149</ol>
2150
2151<h3><a name="What">What does internationalization support mean ?</a></h3>
2152
2153<p>XML was designed from the start to allow the support of any character set
2154by using Unicode. Any conformant XML parser has to support the UTF-8 and
2155UTF-16 default encodings which can both express the full unicode ranges. UTF8
2156is a variable length encoding whose greatest point are to resuse the same
2157emcoding for ASCII and to save space for Western encodings, but it is a bit
2158more complex to handle in practice. UTF-16 use 2 bytes per characters (and
2159sometimes combines two pairs), it makes implementation easier, but looks a
2160bit overkill for Western languages encoding. Moreover the XML specification
2161allows document to be encoded in other encodings at the condition that they
2162are clearly labelled as such. For example the following is a wellformed XML
2163document encoded in ISO-8859 1 and using accentuated letter that we French
2164likes for both markup and content:</p>
2165<pre>&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2166&lt;très&gt;là&lt;/très&gt;</pre>
2167
2168<p>Having internationalization support in libxml means the foolowing:</p>
2169<ul>
2170 <li>the document is properly parsed</li>
2171 <li>informations about it's encoding are saved</li>
2172 <li>it can be modified</li>
2173 <li>it can be saved in its original encoding</li>
2174 <li>it can also be saved in another encoding supported by libxml (for
2175 example straight UTF8 or even an ASCII form)</li>
2176</ul>
2177
2178<p>Another very important point is that the whole libxml API, with the
2179exception of a few routines to read with a specific encoding or save to a
2180specific encoding, is completely agnostic about the original encoding of the
2181document.</p>
2182
2183<p>It should be noted too that the HTML parser embedded in libxml now obbey
2184the same rules too, the following document will be (as of 2.2.2) handled in
2185an internationalized fashion by libxml too:</p>
2186<pre>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
2187 "http://www.w3.org/TR/REC-html40/loose.dtd"&gt;
2188&lt;html lang="fr"&gt;
2189&lt;head&gt;
2190 &lt;META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"&gt;
2191&lt;/head&gt;
2192&lt;body&gt;
2193&lt;p&gt;W3C crée des standards pour le Web.&lt;/body&gt;
2194&lt;/html&gt;</pre>
2195
2196<h3><a name="internal">The internal encoding, how and why</a></h3>
2197
2198<p>One of the core decision was to force all documents to be converted to a
2199default internal encoding, and that encoding to be UTF-8, here are the
2200rationale for those choices:</p>
2201<ul>
2202 <li>keeping the native encoding in the internal form would force the libxml
2203 users (or the code associated) to be fully aware of the encoding of the
2204 original document, for examples when adding a text node to a document,
2205 the content would have to be provided in the document encoding, i.e. the
2206 client code would have to check it before hand, make sure it's conformant
2207 to the encoding, etc ... Very hard in practice, though in some specific
2208 cases this may make sense.</li>
2209 <li>the second decision was which encoding. From the XML spec only UTF8 and
2210 UTF16 really makes sense as being the two only encodings for which there
2211 is amndatory support. UCS-4 (32 bits fixed size encoding) could be
2212 considered an intelligent choice too since it's a direct Unicode mapping
2213 support. I selected UTF-8 on the basis of efficiency and compatibility
2214 with surrounding software:
2215 <ul>
2216 <li>UTF-8 while a bit more complex to convert from/to (i.e. slightly
2217 more costly to import and export CPU wise) is also far more compact
2218 than UTF-16 (and UCS-4) for a majority of the documents I see it used
2219 for right now (RPM RDF catalogs, advogato data, various configuration
2220 file formats, etc.) and the key point for today's computer
2221 architecture is efficient uses of caches. If one nearly double the
2222 memory requirement to store the same amount of data, this will trash
2223 caches (main memory/external caches/internal caches) and my take is
2224 that this harms the system far more than the CPU requirements needed
2225 for the conversion to UTF-8</li>
2226 <li>Most of libxml version 1 users were using it with straight ASCII
2227 most of the time, doing the conversion with an internal encoding
2228 requiring all their code to be rewritten was a serious show-stopper
2229 for using UTF-16 or UCS-4.</li>
2230 <li>UTF-8 is being used as the de-facto internal encoding standard for
2231 related code like the <a href="http://www.pango.org/">pango</a>
2232 upcoming Gnome text widget, and a lot of Unix code (yep another place
2233 where Unix programmer base takes a different approach from Microsoft
2234 - they are using UTF-16)</li>
2235 </ul>
2236 </li>
2237</ul>
2238
2239<p>What does this mean in practice for the libxml user:</p>
2240<ul>
2241 <li>xmlChar, the libxml data type is a byte, those bytes must be assembled
2242 as UTF-8 valid strings. The proper way to terminate an xmlChar * string
2243 is simply to append 0 byte, as usual.</li>
2244 <li>One just need to make sure that when using chars outside the ASCII set,
2245 the values has been properly converted to UTF-8</li>
2246</ul>
2247
2248<h3><a name="implemente">How is it implemented ?</a></h3>
2249
2250<p>Let's describe how all this works within libxml, basically the I18N
2251(internationalization) support get triggered only during I/O operation, i.e.
2252when reading a document or saving one. Let's look first at the reading
2253sequence:</p>
2254<ol>
2255 <li>when a document is processed, we usually don't know the encoding, a
2256 simple heuristic allows to detect UTF-18 and UCS-4 from whose where the
2257 ASCII range (0-0x7F) maps with ASCII</li>
2258 <li>the xml declaration if available is parsed, including the encoding
2259 declaration. At that point, if the autodetected encoding is different
2260 from the one declared a call to xmlSwitchEncoding() is issued.</li>
2261 <li>If there is no encoding declaration, then the input has to be in either
2262 UTF-8 or UTF-16, if it is not then at some point when processing the
2263 input, the converter/checker of UTF-8 form will raise an encoding error.
2264 You may end-up with a garbled document, or no document at all ! Example:
2265 <pre>~/XML -&gt; ./xmllint err.xml
2266err.xml:1: error: Input is not proper UTF-8, indicate encoding !
2267&lt;très&gt;là&lt;/très&gt;
2268 ^
2269err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C
2270&lt;très&gt;là&lt;/très&gt;
2271 ^</pre>
2272 </li>
2273 <li>xmlSwitchEncoding() does an encoding name lookup, canonalize it, and
2274 then search the default registered encoding converters for that encoding.
2275 If it's not within the default set and iconv() support has been compiled
2276 it, it will ask iconv for such an encoder. If this fails then the parser
2277 will report an error and stops processing:
2278 <pre>~/XML -&gt; ./xmllint err2.xml
2279err2.xml:1: error: Unsupported encoding UnsupportedEnc
2280&lt;?xml version="1.0" encoding="UnsupportedEnc"?&gt;
2281 ^</pre>
2282 </li>
2283 <li>From that point the encoder process progressingly the input (it is
2284 plugged as a front-end to the I/O module) for that entity. It captures
2285 and convert on-the-fly the document to be parsed to UTF-8. The parser
2286 itself just does UTF-8 checking of this input and process it
2287 transparently. The only difference is that the encoding information has
2288 been added to the parsing context (more precisely to the input
2289 corresponding to this entity).</li>
2290 <li>The result (when using DOM) is an internal form completely in UTF-8
2291 with just an encoding information on the document node.</li>
2292</ol>
2293
2294<p>Ok then what's happen when saving the document (assuming you
2295colllected/built an xmlDoc DOM like structure) ? It depends on the function
2296called, xmlSaveFile() will just try to save in the original encoding, while
2297xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given
2298encoding:</p>
2299<ol>
2300 <li>if no encoding is given, libxml will look for an encoding value
2301 associated to the document and if it exists will try to save to that
2302 encoding,
2303 <p>otherwise everything is written in the internal form, i.e. UTF-8</p>
2304 </li>
2305 <li>so if an encoding was specified, either at the API level or on the
2306 document, libxml will again canonalize the encoding name, lookup for a
2307 converter in the registered set or through iconv. If not found the
2308 function will return an error code</li>
2309 <li>the converter is placed before the I/O buffer layer, as another kind of
2310 buffer, then libxml will simply push the UTF-8 serialization to through
2311 that buffer, which will then progressively be converted and pushed onto
2312 the I/O layer.</li>
2313 <li>It is possible that the converter code fails on some input, for example
2314 trying to push an UTF-8 encoded chinese character through the UTF-8 to
2315 ISO-8859-1 converter won't work. Since the encoders are progressive they
2316 will just report the error and the number of bytes converted, at that
2317 point libxml will decode the offending character, remove it from the
2318 buffer and replace it with the associated charRef encoding &amp;#123; and
2319 resume the convertion. This guarante that any document will be saved
2320 without losses (except for markup names where this is not legal, this is
2321 a problem in the current version, in pactice avoid using non-ascci
2322 characters for tags or attributes names @@). A special "ascii" encoding
2323 name is used to save documents to a pure ascii form can be used when
2324 portability is really crucial</li>
2325</ol>
2326
2327<p>Here is a few examples based on the same test document:</p>
2328<pre>~/XML -&gt; ./xmllint isolat1
2329&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2330&lt;très&gt;là&lt;/très&gt;
2331~/XML -&gt; ./xmllint --encode UTF-8 isolat1
2332&lt;?xml version="1.0" encoding="UTF-8"?&gt;
2333&lt;très&gt;là  &lt;/très&gt;
2334~/XML -&gt; </pre>
2335
2336<p>The same processing is applied (and reuse most of the code) for HTML I18N
2337processing. Looking up and modifying the content encoding is a bit more
2338difficult since it is located in a &lt;meta&gt; tag under the &lt;head&gt;,
2339so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have
2340been provided. The parser also attempts to switch encoding on the fly when
2341detecting such a tag on input. Except for that the processing is the same
2342(and again reuses the same code).</p>
2343
2344<h3><a name="Default">Default supported encodings</a></h3>
2345
2346<p>libxml has a set of default converters for the following encodings
2347(located in encoding.c):</p>
2348<ol>
2349 <li>UTF-8 is supported by default (null handlers)</li>
2350 <li>UTF-16, both little and big endian</li>
2351 <li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li>
2352 <li>ASCII, useful mostly for saving</li>
2353 <li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML
2354 predefined entities like &amp;copy; for the Copyright sign.</li>
2355</ol>
2356
2357<p>More over when compiled on an Unix platfor with iconv support the full set
2358of encodings supported by iconv can be instantly be used by libxml. On a
2359linux machine with glibc-2.1 the list of supported encodings and aliases fill
23603 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the
2361various Japanese ones.</p>
2362
2363<h4>Encoding aliases</h4>
2364
2365<p>From 2.2.3, libxml has support to register encoding names aliases. The
2366goal is to be able to parse document whose encoding is supported but where
2367the name differs (for example from the default set of names accepted by
2368iconv). The following functions allow to register and handle new aliases for
2369existing encodings. Once registered libxml will automatically lookup the
2370aliases when handling a document:</p>
2371<ul>
2372 <li>int xmlAddEncodingAlias(const char *name, const char *alias);</li>
2373 <li>int xmlDelEncodingAlias(const char *alias);</li>
2374 <li>const char * xmlGetEncodingAlias(const char *alias);</li>
2375 <li>void xmlCleanupEncodingAliases(void);</li>
2376</ul>
2377
2378<h3><a name="extend">How to extend the existing support</a></h3>
2379
2380<p>Well adding support for new encoding, or overriding one of the encoders
2381(assuming it is buggy) should not be hard, just write an input and output
2382conversion routines to/from UTF-8, and register them using
2383xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be
2384called automatically if the parser(s) encounter such an encoding name
2385(register it uppercase, this will help). The description of the encoders,
2386their arguments and expected return values are described in the encoding.h
2387header.</p>
2388
2389<p>A quick note on the topic of subverting the parser to use a different
2390internal encoding than UTF-8, in some case people will absolutely want to
2391keep the internal encoding different, I think it's still possible (but the
2392encoding must be compliant with ASCII on the same subrange) though I didn't
2393tried it. The key is to override the default conversion routines (by
2394registering null encoders/decoders for your charsets), and bypass the UTF-8
2395checking of the parser by setting the parser context charset
2396(ctxt-&gt;charset) to something different than XML_CHAR_ENCODING_UTF8, but
2397there is no guarantee taht this will work. You may also have some troubles
2398saving back.</p>
2399
2400<p>Basically proper I18N support is important, this requires at least
2401libxml-2.0.0, but a lot of features and corrections are really available only
2402starting 2.2.</p>
2403
2404<h2><a name="IO">I/O Interfaces</a></h2>
2405
2406<p>Table of Content:</p>
2407<ol>
2408 <li><a href="#General1">General overview</a></li>
2409 <li><a href="#basic">The basic buffer type</a></li>
2410 <li><a href="#Input">Input I/O handlers</a></li>
2411 <li><a href="#Output">Output I/O handlers</a></li>
2412 <li><a href="#entities">The entities loader</a></li>
2413 <li><a href="#Example2">Example of customized I/O</a></li>
2414</ol>
2415
2416<h3><a name="General1">General overview</a></h3>
2417
2418<p>The module <code><a
2419href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides
2420the interfaces to the libxml I/O system. This consists of 4 main parts:</p>
2421<ul>
2422 <li>Entities loader, this is a routine which tries to fetch the entities
2423 (files) based on their PUBLIC and SYSTEM identifiers. The default loader
2424 don't look at the public identifier since libxml do not maintain a
2425 catalog. You can redefine you own entity loader by using
2426 <code>xmlGetExternalEntityLoader()</code> and
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2427 <code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the
2428 example</a>.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2429 <li>Input I/O buffers which are a commodity structure used by the parser(s)
2430 input layer to handle fetching the informations to feed the parser. This
2431 provides buffering and is also a placeholder where the encoding
2432 convertors to UTF8 are piggy-backed.</li>
2433 <li>Output I/O buffers are similar to the Input ones and fulfill similar
2434 task but when generating a serialization from a tree.</li>
2435 <li>A mechanism to register sets of I/O callbacks and associate them with
2436 specific naming schemes like the protocol part of the URIs.
2437 <p>This affect the default I/O operations and allows to use specific I/O
2438 handlers for certain names.</p>
2439 </li>
2440</ul>
2441
2442<p>The general mechanism used when loading http://rpmfind.net/xml.html for
2443example in the HTML parser is the following:</p>
2444<ol>
2445 <li>The default entity loader calls <code>xmlNewInputFromFile()</code> with
2446 the parsing context and the URI string.</li>
2447 <li>the URI string is checked against the existing registered handlers
2448 using their match() callback function, if the HTTP module was compiled
2449 in, it is registered and its match() function will succeeds</li>
2450 <li>the open() function of the handler is called and if successful will
2451 return an I/O Input buffer</li>
2452 <li>the parser will the start reading from this buffer and progressively
2453 fetch information from the resource, calling the read() function of the
2454 handler until the resource is exhausted</li>
2455 <li>if an encoding change is detected it will be installed on the input
2456 buffer, providing buffering and efficient use of the conversion
2457 routines</li>
2458 <li>once the parser has finished, the close() function of the handler is
2459 called once and the Input buffer and associed resources are
2460 deallocated.</li>
2461</ol>
2462
2463<p>The user defined callbacks are checked first to allow overriding of the
2464default libxml I/O routines.</p>
2465
2466<h3><a name="basic">The basic buffer type</a></h3>
2467
2468<p>All the buffer manipulation handling is done using the
2469<code>xmlBuffer</code> type define in <code><a
2470href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a
2471resizable memory buffer. The buffer allocation strategy can be selected to be
2472either best-fit or use an exponential doubling one (CPU vs. memory use
2473tradeoff). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and
2474<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a
2475system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number
2476of functions allows to manipulate buffers with names starting with the
2477<code>xmlBuffer...</code> prefix.</p>
2478
2479<h3><a name="Input">Input I/O handlers</a></h3>
2480
2481<p>An Input I/O handler is a simple structure
2482<code>xmlParserInputBuffer</code> containing a context associated to the
2483resource (file descriptor, or pointer to a protocol handler), the read() and
2484close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset
2485encoding handler are also present to support charset conversion when
2486needed.</p>
2487
2488<h3><a name="Output">Output I/O handlers</a></h3>
2489
2490<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an
2491Input one except the callbacks are write() and close().</p>
2492
2493<h3><a name="entities">The entities loader</a></h3>
2494
2495<p>The entity loader resolves requests for new entities and create inputs for
2496the parser. Creating an input from a filename or an URI string is done
2497through the xmlNewInputFromFile() routine. The default entity loader do not
2498handle the PUBLIC identifier associated with an entity (if any). So it just
2499calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in
2500XML).</p>
2501
2502<p>If you want to hook up a catalog mechanism then you simply need to
2503override the default entity loader, here is an example:</p>
2504<pre>#include &lt;libxml/xmlIO.h&gt;
2505
2506xmlExternalEntityLoader defaultLoader = NULL;
2507
2508xmlParserInputPtr
2509xmlMyExternalEntityLoader(const char *URL, const char *ID,
2510 xmlParserCtxtPtr ctxt) {
2511 xmlParserInputPtr ret;
2512 const char *fileID = NULL;
2513 /* lookup for the fileID depending on ID */
2514
2515 ret = xmlNewInputFromFile(ctxt, fileID);
2516 if (ret != NULL)
2517 return(ret);
2518 if (defaultLoader != NULL)
2519 ret = defaultLoader(URL, ID, ctxt);
2520 return(ret);
2521}
2522
2523int main(..) {
2524 ...
2525
2526 /*
2527 * Install our own entity loader
2528 */
2529 defaultLoader = xmlGetExternalEntityLoader();
2530 xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
2531
2532 ...
2533}</pre>
2534
2535<h3><a name="Example2">Example of customized I/O</a></h3>
2536
2537<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a
2538real use case</a>, xmlDocDump() closes the FILE * passed by the application
2539and this was a problem. The <a
2540href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a
2541new output handler with the closing call deactivated:</p>
2542<ol>
2543 <li>First define a new I/O ouput allocator where the output don't close the
2544 file:
2545 <pre>xmlOutputBufferPtr
2546xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) {
2547    xmlOutputBufferPtr ret;
2548    
2549    if (xmlOutputCallbackInitialized == 0)
2550        xmlRegisterDefaultOutputCallbacks();
2551
2552    if (file == NULL) return(NULL);
2553    ret = xmlAllocOutputBuffer(encoder);
2554    if (ret != NULL) {
2555        ret-&gt;context = file;
2556        ret-&gt;writecallback = xmlFileWrite;
2557        ret-&gt;closecallback = NULL; /* No close callback */
2558    }
2559    return(ret); <br>
Daniel Veillard1eb24242002-03-18 11:33:03 +0000[diff] [blame]2560
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]2561
2562
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]2563
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]2564
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame^]2565
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2566} </pre>
2567 </li>
2568 <li>And then use it to save the document:
2569 <pre>FILE *f;
2570xmlOutputBufferPtr output;
2571xmlDocPtr doc;
2572int res;
2573
2574f = ...
2575doc = ....
2576
2577output = xmlOutputBufferCreateOwn(f, NULL);
2578res = xmlSaveFileTo(output, doc, NULL);
2579 </pre>
2580 </li>
2581</ol>
2582
2583<h2><a name="Catalog">Catalog support</a></h2>
2584
2585<p>Table of Content:</p>
2586<ol>
2587 <li><a href="General2">General overview</a></li>
2588 <li><a href="#definition">The definition</a></li>
2589 <li><a href="#Simple">Using catalogs</a></li>
2590 <li><a href="#Some">Some examples</a></li>
2591 <li><a href="#reference">How to tune catalog usage</a></li>
2592 <li><a href="#validate">How to debug catalog processing</a></li>
2593 <li><a href="#Declaring">How to create and maintain catalogs</a></li>
2594 <li><a href="#implemento">The implementor corner quick review of the
2595 API</a></li>
2596 <li><a href="#Other">Other resources</a></li>
2597</ol>
2598
2599<h3><a name="General2">General overview</a></h3>
2600
2601<p>What is a catalog? Basically it's a lookup mechanism used when an entity
2602(a file or a remote resource) references another entity. The catalog lookup
2603is inserted between the moment the reference is recognized by the software
2604(XML parser, stylesheet processing, or even images referenced for inclusion
2605in a rendering) and the time where loading that resource is actually
2606started.</p>
2607
2608<p>It is basically used for 3 things:</p>
2609<ul>
2610 <li>mapping from "logical" names, the public identifiers and a more
2611 concrete name usable for download (and URI). For example it can associate
2612 the logical name
2613 <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
2614 <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be
2615 downloaded</p>
2616 <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
2617 </li>
2618 <li>remapping from a given URL to another one, like an HTTP indirection
2619 saying that
2620 <p>"http://www.oasis-open.org/committes/tr.xsl"</p>
2621 <p>should really be looked at</p>
2622 <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
2623 </li>
2624 <li>providing a local cache mechanism allowing to load the entities
2625 associated to public identifiers or remote resources, this is a really
2626 important feature for any significant deployment of XML or SGML since it
2627 allows to avoid the aleas and delays associated to fetching remote
2628 resources.</li>
2629</ul>
2630
2631<h3><a name="definition">The definitions</a></h3>
2632
2633<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p>
2634<ul>
2635 <li>the older SGML catalogs, the official spec is SGML Open Technical
2636 Resolution TR9401:1997, but is better understood by reading <a
2637 href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from
2638 James Clark. This is relatively old and not the preferred mode of
2639 operation of libxml.</li>
2640 <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2641 Catalogs</a> is far more flexible, more recent, uses an XML syntax and
2642 should scale quite better. This is the default option of libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2643</ul>
2644
2645<p></p>
2646
2647<h3><a name="Simple">Using catalog</a></h3>
2648
2649<p>In a normal environment libxml will by default check the presence of a
2650catalog in /etc/xml/catalog, and assuming it has been correctly populated,
2651the processing is completely transparent to the document user. To take a
2652concrete example, suppose you are authoring a DocBook document, this one
2653starts with the following DOCTYPE definition:</p>
2654<pre>&lt;?xml version='1.0'?&gt;
2655&lt;!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
2656 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"&gt;</pre>
2657
2658<p>When validating the document with libxml, the catalog will be
2659automatically consulted to lookup the public identifier "-//Norman Walsh//DTD
2660DocBk XML V3.1.4//EN" and the system identifier
2661"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have
2662been installed on your system and the catalogs actually point to them, libxml
2663will fetch them from the local disk.</p>
2664
2665<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this
2666DOCTYPE example it's a really old version, but is fine as an example.</p>
2667
2668<p>Libxml will check the catalog each time that it is requested to load an
2669entity, this includes DTD, external parsed entities, stylesheets, etc ... If
2670your system is correctly configured all the authoring phase and processing
2671should use only local files, even if your document stays portable because it
2672uses the canonical public and system ID, referencing the remote document.</p>
2673
2674<h3><a name="Some">Some examples:</a></h3>
2675
2676<p>Here is a couple of fragments from XML Catalogs used in libxml early
2677regression tests in <code>test/catalogs</code> :</p>
2678<pre>&lt;?xml version="1.0"?&gt;
2679&lt;!DOCTYPE catalog PUBLIC
2680 "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2681 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2682&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2683 &lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2684 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2685...</pre>
2686
2687<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are
2688written in XML, there is a specific namespace for catalog elements
2689"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this
2690catalog is a <code>public</code> mapping it allows to associate a Public
2691Identifier with an URI.</p>
2692<pre>...
2693 &lt;rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2694 rewritePrefix="file:///usr/share/xml/docbook/"/&gt;
2695...</pre>
2696
2697<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that
2698any URI starting with a given prefix should be looked at another URI
2699constructed by replacing the prefix with an new one. In effect this acts like
2700a cache system for a full area of the Web. In practice it is extremely useful
2701with a file prefix if you have installed a copy of those resources on your
2702local system.</p>
2703<pre>...
2704&lt;delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
2705 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2706&lt;delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
2707 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2708&lt;delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
2709 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2710&lt;delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2711 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2712&lt;delegateURI uriStartString="http://www.oasis-open.org/docbook/"
2713 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2714...</pre>
2715
2716<p>Delegation is the core features which allows to build a tree of catalogs,
2717easier to maintain than a single catalog, based on Public Identifier, System
2718Identifier or URI prefixes it instructs the catalog software to look up
2719entries in another resource. This feature allow to build hierarchies of
2720catalogs, the set of entries presented should be sufficient to redirect the
2721resolution of all DocBook references to the specific catalog in
2722<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all
2723references for DocBook 4.2.1 to a specific catalog installed at the same time
2724as the DocBook resources on the local machine.</p>
2725
2726<h3><a name="reference">How to tune catalog usage:</a></h3>
2727
2728<p>The user can change the default catalog behaviour by redirecting queries
2729to its own set of catalogs, this can be done by setting the
2730<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an
2731empty one should deactivate loading the default <code>/etc/xml/catalog</code>
2732default catalog</p>
2733
2734<h3><a name="validate">How to debug catalog processing:</a></h3>
2735
2736<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will
2737make libxml output debugging informations for each catalog operations, for
2738example:</p>
2739<pre>orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2740warning: failed to load external entity "title.xml"
2741orchis:~/XML -&gt; export XML_DEBUG_CATALOG=
2742orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2743Failed to parse catalog /etc/xml/catalog
2744Failed to parse catalog /etc/xml/catalog
2745warning: failed to load external entity "title.xml"
2746Catalogs cleanup
2747orchis:~/XML -&gt; </pre>
2748
2749<p>The test/ent2 references an entity, running the parser from memory makes
2750the base URI unavailable and the the "title.xml" entity cannot be loaded.
2751Setting up the debug environment variable allows to detect that an attempt is
2752made to load the <code>/etc/xml/catalog</code> but since it's not present the
2753resolution fails.</p>
2754
2755<p>But the most advanced way to debug XML catalog processing is to use the
2756<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load
2757catalogs and make resolution queries to see what is going on. This is also
2758used for the regression tests:</p>
2759<pre>orchis:~/XML -&gt; ./xmlcatalog test/catalogs/docbook.xml \
2760 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2761http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2762orchis:~/XML -&gt; </pre>
2763
2764<p>For debugging what is going on, adding one -v flags increase the verbosity
2765level to indicate the processing done (adding a second flag also indicate
2766what elements are recognized at parsing):</p>
2767<pre>orchis:~/XML -&gt; ./xmlcatalog -v test/catalogs/docbook.xml \
2768 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2769Parsing catalog test/catalogs/docbook.xml's content
2770Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
2771http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2772Catalogs cleanup
2773orchis:~/XML -&gt; </pre>
2774
2775<p>A shell interface is also available to debug and process multiple queries
2776(and for regression tests):</p>
2777<pre>orchis:~/XML -&gt; ./xmlcatalog -shell test/catalogs/docbook.xml \
2778 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2779&gt; help
2780Commands available:
2781public PublicID: make a PUBLIC identifier lookup
2782system SystemID: make a SYSTEM identifier lookup
2783resolve PublicID SystemID: do a full resolver lookup
2784add 'type' 'orig' 'replace' : add an entry
2785del 'values' : remove values
2786dump: print the current catalog state
2787debug: increase the verbosity level
2788quiet: decrease the verbosity level
2789exit: quit the shell
2790&gt; public "-//OASIS//DTD DocBook XML V4.1.2//EN"
2791http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2792&gt; quit
2793orchis:~/XML -&gt; </pre>
2794
2795<p>This should be sufficient for most debugging purpose, this was actually
2796used heavily to debug the XML Catalog implementation itself.</p>
2797
2798<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3>
2799
2800<p>Basically XML Catalogs are XML files, you can either use XML tools to
2801manage them or use <strong>xmlcatalog</strong> for this. The basic step is
2802to create a catalog the -create option provide this facility:</p>
2803<pre>orchis:~/XML -&gt; ./xmlcatalog --create tst.xml
2804&lt;?xml version="1.0"?&gt;
2805&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2806 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2807&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2808orchis:~/XML -&gt; </pre>
2809
2810<p>By default xmlcatalog does not overwrite the original catalog and save the
2811result on the standard output, this can be overridden using the -noout
2812option. The <code>-add</code> command allows to add entries in the
2813catalog:</p>
2814<pre>orchis:~/XML -&gt; ./xmlcatalog --noout --create --add "public" \
2815 "-//OASIS//DTD DocBook XML V4.1.2//EN" \
2816 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
2817orchis:~/XML -&gt; cat tst.xml
2818&lt;?xml version="1.0"?&gt;
2819&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
2820 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2821&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2822&lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2823 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2824&lt;/catalog&gt;
2825orchis:~/XML -&gt; </pre>
2826
2827<p>The <code>-add</code> option will always take 3 parameters even if some of
2828the XML Catalog constructs (like nextCatalog) will have only a single
2829argument, just pass a third empty string, it will be ignored.</p>
2830
2831<p>Similarly the <code>-del</code> option remove matching entries from the
2832catalog:</p>
2833<pre>orchis:~/XML -&gt; ./xmlcatalog --del \
2834 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
2835&lt;?xml version="1.0"?&gt;
2836&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2837 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2838&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2839orchis:~/XML -&gt; </pre>
2840
2841<p>The catalog is now empty. Note that the matching of <code>-del</code> is
2842exact and would have worked in a similar fashion with the Public ID
2843string.</p>
2844
2845<p>This is rudimentary but should be sufficient to manage a not too complex
2846catalog tree of resources.</p>
2847
2848<h3><a name="implemento">The implementor corner quick review of the
2849API:</a></h3>
2850
2851<p>First, and like for every other module of libxml, there is an
2852automatically generated <a href="html/libxml-catalog.html">API page for
2853catalog support</a>.</p>
2854
2855<p>The header for the catalog interfaces should be included as:</p>
2856<pre>#include &lt;libxml/catalog.h&gt;</pre>
2857
2858<p>The API is voluntarily kept very simple. First it is not obvious that
2859applications really need access to it since it is the default behaviour of
2860libxml (Note: it is possible to completely override libxml default catalog by
2861using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to
2862plug an application specific resolver).</p>
2863
2864<p>Basically libxml support 2 catalog lists:</p>
2865<ul>
2866 <li>the default one, global shared by all the application</li>
2867 <li>a per-document catalog, this one is built if the document uses the
2868 <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is
2869 associated to the parser context and destroyed when the parsing context
2870 is destroyed.</li>
2871</ul>
2872
2873<p>the document one will be used first if it exists.</p>
2874
2875<h4>Initialization routines:</h4>
2876
2877<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be
2878used at startup to initialize the catalog, if the catalog should be
2879initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs()
2880should be called before xmlInitializeCatalog() which would otherwise do a
2881default initialization first.</p>
2882
2883<p>The xmlCatalogAddLocal() call is used by the parser to grow the document
2884own catalog list if needed.</p>
2885
2886<h4>Preferences setup:</h4>
2887
2888<p>The XML Catalog spec requires the possibility to select default
2889preferences between public and system delegation,
2890xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and
2891xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should
2892be forbidden, allowed for global catalog, for document catalog or both, the
2893default is to allow both.</p>
2894
2895<p>And of course xmlCatalogSetDebug() allows to generate debug messages
2896(through the xmlGenericError() mechanism).</p>
2897
2898<h4>Querying routines:</h4>
2899
2900<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic()
2901and xmlCatalogResolveURI() are relatively explicit if you read the XML
2902Catalog specification they correspond to section 7 algorithms, they should
2903also work if you have loaded an SGML catalog with a simplified semantic.</p>
2904
2905<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but
2906operate on the document catalog list</p>
2907
2908<h4>Cleanup and Miscellaneous:</h4>
2909
2910<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is
2911the per-document equivalent.</p>
2912
2913<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the
2914first catalog in the global list, and xmlCatalogDump() allows to dump a
2915catalog state, those routines are primarily designed for xmlcatalog, I'm not
2916sure that exposing more complex interfaces (like navigation ones) would be
2917really useful.</p>
2918
2919<p>The xmlParseCatalogFile() is a function used to load XML Catalog files,
2920it's similar as xmlParseFile() except it bypass all catalog lookups, it's
2921provided because this functionality may be useful for client tools.</p>
2922
2923<h4>threaded environments:</h4>
2924
2925<p>Since the catalog tree is built progressively, some care has been taken to
2926try to avoid troubles in multithreaded environments. The code is now thread
2927safe assuming that the libxml library has been compiled with threads
2928support.</p>
2929
2930<p></p>
2931
2932<h3><a name="Other">Other resources</a></h3>
2933
2934<p>The XML Catalog specification is relatively recent so there isn't much
2935literature to point at:</p>
2936<ul>
2937 <li>You can find an good rant from Norm Walsh about <a
2938 href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the
2939 need for catalogs</a>, it provides a lot of context informations even if
2940 I don't agree with everything presented.</li>
2941 <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML
2942 catalog proposal</a> from John Cowan</li>
2943 <li>The <a href="http://www.rddl.org/">Resource Directory Description
2944 Language</a> (RDDL) another catalog system but more oriented toward
2945 providing metadata for XML namespaces.</li>
2946 <li>the page from the OASIS Technical <a
2947 href="http://www.oasis-open.org/committees/entity/">Committee on Entity
2948 Resolution</a> who maintains XML Catalog, you will find pointers to the
2949 specification update, some background and pointers to others tools
2950 providing XML Catalog support</li>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]2951 <li>Here is a <a href="buildDocBookCatalog">shell script</a> to generate
2952 XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/
2953 directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on
2954 the resources found on the system. Otherwise it will just create
2955 ~/xmlcatalog and ~/dbkxmlcatalog and doing:
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]2956 <p><code>export XMLCATALOG=$HOME/xmlcatalog</code></p>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]2957 <p>should allow to process DocBook documentations without requiring
2958 network accesses for the DTd or stylesheets</p>
2959 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2960 <li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]2961 small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems
2962 to work fine for me too</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2963 <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog
2964 manual page</a></li>
2965</ul>
2966
2967<p>If you have suggestions for corrections or additions, simply contact
2968me:</p>
2969
2970<h2><a name="library">The parser interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2971
2972<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]2973using the XML library from the C language. It is not intended to be
2974extensive. I hope the automatically generated documents will provide the
2975completeness required, but as a separate set of documents. The interfaces of
2976the XML library are by principle low level, there is nearly zero abstraction.
2977Those interested in a higher level API should <a href="#DOM">look at
2978DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]2979
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]2980<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
2981separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2982interfaces</a>. Let's have a look at how the XML parser can be called:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]2983
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2984<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2985
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2986<p>Usually, the first thing to do is to read an XML input. The parser accepts
2987documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2988defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]2989<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2990 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2991 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2992 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]2993</dl>
2994<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2995 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]2996 <dd><p>Parse an XML document contained in a (possibly compressed)
2997 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2998 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]2999</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3000
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3001<p>The parser returns a pointer to the document structure (or NULL in case of
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3002failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3003
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3004<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3005
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3006<p>In order for the application to keep the control when the document is
3007being fetched (which is common for GUI based programs) libxml provides a push
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3008interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3009<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
3010 void *user_data,
3011 const char *chunk,
3012 int size,
3013 const char *filename);
3014int xmlParseChunk (xmlParserCtxtPtr ctxt,
3015 const char *chunk,
3016 int size,
3017 int terminate);</pre>
3018
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3019<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3020<pre> FILE *f;
3021
3022 f = fopen(filename, "r");
3023 if (f != NULL) {
3024 int res, size = 1024;
3025 char chars[1024];
3026 xmlParserCtxtPtr ctxt;
3027
3028 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3029 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3030 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
3031 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3032 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3033 xmlParseChunk(ctxt, chars, res, 0);
3034 }
3035 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3036 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3037 xmlFreeParserCtxt(ctxt);
3038 }
3039 }</pre>
3040
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3041<p>The HTML parser embedded into libxml also has a push interface; the
3042functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3043
3044<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
3045
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3046<p>The tree-building interface makes the parser memory-hungry, first loading
3047the document in memory and then building the tree itself. Reading a document
3048without building the tree is possible using the SAX interfaces (see SAX.h and
3049<a href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3050Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3051limited to SAX: just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3052<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3053
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3054<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3055
3056<p>The other way to get an XML tree in memory is by building it. Basically
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3057there is a set of functions dedicated to building new elements. (These are
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3058also described in &lt;libxml/tree.h&gt;.) For example, here is a piece of
3059code that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3060<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3061 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3062 xmlNodePtr tree, subtree;
3063
3064 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3065 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
3066 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
3067 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
3068 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3069 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3070 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3071 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
3072 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
3073 subtree = xmlNewChild(tree, NULL, "image", NULL);
3074 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3075
3076<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3077
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3078<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3079
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3080<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3081code has access to the internal structure of all the elements of the tree.
3082The names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]3083<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3084<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3085example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3086<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3087
3088<p>points to the title element,</p>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3089<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3090
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3091<p>points to the text node containing the chapter title "The Linux
3092adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3093
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]3094<p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em> to be
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3095present before the document root, so <code>doc-&gt;children</code> may point
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3096to an element which is not the document Root Element; a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]3097<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]3098
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3099<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3100
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3101<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3102is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3103<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3104 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
3105 xmlChar *value);</code></dt>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3106 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node.
3107 The value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3108 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3109</dl>
3110<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3111 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3112 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +0000[diff] [blame]3113 <dd><p>This function returns a pointer to new copy of the property
3114 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3115 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3116</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3117
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3118<p>Two functions are provided for reading and writing the text associated
3119with elements:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3120<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3121 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3122 *value);</code></dt>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3123 <dd><p>This function takes an "external" string and converts it to one
3124 text node or possibly to a list of entity and text nodes. All
3125 non-predefined entity references like &amp;Gnome; will be stored
3126 internally as entity nodes, hence the result of the function may not be
3127 a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3128 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3129</dl>
3130<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3131 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3132 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3133 <dd><p>This function is the inverse of
3134 <code>xmlStringGetNodeList()</code>. It generates a new string
3135 containing the content of the text and entity nodes. Note the extra
3136 argument inLine. If this argument is set to 1, the function will expand
3137 entity references. For example, instead of returning the &amp;Gnome;
3138 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3139 "GNU Network Object Model Environment").</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3140 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3141</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3142
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3143<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3144
3145<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3146<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3147 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3148 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3149 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3150 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3151</dl>
3152<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3153 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3154 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3155 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3156</dl>
3157<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3158 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3159 <dd><p>Saves the document to a file. In this case, the compression
3160 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3161 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3162</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3163
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3164<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3165
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3166<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3167accesses. The level of compression on saves can be turned on either globally
3168or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3169<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3170 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3171 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3172 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3173</dl>
3174<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3175 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3176 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3177 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3178</dl>
3179<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3180 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3181 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3182 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3183</dl>
3184<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3185 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3186 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3187 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3188</dl>
3189
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3190<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3191
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3192<p>Entities in principle are similar to simple C macros. An entity defines an
3193abbreviation for a given string that you can reuse many times throughout the
3194content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3195may occur frequently within a document, or to confine the change needed to a
3196document to a restricted area in the internal subset of the document (at the
3197beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3198<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]31992 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]32003 &lt;!ENTITY xml "Extensible Markup Language"&gt;
32014 ]&gt;
32025 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]32036 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]32047 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3205
3206<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3207its name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3208are 5 predefined entities in libxml allowing you to escape charaters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3209predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3210<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3211for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3212<strong>&amp;quot;</strong> for the character '"', and
3213<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3214
3215<p>One of the problems related to entities is that you may want the parser to
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3216substitute an entity's content so that you can see the replacement text in
3217your application. Or you may prefer to keep entity references as such in the
3218content to be able to save the document back without losing this usually
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3219precious information (if the user went through the pain of explicitly
3220defining entities, he may have a a rather negative attitude if you blindly
3221susbtitute them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3222href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3223function allows you to check and change the behaviour, which is to not
3224substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3225
3226<p>Here is the DOM tree built by libxml for the previous document in the
3227default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3228<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3229DOCUMENT
3230version=1.0
3231 ELEMENT EXAMPLE
3232 TEXT
3233 content=
3234 ENTITY_REF
3235 INTERNAL_GENERAL_ENTITY xml
3236 content=Extensible Markup Language
3237 TEXT
3238 content=</pre>
3239
3240<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3241<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3242DOCUMENT
3243version=1.0
3244 ELEMENT EXAMPLE
3245 TEXT
3246 content= Extensible Markup Language</pre>
3247
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3248<p>So, entities or no entities? Basically, it depends on your use case. I
3249suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3250entities in your XML document or data if you are not willing to handle the
3251entity references elements in the DOM tree.</p>
3252
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3253<p>Note that at save time libxml enforces the conversion of the predefined
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3254entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3255transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3256reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3257finding them in the input).</p>
3258
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3259<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3260on top of the libxml SAX interface is difficult!!! If you plan to use
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3261non-predefined entities in your documents, then the learning cuvre to handle
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3262then using the SAX API may be long. If you plan to use complex documents, I
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3263strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]3264deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3265
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3266<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3267
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3268<p>The libxml library implements <a
3269href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
3270recognizing namespace contructs in the input, and does namespace lookup
3271automatically when building the DOM tree. A namespace declaration is
3272associated with an in-memory structure and all elements or attributes within
3273that namespace point to it. Hence testing the namespace is a simple and fast
3274equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3275
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3276<p>I suggest that people using libxml use a namespace, and declare it in the
3277root element of their document as the default namespace. Then they don't need
3278to use the prefix in the content but we will have a basis for future semantic
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3279refinement and merging of data from different sources. This doesn't increase
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3280the size of the XML output significantly, but significantly increases its
3281value in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3282<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
3283 &lt;elem1&gt;...&lt;/elem1&gt;
3284 &lt;elem2&gt;...&lt;/elem2&gt;
3285&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3286
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3287<p>The namespace value has to be an absolute URL, but the URL doesn't have to
3288point to any existing resource on the Web. It will bind all the element and
3289atributes with that URL. I suggest to use an URL within a domain you control,
3290and that the URL should contain some kind of version information if possible.
3291For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a good
3292namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3293
3294<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3295version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3296and if the version information don't match something you know, warn the user
3297and be liberal in what you accept as the input. Also do *not* try to base
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3298namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3299same as &lt;bar:text&gt; in another document. What really matters is the URI
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3300associated with the element or the attribute, not the prefix string (which is
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3301just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3302<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3303prefix and its URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3304
3305<p>@@Interfaces@@</p>
3306
3307<p>@@Examples@@</p>
3308
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3309<p>Usually people object to using namespaces together with validity checking.
3310I will try to make sure that using namespaces won't break validity checking,
3311so even if you plan to use or currently are using validation I strongly
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3312suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3313<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3314flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3315from multiple DTDs will certainly break current validation schemes. I will
3316try to provide ways to do this, but this may not be portable or
3317standardized.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3318
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3319<h2><a name="Upgrading">Upgrading 1.x code</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3320
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3321<p>Incompatible changes:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3322
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3323<p>Version 2 of libxml is the first version introducing serious backward
3324incompatible changes. The main goals were:</p>
3325<ul>
3326 <li>a general cleanup. A number of mistakes inherited from the very early
3327 versions couldn't be changed due to compatibility constraints. Example
3328 the "childs" element in the nodes.</li>
3329 <li>Uniformization of the various nodes, at least for their header and link
3330 parts (doc, parent, children, prev, next), the goal is a simpler
3331 programming model and simplifying the task of the DOM implementors.</li>
3332 <li>better conformances to the XML specification, for example version 1.x
3333 had an heuristic to try to detect ignorable white spaces. As a result the
3334 SAX event generated were ignorableWhitespace() while the spec requires
3335 character() in that case. This also mean that a number of DOM node
3336 containing blank text may populate the DOM tree which were not present
3337 before.</li>
3338</ul>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3339
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3340<h3>How to fix libxml-1.x code:</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3341
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3342<p>So client code of libxml designed to run with version 1.x may have to be
3343changed to compile against version 2.x of libxml. Here is a list of changes
3344that I have collected, they may not be sufficient, so in case you find other
3345change which are required, <a href="mailto:Daniel.Ïeillardw3.org">drop me a
3346mail</a>:</p>
3347<ol>
3348 <li>The package name have changed from libxml to libxml2, the library name
3349 is now -lxml2 . There is a new xml2-config script which should be used to
3350 select the right parameters libxml2</li>
3351 <li>Node <strong>childs</strong> field has been renamed
3352 <strong>children</strong> so s/childs/children/g should be applied
3353 (probablility of having "childs" anywere else is close to 0+</li>
3354 <li>The document don't have anymore a <strong>root</strong> element it has
3355 been replaced by <strong>children</strong> and usually you will get a
3356 list of element here. For example a Dtd element for the internal subset
3357 and it's declaration may be found in that list, as well as processing
3358 instructions or comments found before or after the document root element.
3359 Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of
3360 a document. Alternatively if you are sure to not reference Dtds nor have
3361 PIs or comments before or after the root element
3362 s/-&gt;root/-&gt;children/g will probably do it.</li>
3363 <li>The white space issue, this one is more complex, unless special case of
3364 validating parsing, the line breaks and spaces usually used for indenting
3365 and formatting the document content becomes significant. So they are
3366 reported by SAX and if your using the DOM tree, corresponding nodes are
3367 generated. Too approach can be taken:
3368 <ol>
3369 <li>lazy one, use the compatibility call
3370 <strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are
3371 relying on a special (and possibly broken) set of heuristics of
3372 libxml to detect ignorable blanks. Don't complain if it breaks or
3373 make your application not 100% clean w.r.t. to it's input.</li>
3374 <li>the Right Way: change you code to accept possibly unsignificant
3375 blanks characters, or have your tree populated with weird blank text
3376 nodes. You can spot them using the comodity function
3377 <strong>xmlIsBlankNode(node)</strong> returning 1 for such blank
3378 nodes.</li>
3379 </ol>
3380 <p>Note also that with the new default the output functions don't add any
3381 extra indentation when saving a tree in order to be able to round trip
3382 (read and save) without inflating the document with extra formatting
3383 chars.</p>
3384 </li>
3385 <li>The include path has changed to $prefix/libxml/ and the includes
3386 themselves uses this new prefix in includes instructions... If you are
3387 using (as expected) the
3388 <pre>xml2-config --cflags</pre>
3389 <p>output to generate you compile commands this will probably work out of
3390 the box</p>
3391 </li>
3392 <li>xmlDetectCharEncoding takes an extra argument indicating the lenght in
3393 byte of the head of the document available for character detection.</li>
3394</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3395
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3396<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3397
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3398<p>Two new version of libxml (1.8.11) and libxml2 (2.3.4) have been released
3399to allow smoth upgrade of existing libxml v1code while retaining
3400compatibility. They offers the following:</p>
3401<ol>
3402 <li>similar include naming, one should use
3403 <strong>#include&lt;libxml/...&gt;</strong> in both cases.</li>
3404 <li>similar identifiers defined via macros for the child and root fields:
3405 respectively <strong>xmlChildrenNode</strong> and
3406 <strong>xmlRootNode</strong></li>
3407 <li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be
3408 inserted once in the client code</li>
3409</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3410
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3411<p>So the roadmap to upgrade your existing libxml applications is the
3412following:</p>
3413<ol>
3414 <li>install the libxml-1.8.8 (and libxml-devel-1.8.8) packages</li>
3415 <li>find all occurences where the xmlDoc <strong>root</strong> field is
3416 used and change it to <strong>xmlRootNode</strong></li>
3417 <li>similary find all occurences where the xmlNode <strong>childs</strong>
3418 field is used and change it to <strong>xmlChildrenNode</strong></li>
3419 <li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your
3420 <strong>main()</strong> or in the library init entry point</li>
3421 <li>Recompile, check compatibility, it should still work</li>
3422 <li>Change your configure script to look first for xml2-config and fallback
3423 using xml-config . Use the --cflags and --libs ouptut of the command as
3424 the Include and Linking parameters needed to use libxml.</li>
3425 <li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and
3426 libxml-devel-1.8.y can be kept simultaneously)</li>
3427 <li>remove your config.cache, relaunch your configuration mechanism, and
3428 recompile, if steps 2 and 3 were done right it should compile as-is</li>
3429 <li>Test that your application is still running correctly, if not this may
3430 be due to extra empty nodes due to formating spaces being kept in libxml2
3431 contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your
3432 code before calling the parser (next to
3433 <strong>LIBXML_TEST_VERSION</strong> is a fine place).</li>
3434</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3435
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3436<p>Following those steps should work. It worked for some of my own code.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3437
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3438<p>Let me put some emphasis on the fact that there is far more changes from
3439libxml 1.x to 2.x than the ones you may have to patch for. The overall code
3440has been considerably cleaned up and the conformance to the XML specification
3441has been drastically improved too. Don't take those changes as an excuse to
3442not upgrade, it may cost a lot on the long term ...</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3443
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]3444<h2><a name="Thread">Thread safety</a></h2>
3445
3446<p>Starting with 2.4.7, libxml makes provisions to ensure that concurent
3447threads can safely work in parallel parsing different documents. There is
3448however a couple of things to do to ensure it:</p>
3449<ul>
3450 <li>configure the library accordingly using the --with-threads options</li>
3451 <li>call xmlInitParser() in the "main" thread before using any of the
3452 libxml API (except possibly selecting a different memory allocator)</li>
3453</ul>
3454
3455<p>Note that the thread safety cannot be ensured for multiple threads sharing
3456the same document, the locking must be done at the application level, libxml
3457exports a basic mutex and reentrant mutexes API in &lt;libxml/threads.h&gt;.
3458The parts of the library checked for thread safety are:</p>
3459<ul>
3460 <li>concurrent loading</li>
3461 <li>file access resolution</li>
3462 <li>catalog access</li>
3463 <li>catalog building</li>
3464 <li>entities lookup/accesses</li>
3465 <li>validation</li>
3466 <li>global variables per-thread override</li>
3467 <li>memory handling</li>
3468</ul>
3469
3470<p>XPath is supposed to be thread safe now, but this wasn't tested
3471seriously.</p>
3472
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3473<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3474
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3475<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document
3476Object Model</em>; this is an API for accessing XML or HTML structured
3477documents. Native support for DOM in Gnome is on the way (module gnome-dom),
3478and will be based on gnome-xml. This will be a far cleaner interface to
3479manipulate XML files within Gnome since it won't expose the internal
3480structure.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3481
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3482<p>The current DOM implementation on top of libxml is the <a
Daniel Veillarda47fb3d2001-03-25 17:23:49 +0000[diff] [blame]3483href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this
3484is a full DOM interface, thanks to Paolo Casarini, check the <a
3485href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more
3486informations.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3487
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3488<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3489
3490<p>Here is a real size example, where the actual content of the application
3491data is not kept in the DOM tree but uses internal structures. It is based on
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3492a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3493storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
3494base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3495<pre>&lt;?xml version="1.0"?&gt;
3496&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
3497 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3498
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3499 &lt;gjob:Job&gt;
3500 &lt;gjob:Project ID="3"/&gt;
3501 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
3502 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3503
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3504 &lt;gjob:Update&gt;
3505 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
3506 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
3507 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
3508 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3509
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3510 &lt;gjob:Developers&gt;
3511 &lt;gjob:Developer&gt;
3512 &lt;/gjob:Developer&gt;
3513 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3514
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3515 &lt;gjob:Contact&gt;
3516 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
3517 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
3518 &lt;gjob:Company&gt;
3519 &lt;/gjob:Company&gt;
3520 &lt;gjob:Organisation&gt;
3521 &lt;/gjob:Organisation&gt;
3522 &lt;gjob:Webpage&gt;
3523 &lt;/gjob:Webpage&gt;
3524 &lt;gjob:Snailmail&gt;
3525 &lt;/gjob:Snailmail&gt;
3526 &lt;gjob:Phone&gt;
3527 &lt;/gjob:Phone&gt;
3528 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3529
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3530 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3531 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3532 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3533
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3534 &lt;gjob:Skills&gt;
3535 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3536
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3537 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3538 A GNOME based system that will allow a superuser to configure
3539 compressed and uncompressed files and/or file systems to be backed
3540 up with a supported media in the system. This should be able to
3541 perform via find commands generating a list of files that are passed
3542 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
3543 or via operations performed on the filesystem itself. Email
3544 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3545 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3546
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3547 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3548
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3549 &lt;/gjob:Jobs&gt;
3550&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3551
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3552<p>While loading the XML file into an internal DOM tree is a matter of
3553calling only a couple of functions, browsing the tree to gather the ata and
3554generate the internal structures is harder, and more error prone.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3555
3556<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3557structure. For example, the ordering of the attributes is not significant,
3558the XML specification is clear about it. It's also usually a good idea not to
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3559depend on the order of the children of a given node, unless it really makes
3560things harder. Here is some code to parse the information for a person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3561<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3562 * A person record
3563 */
3564typedef struct person {
3565 char *name;
3566 char *email;
3567 char *company;
3568 char *organisation;
3569 char *smail;
3570 char *webPage;
3571 char *phone;
3572} person, *personPtr;
3573
3574/*
3575 * And the code needed to parse it
3576 */
3577personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3578 personPtr ret = NULL;
3579
3580DEBUG("parsePerson\n");
3581 /*
3582 * allocate the struct
3583 */
3584 ret = (personPtr) malloc(sizeof(person));
3585 if (ret == NULL) {
3586 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3587 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3588 }
3589 memset(ret, 0, sizeof(person));
3590
3591 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3592 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3593 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3594 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
3595 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3596 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
3597 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3598 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3599 }
3600
3601 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3602}</pre>
3603
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3604<p>Here are a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3605<ul>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3606 <li>Usually a recursive parsing style is the more convenient one: XML data
3607 is by nature subject to repetitive constructs and usually exibits highly
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3608 stuctured patterns.</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3609 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>,
3610 i.e. the pointer to the global XML document and the namespace reserved to
3611 the application. Document wide information are needed for example to
3612 decode entities and it's a good coding practice to define a namespace for
3613 your application set of data and test that the element and attributes
3614 you're analyzing actually pertains to your application space. This is
3615 done by a simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3616 <li>To retrieve text and attributes value, you can use the function
3617 <em>xmlNodeListGetString</em> to gather all the text and entity reference
3618 nodes generated by the DOM output and produce an single text string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3619</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3620
3621<p>Here is another piece of code used to parse another level of the
3622structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3623<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3624/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3625 * a Description for a Job
3626 */
3627typedef struct job {
3628 char *projectID;
3629 char *application;
3630 char *category;
3631 personPtr contact;
3632 int nbDevelopers;
3633 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
3634} job, *jobPtr;
3635
3636/*
3637 * And the code needed to parse it
3638 */
3639jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3640 jobPtr ret = NULL;
3641
3642DEBUG("parseJob\n");
3643 /*
3644 * allocate the struct
3645 */
3646 ret = (jobPtr) malloc(sizeof(job));
3647 if (ret == NULL) {
3648 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3649 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3650 }
3651 memset(ret, 0, sizeof(job));
3652
3653 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3654 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3655 while (cur != NULL) {
3656
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3657 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
3658 ret-&gt;projectID = xmlGetProp(cur, "ID");
3659 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3660 fprintf(stderr, "Project has no ID\n");
3661 }
3662 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3663 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
3664 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3665 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
3666 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3667 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
3668 ret-&gt;contact = parsePerson(doc, ns, cur);
3669 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3670 }
3671
3672 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3673}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3674
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3675<p>Once you are used to it, writing this kind of code is quite simple, but
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3676boring. Ultimately, it could be possble to write stubbers taking either C
3677data structure definitions, a set of XML examples or an XML DTD and produce
3678the code needed to import and export the content between C data and XML
3679storage. This is left as an exercise to the reader :-)</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3680
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]3681<p>Feel free to use <a href="example/gjobread.c">the code for the full C
3682parsing example</a> as a template, it is also available with Makefile in the
3683Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3684
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3685<h2><a name="Contributi">Contributions</a></h2>
3686<ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3687 <li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of
3688 patches, Gary Pennington worked on the validation API, threading support
3689 and Solaris port.</li>
3690 <li>John Fleck helps maintaining the documentation and man pages.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3691 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
3692 for libxml:<br>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]3693 Website: <a
3694 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
3695 Download: <a
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]3696 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]3697 <li><a href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now
3698 the maintainer of the Windows port, <a
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]3699 href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
3700 provides binaries</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3701 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides
3702 <a href="http://garypennington.net/libxml2/">Solaris binaries</a></li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]3703 <li><a
3704 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3705 Sergeant</a> developped <a
3706 href="http://axkit.org/download/">XML::LibXSLT</a>, a perl wrapper for
3707 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
3708 application server</a></li>
3709 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> and <a
3710 href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a
Daniel Veillardca989762001-06-23 17:39:29 +0000[diff] [blame]3711 href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]3712 documentation</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3713 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
3714 href="http://xmlsoft.org/messages/0488.html">man pages</a></li>
Daniel Veillard5168dbf2001-07-07 00:18:23 +0000[diff] [blame]3715 <li>there is a module for <a
3716 href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support
3717 in OpenNSD/AOLServer</a></li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]3718 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provided the
3719 first version of libxml/libxslt <a
3720 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]3721 <li>Petr Kozelka provides <a
3722 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
3723 libxml2</a> with Kylix and Delphi and other Pascal compilers</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]3724 <li><a href="mailto:aleksey@aleksey.com">Aleksey Sanin</a> implemented the
3725 <a href="http://www.w3.org/Signature/">XML Canonicalization and XML
3726 Digital Signature</a> <a
3727 href="http://www.aleksey.com/xmlsec/">implementations for libxml2</a></li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3728</ul>
3729
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3730<p></p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3731</body>
3732</html>