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4<head>
Daniel Veillardec78c0f2000-08-25 10:25:23 +00005 <title>The XML C library for Gnome</title>
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Daniel Veillardec78c0f2000-08-25 10:25:23 +000011<h1 align="center">The XML C library for Gnome</h1>
Daniel Veillardb05deb71999-08-10 19:04:08 +000012
Daniel Veillard9c466822001-10-25 12:03:39 +000013<h1>Note: this is the flat content of the <a href="index.html">web
14site</a></h1>
15
Daniel Veillardc9484202001-10-24 12:35:52 +000016<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +000017
18<p></p>
Daniel Veillard9c466822001-10-25 12:03:39 +000019
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
24markup language.</p>
25
26<p>Libxml2 implements a number of existing standards related to markup
27languages:</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +000028<ul>
Daniel Veillard9c466822001-10-25 12:03:39 +000029 <li>the XML standard: <a
30 href="http://www.w3.org/TR/REC-xml">http://www.w3.org/TR/REC-xml</a></li>
31 <li>Namespaces in XML: <a
32 href="http://www.w3.org/TR/REC-xml-names/">http://www.w3.org/TR/REC-xml-names/</a></li>
33 <li>XML Base: <a
34 href="http://www.w3.org/TR/xmlbase/">http://www.w3.org/TR/xmlbase/</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +000035 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc2396.txt">RFC 2396</a> :
36 Uniform Resource Identifiers <a
Daniel Veillard9c466822001-10-25 12:03:39 +000037 href="http://www.ietf.org/rfc/rfc2396.txt">http://www.ietf.org/rfc/rfc2396.txt</a></li>
38 <li>XML Path Language (XPath) 1.0: <a
39 href="http://www.w3.org/TR/xpath">http://www.w3.org/TR/xpath</a></li>
40 <li>HTML4 parser: <a
41 href="http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</a></li>
42 <li>most of XML Pointer Language (XPointer) Version 1.0: <a
43 href="http://www.w3.org/TR/xptr">http://www.w3.org/TR/xptr</a></li>
44 <li>XML Inclusions (XInclude) Version 1.0: <a
45 href="http://www.w3.org/TR/xinclude/">http://www.w3.org/TR/xinclude/</a></li>
46 <li>[ISO-8859-1], <a
47 href="http://www.cis.ohio-state.edu/rfc/rfc2044.txt">rfc2044</a> [UTF-8]
48 and <a href="http://www.cis.ohio-state.edu/rfc/rfc2781.txt">rfc2781</a>
49 [UTF-16] core encodings</li>
50 <li>part of SGML Open Technical Resolution TR9401:1997</li>
51 <li>XML Catalogs Working Draft 06 August 2001: <a
52 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 Veillard96984452000-08-31 13:50:12 +000053</ul>
54
Daniel Veillard9c466822001-10-25 12:03:39 +000055<p>In most cases libxml tries to implement the specifications in a relatively
Daniel Veillarda5393562002-02-20 11:40:49 +000056strict way. As of release 2.4.16, libxml2 passes all 1800+ tests from the <a
57href="http://www.oasis-open.org/committees/xml-conformance/">OASIS XML Tests
58Suite</a>.</p>
Daniel Veillard5b16f582002-02-20 11:38:46 +000059
60<p>To some extent libxml2 provide some support for the following other
61specification but don't claim to implement them:</p>
Daniel Veillard9c466822001-10-25 12:03:39 +000062<ul>
63 <li>Document Object Model (DOM) <a
64 href="http://www.w3.org/TR/DOM-Level-2-Core/">http://www.w3.org/TR/DOM-Level-2-Core/</a>
65 it doesn't implement the API itself, gdome2 does this in top of
66 libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +000067 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc959.txt">RFC 959</a> :
68 libxml implements a basic FTP client code</li>
69 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc1945.txt">RFC 1945</a> :
70 HTTP/1.0, again a basic HTTP client code</li>
Daniel Veillard9c466822001-10-25 12:03:39 +000071 <li>SAX: a minimal SAX implementation compatible with early expat
72 versions</li>
73 <li>DocBook SGML v4: libxml2 includes a hackish parser to transition to
74 XML</li>
75</ul>
76
Daniel Veillard845cce42002-01-09 11:51:37 +000077<p>Libxml2 is known to be very portable, should build and work without
78serious troubles on a variety of systems (Linux, Unix, Windows, CygWin,
79MacOs, MacOsX, RISC Os, OS/2, VMS, QNX, MVS, ...)</p>
Daniel Veillard9c466822001-10-25 12:03:39 +000080
Daniel Veillard96984452000-08-31 13:50:12 +000081<p>Separate documents:</p>
82<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +000083 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a> providing an
84 implementation of XSLT 1.0 and extensions on top of libxml2</li>
Daniel Veillardc6271d22001-10-27 07:50:58 +000085 <li><a href="http://www.cs.unibo.it/~casarini/gdome2/">the gdome2 page</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +000086 : a standard DOM2 implementation based on libxml2</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +000087</ul>
88
89<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +000090
Daniel Veillardf13e1ed2000-03-06 07:41:49 +000091<p>This document describes libxml, the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +000092href="http://www.w3.org/XML/">XML</a> C library developped for the <a
93href="http://www.gnome.org/">Gnome</a> project. <a
94href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
95structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +000096
Daniel Veillard0142b842000-01-14 14:45:24 +000097<p>Here are some key points about libxml:</p>
98<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +000099 <li>Libxml exports Push and Pull type parser interfaces for both XML and
100 HTML.</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000101 <li>Libxml can do DTD validation at parse time, using a parsed document
102 instance, or with an arbitrary DTD.</li>
103 <li>Libxml now includes nearly complete <a
Daniel Veillard8c2ecaf2001-07-10 17:53:07 +0000104 href="http://www.w3.org/TR/xpath">XPath</a>, <a
105 href="http://www.w3.org/TR/xptr">XPointer</a> and <a
106 href="http://www.w3.org/TR/xinclude">XInclude</a> implementations.</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000107 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard189446d2000-10-13 10:23:06 +0000108 sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillardab8500d2000-10-15 21:06:19 +0000109 Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000110 <li>Basic support for HTTP and FTP client allowing aplications to fetch
111 remote resources</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000112 <li>The design is modular, most of the extensions can be compiled out.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000113 <li>The internal document repesentation is as close as possible to the <a
114 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
115 <li>Libxml also has a <a href="http://www.megginson.com/SAX/index.html">SAX
Daniel Veillard402e8c82000-02-29 22:57:47 +0000116 like interface</a>; the interface is designed to be compatible with <a
117 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillardc575b992002-02-08 13:28:40 +0000118 <li>This library is released under the <a
119 href="http://www.opensource.org/licenses/mit-license.html">MIT
120 Licence</a> see the Copyright file in the distribution for the precise
121 wording.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000122</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000123
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000124<p>Warning: unless you are forced to because your application links with a
125Gnome library requiring it, <strong><span
126style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use
127libxml2</p>
128
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000129<h2><a name="FAQ">FAQ</a></h2>
130
131<p>Table of Content:</p>
132<ul>
133 <li><a href="FAQ.html#Licence">Licence(s)</a></li>
134 <li><a href="FAQ.html#Installati">Installation</a></li>
135 <li><a href="FAQ.html#Compilatio">Compilation</a></li>
136 <li><a href="FAQ.html#Developer">Developer corner</a></li>
137</ul>
138
139<h3><a name="Licence">Licence</a>(s)</h3>
140<ol>
141 <li><em>Licensing Terms for libxml</em>
Daniel Veillardc575b992002-02-08 13:28:40 +0000142 <p>libxml is released under the <a
143 href="http://www.opensource.org/licenses/mit-license.html">MIT
144 Licence</a>, see the file Copyright in the distribution for the precise
145 wording</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000146 </li>
147 <li><em>Can I embed libxml in a proprietary application ?</em>
Daniel Veillardc575b992002-02-08 13:28:40 +0000148 <p>Yes. The MIT Licence allows you to also keep proprietary the changes
149 you made to libxml, but it would be graceful to provide back bugfixes and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000150 improvements as patches for possible incorporation in the main
151 development tree</p>
152 </li>
153</ol>
154
155<h3><a name="Installati">Installation</a></h3>
156<ol>
157 <li>Unless you are forced to because your application links with a Gnome
158 library requiring it, <strong><span style="background-color: #FF0000">Do
159 Not Use libxml1</span></strong>, use libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000160 <li><em>Where can I get libxml</em> ?
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000161 <p>The original distribution comes from <a
162 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a
163 href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">gnome.org</a></p>
164 <p>Most linux and Bsd distribution includes libxml, this is probably the
165 safer way for end-users</p>
166 <p>David Doolin provides precompiled Windows versions at <a
167 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
168 </li>
169 <li><em>I see libxml and libxml2 releases, which one should I install ?</em>
170 <ul>
171 <li>If you are not concerned by any existing backward compatibility
172 with existing application, install libxml2 only</li>
173 <li>If you are not doing development, you can safely install both.
174 usually the packages <a
175 href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a
176 href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a> are
177 compatible (this is not the case for development packages)</li>
178 <li>If you are a developer and your system provides separate packaging
179 for shared libraries and the development components, it is possible
180 to install libxml and libxml2, and also <a
181 href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>
182 and <a
183 href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>
184 too for libxml2 &gt;= 2.3.0</li>
185 <li>If you are developing a new application, please develop against
186 libxml2(-devel)</li>
187 </ul>
188 </li>
189 <li><em>I can't install the libxml package it conflicts with libxml0</em>
190 <p>You probably have an old libxml0 package used to provide the shared
191 library for libxml.so.0, you can probably safely remove it. Anyway the
192 libxml packages provided on <a
193 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provides
194 libxml.so.0</p>
195 </li>
196 <li><em>I can't install the libxml(2) RPM package due to failed
197 dependancies</em>
198 <p>The most generic solution is to refetch the latest src.rpm , and
199 rebuild it locally with</p>
200 <p><code>rpm --rebuild libxml(2)-xxx.src.rpm</code></p>
201 <p>if everything goes well it will generate two binary rpm (one providing
202 the shared libs and xmllint, and the other one, the -devel package
203 providing includes, static libraries and scripts needed to build
204 applications with libxml(2)) that you can install locally.</p>
205 </li>
206</ol>
207
208<h3><a name="Compilatio">Compilation</a></h3>
209<ol>
210 <li><em>What is the process to compile libxml ?</em>
211 <p>As most UNIX libraries libxml follows the "standard":</p>
212 <p><code>gunzip -c xxx.tar.gz | tar xvf -</code></p>
213 <p><code>cd libxml-xxxx</code></p>
214 <p><code>./configure --help</code></p>
215 <p>to see the options, then the compilation/installation proper</p>
216 <p><code>./configure [possible options]</code></p>
217 <p><code>make</code></p>
218 <p><code>make install</code></p>
219 <p>At that point you may have to rerun ldconfig or similar utility to
220 update your list of installed shared libs.</p>
221 </li>
222 <li><em>What other libraries are needed to compile/install libxml ?</em>
223 <p>Libxml does not requires any other library, the normal C ANSI API
224 should be sufficient (please report any violation to this rule you may
225 find).</p>
226 <p>However if found at configuration time libxml will detect and use the
227 following libs:</p>
228 <ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000229 <li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a> : a
230 highly portable and available widely compression library</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000231 <li>iconv: a powerful character encoding conversion library. It's
232 included by default on recent glibc libraries, so it doesn't need to
233 be installed specifically on linux. It seems it's now <a
234 href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part
235 of the official UNIX</a> specification. Here is one <a
236 href="http://clisp.cons.org/~haible/packages-libiconv.html">implementation
237 of the library</a> which source can be found <a
238 href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>.</li>
239 </ul>
240 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000241 <li><em>make check fails on some platforms</em>
242 <p>Sometime the regression tests results don't completely match the value
243 produced by the parser, and the makefile uses diff to print the delta. On
244 some platforms the diff return breaks the compilation process, if the
Daniel Veillarde46182c2002-02-12 14:29:11 +0000245 diff is small this is probably not a serious problem.</p>
246 <p>Sometimes (especially on Solaris) make checks fails due to limitations
247 in make. Try using GNU-make instead.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000248 </li>
249 <li><em>I use the CVS version and there is no configure script</em>
250 <p>The configure (and other Makefiles) are generated. Use the autogen.sh
251 script to regenerate the configure and Makefiles, like:</p>
252 <p><code>./autogen.sh --prefix=/usr --disable-shared</code></p>
253 </li>
254 <li><em>I have troubles when running make tests with gcc-3.0</em>
255 <p>It seems the initial release of gcc-3.0 has a problem with the
256 optimizer which miscompiles the URI module. Please use another
257 compiler</p>
258 </li>
259</ol>
260
261<h3><a name="Developer">Developer</a> corner</h3>
262<ol>
263 <li><em>xmlDocDump() generates output on one line</em>
264 <p>libxml will not <strong>invent</strong> spaces in the content of a
265 document since <strong>all spaces in the content of a document are
266 significant</strong>. If you build a tree from the API and want
267 indentation:</p>
268 <ol>
269 <li>the correct way is to generate those yourself too</li>
270 <li>the dangerous way is to ask libxml to add those blanks to your
271 content <strong>modifying the content of your document in the
272 process</strong>. The result may not be what you expect. There is
273 <strong>NO</strong> way to guarantee that such a modification won't
274 impact other part of the content of your document. See <a
275 href="http://xmlsoft.org/html/libxml-parser.html#XMLKEEPBLANKSDEFAULT">xmlKeepBlanksDefault
276 ()</a> and <a
277 href="http://xmlsoft.org/html/libxml-tree.html#XMLSAVEFORMATFILE">xmlSaveFormatFile
278 ()</a></li>
279 </ol>
280 </li>
281 <li>Extra nodes in the document:
282 <p><em>For a XML file as below:</em></p>
283 <pre>&lt;?xml version="1.0"?&gt;
284&lt;PLAN xmlns="http://www.argus.ca/autotest/1.0/"&gt;
285&lt;NODE CommFlag="0"/&gt;
286&lt;NODE CommFlag="1"/&gt;
287&lt;/PLAN&gt;</pre>
288 <p><em>after parsing it with the function
289 pxmlDoc=xmlParseFile(...);</em></p>
290 <p><em>I want to the get the content of the first node (node with the
291 CommFlag="0")</em></p>
292 <p><em>so I did it as following;</em></p>
293 <pre>xmlNodePtr pode;
294pnode=pxmlDoc-&gt;children-&gt;children;</pre>
295 <p><em>but it does not work. If I change it to</em></p>
296 <pre>pnode=pxmlDoc-&gt;children-&gt;children-&gt;next;</pre>
297 <p><em>then it works. Can someone explain it to me.</em></p>
298 <p></p>
299 <p>In XML all characters in the content of the document are significant
300 <strong>including blanks and formatting line breaks</strong>.</p>
301 <p>The extra nodes you are wondering about are just that, text nodes with
302 the formatting spaces wich are part of the document but that people tend
303 to forget. There is a function <a
304 href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault
305 ()</a> to remove those at parse time, but that's an heuristic, and its
306 use should be limited to case where you are sure there is no
307 mixed-content in the document.</p>
308 </li>
309 <li><em>I get compilation errors of existing code like when accessing
310 <strong>root</strong> or <strong>childs fields</strong> of nodes</em>
311 <p>You are compiling code developed for libxml version 1 and using a
312 libxml2 development environment. Either switch back to libxml v1 devel or
313 even better fix the code to compile with libxml2 (or both) by <a
314 href="upgrade.html">following the instructions</a>.</p>
315 </li>
316 <li><em>I get compilation errors about non existing
317 <strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong>
318 fields</em>
319 <p>The source code you are using has been <a
320 href="upgrade.html">upgraded</a> to be able to compile with both libxml
321 and libxml2, but you need to install a more recent version:
322 libxml(-devel) &gt;= 1.8.8 or libxml2(-devel) &gt;= 2.1.0</p>
323 </li>
324 <li><em>XPath implementation looks seriously broken</em>
325 <p>XPath implementation prior to 2.3.0 was really incomplete, upgrade to
326 a recent version, the implementation and debug of libxslt generated fixes
327 for most obvious problems.</p>
328 </li>
329 <li><em>The example provided in the web page does not compile</em>
330 <p>It's hard to maintain the documentation in sync with the code
331 &lt;grin/&gt; ...</p>
332 <p>Check the previous points 1/ and 2/ raised before, and send
333 patches.</p>
334 </li>
335 <li><em>Where can I get more examples and informations than in the web
336 page</em>
337 <p>Ideally a libxml book would be nice. I have no such plan ... But you
338 can:</p>
339 <ul>
340 <li>check more deeply the <a href="html/libxml-lib.html">existing
341 generated doc</a></li>
342 <li>looks for examples of use for libxml function using the Gnome code
343 for example the following will query the full Gnome CVs base for the
344 use of the <strong>xmlAddChild()</strong> function:
345 <p><a
346 href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p>
347 <p>This may be slow, a large hardware donation to the gnome project
348 could cure this :-)</p>
349 </li>
350 <li><a
351 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Browse
Daniel Veillardaf43f632002-03-08 15:05:20 +0000352 the libxml source</a> , I try to write code as clean and documented
353 as possible, so looking at it may be helpful</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000354 </ul>
355 </li>
356 <li>What about C++ ?
357 <p>libxml is written in pure C in order to allow easy reuse on a number
358 of platforms, including embedded systems. I don't intend to convert to
359 C++.</p>
360 <p>There is however a C++ wrapper provided by Ari Johnson
361 &lt;ari@btigate.com&gt; which may fullfill your needs:</p>
362 <p>Website: <a
363 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
364 <p>Download: <a
365 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
366 </li>
367 <li>How to validate a document a posteriori ?
368 <p>It is possible to validate documents which had not been validated at
369 initial parsing time or documents who have been built from scratch using
370 the API. Use the <a
371 href="http://xmlsoft.org/html/libxml-valid.html#XMLVALIDATEDTD">xmlValidateDtd()</a>
372 function. It is also possible to simply add a Dtd to an existing
373 document:</p>
374 <pre>xmlDocPtr doc; /* your existing document */
375 xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */
376 dtd-&gt;name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */
377
378 doc-&gt;intSubset = dtd;
379 if (doc-&gt;children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
380 else xmlAddPrevSibling(doc-&gt;children, (xmlNodePtr)dtd);
381 </pre>
382 </li>
383 <li>etc ...</li>
384</ol>
385
386<p></p>
387
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000388<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000389
Daniel Veillard402e8c82000-02-29 22:57:47 +0000390<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000391<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000392 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000393 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000394 documentation</a> automatically extracted from code comments (using <a
395 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
396 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000397 <li>Look at the documentation about <a href="encoding.html">libxml
398 internationalization support</a></li>
Daniel Veillardbc66f852002-01-14 09:49:20 +0000399 <li>This page provides a global overview and <a href="example.html">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000400 examples</a> on how to use libxml.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000401 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
Daniel Veillard402e8c82000-02-29 22:57:47 +0000402 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
403 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000404 <li>George Lebl wrote <a
405 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000406 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000407 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
408 file</a></li>
409 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
410 starting a new project using libxml you should really use the 2.x
411 version.</li>
Daniel Veillard845cce42002-01-09 11:51:37 +0000412 <li>And don't forget to look at the <a
413 href="http://mail.gnome.org/archives/xml/">mailing-list archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000414</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000415
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000416<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000417
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000418<p>Well, bugs or missing features are always possible, and I will make a
419point of fixing them in a timely fashion. The best way to report a bug is to
420use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome
421bug tracking database</a> (make sure to use the "libxml" module name). I look
422at reports there regularly and it's good to have a reminder when a bug is
Daniel Veillard51095312001-10-28 18:51:57 +0000423still open. Be sure to specify that the bug is for the package libxml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000424
Daniel Veillard0142b842000-01-14 14:45:24 +0000425<p>There is also a mailing-list <a
Daniel Veillard3197f162001-04-04 00:40:08 +0000426href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a
427href="http://mail.gnome.org/archives/xml/">on-line archive</a> (<a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000428href="http://xmlsoft.org/messages">old</a>). To subscribe to this list,
429please visit the <a
430href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and
431follow the instructions. <strong>Do not send code, I won't debug it</strong>
432(but patches are really appreciated!).</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000433
Daniel Veillard008186f2001-09-13 14:24:44 +0000434<p>Check the following <strong><span style="color: #FF0000">before
435posting</span></strong>:</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000436<ul>
Daniel Veillarddadd0872001-09-15 09:21:44 +0000437 <li>read the <a href="FAQ.html">FAQ</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000438 <li>make sure you are <a href="ftp://xmlsoft.org/">using a recent
439 version</a>, and that the problem still shows up in those</li>
440 <li>check the <a href="http://mail.gnome.org/archives/xml/">list
441 archives</a> to see if the problem was reported already, in this case
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000442 there is probably a fix available, similary check the <a
443 href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">registered
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000444 open bugs</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000445 <li>make sure you can reproduce the bug with xmllint or one of the test
446 programs found in source in the distribution</li>
447 <li>Please send the command showing the error as well as the input (as an
448 attachement)</li>
449</ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000450
Daniel Veillarddadd0872001-09-15 09:21:44 +0000451<p>Then send the bug with associated informations to reproduce it to the <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000452href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml
Daniel Veillard008186f2001-09-13 14:24:44 +0000453related I will approve it.. Please do not send me mail directly, it makes
454things really harder to track and in some cases I'm not the best person to
455answer a given question, ask the list instead.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000456
Daniel Veillard91e9d582001-02-26 07:31:12 +0000457<p>Of course, bugs reported with a suggested patch for fixing them will
Daniel Veillardec303412000-03-24 13:41:54 +0000458probably be processed faster.</p>
459
460<p>If you're looking for help, a quick look at <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000461href="http://mail.gnome.org/archives/xml/">the list archive</a> may actually
Daniel Veillardec303412000-03-24 13:41:54 +0000462provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000463questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillardec303412000-03-24 13:41:54 +0000464documentantion</a> is not as polished as I would like (i need to learn more
465about Docbook), but it's a good starting point.</p>
466
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000467<h2><a name="help">How to help</a></h2>
468
469<p>You can help the project in various ways, the best thing to do first is to
470subscribe to the mailing-list as explained before, check the <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000471href="http://mail.gnome.org/archives/xml/">archives </a>and the <a
472href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome bug
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000473database:</a>:</p>
474<ol>
475 <li>provide patches when you find problems</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000476 <li>provide the diffs when you port libxml to a new platform. They may not
Daniel Veillardab8500d2000-10-15 21:06:19 +0000477 be integrated in all cases but help pinpointing portability problems
478 and</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000479 <li>provide documentation fixes (either as patches to the code comments or
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000480 as HTML diffs).</li>
481 <li>provide new documentations pieces (translations, examples, etc ...)</li>
482 <li>Check the TODO file and try to close one of the items</li>
483 <li>take one of the points raised in the archive or the bug database and
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000484 provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me
485 </a>before to avoid synchronization problems and check that the suggested
486 fix will fit in nicely :-)</li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000487</ol>
488
Daniel Veillard10a2c651999-12-12 13:03:50 +0000489<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000490
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000491<p>The latest versions of libxml can be found on <a
Daniel Veillard20c8cf22001-06-26 22:47:36 +0000492href="ftp://xmlsoft.org/">xmlsoft.org</a> (<a
493href="ftp://speakeasy.rpmfind.net/pub/libxml/">Seattle</a>, <a
494href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000495href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000496as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000497archive</a> or <a
Daniel Veillarda41123c2001-04-22 19:31:20 +0000498href="ftp://ftp.gnome.org/pub/GNOME/stable/redhat/i386/libxml/">RPM
499packages</a>. (NOTE that you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000500href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
501href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard95189532001-07-26 18:30:26 +0000502packages installed to compile applications using libxml.) <a
503href="mailto:izlatkovic@daenet.de">Igor Zlatkovic</a> is now the maintainer
504of the Windows port, <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000505href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
Daniel Veillardc6271d22001-10-27 07:50:58 +0000506provides binaries</a>. <a href="mailto:Gary.Pennington@sun.com">Gary
Daniel Veillard1aadc442001-11-28 13:10:32 +0000507Pennington</a> provides <a href="http://garypennington.net/libxml2/">Solaris
508binaries</a>.</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000509
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000510<p><a name="Snapshot">Snapshot:</a></p>
511<ul>
512 <li>Code from the W3C cvs base libxml <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000513 href="ftp://xmlsoft.org/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000514 <li>Docs, content of the web site, the list archive included <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000515 href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000516</ul>
517
Daniel Veillardc6271d22001-10-27 07:50:58 +0000518<p><a name="Contribs">Contributions:</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000519
520<p>I do accept external contributions, especially if compiling on another
Daniel Veillardc6271d22001-10-27 07:50:58 +0000521platform, get in touch with me to upload the package, wrappers for various
Daniel Veillard51095312001-10-28 18:51:57 +0000522languages have been provided, and can be found in the <a
523href="contribs.html">contrib section</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000524
Daniel Veillard82687162001-01-22 15:32:01 +0000525<p>Libxml is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000526<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000527 <li><p>The <a
528 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Gnome
Daniel Veillard402e8c82000-02-29 22:57:47 +0000529 CVS base</a>. Check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000530 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a>
531 page; the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000532 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000533 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000534</ul>
535
536<h2><a name="News">News</a></h2>
537
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000538<h3>CVS only : check the <a
539href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000540for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000541
Daniel Veillard91e9d582001-02-26 07:31:12 +0000542<p>Items floating around but not actively worked on, get in touch with me if
Daniel Veillardab8500d2000-10-15 21:06:19 +0000543you want to test those</p>
544<ul>
Daniel Veillard28929b22000-11-13 18:22:49 +0000545 <li>Finishing up <a href="http://www.w3.org/TR/xptr">XPointer</a> and <a
546 href="http://www.w3.org/TR/xinclude">XInclude</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000547</ul>
548
549<h3>2.4.17: Mar 8 2002</h3>
550<ul>
551 <li>a lot of bug fixes, including "namespace nodes have no parents in
552 XPath"</li>
553 <li>fixed/improved the Python wrappers, added more examples and more
554 regression tests, XPath extension functions can now return node-sets</li>
555 <li>added the XML Canonalization support from Aleksey Sanin</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000556</ul>
557
Daniel Veillard5f4b5992002-02-20 10:22:49 +0000558<h3>2.4.16: Feb 20 2002</h3>
559<ul>
560 <li>a lot of bug fixes, most of them were triggered by the XML Testsuite
561 from OASIS and W3C. Compliance has been significantly improved.</li>
562 <li>a couple of portability fixes too.</li>
563</ul>
564
Daniel Veillard397ff112002-02-11 18:27:20 +0000565<h3>2.4.15: Feb 11 2002</h3>
566<ul>
567 <li>Fixed the Makefiles, especially the python module ones</li>
568 <li>A few bug fixes and cleanup</li>
569 <li>Includes cleanup</li>
570</ul>
571
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000572<h3>2.4.14: Feb 8 2002</h3>
573<ul>
574 <li>Change of Licence to the <a
575 href="http://www.opensource.org/licenses/mit-license.html">MIT
576 Licence</a> basisally for integration in XFree86 codebase, and removing
577 confusion around the previous dual-licencing</li>
578 <li>added Python bindings, beta software but should already be quite
579 complete</li>
580 <li>a large number of fixes and cleanups, especially for all tree
581 manipulations</li>
582 <li>cleanup of the headers, generation of a reference API definition in
583 XML</li>
584</ul>
585
586<h3>2.4.13: Jan 14 2002</h3>
Daniel Veillard744683d2002-01-14 17:30:20 +0000587<ul>
588 <li>update of the documentation: John Fleck and Charlie Bozeman</li>
589 <li>cleanup of timing code from Justin Fletcher</li>
590 <li>fixes for Windows and initial thread support on Win32: Igor and Serguei
591 Narojnyi</li>
592 <li>Cygwin patch from Robert Collins</li>
593 <li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li>
594</ul>
595
Daniel Veillardef90ba72001-12-07 14:24:22 +0000596<h3>2.4.12: Dec 7 2001</h3>
597<ul>
598 <li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman),
599 XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups
600 (robert)</li>
601 <li>Eric Lavigne contributed project files for MacOS</li>
602 <li>some makefiles cleanups</li>
603</ul>
604
Daniel Veillarda4871052001-11-26 13:19:48 +0000605<h3>2.4.11: Nov 26 2001</h3>
606<ul>
607 <li>fixed a couple of errors in the includes, fixed a few bugs, some code
608 cleanups</li>
609 <li>xmllint man pages improvement by Heiko Rupp</li>
610 <li>updated VMS build instructions from John A Fotheringham</li>
611 <li>Windows Makefiles updates from Igor</li>
612</ul>
613
Daniel Veillard43d3f612001-11-10 11:57:23 +0000614<h3>2.4.10: Nov 10 2001</h3>
615<ul>
616 <li>URI escaping fix (Joel Young)</li>
617 <li>added xmlGetNodePath() (for paths or XPointers generation)</li>
618 <li>Fixes namespace handling problems when using DTD and validation</li>
619 <li>improvements on xmllint: Morus Walter patches for --format and
620 --encode, Stefan Kost and Heiko Rupp improvements on the --shell</li>
621 <li>fixes for xmlcatalog linking pointed by Weiqi Gao</li>
622 <li>fixes to the HTML parser</li>
623</ul>
624
625<h3>2.4.9: Nov 6 2001</h3>
626<ul>
627 <li>fixes more catalog bugs</li>
628 <li>avoid a compilation problem, improve xmlGetLineNo()</li>
629</ul>
630
Daniel Veillarded421aa2001-11-04 21:22:45 +0000631<h3>2.4.8: Nov 4 2001</h3>
632<ul>
633 <li>fixed SGML catalogs broken in previous release, updated xmlcatalog
634 tool</li>
635 <li>fixed a compile errors and some includes troubles.</li>
636</ul>
637
Daniel Veillard52dcab32001-10-30 12:51:17 +0000638<h3>2.4.7: Oct 30 2001</h3>
639<ul>
640 <li>exported some debugging interfaces</li>
641 <li>serious rewrite of the catalog code</li>
642 <li>integrated Gary Pennington thread safety patch, added configure option
643 and regression tests</li>
644 <li>removed an HTML parser bug</li>
645 <li>fixed a couple of potentially serious validation bugs</li>
646 <li>integrated the SGML DocBook support in xmllint</li>
647 <li>changed the nanoftp anonymous login passwd</li>
648 <li>some I/O cleanup and a couple of interfaces for Perl wrapper</li>
649 <li>general bug fixes</li>
650 <li>updated xmllint man page by John Fleck</li>
651 <li>some VMS and Windows updates</li>
652</ul>
653
Daniel Veillard60087f32001-10-10 09:45:09 +0000654<h3>2.4.6: Oct 10 2001</h3>
655<ul>
Daniel Veillard52dcab32001-10-30 12:51:17 +0000656 <li>added an updated man pages by John Fleck</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000657 <li>portability and configure fixes</li>
658 <li>an infinite loop on the HTML parser was removed (William)</li>
659 <li>Windows makefile patches from Igor</li>
660 <li>fixed half a dozen bugs reported fof libxml or libxslt</li>
661 <li>updated xmlcatalog to be able to modify SGML super catalogs</li>
662</ul>
663
Daniel Veillarddadd0872001-09-15 09:21:44 +0000664<h3>2.4.5: Sep 14 2001</h3>
665<ul>
666 <li>Remove a few annoying bugs in 2.4.4</li>
667 <li>forces the HTML serializer to output decimal charrefs since some
668 version of Netscape can't handle hexadecimal ones</li>
669</ul>
670
671<h3>1.8.16: Sep 14 2001</h3>
672<ul>
673 <li>maintenance release of the old libxml1 branch, couple of bug and
674 portability fixes</li>
675</ul>
676
Daniel Veillard04382ae2001-09-12 18:51:30 +0000677<h3>2.4.4: Sep 12 2001</h3>
678<ul>
679 <li>added --convert to xmlcatalog, bug fixes and cleanups of XML
680 Catalog</li>
681 <li>a few bug fixes and some portability changes</li>
682 <li>some documentation cleanups</li>
683</ul>
684
Daniel Veillard39936902001-08-24 00:49:01 +0000685<h3>2.4.3: Aug 23 2001</h3>
686<ul>
687 <li>XML Catalog support see the doc</li>
688 <li>New NaN/Infinity floating point code</li>
689 <li>A few bug fixes</li>
690</ul>
691
692<h3>2.4.2: Aug 15 2001</h3>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000693<ul>
694 <li>adds xmlLineNumbersDefault() to control line number generation</li>
695 <li>lot of bug fixes</li>
696 <li>the Microsoft MSC projects files shuld now be up to date</li>
697 <li>inheritance of namespaces from DTD defaulted attributes</li>
698 <li>fixes a serious potential security bug</li>
699 <li>added a --format option to xmllint</li>
700</ul>
701
702<h3>2.4.1: July 24 2001</h3>
703<ul>
704 <li>possibility to keep line numbers in the tree</li>
705 <li>some computation NaN fixes</li>
706 <li>extension of the XPath API</li>
707 <li>cleanup for alpha and ia64 targets</li>
708 <li>patch to allow saving through HTTP PUT or POST</li>
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000709</ul>
710
711<h3>2.4.0: July 10 2001</h3>
712<ul>
713 <li>Fixed a few bugs in XPath, validation, and tree handling.</li>
714 <li>Fixed XML Base implementation, added a coupel of examples to the
715 regression tests</li>
716 <li>A bit of cleanup</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000717</ul>
718
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000719<h3>2.3.14: July 5 2001</h3>
720<ul>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000721 <li>fixed some entities problems and reduce mem requirement when
722 substituing them</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000723 <li>lots of improvements in the XPath queries interpreter can be
724 substancially faster</li>
725 <li>Makefiles and configure cleanups</li>
726 <li>Fixes to XPath variable eval, and compare on empty node set</li>
727 <li>HTML tag closing bug fixed</li>
728 <li>Fixed an URI reference computating problem when validating</li>
729</ul>
730
Daniel Veillard2adbb512001-06-28 16:20:36 +0000731<h3>2.3.13: June 28 2001</h3>
732<ul>
733 <li>2.3.12 configure.in was broken as well as the push mode XML parser</li>
734 <li>a few more fixes for compilation on Windows MSC by Yon Derek</li>
735</ul>
736
737<h3>1.8.14: June 28 2001</h3>
738<ul>
739 <li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li>
740 <li>Small Makefile fix</li>
741</ul>
742
Daniel Veillard11648102001-06-26 16:08:24 +0000743<h3>2.3.12: June 26 2001</h3>
744<ul>
745 <li>lots of cleanup</li>
746 <li>a couple of validation fix</li>
747 <li>fixed line number counting</li>
748 <li>fixed serious problems in the XInclude processing</li>
749 <li>added support for UTF8 BOM at beginning of entities</li>
750 <li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0
751 miscompile uri.c (William), Thomas Leitner provided a fix for the
752 optimizer on Tru64</li>
753 <li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for
754 compilation on Windows MSC</li>
755 <li>update of libxml-doc.el (Felix Natter)</li>
756 <li>fixed 2 bugs in URI normalization code</li>
757</ul>
758
Daniel Veillarde3c81b52001-06-17 14:50:34 +0000759<h3>2.3.11: June 17 2001</h3>
760<ul>
761 <li>updates to trio, Makefiles and configure should fix some portability
762 problems (alpha)</li>
763 <li>fixed some HTML serialization problems (pre, script, and block/inline
764 handling), added encoding aware APIs, cleanup of this code</li>
765 <li>added xmlHasNsProp()</li>
766 <li>implemented a specific PI for encoding support in the DocBook SGML
767 parser</li>
768 <li>some XPath fixes (-Infinity, / as a function parameter and namespaces
769 node selection)</li>
770 <li>fixed a performance problem and an error in the validation code</li>
771 <li>fixed XInclude routine to implement the recursive behaviour</li>
772 <li>fixed xmlFreeNode problem when libxml is included statically twice</li>
773 <li>added --version to xmllint for bug reports</li>
774</ul>
775
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000776<h3>2.3.10: June 1 2001</h3>
777<ul>
778 <li>fixed the SGML catalog support</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000779 <li>a number of reported bugs got fixed, in XPath, iconv detection,
780 XInclude processing</li>
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000781 <li>XPath string function should now handle unicode correctly</li>
782</ul>
783
Daniel Veillard4623acd2001-05-19 15:13:15 +0000784<h3>2.3.9: May 19 2001</h3>
785
786<p>Lots of bugfixes, and added a basic SGML catalog support:</p>
787<ul>
788 <li>HTML push bugfix #54891 and another patch from Jonas Borgström</li>
789 <li>some serious speed optimisation again</li>
790 <li>some documentation cleanups</li>
791 <li>trying to get better linking on solaris (-R)</li>
792 <li>XPath API cleanup from Thomas Broyer</li>
793 <li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed
794 xmlValidGetValidElements()</li>
795 <li>Added an INSTALL file</li>
796 <li>Attribute removal added to API: #54433</li>
797 <li>added a basic support for SGML catalogs</li>
798 <li>fixed xmlKeepBlanksDefault(0) API</li>
799 <li>bugfix in xmlNodeGetLang()</li>
800 <li>fixed a small configure portability problem</li>
801 <li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li>
802</ul>
803
Daniel Veillarda265af72001-05-14 11:13:58 +0000804<h3>1.8.13: May 14 2001</h3>
805<ul>
806 <li>bugfixes release of the old libxml1 branch used by Gnome</li>
807</ul>
808
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000809<h3>2.3.8: May 3 2001</h3>
810<ul>
811 <li>Integrated an SGML DocBook parser for the Gnome project</li>
812 <li>Fixed a few things in the HTML parser</li>
813 <li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating
814 point portability issue</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000815 <li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for
816 DOM+validation using the XML REC as input and a 700MHz celeron).</li>
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000817 <li>incorporated more Windows cleanup</li>
818 <li>added xmlSaveFormatFile()</li>
819 <li>fixed problems in copying nodes with entities references (gdome)</li>
820 <li>removed some troubles surrounding the new validation module</li>
821</ul>
822
Daniel Veillarda41123c2001-04-22 19:31:20 +0000823<h3>2.3.7: April 22 2001</h3>
824<ul>
825 <li>lots of small bug fixes, corrected XPointer</li>
826 <li>Non determinist content model validation support</li>
827 <li>added xmlDocCopyNode for gdome2</li>
828 <li>revamped the way the HTML parser handles end of tags</li>
829 <li>XPath: corrctions of namespacessupport and number formatting</li>
830 <li>Windows: Igor Zlatkovic patches for MSC compilation</li>
831 <li>HTML ouput fixes from P C Chow and William M. Brack</li>
832 <li>Improved validation speed sensible for DocBook</li>
833 <li>fixed a big bug with ID declared in external parsed entities</li>
834 <li>portability fixes, update of Trio from Bjorn Reese</li>
835</ul>
836
Daniel Veillardafc73112001-04-11 11:51:41 +0000837<h3>2.3.6: April 8 2001</h3>
838<ul>
839 <li>Code cleanup using extreme gcc compiler warning options, found and
840 cleared half a dozen potential problem</li>
841 <li>the Eazel team found an XML parser bug</li>
842 <li>cleaned up the user of some of the string formatting function. used the
843 trio library code to provide the one needed when the platform is missing
844 them</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000845 <li>xpath: removed a memory leak and fixed the predicate evaluation
846 problem, extended the testsuite and cleaned up the result. XPointer seems
847 broken ...</li>
Daniel Veillardafc73112001-04-11 11:51:41 +0000848</ul>
849
Daniel Veillard56a4cb82001-03-24 17:00:36 +0000850<h3>2.3.5: Mar 23 2001</h3>
851<ul>
852 <li>Biggest change is separate parsing and evaluation of XPath expressions,
853 there is some new APIs for this too</li>
854 <li>included a number of bug fixes(XML push parser, 51876, notations,
855 52299)</li>
856 <li>Fixed some portability issues</li>
857</ul>
858
Daniel Veillarde356c282001-03-10 12:32:04 +0000859<h3>2.3.4: Mar 10 2001</h3>
860<ul>
861 <li>Fixed bugs #51860 and #51861</li>
862 <li>Added a global variable xmlDefaultBufferSize to allow default buffer
863 size to be application tunable.</li>
864 <li>Some cleanup in the validation code, still a bug left and this part
865 should probably be rewritten to support ambiguous content model :-\</li>
866 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3
867 parser</li>
868 <li>Fixed another bug in xmlNodeGetContent()</li>
869 <li>Bjorn fixed XPath node collection and Number formatting</li>
870 <li>Fixed a loop reported in the HTML parsing</li>
871 <li>blank space are reported even if the Dtd content model proves that they
872 are formatting spaces, this is for XmL conformance</li>
873</ul>
874
Daniel Veillardb402c072001-03-01 17:28:58 +0000875<h3>2.3.3: Mar 1 2001</h3>
876<ul>
877 <li>small change in XPath for XSLT</li>
878 <li>documentation cleanups</li>
879 <li>fix in validation by Gary Pennington</li>
880 <li>serious parsing performances improvements</li>
881</ul>
882
Daniel Veillardec70e912001-02-26 20:10:45 +0000883<h3>2.3.2: Feb 24 2001</h3>
Daniel Veillard71681102001-02-24 17:48:53 +0000884<ul>
885 <li>chasing XPath bugs, found a bunch, completed some TODO</li>
886 <li>fixed a Dtd parsing bug</li>
887 <li>fixed a bug in xmlNodeGetContent</li>
888 <li>ID/IDREF support partly rewritten by Gary Pennington</li>
889</ul>
890
Daniel Veillardec70e912001-02-26 20:10:45 +0000891<h3>2.3.1: Feb 15 2001</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000892<ul>
893 <li>some XPath and HTML bug fixes for XSLT</li>
894 <li>small extension of the hash table interfaces for DOM gdome2
895 implementation</li>
896 <li>A few bug fixes</li>
897</ul>
898
Daniel Veillardec70e912001-02-26 20:10:45 +0000899<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 +0000900<ul>
901 <li>Lots of XPath bug fixes</li>
902 <li>Add a mode with Dtd lookup but without validation error reporting for
903 XSLT</li>
904 <li>Add support for text node without escaping (XSLT)</li>
905 <li>bug fixes for xmlCheckFilename</li>
906 <li>validation code bug fixes from Gary Pennington</li>
907 <li>Patch from Paul D. Smith correcting URI path normalization</li>
908 <li>Patch to allow simultaneous install of libxml-devel and
909 libxml2-devel</li>
910 <li>the example Makefile is now fixed</li>
911 <li>added HTML to the RPM packages</li>
912 <li>tree copying bugfixes</li>
913 <li>updates to Windows makefiles</li>
914 <li>optimisation patch from Bjorn Reese</li>
915</ul>
916
Daniel Veillardec70e912001-02-26 20:10:45 +0000917<h3>2.2.11: Jan 4 2001</h3>
Daniel Veillard503b8932001-01-05 06:36:31 +0000918<ul>
919 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
920 <li>added htmlHandleOmittedElem()</li>
921 <li>Applied Bjorn Reese's IPV6 first patch</li>
922 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000923 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000924</ul>
925
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000926<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000927<ul>
928 <li>Fix the Windows problems of 2.2.8</li>
929 <li>integrate OpenVMS patches</li>
930 <li>better handling of some nasty HTML input</li>
931 <li>Improved the XPointer implementation</li>
932 <li>integrate a number of provided patches</li>
933</ul>
934
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000935<h3>2.2.9: Nov 25 2000</h3>
936<ul>
937 <li>erroneous release :-(</li>
938</ul>
939
Daniel Veillard28929b22000-11-13 18:22:49 +0000940<h3>2.2.8: Nov 13 2000</h3>
941<ul>
942 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
943 support</li>
944 <li>Patch in conditional section handling</li>
945 <li>updated MS compiler project</li>
946 <li>fixed some XPath problems</li>
947 <li>added an URI escaping function</li>
948 <li>some other bug fixes</li>
949</ul>
950
951<h3>2.2.7: Oct 31 2000</h3>
952<ul>
953 <li>added message redirection</li>
954 <li>XPath improvements (thanks TOM !)</li>
955 <li>xmlIOParseDTD() added</li>
956 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
957 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
958</ul>
959
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000960<h3>2.2.6: Oct 25 2000:</h3>
961<ul>
962 <li>Added an hash table module, migrated a number of internal structure to
963 those</li>
964 <li>Fixed a posteriori validation problems</li>
965 <li>HTTP module cleanups</li>
966 <li>HTML parser improvements (tag errors, script/style handling, attribute
967 normalization)</li>
968 <li>coalescing of adjacent text nodes</li>
969 <li>couple of XPath bug fixes, exported the internal API</li>
970</ul>
971
Daniel Veillardab8500d2000-10-15 21:06:19 +0000972<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000973<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000974 <li>XPointer implementation and testsuite</li>
975 <li>Lot of XPath fixes, added variable and functions registration, more
976 tests</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000977 <li>Portability fixes, lots of enhancements toward an easy Windows build
978 and release</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000979 <li>Late validation fixes</li>
980 <li>Integrated a lot of contributed patches</li>
981 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000982 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000983</ul>
984
985<h3>2.2.4: Oct 1 2000:</h3>
986<ul>
987 <li>main XPath problem fixed</li>
988 <li>Integrated portability patches for Windows</li>
989 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000990</ul>
991
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000992<h3>2.2.3: Sep 17 2000</h3>
993<ul>
994 <li>bug fixes</li>
995 <li>cleanup of entity handling code</li>
996 <li>overall review of all loops in the parsers, all sprintf usage has been
997 checked too</li>
998 <li>Far better handling of larges Dtd. Validating against Docbook XML Dtd
999 works smoothly now.</li>
1000</ul>
1001
1002<h3>1.8.10: Sep 6 2000</h3>
1003<ul>
1004 <li>bug fix release for some Gnome projects</li>
1005</ul>
1006
1007<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +00001008<ul>
1009 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +00001010 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +00001011</ul>
1012
Daniel Veillardd5f97f82000-09-17 16:38:14 +00001013<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +00001014<ul>
1015 <li>a purely bug fixes release</li>
1016 <li>fixed an encoding support problem when parsing from a memory block</li>
1017 <li>fixed a DOCTYPE parsing problem</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001018 <li>removed a bug in the function allowing to override the memory
1019 allocation routines</li>
Daniel Veillarda2679fa2000-07-22 02:38:15 +00001020</ul>
1021
Daniel Veillardd5f97f82000-09-17 16:38:14 +00001022<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +00001023<ul>
1024 <li>applied a lot of portability fixes</li>
1025 <li>better encoding support/cleanup and saving (content is now always
1026 encoded in UTF-8)</li>
1027 <li>the HTML parser now correctly handles encodings</li>
1028 <li>added xmlHasProp()</li>
1029 <li>fixed a serious problem with &amp;#38;</li>
1030 <li>propagated the fix to FTP client</li>
1031 <li>cleanup, bugfixes, etc ...</li>
1032 <li>Added a page about <a href="encoding.html">libxml Internationalization
1033 support</a></li>
1034</ul>
1035
Daniel Veillard60979bd2000-07-10 12:17:33 +00001036<h3>1.8.9: July 9 2000</h3>
1037<ul>
1038 <li>fixed the spec the RPMs should be better</li>
1039 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
1040 rpmfind users problem</li>
1041</ul>
1042
Daniel Veillard6388e172000-07-03 16:07:19 +00001043<h3>2.1.1: July 1 2000</h3>
1044<ul>
1045 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
1046 <li>improvements on the HTML parser</li>
1047</ul>
1048
Daniel Veillard3f6f7f62000-06-30 17:58:25 +00001049<h3>2.1.0 and 1.8.8: June 29 2000</h3>
1050<ul>
1051 <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to
1052 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
1053 about &amp;#38; charref parsing</li>
1054 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
1055 also contains numerous fixes and enhancements:
1056 <ul>
1057 <li>added xmlStopParser() to stop parsing</li>
1058 <li>improved a lot parsing speed when there is large CDATA blocs</li>
1059 <li>includes XPath patches provided by Picdar Technology</li>
1060 <li>tried to fix as much as possible DtD validation and namespace
1061 related problems</li>
1062 <li>output to a given encoding has been added/tested</li>
1063 <li>lot of various fixes</li>
1064 </ul>
1065 </li>
1066</ul>
1067
Daniel Veillarde0aed302000-04-16 08:52:20 +00001068<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +00001069<ul>
1070 <li>First public release of libxml2. If you are using libxml, it's a good
Daniel Veillarde0aed302000-04-16 08:52:20 +00001071 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally
1072 scheduled for Apr 3 the relase occured only on Apr 12 due to massive
1073 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +00001074 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +00001075 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +00001076 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +00001077 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +00001078 <pre>#include "xxx.h"</pre>
1079 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +00001080 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
1081 <li>the memory allocation routines used by libxml can now be overloaded
1082 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +00001083 <li>The previously CVS only tool tester has been renamed
1084 <strong>xmllint</strong> and is now installed as part of the libxml2
1085 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +00001086 <li>The I/O interface has been revamped. There is now ways to plug in
1087 specific I/O modules, either at the URI scheme detection level using
1088 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
1089 parser context using xmlCreateIOParserCtxt()</li>
1090 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
1091 number of the libxml module in use</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001092 <li>a number of optional features of libxml can now be excluded at
1093 configure time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001094</ul>
1095
1096<h3>2.0.0beta: Mar 14 2000</h3>
1097<ul>
1098 <li>This is a first Beta release of libxml version 2</li>
Daniel Veillarde356c282001-03-10 12:32:04 +00001099 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org
1100 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and
1101 RPMs</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001102 <li>This version is now the head in the Gnome CVS base, the old one is
1103 available under the tag LIB_XML_1_X</li>
1104 <li>This includes a very large set of changes. Froma programmatic point of
1105 view applications should not have to be modified too much, check the <a
1106 href="upgrade.html">upgrade page</a></li>
1107 <li>Some interfaces may changes (especially a bit about encoding).</li>
1108 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +00001109 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001110 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
1111 handled now</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001112 <li>Better handling of entities, especially well formedness checking
1113 and proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +00001114 <li>DTD conditional sections</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001115 <li>Validation now correcly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +00001116 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
1117 structures to accomodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +00001118 </ul>
1119 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001120 <li>Serious progress were made toward compliance, <a
1121 href="conf/result.html">here are the result of the test</a> against the
1122 OASIS testsuite (except the japanese tests since I don't support that
1123 encoding yet). This URL is rebuilt every couple of hours using the CVS
1124 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +00001125</ul>
1126
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001127<h3>1.8.7: Mar 6 2000</h3>
1128<ul>
1129 <li>This is a bug fix release:</li>
1130 <li>It is possible to disable the ignorable blanks heuristic used by
1131 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001132 that for adherence to XML spec, this behaviour will be disabled by
1133 default in 2.x . The same function will allow to keep compatibility for
1134 old code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +00001135 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
1136 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001137 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
1138 compilation on some platforms has been fixed</li>
1139 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
1140 URIs</li>
1141</ul>
1142
Daniel Veillarde41f2b72000-01-30 20:00:07 +00001143<h3>1.8.6: Jan 31 2000</h3>
1144<ul>
1145 <li>added a nanoFTP transport module, debugged until the new version of <a
1146 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
1147 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +00001148</ul>
1149
1150<h3>1.8.5: Jan 21 2000</h3>
1151<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +00001152 <li>adding APIs to parse a well balanced chunk of XML (production <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001153 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the
1154 XML spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +00001155 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +00001156 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
1157 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +00001158 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
1159 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +00001160</ul>
1161
1162<h3>1.8.4: Jan 13 2000</h3>
1163<ul>
1164 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
1165 <li>all exit() call should have been removed from libxml</li>
1166 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
1167 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +00001168</ul>
1169
1170<h3>1.8.3: Jan 5 2000</h3>
1171<ul>
1172 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001173 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillarddbfd6411999-12-28 16:35:14 +00001174 <li>lots of bug fixes and improvement added over XMas hollidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +00001175 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +00001176 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
1177 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +00001178 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +00001179 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +00001180 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +00001181</ul>
1182
1183<h3>1.8.2: Dec 21 1999</h3>
1184<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +00001185 <li>I got another problem with includes and C++, I hope this issue is fixed
1186 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +00001187 <li>Added a few tree modification functions: xmlReplaceNode,
1188 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
1189 xmlDocSetRootElement</li>
1190 <li>Tried to improve the HTML output with help from <a
1191 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +00001192</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +00001193
Daniel Veillarde4e51311999-12-18 15:32:46 +00001194<h3>1.8.1: Dec 18 1999</h3>
1195<ul>
1196 <li>various patches to avoid troubles when using libxml with C++ compilers
1197 the "namespace" keyword and C escaping in include files</li>
1198 <li>a problem in one of the core macros IS_CHAR was corrected</li>
1199 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
1200 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +00001201 <li>fixed a posteriori validation (validation after parsing, or by using a
1202 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +00001203 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +00001204</ul>
1205
1206<h3>1.8.0: Dec 12 1999</h3>
1207<ul>
1208 <li>cleanup, especially memory wise</li>
1209 <li>the parser should be more reliable, especially the HTML one, it should
1210 not crash, whatever the input !</li>
1211 <li>Integrated various patches, especially a speedup improvement for large
1212 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
1213 configure with --with-buffers to enable them.</li>
1214 <li>attribute normalization, oops should have been added long ago !</li>
1215 <li>attributes defaulted from Dtds should be available, xmlSetProp() now
1216 does entities escapting by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +00001217</ul>
Daniel Veillard35008381999-10-25 13:15:52 +00001218
1219<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001220<ul>
Daniel Veillard35008381999-10-25 13:15:52 +00001221 <li>Lots of HTML improvement</li>
1222 <li>Fixed some errors when saving both XML and HTML</li>
1223 <li>More examples, the regression tests should now look clean</li>
1224 <li>Fixed a bug with contiguous charref</li>
1225</ul>
1226
1227<h3>1.7.3: Sep 29 1999</h3>
1228<ul>
1229 <li>portability problems fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001230 <li>snprintf was used unconditionnally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +00001231 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001232</ul>
1233
1234<h3>1.7.1: Sep 24 1999</h3>
1235<ul>
1236 <li>The basic type for strings manipulated by libxml has been renamed in
1237 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001238 is that CHAR was conflicting with a predefined type on Windows. However
1239 on non WIN32 environment, compatibility is provided by the way of a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001240 <strong>#define </strong>.</li>
1241 <li>Changed another error : the use of a structure field called errno, and
1242 leading to troubles on platforms where it's a macro</li>
1243</ul>
1244
1245<h3>1.7.0: sep 23 1999</h3>
1246<ul>
1247 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00001248 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001249 <li>Added an errno to report errors by another mean than a simple printf
1250 like callback</li>
1251 <li>Finished ID/IDREF support and checking when validation</li>
1252 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00001253 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001254 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
1255 implementation</li>
1256 <li>Added an HTML parser front-end</li>
1257</ul>
1258
1259<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001260
Daniel Veillard402e8c82000-02-29 22:57:47 +00001261<p><a href="http://www.w3.org/TR/REC-xml">XML is a standard</a> for
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001262markup-based structured documents. Here is <a name="example">an example XML
1263document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00001264<pre>&lt;?xml version="1.0"?&gt;
1265&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
1266 &lt;head&gt;
1267 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
1268 &lt;/head&gt;
1269 &lt;chapter&gt;
1270 &lt;title&gt;The Linux adventure&lt;/title&gt;
1271 &lt;p&gt;bla bla bla ...&lt;/p&gt;
1272 &lt;image href="linus.gif"/&gt;
1273 &lt;p&gt;...&lt;/p&gt;
1274 &lt;/chapter&gt;
1275&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00001276
Daniel Veillard402e8c82000-02-29 22:57:47 +00001277<p>The first line specifies that it's an XML document and gives useful
1278information about its encoding. Then the document is a text format whose
1279structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001280to be closed</strong>. XML is pedantic about this. However, if a tag is empty
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001281(no content), a single tag can serve as both the opening and closing tag if
1282it ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note
1283that, for example, the image tag has no content (just an attribute) and is
1284closed by ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +00001285
Daniel Veillard402e8c82000-02-29 22:57:47 +00001286<p>XML can be applied sucessfully to a wide range of uses, from long term
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001287structured document maintenance (where it follows the steps of SGML) to
1288simple data encoding mechanisms like configuration file formatting (glade),
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001289spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
1290it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001291
Daniel Veillard82687162001-01-22 15:32:01 +00001292<h2><a name="XSLT">XSLT</a></h2>
1293
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +00001294<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
1295
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001296<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a
1297language for transforming XML documents into other XML documents (or
1298HTML/textual output).</p>
Daniel Veillard82687162001-01-22 15:32:01 +00001299
1300<p>A separate library called libxslt is being built on top of libxml2. This
1301module "libxslt" can be found in the Gnome CVS base too.</p>
1302
Daniel Veillard383b1472001-01-23 11:39:52 +00001303<p>You can check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001304href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a>
1305supported and the progresses on the <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001306href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog"
1307name="Changelog">Changelog</a></p>
1308
1309<h2><a name="Python">Python and bindings</a></h2>
1310
1311<p>There is a number of language bindings and wrappers available for libxml2,
1312the list below is not exhaustive. Please contact the <a
1313href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a>
1314(<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in
1315order to get updates to this list or to discuss the specific topic of libxml2
1316or libxslt wrappers or bindings:</p>
1317<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001318 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
1319 for libxml:<br>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001320 Website: <a
1321 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
1322 Download: <a
1323 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
1324 <li>There is another <a href="http://libgdome-cpp.berlios.de/">C++ wrapper
1325 based on the gdome2 </a>bindings maintained by Tobias Peters.</li>
1326 <li><a
1327 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillardaf43f632002-03-08 15:05:20 +00001328 Sergeant</a> developped <a
1329 href="http://axkit.org/download/">XML::LibXSLT</a>, a perl wrapper for
1330 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
1331 application server</a></li>
1332 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides and
1333 earlier version of the libxml/libxslt <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001334 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
1335 <li>Petr Kozelka provides <a
1336 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
1337 libxml2</a> with Kylix, Delphi and other Pascal compilers</li>
1338 <li>Wai-Sun "Squidster" Chia provides <a
1339 href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
1340 libxml2 bindings are also available in Ruby through the <a
1341 href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
1342 maintained by Tobias Peters.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001343 <li>Steve Ball and contributors maintains <a
1344 href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
1345 Tcl</a></li>
1346 <li>There is support for libxml2 in the DOM module of PHP.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001347</ul>
1348
1349<p>The distribution includes a set of Python bindings, which are garanteed to
1350be maintained as part of the library in the future, though the Python
Daniel Veillard0b79dfe2002-02-23 13:02:31 +00001351interface have not yet reached the maturity of the C API.</p>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001352
1353<p>To install the Python bindings there are 2 options:</p>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +00001354<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001355 <li>If you use an RPM based distribution, simply install the <a
1356 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python
1357 RPM</a> (and if needed the <a
1358 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
1359 RPM</a>).</li>
1360 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python
1361 module distribution</a> corresponding to your installed version of
1362 libxml2 and libxslt. Note that to install it you will need both libxml2
1363 and libxslt installed and run "python setup.py build install" in the
1364 module tree.</li>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +00001365</ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001366
1367<p>The distribution includes a set of examples and regression tests for the
1368python bindings in the <code>python/tests</code> directory. Here are some
1369excepts from those tests:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001370
1371<h3>tst.py:</h3>
1372
1373<p>This is a basic test of the file interface and DOM navigation:</p>
1374<pre>import libxml2
1375
1376doc = libxml2.parseFile("tst.xml")
1377if doc.name != "tst.xml":
1378 print "doc.name failed"
1379 sys.exit(1)
1380root = doc.children
1381if root.name != "doc":
1382 print "root.name failed"
1383 sys.exit(1)
1384child = root.children
1385if child.name != "foo":
1386 print "child.name failed"
1387 sys.exit(1)
1388doc.freeDoc()</pre>
1389
1390<p>The Python module is called libxml2, parseFile is the equivalent of
1391xmlParseFile (most of the bindings are automatically generated, and the xml
1392prefix is removed and the casing convention are kept). All node seen at the
1393binding level share the same subset of accesors:</p>
1394<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001395 <li><code>name</code> : returns the node name</li>
1396 <li><code>type</code> : returns a string indicating the node
1397 typ<code>e</code></li>
1398 <li><code>content</code> : returns the content of the node, it is based on
1399 xmlNodeGetContent() and hence is recursive.</li>
1400 <li><code>parent</code> , <code>children</code>, <code>last</code>,
1401 <code>next</code>, <code>prev</code>, <code>doc</code>,
1402 <code>properties</code>: pointing to the associated element in the tree,
1403 those may return None in case no such link exists.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001404</ul>
1405
1406<p>Also note the need to explicitely deallocate documents with freeDoc() .
1407Reference counting for libxml2 trees would need quite a lot of work to
1408function properly, and rather than risk memory leaks if not implemented
1409correctly it sounds safer to have an explicit function to free a tree. The
1410wrapper python objects like doc, root or child are them automatically garbage
1411collected.</p>
1412
1413<h3>validate.py:</h3>
1414
1415<p>This test check the validation interfaces and redirection of error
1416messages:</p>
1417<pre>import libxml2
1418
1419#desactivate error messages from the validation
1420def noerr(ctx, str):
1421 pass
1422
1423libxml2.registerErrorHandler(noerr, None)
1424
1425ctxt = libxml2.createFileParserCtxt("invalid.xml")
1426ctxt.validate(1)
1427ctxt.parseDocument()
1428doc = ctxt.doc()
1429valid = ctxt.isValid()
1430doc.freeDoc()
1431if valid != 0:
1432 print "validity chec failed"</pre>
1433
1434<p>The first thing to notice is the call to registerErrorHandler(), it
1435defines a new error handler global to the library. It is used to avoid seeing
1436the error messages when trying to validate the invalid document.</p>
1437
1438<p>The main interest of that test is the creation of a parser context with
1439createFileParserCtxt() and how the behaviour can be changed before calling
1440parseDocument() . Similary the informations resulting from the parsing phase
1441are also available using context methods.</p>
1442
1443<p>Contexts like nodes are defined as class and the libxml2 wrappers maps the
1444C function interfaces in terms of objects method as much as possible. The
1445best to get a complete view of what methods are supported is to look at the
1446libxml2.py module containing all the wrappers.</p>
1447
1448<h3>push.py:</h3>
1449
1450<p>This test show how to activate the push parser interface:</p>
1451<pre>import libxml2
1452
1453ctxt = libxml2.createPushParser(None, "&lt;foo", 4, "test.xml")
1454ctxt.parseChunk("/&gt;", 2, 1)
1455doc = ctxt.doc()
1456
1457doc.freeDoc()</pre>
1458
1459<p>The context is created with a speciall call based on the
1460xmlCreatePushParser() from the C library. The first argument is an optional
1461SAX callback object, then the initial set of data, the lenght and the name of
1462the resource in case URI-References need to be computed by the parser.</p>
1463
1464<p>Then the data are pushed using the parseChunk() method, the last call
1465setting the thrird argument terminate to 1.</p>
1466
1467<h3>pushSAX.py:</h3>
1468
1469<p>this test show the use of the event based parsing interfaces. In this case
1470the parser does not build a document, but provides callback information as
1471the parser makes progresses analyzing the data being provided:</p>
1472<pre>import libxml2
1473log = ""
1474
1475class callback:
1476 def startDocument(self):
1477 global log
1478 log = log + "startDocument:"
1479
1480 def endDocument(self):
1481 global log
1482 log = log + "endDocument:"
1483
1484 def startElement(self, tag, attrs):
1485 global log
1486 log = log + "startElement %s %s:" % (tag, attrs)
1487
1488 def endElement(self, tag):
1489 global log
1490 log = log + "endElement %s:" % (tag)
1491
1492 def characters(self, data):
1493 global log
1494 log = log + "characters: %s:" % (data)
1495
1496 def warning(self, msg):
1497 global log
1498 log = log + "warning: %s:" % (msg)
1499
1500 def error(self, msg):
1501 global log
1502 log = log + "error: %s:" % (msg)
1503
1504 def fatalError(self, msg):
1505 global log
1506 log = log + "fatalError: %s:" % (msg)
1507
1508handler = callback()
1509
1510ctxt = libxml2.createPushParser(handler, "&lt;foo", 4, "test.xml")
1511chunk = " url='tst'&gt;b"
1512ctxt.parseChunk(chunk, len(chunk), 0)
1513chunk = "ar&lt;/foo&gt;"
1514ctxt.parseChunk(chunk, len(chunk), 1)
1515
Daniel Veillardfcbfa2d2002-02-21 17:54:27 +00001516reference = "startDocument:startElement foo {'url': 'tst'}:" + \
1517 "characters: bar:endElement foo:endDocument:"
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001518if log != reference:
1519 print "Error got: %s" % log
1520 print "Exprected: %s" % reference</pre>
1521
1522<p>The key object in that test is the handler, it provides a number of entry
1523points which can be called by the parser as it makes progresses to indicate
1524the information set obtained. The full set of callback is larger than what
1525the callback class in that specific example implements (see the SAX
1526definition for a complete list). The wrapper will only call those supplied by
1527the object when activated. The startElement receives the names of the element
1528and a dictionnary containing the attributes carried by this element.</p>
1529
1530<p>Also note that the reference string generated from the callback shows a
1531single character call even though the string "bar" is passed to the parser
1532from 2 different call to parseChunk()</p>
1533
1534<h3>xpath.py:</h3>
1535
1536<p>This is a basic test of XPath warppers support</p>
1537<pre>import libxml2
1538
1539doc = libxml2.parseFile("tst.xml")
1540ctxt = doc.xpathNewContext()
1541res = ctxt.xpathEval("//*")
1542if len(res) != 2:
1543 print "xpath query: wrong node set size"
1544 sys.exit(1)
1545if res[0].name != "doc" or res[1].name != "foo":
1546 print "xpath query: wrong node set value"
1547 sys.exit(1)
1548doc.freeDoc()
1549ctxt.xpathFreeContext()</pre>
1550
1551<p>This test parses a file, then create an XPath context to evaluate XPath
1552expression on it. The xpathEval() method execute an XPath query and returns
1553the result mapped in a Python way. String and numbers are natively converted,
1554and node sets are returned as a tuple of libxml2 Python nodes wrappers. Like
1555the document, the XPath context need to be freed explicitely, also not that
1556the result of the XPath query may point back to the document tree and hence
1557the document must be freed after the result of the query is used.</p>
1558
1559<h3>xpathext.py:</h3>
1560
1561<p>This test shows how to extend the XPath engine with functions written in
1562python:</p>
1563<pre>import libxml2
1564
1565def foo(ctx, x):
1566 return x + 1
1567
1568doc = libxml2.parseFile("tst.xml")
1569ctxt = doc.xpathNewContext()
1570libxml2.registerXPathFunction(ctxt._o, "foo", None, foo)
1571res = ctxt.xpathEval("foo(1)")
1572if res != 2:
1573 print "xpath extension failure"
1574doc.freeDoc()
1575ctxt.xpathFreeContext()</pre>
1576
1577<p>Note how the extension function is registered with the context (but that
1578part is not yet finalized, ths may change slightly in the future).</p>
1579
1580<h3>tstxpath.py:</h3>
1581
1582<p>This test is similar to the previousone but shows how the extension
1583function can access the XPath evaluation context:</p>
1584<pre>def foo(ctx, x):
1585 global called
1586
1587 #
1588 # test that access to the XPath evaluation contexts
1589 #
1590 pctxt = libxml2.xpathParserContext(_obj=ctx)
1591 ctxt = pctxt.context()
1592 called = ctxt.function()
1593 return x + 1</pre>
1594
1595<p>All the interfaces around the XPath parser(or rather evaluation) context
1596are not finalized, but it should be sufficient to do contextual work at the
1597evaluation point.</p>
1598
1599<h3>Memory debugging:</h3>
1600
1601<p>last but not least, all tests starts with the following prologue:</p>
1602<pre>#memory debug specific
Daniel Veillardaf43f632002-03-08 15:05:20 +00001603libxml2.debugMemory(1)</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001604
1605<p>and ends with the following epilogue:</p>
1606<pre>#memory debug specific
1607libxml2.cleanupParser()
1608if libxml2.debugMemory(1) == 0:
1609 print "OK"
1610else:
1611 print "Memory leak %d bytes" % (libxml2.debugMemory(1))
1612 libxml2.dumpMemory()</pre>
1613
1614<p>Those activate the memory debugging interface of libxml2 where all
1615alloacted block in the library are tracked. The prologue then cleans up the
1616library state and checks that all allocated memory has been freed. If not it
1617calls dumpMemory() which saves that list in a <code>.memdump</code> file.</p>
Daniel Veillard82687162001-01-22 15:32:01 +00001618
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00001619<h2><a name="architecture">libxml architecture</a></h2>
Daniel Veillard4540be42000-08-19 16:40:28 +00001620
Daniel Veillardec70e912001-02-26 20:10:45 +00001621<p>Libxml is made of multiple components; some of them are optional, and most
1622of the block interfaces are public. The main components are:</p>
Daniel Veillard4540be42000-08-19 16:40:28 +00001623<ul>
1624 <li>an Input/Output layer</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +00001625 <li>FTP and HTTP client layers (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00001626 <li>an Internationalization layer managing the encodings support</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +00001627 <li>a URI module</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00001628 <li>the XML parser and its basic SAX interface</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +00001629 <li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00001630 <li>a SAX tree module to build an in-memory DOM representation</li>
1631 <li>a tree module to manipulate the DOM representation</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +00001632 <li>a validation module using the DOM representation (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00001633 <li>an XPath module for global lookup in a DOM representation
Daniel Veillard91e9d582001-02-26 07:31:12 +00001634 (optional)</li>
1635 <li>a debug module (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00001636</ul>
1637
1638<p>Graphically this gives the following:</p>
1639
1640<p><img src="libxml.gif" alt="a graphical view of the various"></p>
1641
1642<p></p>
1643
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001644<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +00001645
1646<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +00001647returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001648<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +00001649as the file name, the document type, and a <strong>children</strong> pointer
1650which is the root of the document (or more exactly the first child under the
1651root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard91e9d582001-02-26 07:31:12 +00001652chained in double-linked lists of siblings and with a children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +00001653relationship. An xmlNode can also carry properties (a chain of xmlAttr
1654structures). An attribute may have a value which is a list of TEXT or
1655ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00001656
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001657<p>Here is an example (erroneous with respect to the XML spec since there
1658should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00001659
1660<p><img src="structure.gif" alt=" structure.gif "></p>
1661
1662<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +00001663called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001664prints them back as parsed. This is useful for detecting errors both in XML
1665code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard91e9d582001-02-26 07:31:12 +00001666which prints the actual in-memory structure of the document; here is the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001667result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00001668<pre>DOCUMENT
1669version=1.0
1670standalone=true
1671 ELEMENT EXAMPLE
1672 ATTRIBUTE prop1
1673 TEXT
1674 content=gnome is great
1675 ATTRIBUTE prop2
1676 ENTITY_REF
1677 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +00001678 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +00001679 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00001680 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +00001681 TEXT
1682 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00001683 ELEMENT chapter
1684 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +00001685 TEXT
1686 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00001687 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +00001688 TEXT
1689 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00001690 ELEMENT image
1691 ATTRIBUTE href
1692 TEXT
1693 content=linus.gif
1694 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +00001695 TEXT
1696 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00001697
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001698<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +00001699
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001700<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001701
Daniel Veillard402e8c82000-02-29 22:57:47 +00001702<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001703memory. In that case (and if you don't expect to save back the XML document
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001704loaded using libxml), it's better to use the SAX interface of libxml. SAX is
1705a <strong>callback-based interface</strong> to the parser. Before parsing,
1706the application layer registers a customized set of callbacks which are
1707called by the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001708
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001709<p>To get more detailed step-by-step guidance on using the SAX interface of
Daniel Veillard4540be42000-08-19 16:40:28 +00001710libxml, see the <a
1711href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
1712documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001713Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001714
1715<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
1716program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001717binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +00001718distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001719testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001720<pre>SAX.setDocumentLocator()
1721SAX.startDocument()
1722SAX.getEntity(amp)
1723SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
1724SAX.characters( , 3)
1725SAX.startElement(head)
1726SAX.characters( , 4)
1727SAX.startElement(title)
1728SAX.characters(Welcome to Gnome, 16)
1729SAX.endElement(title)
1730SAX.characters( , 3)
1731SAX.endElement(head)
1732SAX.characters( , 3)
1733SAX.startElement(chapter)
1734SAX.characters( , 4)
1735SAX.startElement(title)
1736SAX.characters(The Linux adventure, 19)
1737SAX.endElement(title)
1738SAX.characters( , 4)
1739SAX.startElement(p)
1740SAX.characters(bla bla bla ..., 15)
1741SAX.endElement(p)
1742SAX.characters( , 4)
1743SAX.startElement(image, href='linus.gif')
1744SAX.endElement(image)
1745SAX.characters( , 4)
1746SAX.startElement(p)
1747SAX.characters(..., 3)
1748SAX.endElement(p)
1749SAX.characters( , 3)
1750SAX.endElement(chapter)
1751SAX.characters( , 1)
1752SAX.endElement(EXAMPLE)
1753SAX.endDocument()</pre>
1754
Daniel Veillardec70e912001-02-26 20:10:45 +00001755<p>Most of the other interfaces of libxml are based on the DOM tree-building
1756facility, so nearly everything up to the end of this document presupposes the
1757use of the standard DOM tree build. Note that the DOM tree itself is built by
1758a set of registered default callbacks, without internal specific
1759interface.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001760
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00001761<h2><a name="Validation">Validation &amp; DTDs</a></h2>
1762
1763<p>Table of Content:</p>
1764<ol>
1765 <li><a href="#General5">General overview</a></li>
1766 <li><a href="#definition">The definition</a></li>
1767 <li><a href="#Simple">Simple rules</a>
1768 <ol>
Daniel Veillard9c466822001-10-25 12:03:39 +00001769 <li><a href="#reference">How to reference a DTD from a document</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00001770 <li><a href="#Declaring">Declaring elements</a></li>
1771 <li><a href="#Declaring1">Declaring attributes</a></li>
1772 </ol>
1773 </li>
1774 <li><a href="#Some">Some examples</a></li>
1775 <li><a href="#validate">How to validate</a></li>
1776 <li><a href="#Other">Other resources</a></li>
1777</ol>
1778
1779<h3><a name="General5">General overview</a></h3>
1780
1781<p>Well what is validation and what is a DTD ?</p>
1782
1783<p>DTD is the acronym for Document Type Definition. This is a description of
1784the content for a familly of XML files. This is part of the XML 1.0
1785specification, and alows to describe and check that a given document instance
1786conforms to a set of rules detailing its structure and content.</p>
1787
1788<p>Validation is the process of checking a document against a DTD (more
1789generally against a set of construction rules).</p>
1790
1791<p>The validation process and building DTDs are the two most difficult parts
1792of the XML life cycle. Briefly a DTD defines all the possibles element to be
1793found within your document, what is the formal shape of your document tree
1794(by defining the allowed content of an element, either text, a regular
1795expression for the allowed list of children, or mixed content i.e. both text
1796and children). The DTD also defines the allowed attributes for all elements
1797and the types of the attributes.</p>
1798
1799<h3><a name="definition1">The definition</a></h3>
1800
1801<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a
1802href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of
1803Rev1</a>):</p>
1804<ul>
1805 <li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring
1806 elements</a></li>
1807 <li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring
1808 attributes</a></li>
1809</ul>
1810
1811<p>(unfortunately) all this is inherited from the SGML world, the syntax is
1812ancient...</p>
1813
1814<h3><a name="Simple1">Simple rules</a></h3>
1815
1816<p>Writing DTD can be done in multiple ways, the rules to build them if you
1817need something fixed or something which can evolve over time can be radically
1818different. Really complex DTD like Docbook ones are flexible but quite harder
1819to design. I will just focuse on DTDs for a formats with a fixed simple
1820structure. It is just a set of basic rules, and definitely not exhaustive nor
1821useable for complex DTD design.</p>
1822
1823<h4><a name="reference1">How to reference a DTD from a document</a>:</h4>
1824
1825<p>Assuming the top element of the document is <code>spec</code> and the dtd
1826is placed in the file <code>mydtd</code> in the subdirectory
1827<code>dtds</code> of the directory from where the document were loaded:</p>
1828
1829<p><code>&lt;!DOCTYPE spec SYSTEM "dtds/mydtd"&gt;</code></p>
1830
1831<p>Notes:</p>
1832<ul>
1833 <li>the system string is actually an URI-Reference (as defined in <a
1834 href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a
1835 full URL string indicating the location of your DTD on the Web, this is a
1836 really good thing to do if you want others to validate your document</li>
1837 <li>it is also possible to associate a <code>PUBLIC</code> identifier (a
1838 magic string) so that the DTd is looked up in catalogs on the client side
1839 without having to locate it on the web</li>
1840 <li>a dtd contains a set of elements and attributes declarations, but they
1841 don't define what the root of the document should be. This is explicitely
1842 told to the parser/validator as the first element of the
1843 <code>DOCTYPE</code> declaration.</li>
1844</ul>
1845
1846<h4><a name="Declaring2">Declaring elements</a>:</h4>
1847
1848<p>The following declares an element <code>spec</code>:</p>
1849
1850<p><code>&lt;!ELEMENT spec (front, body, back?)&gt;</code></p>
1851
1852<p>it also expresses that the spec element contains one <code>front</code>,
1853one <code>body</code> and one optionnal <code>back</code> children elements
1854in this order. The declaration of one element of the structure and its
1855content are done in a single declaration. Similary the following declares
1856<code>div1</code> elements:</p>
1857
Daniel Veillard51737272002-01-23 23:10:38 +00001858<p><code>&lt;!ELEMENT div1 (head, (p | list | note)*, div2?)&gt;</code></p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00001859
1860<p>means div1 contains one <code>head</code> then a series of optional
1861<code>p</code>, <code>list</code>s and <code>note</code>s and then an
1862optional <code>div2</code>. And last but not least an element can contain
1863text:</p>
1864
1865<p><code>&lt;!ELEMENT b (#PCDATA)&gt;</code></p>
1866
1867<p><code>b</code> contains text or being of mixed content (text and elements
1868in no particular order):</p>
1869
1870<p><code>&lt;!ELEMENT p (#PCDATA|a|ul|b|i|em)*&gt;</code></p>
1871
1872<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>,
1873<code>b</code>, <code>i </code>or <code>em</code> elements in no particular
1874order.</p>
1875
1876<h4><a name="Declaring1">Declaring attributes</a>:</h4>
1877
1878<p>again the attributes declaration includes their content definition:</p>
1879
1880<p><code>&lt;!ATTLIST termdef name CDATA #IMPLIED&gt;</code></p>
1881
1882<p>means that the element <code>termdef</code> can have a <code>name</code>
1883attribute containing text (<code>CDATA</code>) and which is optionnal
1884(<code>#IMPLIED</code>). The attribute value can also be defined within a
1885set:</p>
1886
1887<p><code>&lt;!ATTLIST list type (bullets|ordered|glossary)
1888"ordered"&gt;</code></p>
1889
1890<p>means <code>list</code> element have a <code>type</code> attribute with 3
1891allowed values "bullets", "ordered" or "glossary" and which default to
1892"ordered" if the attribute is not explicitely specified.</p>
1893
1894<p>The content type of an attribute can be text (<code>CDATA</code>),
1895anchor/reference/references
1896(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies)
1897(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s)
1898(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a
1899<code>chapter</code> element can have an optional <code>id</code> attribute
1900of type <code>ID</code>, usable for reference from attribute of type
1901IDREF:</p>
1902
1903<p><code>&lt;!ATTLIST chapter id ID #IMPLIED&gt;</code></p>
1904
1905<p>The last value of an attribute definition can be <code>#REQUIRED
1906</code>meaning that the attribute has to be given, <code>#IMPLIED</code>
1907meaning that it is optional, or the default value (possibly prefixed by
1908<code>#FIXED</code> if it is the only allowed).</p>
1909
1910<p>Notes:</p>
1911<ul>
1912 <li>usually the attributes pertaining to a given element are declared in a
1913 single expression, but it is just a convention adopted by a lot of DTD
1914 writers:
1915 <pre>&lt;!ATTLIST termdef
1916 id ID #REQUIRED
1917 name CDATA #IMPLIED&gt;</pre>
1918 <p>The previous construct defines both <code>id</code> and
1919 <code>name</code> attributes for the element <code>termdef</code></p>
1920 </li>
1921</ul>
1922
1923<h3><a name="Some1">Some examples</a></h3>
1924
1925<p>The directory <code>test/valid/dtds/</code> in the libxml distribution
1926contains some complex DTD examples. The <code>test/valid/dia.xml</code>
1927example shows an XML file where the simple DTD is directly included within
1928the document.</p>
1929
1930<h3><a name="validate1">How to validate</a></h3>
1931
1932<p>The simplest is to use the xmllint program comming with libxml. The
1933<code>--valid</code> option turn on validation of the files given as input,
1934for example the following validates a copy of the first revision of the XML
19351.0 specification:</p>
1936
1937<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p>
1938
1939<p>the -- noout is used to not output the resulting tree.</p>
1940
1941<p>The <code>--dtdvalid dtd</code> allows to validate the document(s) against
1942a given DTD.</p>
1943
1944<p>Libxml exports an API to handle DTDs and validation, check the <a
1945href="http://xmlsoft.org/html/libxml-valid.html">associated
1946description</a>.</p>
1947
1948<h3><a name="Other1">Other resources</a></h3>
1949
1950<p>DTDs are as old as SGML. So there may be a number of examples on-line, I
1951will just list one for now, others pointers welcome:</p>
1952<ul>
1953 <li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li>
1954</ul>
1955
1956<p>I suggest looking at the examples found under test/valid/dtd and any of
1957the large number of books available on XML. The dia example in test/valid
1958should be both simple and complete enough to allow you to build your own.</p>
1959
1960<p></p>
1961
1962<h2><a name="Memory">Memory Management</a></h2>
1963
1964<p>Table of Content:</p>
1965<ol>
1966 <li><a href="#General3">General overview</a></li>
Daniel Veillard9c466822001-10-25 12:03:39 +00001967 <li><a href="#setting">Setting libxml set of memory routines</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00001968 <li><a href="#cleanup">Cleaning up after parsing</a></li>
1969 <li><a href="#Debugging">Debugging routines</a></li>
1970 <li><a href="#General4">General memory requirements</a></li>
1971</ol>
1972
1973<h3><a name="General3">General overview</a></h3>
1974
1975<p>The module <code><a
1976href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
1977provides the interfaces to the libxml memory system:</p>
1978<ul>
1979 <li>libxml does not use the libc memory allocator directly but xmlFree(),
1980 xmlMalloc() and xmlRealloc()</li>
1981 <li>those routines can be reallocated to a specific set of routine, by
1982 default the libc ones i.e. free(), malloc() and realloc()</li>
1983 <li>the xmlmemory.c module includes a set of debugging routine</li>
1984</ul>
1985
1986<h3><a name="setting">Setting libxml set of memory routines</a></h3>
1987
1988<p>It is sometimes useful to not use the default memory allocator, either for
1989debugging, analysis or to implement a specific behaviour on memory management
1990(like on embedded systems). Two function calls are available to do so:</p>
1991<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001992 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet
1993 ()</a> which return the current set of functions in use by the parser</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00001994 <li><a
1995 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001996 which allow to set up a new set of memory allocation functions</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00001997</ul>
1998
1999<p>Of course a call to xmlMemSetup() should probably be done before calling
2000any other libxml routines (unless you are sure your allocations routines are
2001compatibles).</p>
2002
2003<h3><a name="cleanup">Cleaning up after parsing</a></h3>
2004
2005<p>Libxml is not stateless, there is a few set of memory structures needing
2006allocation before the parser is fully functionnal (some encoding structures
2007for example). This also mean that once parsing is finished there is a tiny
2008amount of memory (a few hundred bytes) which can be recollected if you don't
2009reuse the parser immediately:</p>
2010<ul>
2011 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser
Daniel Veillardaf43f632002-03-08 15:05:20 +00002012 ()</a> is a centralized routine to free the parsing states. Note that it
2013 won't deallocate any produced tree if any (use the xmlFreeDoc() and
2014 related routines for this).</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002015 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser
Daniel Veillardaf43f632002-03-08 15:05:20 +00002016 ()</a> is the dual routine allowing to preallocate the parsing state
2017 which can be useful for example to avoid initialization reentrancy
2018 problems when using libxml in multithreaded applications</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002019</ul>
2020
2021<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild
2022at the next invocation of parser routines, but be careful of the consequences
2023in multithreaded applications.</p>
2024
2025<h3><a name="Debugging">Debugging routines</a></h3>
2026
2027<p>When configured using --with-mem-debug flag (off by default), libxml uses
2028a set of memory allocation debugging routineskeeping track of all allocated
2029blocks and the location in the code where the routine was called. A couple of
2030other debugging routines allow to dump the memory allocated infos to a file
2031or call a specific routine when a given block number is allocated:</p>
2032<ul>
2033 <li><a
2034 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002035 <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002036 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>
2037 and <a
2038 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>
2039 are the memory debugging replacement allocation routines</li>
2040 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump
Daniel Veillardaf43f632002-03-08 15:05:20 +00002041 ()</a> dumps all the informations about the allocated memory block lefts
2042 in the <code>.memdump</code> file</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002043</ul>
2044
2045<p>When developping libxml memory debug is enabled, the tests programs call
2046xmlMemoryDump () and the "make test" regression tests will check for any
2047memory leak during the full regression test sequence, this helps a lot
2048ensuring that libxml does not leak memory and bullet proof memory
2049allocations use (some libc implementations are known to be far too permissive
2050resulting in major portability problems!).</p>
2051
2052<p>If the .memdump reports a leak, it displays the allocation function and
2053also tries to give some informations about the content and structure of the
2054allocated blocks left. This is sufficient in most cases to find the culprit,
2055but not always. Assuming the allocation problem is reproductible, it is
2056possible to find more easilly:</p>
2057<ol>
2058 <li>write down the block number xxxx not allocated</li>
2059 <li>export the environement variable XML_MEM_BREAKPOINT=xxxx</li>
2060 <li>run the program under a debugger and set a breakpoint on
2061 xmlMallocBreakpoint() a specific function called when this precise block
2062 is allocated</li>
2063 <li>when the breakpoint is reached you can then do a fine analysis of the
2064 allocation an step to see the condition resulting in the missing
2065 deallocation.</li>
2066</ol>
2067
2068<p>I used to use a commercial tool to debug libxml memory problems but after
2069noticing that it was not detecting memory leaks that simple mechanism was
2070used and proved extremely efficient until now.</p>
2071
2072<h3><a name="General4">General memory requirements</a></h3>
2073
2074<p>How much libxml memory require ? It's hard to tell in average it depends
2075of a number of things:</p>
2076<ul>
2077 <li>the parser itself should work in a fixed amout of memory, except for
2078 information maintained about the stacks of names and entities locations.
2079 The I/O and encoding handlers will probably account for a few KBytes.
2080 This is true for both the XML and HTML parser (though the HTML parser
2081 need more state).</li>
2082 <li>If you are generating the DOM tree then memory requirements will grow
2083 nearly lineary with the size of the data. In general for a balanced
2084 textual document the internal memory requirement is about 4 times the
2085 size of the UTF8 serialization of this document (exmple the XML-1.0
2086 recommendation is a bit more of 150KBytes and takes 650KBytes of main
2087 memory when parsed). Validation will add a amount of memory required for
2088 maintaining the external Dtd state which should be linear with the
2089 complexity of the content model defined by the Dtd</li>
2090 <li>If you don't care about the advanced features of libxml like
2091 validation, DOM, XPath or XPointer, but really need to work fixed memory
2092 requirements, then the SAX interface should be used.</li>
2093</ul>
2094
2095<p></p>
2096
2097<h2><a name="Encodings">Encodings support</a></h2>
2098
2099<p>Table of Content:</p>
2100<ol>
2101 <li><a href="encoding.html#What">What does internationalization support
2102 mean ?</a></li>
2103 <li><a href="encoding.html#internal">The internal encoding, how and
2104 why</a></li>
2105 <li><a href="encoding.html#implemente">How is it implemented ?</a></li>
2106 <li><a href="encoding.html#Default">Default supported encodings</a></li>
2107 <li><a href="encoding.html#extend">How to extend the existing
2108 support</a></li>
2109</ol>
2110
2111<h3><a name="What">What does internationalization support mean ?</a></h3>
2112
2113<p>XML was designed from the start to allow the support of any character set
2114by using Unicode. Any conformant XML parser has to support the UTF-8 and
2115UTF-16 default encodings which can both express the full unicode ranges. UTF8
2116is a variable length encoding whose greatest point are to resuse the same
2117emcoding for ASCII and to save space for Western encodings, but it is a bit
2118more complex to handle in practice. UTF-16 use 2 bytes per characters (and
2119sometimes combines two pairs), it makes implementation easier, but looks a
2120bit overkill for Western languages encoding. Moreover the XML specification
2121allows document to be encoded in other encodings at the condition that they
2122are clearly labelled as such. For example the following is a wellformed XML
2123document encoded in ISO-8859 1 and using accentuated letter that we French
2124likes for both markup and content:</p>
2125<pre>&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2126&lt;très&gt;là&lt;/très&gt;</pre>
2127
2128<p>Having internationalization support in libxml means the foolowing:</p>
2129<ul>
2130 <li>the document is properly parsed</li>
2131 <li>informations about it's encoding are saved</li>
2132 <li>it can be modified</li>
2133 <li>it can be saved in its original encoding</li>
2134 <li>it can also be saved in another encoding supported by libxml (for
2135 example straight UTF8 or even an ASCII form)</li>
2136</ul>
2137
2138<p>Another very important point is that the whole libxml API, with the
2139exception of a few routines to read with a specific encoding or save to a
2140specific encoding, is completely agnostic about the original encoding of the
2141document.</p>
2142
2143<p>It should be noted too that the HTML parser embedded in libxml now obbey
2144the same rules too, the following document will be (as of 2.2.2) handled in
2145an internationalized fashion by libxml too:</p>
2146<pre>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
2147 "http://www.w3.org/TR/REC-html40/loose.dtd"&gt;
2148&lt;html lang="fr"&gt;
2149&lt;head&gt;
2150 &lt;META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"&gt;
2151&lt;/head&gt;
2152&lt;body&gt;
2153&lt;p&gt;W3C crée des standards pour le Web.&lt;/body&gt;
2154&lt;/html&gt;</pre>
2155
2156<h3><a name="internal">The internal encoding, how and why</a></h3>
2157
2158<p>One of the core decision was to force all documents to be converted to a
2159default internal encoding, and that encoding to be UTF-8, here are the
2160rationale for those choices:</p>
2161<ul>
2162 <li>keeping the native encoding in the internal form would force the libxml
2163 users (or the code associated) to be fully aware of the encoding of the
2164 original document, for examples when adding a text node to a document,
2165 the content would have to be provided in the document encoding, i.e. the
2166 client code would have to check it before hand, make sure it's conformant
2167 to the encoding, etc ... Very hard in practice, though in some specific
2168 cases this may make sense.</li>
2169 <li>the second decision was which encoding. From the XML spec only UTF8 and
2170 UTF16 really makes sense as being the two only encodings for which there
2171 is amndatory support. UCS-4 (32 bits fixed size encoding) could be
2172 considered an intelligent choice too since it's a direct Unicode mapping
2173 support. I selected UTF-8 on the basis of efficiency and compatibility
2174 with surrounding software:
2175 <ul>
2176 <li>UTF-8 while a bit more complex to convert from/to (i.e. slightly
2177 more costly to import and export CPU wise) is also far more compact
2178 than UTF-16 (and UCS-4) for a majority of the documents I see it used
2179 for right now (RPM RDF catalogs, advogato data, various configuration
2180 file formats, etc.) and the key point for today's computer
2181 architecture is efficient uses of caches. If one nearly double the
2182 memory requirement to store the same amount of data, this will trash
2183 caches (main memory/external caches/internal caches) and my take is
2184 that this harms the system far more than the CPU requirements needed
2185 for the conversion to UTF-8</li>
2186 <li>Most of libxml version 1 users were using it with straight ASCII
2187 most of the time, doing the conversion with an internal encoding
2188 requiring all their code to be rewritten was a serious show-stopper
2189 for using UTF-16 or UCS-4.</li>
2190 <li>UTF-8 is being used as the de-facto internal encoding standard for
2191 related code like the <a href="http://www.pango.org/">pango</a>
2192 upcoming Gnome text widget, and a lot of Unix code (yep another place
2193 where Unix programmer base takes a different approach from Microsoft
2194 - they are using UTF-16)</li>
2195 </ul>
2196 </li>
2197</ul>
2198
2199<p>What does this mean in practice for the libxml user:</p>
2200<ul>
2201 <li>xmlChar, the libxml data type is a byte, those bytes must be assembled
2202 as UTF-8 valid strings. The proper way to terminate an xmlChar * string
2203 is simply to append 0 byte, as usual.</li>
2204 <li>One just need to make sure that when using chars outside the ASCII set,
2205 the values has been properly converted to UTF-8</li>
2206</ul>
2207
2208<h3><a name="implemente">How is it implemented ?</a></h3>
2209
2210<p>Let's describe how all this works within libxml, basically the I18N
2211(internationalization) support get triggered only during I/O operation, i.e.
2212when reading a document or saving one. Let's look first at the reading
2213sequence:</p>
2214<ol>
2215 <li>when a document is processed, we usually don't know the encoding, a
2216 simple heuristic allows to detect UTF-18 and UCS-4 from whose where the
2217 ASCII range (0-0x7F) maps with ASCII</li>
2218 <li>the xml declaration if available is parsed, including the encoding
2219 declaration. At that point, if the autodetected encoding is different
2220 from the one declared a call to xmlSwitchEncoding() is issued.</li>
2221 <li>If there is no encoding declaration, then the input has to be in either
2222 UTF-8 or UTF-16, if it is not then at some point when processing the
2223 input, the converter/checker of UTF-8 form will raise an encoding error.
2224 You may end-up with a garbled document, or no document at all ! Example:
2225 <pre>~/XML -&gt; ./xmllint err.xml
2226err.xml:1: error: Input is not proper UTF-8, indicate encoding !
2227&lt;très&gt;là&lt;/très&gt;
2228 ^
2229err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C
2230&lt;très&gt;là&lt;/très&gt;
2231 ^</pre>
2232 </li>
2233 <li>xmlSwitchEncoding() does an encoding name lookup, canonalize it, and
2234 then search the default registered encoding converters for that encoding.
2235 If it's not within the default set and iconv() support has been compiled
2236 it, it will ask iconv for such an encoder. If this fails then the parser
2237 will report an error and stops processing:
2238 <pre>~/XML -&gt; ./xmllint err2.xml
2239err2.xml:1: error: Unsupported encoding UnsupportedEnc
2240&lt;?xml version="1.0" encoding="UnsupportedEnc"?&gt;
2241 ^</pre>
2242 </li>
2243 <li>From that point the encoder process progressingly the input (it is
2244 plugged as a front-end to the I/O module) for that entity. It captures
2245 and convert on-the-fly the document to be parsed to UTF-8. The parser
2246 itself just does UTF-8 checking of this input and process it
2247 transparently. The only difference is that the encoding information has
2248 been added to the parsing context (more precisely to the input
2249 corresponding to this entity).</li>
2250 <li>The result (when using DOM) is an internal form completely in UTF-8
2251 with just an encoding information on the document node.</li>
2252</ol>
2253
2254<p>Ok then what's happen when saving the document (assuming you
2255colllected/built an xmlDoc DOM like structure) ? It depends on the function
2256called, xmlSaveFile() will just try to save in the original encoding, while
2257xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given
2258encoding:</p>
2259<ol>
2260 <li>if no encoding is given, libxml will look for an encoding value
2261 associated to the document and if it exists will try to save to that
2262 encoding,
2263 <p>otherwise everything is written in the internal form, i.e. UTF-8</p>
2264 </li>
2265 <li>so if an encoding was specified, either at the API level or on the
2266 document, libxml will again canonalize the encoding name, lookup for a
2267 converter in the registered set or through iconv. If not found the
2268 function will return an error code</li>
2269 <li>the converter is placed before the I/O buffer layer, as another kind of
2270 buffer, then libxml will simply push the UTF-8 serialization to through
2271 that buffer, which will then progressively be converted and pushed onto
2272 the I/O layer.</li>
2273 <li>It is possible that the converter code fails on some input, for example
2274 trying to push an UTF-8 encoded chinese character through the UTF-8 to
2275 ISO-8859-1 converter won't work. Since the encoders are progressive they
2276 will just report the error and the number of bytes converted, at that
2277 point libxml will decode the offending character, remove it from the
2278 buffer and replace it with the associated charRef encoding &amp;#123; and
2279 resume the convertion. This guarante that any document will be saved
2280 without losses (except for markup names where this is not legal, this is
2281 a problem in the current version, in pactice avoid using non-ascci
2282 characters for tags or attributes names @@). A special "ascii" encoding
2283 name is used to save documents to a pure ascii form can be used when
2284 portability is really crucial</li>
2285</ol>
2286
2287<p>Here is a few examples based on the same test document:</p>
2288<pre>~/XML -&gt; ./xmllint isolat1
2289&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2290&lt;très&gt;là&lt;/très&gt;
2291~/XML -&gt; ./xmllint --encode UTF-8 isolat1
2292&lt;?xml version="1.0" encoding="UTF-8"?&gt;
2293&lt;très&gt;là  &lt;/très&gt;
2294~/XML -&gt; </pre>
2295
2296<p>The same processing is applied (and reuse most of the code) for HTML I18N
2297processing. Looking up and modifying the content encoding is a bit more
2298difficult since it is located in a &lt;meta&gt; tag under the &lt;head&gt;,
2299so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have
2300been provided. The parser also attempts to switch encoding on the fly when
2301detecting such a tag on input. Except for that the processing is the same
2302(and again reuses the same code).</p>
2303
2304<h3><a name="Default">Default supported encodings</a></h3>
2305
2306<p>libxml has a set of default converters for the following encodings
2307(located in encoding.c):</p>
2308<ol>
2309 <li>UTF-8 is supported by default (null handlers)</li>
2310 <li>UTF-16, both little and big endian</li>
2311 <li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li>
2312 <li>ASCII, useful mostly for saving</li>
2313 <li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML
2314 predefined entities like &amp;copy; for the Copyright sign.</li>
2315</ol>
2316
2317<p>More over when compiled on an Unix platfor with iconv support the full set
2318of encodings supported by iconv can be instantly be used by libxml. On a
2319linux machine with glibc-2.1 the list of supported encodings and aliases fill
23203 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the
2321various Japanese ones.</p>
2322
2323<h4>Encoding aliases</h4>
2324
2325<p>From 2.2.3, libxml has support to register encoding names aliases. The
2326goal is to be able to parse document whose encoding is supported but where
2327the name differs (for example from the default set of names accepted by
2328iconv). The following functions allow to register and handle new aliases for
2329existing encodings. Once registered libxml will automatically lookup the
2330aliases when handling a document:</p>
2331<ul>
2332 <li>int xmlAddEncodingAlias(const char *name, const char *alias);</li>
2333 <li>int xmlDelEncodingAlias(const char *alias);</li>
2334 <li>const char * xmlGetEncodingAlias(const char *alias);</li>
2335 <li>void xmlCleanupEncodingAliases(void);</li>
2336</ul>
2337
2338<h3><a name="extend">How to extend the existing support</a></h3>
2339
2340<p>Well adding support for new encoding, or overriding one of the encoders
2341(assuming it is buggy) should not be hard, just write an input and output
2342conversion routines to/from UTF-8, and register them using
2343xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be
2344called automatically if the parser(s) encounter such an encoding name
2345(register it uppercase, this will help). The description of the encoders,
2346their arguments and expected return values are described in the encoding.h
2347header.</p>
2348
2349<p>A quick note on the topic of subverting the parser to use a different
2350internal encoding than UTF-8, in some case people will absolutely want to
2351keep the internal encoding different, I think it's still possible (but the
2352encoding must be compliant with ASCII on the same subrange) though I didn't
2353tried it. The key is to override the default conversion routines (by
2354registering null encoders/decoders for your charsets), and bypass the UTF-8
2355checking of the parser by setting the parser context charset
2356(ctxt-&gt;charset) to something different than XML_CHAR_ENCODING_UTF8, but
2357there is no guarantee taht this will work. You may also have some troubles
2358saving back.</p>
2359
2360<p>Basically proper I18N support is important, this requires at least
2361libxml-2.0.0, but a lot of features and corrections are really available only
2362starting 2.2.</p>
2363
2364<h2><a name="IO">I/O Interfaces</a></h2>
2365
2366<p>Table of Content:</p>
2367<ol>
2368 <li><a href="#General1">General overview</a></li>
2369 <li><a href="#basic">The basic buffer type</a></li>
2370 <li><a href="#Input">Input I/O handlers</a></li>
2371 <li><a href="#Output">Output I/O handlers</a></li>
2372 <li><a href="#entities">The entities loader</a></li>
2373 <li><a href="#Example2">Example of customized I/O</a></li>
2374</ol>
2375
2376<h3><a name="General1">General overview</a></h3>
2377
2378<p>The module <code><a
2379href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides
2380the interfaces to the libxml I/O system. This consists of 4 main parts:</p>
2381<ul>
2382 <li>Entities loader, this is a routine which tries to fetch the entities
2383 (files) based on their PUBLIC and SYSTEM identifiers. The default loader
2384 don't look at the public identifier since libxml do not maintain a
2385 catalog. You can redefine you own entity loader by using
2386 <code>xmlGetExternalEntityLoader()</code> and
Daniel Veillard9c466822001-10-25 12:03:39 +00002387 <code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the
2388 example</a>.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002389 <li>Input I/O buffers which are a commodity structure used by the parser(s)
2390 input layer to handle fetching the informations to feed the parser. This
2391 provides buffering and is also a placeholder where the encoding
2392 convertors to UTF8 are piggy-backed.</li>
2393 <li>Output I/O buffers are similar to the Input ones and fulfill similar
2394 task but when generating a serialization from a tree.</li>
2395 <li>A mechanism to register sets of I/O callbacks and associate them with
2396 specific naming schemes like the protocol part of the URIs.
2397 <p>This affect the default I/O operations and allows to use specific I/O
2398 handlers for certain names.</p>
2399 </li>
2400</ul>
2401
2402<p>The general mechanism used when loading http://rpmfind.net/xml.html for
2403example in the HTML parser is the following:</p>
2404<ol>
2405 <li>The default entity loader calls <code>xmlNewInputFromFile()</code> with
2406 the parsing context and the URI string.</li>
2407 <li>the URI string is checked against the existing registered handlers
2408 using their match() callback function, if the HTTP module was compiled
2409 in, it is registered and its match() function will succeeds</li>
2410 <li>the open() function of the handler is called and if successful will
2411 return an I/O Input buffer</li>
2412 <li>the parser will the start reading from this buffer and progressively
2413 fetch information from the resource, calling the read() function of the
2414 handler until the resource is exhausted</li>
2415 <li>if an encoding change is detected it will be installed on the input
2416 buffer, providing buffering and efficient use of the conversion
2417 routines</li>
2418 <li>once the parser has finished, the close() function of the handler is
2419 called once and the Input buffer and associed resources are
2420 deallocated.</li>
2421</ol>
2422
2423<p>The user defined callbacks are checked first to allow overriding of the
2424default libxml I/O routines.</p>
2425
2426<h3><a name="basic">The basic buffer type</a></h3>
2427
2428<p>All the buffer manipulation handling is done using the
2429<code>xmlBuffer</code> type define in <code><a
2430href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a
2431resizable memory buffer. The buffer allocation strategy can be selected to be
2432either best-fit or use an exponential doubling one (CPU vs. memory use
2433tradeoff). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and
2434<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a
2435system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number
2436of functions allows to manipulate buffers with names starting with the
2437<code>xmlBuffer...</code> prefix.</p>
2438
2439<h3><a name="Input">Input I/O handlers</a></h3>
2440
2441<p>An Input I/O handler is a simple structure
2442<code>xmlParserInputBuffer</code> containing a context associated to the
2443resource (file descriptor, or pointer to a protocol handler), the read() and
2444close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset
2445encoding handler are also present to support charset conversion when
2446needed.</p>
2447
2448<h3><a name="Output">Output I/O handlers</a></h3>
2449
2450<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an
2451Input one except the callbacks are write() and close().</p>
2452
2453<h3><a name="entities">The entities loader</a></h3>
2454
2455<p>The entity loader resolves requests for new entities and create inputs for
2456the parser. Creating an input from a filename or an URI string is done
2457through the xmlNewInputFromFile() routine. The default entity loader do not
2458handle the PUBLIC identifier associated with an entity (if any). So it just
2459calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in
2460XML).</p>
2461
2462<p>If you want to hook up a catalog mechanism then you simply need to
2463override the default entity loader, here is an example:</p>
2464<pre>#include &lt;libxml/xmlIO.h&gt;
2465
2466xmlExternalEntityLoader defaultLoader = NULL;
2467
2468xmlParserInputPtr
2469xmlMyExternalEntityLoader(const char *URL, const char *ID,
2470 xmlParserCtxtPtr ctxt) {
2471 xmlParserInputPtr ret;
2472 const char *fileID = NULL;
2473 /* lookup for the fileID depending on ID */
2474
2475 ret = xmlNewInputFromFile(ctxt, fileID);
2476 if (ret != NULL)
2477 return(ret);
2478 if (defaultLoader != NULL)
2479 ret = defaultLoader(URL, ID, ctxt);
2480 return(ret);
2481}
2482
2483int main(..) {
2484 ...
2485
2486 /*
2487 * Install our own entity loader
2488 */
2489 defaultLoader = xmlGetExternalEntityLoader();
2490 xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
2491
2492 ...
2493}</pre>
2494
2495<h3><a name="Example2">Example of customized I/O</a></h3>
2496
2497<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a
2498real use case</a>, xmlDocDump() closes the FILE * passed by the application
2499and this was a problem. The <a
2500href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a
2501new output handler with the closing call deactivated:</p>
2502<ol>
2503 <li>First define a new I/O ouput allocator where the output don't close the
2504 file:
2505 <pre>xmlOutputBufferPtr
2506xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) {
2507    xmlOutputBufferPtr ret;
2508    
2509    if (xmlOutputCallbackInitialized == 0)
2510        xmlRegisterDefaultOutputCallbacks();
2511
2512    if (file == NULL) return(NULL);
2513    ret = xmlAllocOutputBuffer(encoder);
2514    if (ret != NULL) {
2515        ret-&gt;context = file;
2516        ret-&gt;writecallback = xmlFileWrite;
2517        ret-&gt;closecallback = NULL; /* No close callback */
2518    }
2519    return(ret); <br>
2520
2521
2522
Daniel Veillard9c466822001-10-25 12:03:39 +00002523
2524
Daniel Veillardc6271d22001-10-27 07:50:58 +00002525
Daniel Veillard51095312001-10-28 18:51:57 +00002526
Daniel Veillard52dcab32001-10-30 12:51:17 +00002527
Daniel Veillarded421aa2001-11-04 21:22:45 +00002528
Daniel Veillard43d3f612001-11-10 11:57:23 +00002529
Daniel Veillarda4871052001-11-26 13:19:48 +00002530
Daniel Veillard1aadc442001-11-28 13:10:32 +00002531
Daniel Veillardef90ba72001-12-07 14:24:22 +00002532
Daniel Veillard9ae4b7a2001-12-13 14:24:09 +00002533
Daniel Veillard845cce42002-01-09 11:51:37 +00002534
Daniel Veillard744683d2002-01-14 17:30:20 +00002535
Daniel Veillard35e937a2002-01-19 22:21:54 +00002536
Daniel Veillardc575b992002-02-08 13:28:40 +00002537
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +00002538
Daniel Veillard397ff112002-02-11 18:27:20 +00002539
Daniel Veillarde46182c2002-02-12 14:29:11 +00002540
Daniel Veillard5f4b5992002-02-20 10:22:49 +00002541
Daniel Veillard5b16f582002-02-20 11:38:46 +00002542
Daniel Veillarda5393562002-02-20 11:40:49 +00002543
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00002544
2545
2546
Daniel Veillardaf43f632002-03-08 15:05:20 +00002547
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002548} </pre>
2549 </li>
2550 <li>And then use it to save the document:
2551 <pre>FILE *f;
2552xmlOutputBufferPtr output;
2553xmlDocPtr doc;
2554int res;
2555
2556f = ...
2557doc = ....
2558
2559output = xmlOutputBufferCreateOwn(f, NULL);
2560res = xmlSaveFileTo(output, doc, NULL);
2561 </pre>
2562 </li>
2563</ol>
2564
2565<h2><a name="Catalog">Catalog support</a></h2>
2566
2567<p>Table of Content:</p>
2568<ol>
2569 <li><a href="General2">General overview</a></li>
2570 <li><a href="#definition">The definition</a></li>
2571 <li><a href="#Simple">Using catalogs</a></li>
2572 <li><a href="#Some">Some examples</a></li>
2573 <li><a href="#reference">How to tune catalog usage</a></li>
2574 <li><a href="#validate">How to debug catalog processing</a></li>
2575 <li><a href="#Declaring">How to create and maintain catalogs</a></li>
2576 <li><a href="#implemento">The implementor corner quick review of the
2577 API</a></li>
2578 <li><a href="#Other">Other resources</a></li>
2579</ol>
2580
2581<h3><a name="General2">General overview</a></h3>
2582
2583<p>What is a catalog? Basically it's a lookup mechanism used when an entity
2584(a file or a remote resource) references another entity. The catalog lookup
2585is inserted between the moment the reference is recognized by the software
2586(XML parser, stylesheet processing, or even images referenced for inclusion
2587in a rendering) and the time where loading that resource is actually
2588started.</p>
2589
2590<p>It is basically used for 3 things:</p>
2591<ul>
2592 <li>mapping from "logical" names, the public identifiers and a more
2593 concrete name usable for download (and URI). For example it can associate
2594 the logical name
2595 <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
2596 <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be
2597 downloaded</p>
2598 <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
2599 </li>
2600 <li>remapping from a given URL to another one, like an HTTP indirection
2601 saying that
2602 <p>"http://www.oasis-open.org/committes/tr.xsl"</p>
2603 <p>should really be looked at</p>
2604 <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
2605 </li>
2606 <li>providing a local cache mechanism allowing to load the entities
2607 associated to public identifiers or remote resources, this is a really
2608 important feature for any significant deployment of XML or SGML since it
2609 allows to avoid the aleas and delays associated to fetching remote
2610 resources.</li>
2611</ul>
2612
2613<h3><a name="definition">The definitions</a></h3>
2614
2615<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p>
2616<ul>
2617 <li>the older SGML catalogs, the official spec is SGML Open Technical
2618 Resolution TR9401:1997, but is better understood by reading <a
2619 href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from
2620 James Clark. This is relatively old and not the preferred mode of
2621 operation of libxml.</li>
2622 <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML
Daniel Veillardaf43f632002-03-08 15:05:20 +00002623 Catalogs</a> is far more flexible, more recent, uses an XML syntax and
2624 should scale quite better. This is the default option of libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002625</ul>
2626
2627<p></p>
2628
2629<h3><a name="Simple">Using catalog</a></h3>
2630
2631<p>In a normal environment libxml will by default check the presence of a
2632catalog in /etc/xml/catalog, and assuming it has been correctly populated,
2633the processing is completely transparent to the document user. To take a
2634concrete example, suppose you are authoring a DocBook document, this one
2635starts with the following DOCTYPE definition:</p>
2636<pre>&lt;?xml version='1.0'?&gt;
2637&lt;!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
2638 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"&gt;</pre>
2639
2640<p>When validating the document with libxml, the catalog will be
2641automatically consulted to lookup the public identifier "-//Norman Walsh//DTD
2642DocBk XML V3.1.4//EN" and the system identifier
2643"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have
2644been installed on your system and the catalogs actually point to them, libxml
2645will fetch them from the local disk.</p>
2646
2647<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this
2648DOCTYPE example it's a really old version, but is fine as an example.</p>
2649
2650<p>Libxml will check the catalog each time that it is requested to load an
2651entity, this includes DTD, external parsed entities, stylesheets, etc ... If
2652your system is correctly configured all the authoring phase and processing
2653should use only local files, even if your document stays portable because it
2654uses the canonical public and system ID, referencing the remote document.</p>
2655
2656<h3><a name="Some">Some examples:</a></h3>
2657
2658<p>Here is a couple of fragments from XML Catalogs used in libxml early
2659regression tests in <code>test/catalogs</code> :</p>
2660<pre>&lt;?xml version="1.0"?&gt;
2661&lt;!DOCTYPE catalog PUBLIC
2662 "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2663 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2664&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2665 &lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2666 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2667...</pre>
2668
2669<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are
2670written in XML, there is a specific namespace for catalog elements
2671"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this
2672catalog is a <code>public</code> mapping it allows to associate a Public
2673Identifier with an URI.</p>
2674<pre>...
2675 &lt;rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2676 rewritePrefix="file:///usr/share/xml/docbook/"/&gt;
2677...</pre>
2678
2679<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that
2680any URI starting with a given prefix should be looked at another URI
2681constructed by replacing the prefix with an new one. In effect this acts like
2682a cache system for a full area of the Web. In practice it is extremely useful
2683with a file prefix if you have installed a copy of those resources on your
2684local system.</p>
2685<pre>...
2686&lt;delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
2687 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2688&lt;delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
2689 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2690&lt;delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
2691 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2692&lt;delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2693 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2694&lt;delegateURI uriStartString="http://www.oasis-open.org/docbook/"
2695 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2696...</pre>
2697
2698<p>Delegation is the core features which allows to build a tree of catalogs,
2699easier to maintain than a single catalog, based on Public Identifier, System
2700Identifier or URI prefixes it instructs the catalog software to look up
2701entries in another resource. This feature allow to build hierarchies of
2702catalogs, the set of entries presented should be sufficient to redirect the
2703resolution of all DocBook references to the specific catalog in
2704<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all
2705references for DocBook 4.2.1 to a specific catalog installed at the same time
2706as the DocBook resources on the local machine.</p>
2707
2708<h3><a name="reference">How to tune catalog usage:</a></h3>
2709
2710<p>The user can change the default catalog behaviour by redirecting queries
2711to its own set of catalogs, this can be done by setting the
2712<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an
2713empty one should deactivate loading the default <code>/etc/xml/catalog</code>
2714default catalog</p>
2715
2716<h3><a name="validate">How to debug catalog processing:</a></h3>
2717
2718<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will
2719make libxml output debugging informations for each catalog operations, for
2720example:</p>
2721<pre>orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2722warning: failed to load external entity "title.xml"
2723orchis:~/XML -&gt; export XML_DEBUG_CATALOG=
2724orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2725Failed to parse catalog /etc/xml/catalog
2726Failed to parse catalog /etc/xml/catalog
2727warning: failed to load external entity "title.xml"
2728Catalogs cleanup
2729orchis:~/XML -&gt; </pre>
2730
2731<p>The test/ent2 references an entity, running the parser from memory makes
2732the base URI unavailable and the the "title.xml" entity cannot be loaded.
2733Setting up the debug environment variable allows to detect that an attempt is
2734made to load the <code>/etc/xml/catalog</code> but since it's not present the
2735resolution fails.</p>
2736
2737<p>But the most advanced way to debug XML catalog processing is to use the
2738<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load
2739catalogs and make resolution queries to see what is going on. This is also
2740used for the regression tests:</p>
2741<pre>orchis:~/XML -&gt; ./xmlcatalog test/catalogs/docbook.xml \
2742 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2743http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2744orchis:~/XML -&gt; </pre>
2745
2746<p>For debugging what is going on, adding one -v flags increase the verbosity
2747level to indicate the processing done (adding a second flag also indicate
2748what elements are recognized at parsing):</p>
2749<pre>orchis:~/XML -&gt; ./xmlcatalog -v test/catalogs/docbook.xml \
2750 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2751Parsing catalog test/catalogs/docbook.xml's content
2752Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
2753http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2754Catalogs cleanup
2755orchis:~/XML -&gt; </pre>
2756
2757<p>A shell interface is also available to debug and process multiple queries
2758(and for regression tests):</p>
2759<pre>orchis:~/XML -&gt; ./xmlcatalog -shell test/catalogs/docbook.xml \
2760 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2761&gt; help
2762Commands available:
2763public PublicID: make a PUBLIC identifier lookup
2764system SystemID: make a SYSTEM identifier lookup
2765resolve PublicID SystemID: do a full resolver lookup
2766add 'type' 'orig' 'replace' : add an entry
2767del 'values' : remove values
2768dump: print the current catalog state
2769debug: increase the verbosity level
2770quiet: decrease the verbosity level
2771exit: quit the shell
2772&gt; public "-//OASIS//DTD DocBook XML V4.1.2//EN"
2773http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2774&gt; quit
2775orchis:~/XML -&gt; </pre>
2776
2777<p>This should be sufficient for most debugging purpose, this was actually
2778used heavily to debug the XML Catalog implementation itself.</p>
2779
2780<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3>
2781
2782<p>Basically XML Catalogs are XML files, you can either use XML tools to
2783manage them or use <strong>xmlcatalog</strong> for this. The basic step is
2784to create a catalog the -create option provide this facility:</p>
2785<pre>orchis:~/XML -&gt; ./xmlcatalog --create tst.xml
2786&lt;?xml version="1.0"?&gt;
2787&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2788 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2789&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2790orchis:~/XML -&gt; </pre>
2791
2792<p>By default xmlcatalog does not overwrite the original catalog and save the
2793result on the standard output, this can be overridden using the -noout
2794option. The <code>-add</code> command allows to add entries in the
2795catalog:</p>
2796<pre>orchis:~/XML -&gt; ./xmlcatalog --noout --create --add "public" \
2797 "-//OASIS//DTD DocBook XML V4.1.2//EN" \
2798 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
2799orchis:~/XML -&gt; cat tst.xml
2800&lt;?xml version="1.0"?&gt;
2801&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
2802 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2803&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2804&lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2805 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2806&lt;/catalog&gt;
2807orchis:~/XML -&gt; </pre>
2808
2809<p>The <code>-add</code> option will always take 3 parameters even if some of
2810the XML Catalog constructs (like nextCatalog) will have only a single
2811argument, just pass a third empty string, it will be ignored.</p>
2812
2813<p>Similarly the <code>-del</code> option remove matching entries from the
2814catalog:</p>
2815<pre>orchis:~/XML -&gt; ./xmlcatalog --del \
2816 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
2817&lt;?xml version="1.0"?&gt;
2818&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2819 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2820&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2821orchis:~/XML -&gt; </pre>
2822
2823<p>The catalog is now empty. Note that the matching of <code>-del</code> is
2824exact and would have worked in a similar fashion with the Public ID
2825string.</p>
2826
2827<p>This is rudimentary but should be sufficient to manage a not too complex
2828catalog tree of resources.</p>
2829
2830<h3><a name="implemento">The implementor corner quick review of the
2831API:</a></h3>
2832
2833<p>First, and like for every other module of libxml, there is an
2834automatically generated <a href="html/libxml-catalog.html">API page for
2835catalog support</a>.</p>
2836
2837<p>The header for the catalog interfaces should be included as:</p>
2838<pre>#include &lt;libxml/catalog.h&gt;</pre>
2839
2840<p>The API is voluntarily kept very simple. First it is not obvious that
2841applications really need access to it since it is the default behaviour of
2842libxml (Note: it is possible to completely override libxml default catalog by
2843using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to
2844plug an application specific resolver).</p>
2845
2846<p>Basically libxml support 2 catalog lists:</p>
2847<ul>
2848 <li>the default one, global shared by all the application</li>
2849 <li>a per-document catalog, this one is built if the document uses the
2850 <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is
2851 associated to the parser context and destroyed when the parsing context
2852 is destroyed.</li>
2853</ul>
2854
2855<p>the document one will be used first if it exists.</p>
2856
2857<h4>Initialization routines:</h4>
2858
2859<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be
2860used at startup to initialize the catalog, if the catalog should be
2861initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs()
2862should be called before xmlInitializeCatalog() which would otherwise do a
2863default initialization first.</p>
2864
2865<p>The xmlCatalogAddLocal() call is used by the parser to grow the document
2866own catalog list if needed.</p>
2867
2868<h4>Preferences setup:</h4>
2869
2870<p>The XML Catalog spec requires the possibility to select default
2871preferences between public and system delegation,
2872xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and
2873xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should
2874be forbidden, allowed for global catalog, for document catalog or both, the
2875default is to allow both.</p>
2876
2877<p>And of course xmlCatalogSetDebug() allows to generate debug messages
2878(through the xmlGenericError() mechanism).</p>
2879
2880<h4>Querying routines:</h4>
2881
2882<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic()
2883and xmlCatalogResolveURI() are relatively explicit if you read the XML
2884Catalog specification they correspond to section 7 algorithms, they should
2885also work if you have loaded an SGML catalog with a simplified semantic.</p>
2886
2887<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but
2888operate on the document catalog list</p>
2889
2890<h4>Cleanup and Miscellaneous:</h4>
2891
2892<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is
2893the per-document equivalent.</p>
2894
2895<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the
2896first catalog in the global list, and xmlCatalogDump() allows to dump a
2897catalog state, those routines are primarily designed for xmlcatalog, I'm not
2898sure that exposing more complex interfaces (like navigation ones) would be
2899really useful.</p>
2900
2901<p>The xmlParseCatalogFile() is a function used to load XML Catalog files,
2902it's similar as xmlParseFile() except it bypass all catalog lookups, it's
2903provided because this functionality may be useful for client tools.</p>
2904
2905<h4>threaded environments:</h4>
2906
2907<p>Since the catalog tree is built progressively, some care has been taken to
2908try to avoid troubles in multithreaded environments. The code is now thread
2909safe assuming that the libxml library has been compiled with threads
2910support.</p>
2911
2912<p></p>
2913
2914<h3><a name="Other">Other resources</a></h3>
2915
2916<p>The XML Catalog specification is relatively recent so there isn't much
2917literature to point at:</p>
2918<ul>
2919 <li>You can find an good rant from Norm Walsh about <a
2920 href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the
2921 need for catalogs</a>, it provides a lot of context informations even if
2922 I don't agree with everything presented.</li>
2923 <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML
2924 catalog proposal</a> from John Cowan</li>
2925 <li>The <a href="http://www.rddl.org/">Resource Directory Description
2926 Language</a> (RDDL) another catalog system but more oriented toward
2927 providing metadata for XML namespaces.</li>
2928 <li>the page from the OASIS Technical <a
2929 href="http://www.oasis-open.org/committees/entity/">Committee on Entity
2930 Resolution</a> who maintains XML Catalog, you will find pointers to the
2931 specification update, some background and pointers to others tools
2932 providing XML Catalog support</li>
Daniel Veillard35e937a2002-01-19 22:21:54 +00002933 <li>Here is a <a href="buildDocBookCatalog">shell script</a> to generate
2934 XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/
2935 directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on
2936 the resources found on the system. Otherwise it will just create
2937 ~/xmlcatalog and ~/dbkxmlcatalog and doing:
Daniel Veillardc575b992002-02-08 13:28:40 +00002938 <p><code>export XMLCATALOG=$HOME/xmlcatalog</code></p>
Daniel Veillard35e937a2002-01-19 22:21:54 +00002939 <p>should allow to process DocBook documentations without requiring
2940 network accesses for the DTd or stylesheets</p>
2941 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002942 <li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a
Daniel Veillard35e937a2002-01-19 22:21:54 +00002943 small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems
2944 to work fine for me too</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002945 <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog
2946 manual page</a></li>
2947</ul>
2948
2949<p>If you have suggestions for corrections or additions, simply contact
2950me:</p>
2951
2952<h2><a name="library">The parser interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002953
2954<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00002955using the XML library from the C language. It is not intended to be
2956extensive. I hope the automatically generated documents will provide the
2957completeness required, but as a separate set of documents. The interfaces of
2958the XML library are by principle low level, there is nearly zero abstraction.
2959Those interested in a higher level API should <a href="#DOM">look at
2960DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +00002961
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00002962<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
2963separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002964interfaces</a>. Let's have a look at how the XML parser can be called:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +00002965
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002966<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002967
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002968<p>Usually, the first thing to do is to read an XML input. The parser accepts
2969documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +00002970defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002971<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002972 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002973 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002974 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002975</dl>
2976<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002977 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00002978 <dd><p>Parse an XML document contained in a (possibly compressed)
2979 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002980 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002981</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002982
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002983<p>The parser returns a pointer to the document structure (or NULL in case of
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002984failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002985
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002986<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +00002987
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00002988<p>In order for the application to keep the control when the document is
2989being fetched (which is common for GUI based programs) libxml provides a push
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002990interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +00002991<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
2992 void *user_data,
2993 const char *chunk,
2994 int size,
2995 const char *filename);
2996int xmlParseChunk (xmlParserCtxtPtr ctxt,
2997 const char *chunk,
2998 int size,
2999 int terminate);</pre>
3000
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003001<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +00003002<pre> FILE *f;
3003
3004 f = fopen(filename, "r");
3005 if (f != NULL) {
3006 int res, size = 1024;
3007 char chars[1024];
3008 xmlParserCtxtPtr ctxt;
3009
3010 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +00003011 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +00003012 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
3013 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +00003014 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +00003015 xmlParseChunk(ctxt, chars, res, 0);
3016 }
3017 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +00003018 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +00003019 xmlFreeParserCtxt(ctxt);
3020 }
3021 }</pre>
3022
Daniel Veillardec70e912001-02-26 20:10:45 +00003023<p>The HTML parser embedded into libxml also has a push interface; the
3024functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard0142b842000-01-14 14:45:24 +00003025
3026<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
3027
Daniel Veillardec70e912001-02-26 20:10:45 +00003028<p>The tree-building interface makes the parser memory-hungry, first loading
3029the document in memory and then building the tree itself. Reading a document
3030without building the tree is possible using the SAX interfaces (see SAX.h and
3031<a href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003032Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard91e9d582001-02-26 07:31:12 +00003033limited to SAX: just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +00003034<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +00003035
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003036<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003037
3038<p>The other way to get an XML tree in memory is by building it. Basically
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003039there is a set of functions dedicated to building new elements. (These are
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003040also described in &lt;libxml/tree.h&gt;.) For example, here is a piece of
3041code that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003042<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +00003043 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +00003044 xmlNodePtr tree, subtree;
3045
3046 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +00003047 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
3048 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
3049 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
3050 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +00003051 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +00003052 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +00003053 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
3054 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
3055 subtree = xmlNewChild(tree, NULL, "image", NULL);
3056 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003057
3058<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003059
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003060<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003061
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00003062<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003063code has access to the internal structure of all the elements of the tree.
3064The names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +00003065<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003066<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +00003067example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003068<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003069
3070<p>points to the title element,</p>
Daniel Veillard91e9d582001-02-26 07:31:12 +00003071<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003072
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003073<p>points to the text node containing the chapter title "The Linux
3074adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003075
Daniel Veillardb24054a1999-12-18 15:32:46 +00003076<p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em> to be
Daniel Veillard60979bd2000-07-10 12:17:33 +00003077present before the document root, so <code>doc-&gt;children</code> may point
Daniel Veillard91e9d582001-02-26 07:31:12 +00003078to an element which is not the document Root Element; a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +00003079<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +00003080
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003081<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003082
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003083<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00003084is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003085<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003086 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
3087 xmlChar *value);</code></dt>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003088 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node.
3089 The value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003090 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003091</dl>
3092<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003093 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +00003094 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +00003095 <dd><p>This function returns a pointer to new copy of the property
3096 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003097 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003098</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003099
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003100<p>Two functions are provided for reading and writing the text associated
3101with elements:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003102<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003103 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +00003104 *value);</code></dt>
Daniel Veillardec70e912001-02-26 20:10:45 +00003105 <dd><p>This function takes an "external" string and converts it to one
3106 text node or possibly to a list of entity and text nodes. All
3107 non-predefined entity references like &amp;Gnome; will be stored
3108 internally as entity nodes, hence the result of the function may not be
3109 a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003110 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003111</dl>
3112<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003113 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +00003114 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003115 <dd><p>This function is the inverse of
3116 <code>xmlStringGetNodeList()</code>. It generates a new string
3117 containing the content of the text and entity nodes. Note the extra
3118 argument inLine. If this argument is set to 1, the function will expand
3119 entity references. For example, instead of returning the &amp;Gnome;
3120 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard91e9d582001-02-26 07:31:12 +00003121 "GNU Network Object Model Environment").</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003122 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003123</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003124
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003125<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003126
3127<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003128<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003129 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +00003130 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003131 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003132 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003133</dl>
3134<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003135 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003136 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003137 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003138</dl>
3139<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003140 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003141 <dd><p>Saves the document to a file. In this case, the compression
3142 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003143 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003144</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003145
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003146<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003147
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003148<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003149accesses. The level of compression on saves can be turned on either globally
3150or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003151<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003152 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003153 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003154 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003155</dl>
3156<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003157 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003158 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003159 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003160</dl>
3161<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003162 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003163 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003164 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003165</dl>
3166<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003167 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003168 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003169 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003170</dl>
3171
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003172<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003173
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003174<p>Entities in principle are similar to simple C macros. An entity defines an
3175abbreviation for a given string that you can reuse many times throughout the
3176content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003177may occur frequently within a document, or to confine the change needed to a
3178document to a restricted area in the internal subset of the document (at the
3179beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003180<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +000031812 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +000031823 &lt;!ENTITY xml "Extensible Markup Language"&gt;
31834 ]&gt;
31845 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +000031856 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +000031867 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003187
3188<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing
Daniel Veillard91e9d582001-02-26 07:31:12 +00003189its name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003190are 5 predefined entities in libxml allowing you to escape charaters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003191predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003192<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003193for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003194<strong>&amp;quot;</strong> for the character '"', and
3195<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003196
3197<p>One of the problems related to entities is that you may want the parser to
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003198substitute an entity's content so that you can see the replacement text in
3199your application. Or you may prefer to keep entity references as such in the
3200content to be able to save the document back without losing this usually
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003201precious information (if the user went through the pain of explicitly
3202defining entities, he may have a a rather negative attitude if you blindly
3203susbtitute them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00003204href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003205function allows you to check and change the behaviour, which is to not
3206substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003207
3208<p>Here is the DOM tree built by libxml for the previous document in the
3209default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003210<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003211DOCUMENT
3212version=1.0
3213 ELEMENT EXAMPLE
3214 TEXT
3215 content=
3216 ENTITY_REF
3217 INTERNAL_GENERAL_ENTITY xml
3218 content=Extensible Markup Language
3219 TEXT
3220 content=</pre>
3221
3222<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003223<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003224DOCUMENT
3225version=1.0
3226 ELEMENT EXAMPLE
3227 TEXT
3228 content= Extensible Markup Language</pre>
3229
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003230<p>So, entities or no entities? Basically, it depends on your use case. I
3231suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003232entities in your XML document or data if you are not willing to handle the
3233entity references elements in the DOM tree.</p>
3234
Daniel Veillard91e9d582001-02-26 07:31:12 +00003235<p>Note that at save time libxml enforces the conversion of the predefined
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003236entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard91e9d582001-02-26 07:31:12 +00003237transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003238reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003239finding them in the input).</p>
3240
Daniel Veillard7b9c4b72000-08-25 16:26:50 +00003241<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard91e9d582001-02-26 07:31:12 +00003242on top of the libxml SAX interface is difficult!!! If you plan to use
Daniel Veillard7b9c4b72000-08-25 16:26:50 +00003243non-predefined entities in your documents, then the learning cuvre to handle
Daniel Veillard91e9d582001-02-26 07:31:12 +00003244then using the SAX API may be long. If you plan to use complex documents, I
Daniel Veillard7b9c4b72000-08-25 16:26:50 +00003245strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +00003246deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +00003247
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003248<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003249
Daniel Veillardec303412000-03-24 13:41:54 +00003250<p>The libxml library implements <a
3251href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
3252recognizing namespace contructs in the input, and does namespace lookup
3253automatically when building the DOM tree. A namespace declaration is
3254associated with an in-memory structure and all elements or attributes within
3255that namespace point to it. Hence testing the namespace is a simple and fast
3256equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003257
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003258<p>I suggest that people using libxml use a namespace, and declare it in the
3259root element of their document as the default namespace. Then they don't need
3260to use the prefix in the content but we will have a basis for future semantic
Daniel Veillard91e9d582001-02-26 07:31:12 +00003261refinement and merging of data from different sources. This doesn't increase
Daniel Veillardec70e912001-02-26 20:10:45 +00003262the size of the XML output significantly, but significantly increases its
3263value in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003264<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
3265 &lt;elem1&gt;...&lt;/elem1&gt;
3266 &lt;elem2&gt;...&lt;/elem2&gt;
3267&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003268
Daniel Veillardec70e912001-02-26 20:10:45 +00003269<p>The namespace value has to be an absolute URL, but the URL doesn't have to
3270point to any existing resource on the Web. It will bind all the element and
3271atributes with that URL. I suggest to use an URL within a domain you control,
3272and that the URL should contain some kind of version information if possible.
3273For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a good
3274namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +00003275
3276<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003277version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003278and if the version information don't match something you know, warn the user
3279and be liberal in what you accept as the input. Also do *not* try to base
Daniel Veillard60979bd2000-07-10 12:17:33 +00003280namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
Daniel Veillard91e9d582001-02-26 07:31:12 +00003281same as &lt;bar:text&gt; in another document. What really matters is the URI
Daniel Veillard60979bd2000-07-10 12:17:33 +00003282associated with the element or the attribute, not the prefix string (which is
Daniel Veillard91e9d582001-02-26 07:31:12 +00003283just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillardec303412000-03-24 13:41:54 +00003284<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard91e9d582001-02-26 07:31:12 +00003285prefix and its URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003286
3287<p>@@Interfaces@@</p>
3288
3289<p>@@Examples@@</p>
3290
Daniel Veillard91e9d582001-02-26 07:31:12 +00003291<p>Usually people object to using namespaces together with validity checking.
3292I will try to make sure that using namespaces won't break validity checking,
3293so even if you plan to use or currently are using validation I strongly
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003294suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003295<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard91e9d582001-02-26 07:31:12 +00003296flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003297from multiple DTDs will certainly break current validation schemes. I will
3298try to provide ways to do this, but this may not be portable or
3299standardized.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003300
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003301<h2><a name="Upgrading">Upgrading 1.x code</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003302
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003303<p>Incompatible changes:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003304
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003305<p>Version 2 of libxml is the first version introducing serious backward
3306incompatible changes. The main goals were:</p>
3307<ul>
3308 <li>a general cleanup. A number of mistakes inherited from the very early
3309 versions couldn't be changed due to compatibility constraints. Example
3310 the "childs" element in the nodes.</li>
3311 <li>Uniformization of the various nodes, at least for their header and link
3312 parts (doc, parent, children, prev, next), the goal is a simpler
3313 programming model and simplifying the task of the DOM implementors.</li>
3314 <li>better conformances to the XML specification, for example version 1.x
3315 had an heuristic to try to detect ignorable white spaces. As a result the
3316 SAX event generated were ignorableWhitespace() while the spec requires
3317 character() in that case. This also mean that a number of DOM node
3318 containing blank text may populate the DOM tree which were not present
3319 before.</li>
3320</ul>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003321
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003322<h3>How to fix libxml-1.x code:</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003323
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003324<p>So client code of libxml designed to run with version 1.x may have to be
3325changed to compile against version 2.x of libxml. Here is a list of changes
3326that I have collected, they may not be sufficient, so in case you find other
3327change which are required, <a href="mailto:Daniel.Ïeillardw3.org">drop me a
3328mail</a>:</p>
3329<ol>
3330 <li>The package name have changed from libxml to libxml2, the library name
3331 is now -lxml2 . There is a new xml2-config script which should be used to
3332 select the right parameters libxml2</li>
3333 <li>Node <strong>childs</strong> field has been renamed
3334 <strong>children</strong> so s/childs/children/g should be applied
3335 (probablility of having "childs" anywere else is close to 0+</li>
3336 <li>The document don't have anymore a <strong>root</strong> element it has
3337 been replaced by <strong>children</strong> and usually you will get a
3338 list of element here. For example a Dtd element for the internal subset
3339 and it's declaration may be found in that list, as well as processing
3340 instructions or comments found before or after the document root element.
3341 Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of
3342 a document. Alternatively if you are sure to not reference Dtds nor have
3343 PIs or comments before or after the root element
3344 s/-&gt;root/-&gt;children/g will probably do it.</li>
3345 <li>The white space issue, this one is more complex, unless special case of
3346 validating parsing, the line breaks and spaces usually used for indenting
3347 and formatting the document content becomes significant. So they are
3348 reported by SAX and if your using the DOM tree, corresponding nodes are
3349 generated. Too approach can be taken:
3350 <ol>
3351 <li>lazy one, use the compatibility call
3352 <strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are
3353 relying on a special (and possibly broken) set of heuristics of
3354 libxml to detect ignorable blanks. Don't complain if it breaks or
3355 make your application not 100% clean w.r.t. to it's input.</li>
3356 <li>the Right Way: change you code to accept possibly unsignificant
3357 blanks characters, or have your tree populated with weird blank text
3358 nodes. You can spot them using the comodity function
3359 <strong>xmlIsBlankNode(node)</strong> returning 1 for such blank
3360 nodes.</li>
3361 </ol>
3362 <p>Note also that with the new default the output functions don't add any
3363 extra indentation when saving a tree in order to be able to round trip
3364 (read and save) without inflating the document with extra formatting
3365 chars.</p>
3366 </li>
3367 <li>The include path has changed to $prefix/libxml/ and the includes
3368 themselves uses this new prefix in includes instructions... If you are
3369 using (as expected) the
3370 <pre>xml2-config --cflags</pre>
3371 <p>output to generate you compile commands this will probably work out of
3372 the box</p>
3373 </li>
3374 <li>xmlDetectCharEncoding takes an extra argument indicating the lenght in
3375 byte of the head of the document available for character detection.</li>
3376</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003377
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003378<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003379
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003380<p>Two new version of libxml (1.8.11) and libxml2 (2.3.4) have been released
3381to allow smoth upgrade of existing libxml v1code while retaining
3382compatibility. They offers the following:</p>
3383<ol>
3384 <li>similar include naming, one should use
3385 <strong>#include&lt;libxml/...&gt;</strong> in both cases.</li>
3386 <li>similar identifiers defined via macros for the child and root fields:
3387 respectively <strong>xmlChildrenNode</strong> and
3388 <strong>xmlRootNode</strong></li>
3389 <li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be
3390 inserted once in the client code</li>
3391</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003392
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003393<p>So the roadmap to upgrade your existing libxml applications is the
3394following:</p>
3395<ol>
3396 <li>install the libxml-1.8.8 (and libxml-devel-1.8.8) packages</li>
3397 <li>find all occurences where the xmlDoc <strong>root</strong> field is
3398 used and change it to <strong>xmlRootNode</strong></li>
3399 <li>similary find all occurences where the xmlNode <strong>childs</strong>
3400 field is used and change it to <strong>xmlChildrenNode</strong></li>
3401 <li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your
3402 <strong>main()</strong> or in the library init entry point</li>
3403 <li>Recompile, check compatibility, it should still work</li>
3404 <li>Change your configure script to look first for xml2-config and fallback
3405 using xml-config . Use the --cflags and --libs ouptut of the command as
3406 the Include and Linking parameters needed to use libxml.</li>
3407 <li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and
3408 libxml-devel-1.8.y can be kept simultaneously)</li>
3409 <li>remove your config.cache, relaunch your configuration mechanism, and
3410 recompile, if steps 2 and 3 were done right it should compile as-is</li>
3411 <li>Test that your application is still running correctly, if not this may
3412 be due to extra empty nodes due to formating spaces being kept in libxml2
3413 contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your
3414 code before calling the parser (next to
3415 <strong>LIBXML_TEST_VERSION</strong> is a fine place).</li>
3416</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003417
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003418<p>Following those steps should work. It worked for some of my own code.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003419
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003420<p>Let me put some emphasis on the fact that there is far more changes from
3421libxml 1.x to 2.x than the ones you may have to patch for. The overall code
3422has been considerably cleaned up and the conformance to the XML specification
3423has been drastically improved too. Don't take those changes as an excuse to
3424not upgrade, it may cost a lot on the long term ...</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003425
Daniel Veillard52dcab32001-10-30 12:51:17 +00003426<h2><a name="Thread">Thread safety</a></h2>
3427
3428<p>Starting with 2.4.7, libxml makes provisions to ensure that concurent
3429threads can safely work in parallel parsing different documents. There is
3430however a couple of things to do to ensure it:</p>
3431<ul>
3432 <li>configure the library accordingly using the --with-threads options</li>
3433 <li>call xmlInitParser() in the "main" thread before using any of the
3434 libxml API (except possibly selecting a different memory allocator)</li>
3435</ul>
3436
3437<p>Note that the thread safety cannot be ensured for multiple threads sharing
3438the same document, the locking must be done at the application level, libxml
3439exports a basic mutex and reentrant mutexes API in &lt;libxml/threads.h&gt;.
3440The parts of the library checked for thread safety are:</p>
3441<ul>
3442 <li>concurrent loading</li>
3443 <li>file access resolution</li>
3444 <li>catalog access</li>
3445 <li>catalog building</li>
3446 <li>entities lookup/accesses</li>
3447 <li>validation</li>
3448 <li>global variables per-thread override</li>
3449 <li>memory handling</li>
3450</ul>
3451
3452<p>XPath is supposed to be thread safe now, but this wasn't tested
3453seriously.</p>
3454
Daniel Veillard35008381999-10-25 13:15:52 +00003455<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003456
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003457<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document
3458Object Model</em>; this is an API for accessing XML or HTML structured
3459documents. Native support for DOM in Gnome is on the way (module gnome-dom),
3460and will be based on gnome-xml. This will be a far cleaner interface to
3461manipulate XML files within Gnome since it won't expose the internal
3462structure.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +00003463
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003464<p>The current DOM implementation on top of libxml is the <a
Daniel Veillarda47fb3d2001-03-25 17:23:49 +00003465href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this
3466is a full DOM interface, thanks to Paolo Casarini, check the <a
3467href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more
3468informations.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003469
Daniel Veillard35008381999-10-25 13:15:52 +00003470<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003471
3472<p>Here is a real size example, where the actual content of the application
3473data is not kept in the DOM tree but uses internal structures. It is based on
Daniel Veillard14fff061999-06-22 21:49:07 +00003474a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +00003475storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
3476base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003477<pre>&lt;?xml version="1.0"?&gt;
3478&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
3479 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003480
Daniel Veillard60979bd2000-07-10 12:17:33 +00003481 &lt;gjob:Job&gt;
3482 &lt;gjob:Project ID="3"/&gt;
3483 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
3484 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003485
Daniel Veillard60979bd2000-07-10 12:17:33 +00003486 &lt;gjob:Update&gt;
3487 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
3488 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
3489 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
3490 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003491
Daniel Veillard60979bd2000-07-10 12:17:33 +00003492 &lt;gjob:Developers&gt;
3493 &lt;gjob:Developer&gt;
3494 &lt;/gjob:Developer&gt;
3495 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003496
Daniel Veillard60979bd2000-07-10 12:17:33 +00003497 &lt;gjob:Contact&gt;
3498 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
3499 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
3500 &lt;gjob:Company&gt;
3501 &lt;/gjob:Company&gt;
3502 &lt;gjob:Organisation&gt;
3503 &lt;/gjob:Organisation&gt;
3504 &lt;gjob:Webpage&gt;
3505 &lt;/gjob:Webpage&gt;
3506 &lt;gjob:Snailmail&gt;
3507 &lt;/gjob:Snailmail&gt;
3508 &lt;gjob:Phone&gt;
3509 &lt;/gjob:Phone&gt;
3510 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003511
Daniel Veillard60979bd2000-07-10 12:17:33 +00003512 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003513 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +00003514 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003515
Daniel Veillard60979bd2000-07-10 12:17:33 +00003516 &lt;gjob:Skills&gt;
3517 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003518
Daniel Veillard60979bd2000-07-10 12:17:33 +00003519 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003520 A GNOME based system that will allow a superuser to configure
3521 compressed and uncompressed files and/or file systems to be backed
3522 up with a supported media in the system. This should be able to
3523 perform via find commands generating a list of files that are passed
3524 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
3525 or via operations performed on the filesystem itself. Email
3526 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +00003527 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003528
Daniel Veillard60979bd2000-07-10 12:17:33 +00003529 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003530
Daniel Veillard60979bd2000-07-10 12:17:33 +00003531 &lt;/gjob:Jobs&gt;
3532&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003533
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003534<p>While loading the XML file into an internal DOM tree is a matter of
3535calling only a couple of functions, browsing the tree to gather the ata and
3536generate the internal structures is harder, and more error prone.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003537
3538<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003539structure. For example, the ordering of the attributes is not significant,
3540the XML specification is clear about it. It's also usually a good idea not to
Daniel Veillardec70e912001-02-26 20:10:45 +00003541depend on the order of the children of a given node, unless it really makes
3542things harder. Here is some code to parse the information for a person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003543<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +00003544 * A person record
3545 */
3546typedef struct person {
3547 char *name;
3548 char *email;
3549 char *company;
3550 char *organisation;
3551 char *smail;
3552 char *webPage;
3553 char *phone;
3554} person, *personPtr;
3555
3556/*
3557 * And the code needed to parse it
3558 */
3559personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3560 personPtr ret = NULL;
3561
3562DEBUG("parsePerson\n");
3563 /*
3564 * allocate the struct
3565 */
3566 ret = (personPtr) malloc(sizeof(person));
3567 if (ret == NULL) {
3568 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +00003569 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +00003570 }
3571 memset(ret, 0, sizeof(person));
3572
3573 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +00003574 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +00003575 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +00003576 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
3577 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3578 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
3579 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3580 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +00003581 }
3582
3583 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +00003584}</pre>
3585
Daniel Veillard91e9d582001-02-26 07:31:12 +00003586<p>Here are a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +00003587<ul>
Daniel Veillard91e9d582001-02-26 07:31:12 +00003588 <li>Usually a recursive parsing style is the more convenient one: XML data
3589 is by nature subject to repetitive constructs and usually exibits highly
Daniel Veillardb05deb71999-08-10 19:04:08 +00003590 stuctured patterns.</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003591 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>,
3592 i.e. the pointer to the global XML document and the namespace reserved to
3593 the application. Document wide information are needed for example to
3594 decode entities and it's a good coding practice to define a namespace for
3595 your application set of data and test that the element and attributes
3596 you're analyzing actually pertains to your application space. This is
3597 done by a simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardec70e912001-02-26 20:10:45 +00003598 <li>To retrieve text and attributes value, you can use the function
3599 <em>xmlNodeListGetString</em> to gather all the text and entity reference
3600 nodes generated by the DOM output and produce an single text string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +00003601</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003602
3603<p>Here is another piece of code used to parse another level of the
3604structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003605<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +00003606/*
Daniel Veillard14fff061999-06-22 21:49:07 +00003607 * a Description for a Job
3608 */
3609typedef struct job {
3610 char *projectID;
3611 char *application;
3612 char *category;
3613 personPtr contact;
3614 int nbDevelopers;
3615 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
3616} job, *jobPtr;
3617
3618/*
3619 * And the code needed to parse it
3620 */
3621jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3622 jobPtr ret = NULL;
3623
3624DEBUG("parseJob\n");
3625 /*
3626 * allocate the struct
3627 */
3628 ret = (jobPtr) malloc(sizeof(job));
3629 if (ret == NULL) {
3630 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +00003631 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +00003632 }
3633 memset(ret, 0, sizeof(job));
3634
3635 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +00003636 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +00003637 while (cur != NULL) {
3638
Daniel Veillard60979bd2000-07-10 12:17:33 +00003639 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
3640 ret-&gt;projectID = xmlGetProp(cur, "ID");
3641 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +00003642 fprintf(stderr, "Project has no ID\n");
3643 }
3644 }
Daniel Veillard60979bd2000-07-10 12:17:33 +00003645 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
3646 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3647 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
3648 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3649 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
3650 ret-&gt;contact = parsePerson(doc, ns, cur);
3651 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +00003652 }
3653
3654 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +00003655}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +00003656
Daniel Veillardec70e912001-02-26 20:10:45 +00003657<p>Once you are used to it, writing this kind of code is quite simple, but
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003658boring. Ultimately, it could be possble to write stubbers taking either C
3659data structure definitions, a set of XML examples or an XML DTD and produce
3660the code needed to import and export the content between C data and XML
3661storage. This is left as an exercise to the reader :-)</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003662
Daniel Veillard6f0adb52000-07-03 11:41:26 +00003663<p>Feel free to use <a href="example/gjobread.c">the code for the full C
3664parsing example</a> as a template, it is also available with Makefile in the
3665Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003666
Daniel Veillardc310d562000-06-23 18:32:15 +00003667<h2><a name="Contributi">Contributions</a></h2>
3668<ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003669 <li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of
3670 patches, Gary Pennington worked on the validation API, threading support
3671 and Solaris port.</li>
3672 <li>John Fleck helps maintaining the documentation and man pages.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00003673 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
3674 for libxml:<br>
Daniel Veillardc6271d22001-10-27 07:50:58 +00003675 Website: <a
3676 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
3677 Download: <a
Daniel Veillard51095312001-10-28 18:51:57 +00003678 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00003679 <li><a href="mailto:izlatkovic@daenet.de">Igor Zlatkovic</a> is now the
3680 maintainer of the Windows port, <a
Daniel Veillard95189532001-07-26 18:30:26 +00003681 href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
3682 provides binaries</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00003683 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides
3684 <a href="http://garypennington.net/libxml2/">Solaris binaries</a></li>
Daniel Veillarde356c282001-03-10 12:32:04 +00003685 <li><a
3686 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillardaf43f632002-03-08 15:05:20 +00003687 Sergeant</a> developped <a
3688 href="http://axkit.org/download/">XML::LibXSLT</a>, a perl wrapper for
3689 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
3690 application server</a></li>
3691 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> and <a
3692 href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a
Daniel Veillardca989762001-06-23 17:39:29 +00003693 href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions
Daniel Veillard3f6f7f62000-06-30 17:58:25 +00003694 documentation</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00003695 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
3696 href="http://xmlsoft.org/messages/0488.html">man pages</a></li>
Daniel Veillard5168dbf2001-07-07 00:18:23 +00003697 <li>there is a module for <a
3698 href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support
3699 in OpenNSD/AOLServer</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00003700 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides
3701 libxml/libxslt <a href="http://www.rexx.com/~dkuhlman">wrappers for
3702 Python</a></li>
Daniel Veillard1aadc442001-11-28 13:10:32 +00003703 <li>Petr Kozelka provides <a
3704 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
3705 libxml2</a> with Kylix and Delphi and other Pascal compilers</li>
Daniel Veillardc310d562000-06-23 18:32:15 +00003706</ul>
3707
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003708<p></p>
Daniel Veillardccb09631998-10-27 06:21:04 +00003709</body>
3710</html>