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gerrit-public.fairphone.software / fp2-dev / platform / external / libxml2 / 4b0755c68b0182809a7db5b6ab1478cb2767abfb / . / doc / xml.html
blob: 12fae5c725dd384b414b7a8c07b14afdd5485284 [file] [log] [blame]
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2 "http://www.w3.org/TR/REC-html40/loose.dtd">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3<html>
4<head>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]5 <title>The XML C library for Gnome</title>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]6 <meta name="GENERATOR" content="amaya V3.2">
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]7 <meta http-equiv="Content-Type" content="text/html">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]8</head>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]9
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]10<body bgcolor="#ffffff">
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]11<p><a href="http://www.gnome.org/"><img src="smallfootonly.gif"
12alt="Gnome Logo"></a><a href="http://www.w3.org/Status"><img src="w3c.png"
13alt="W3C Logo"></a></p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]14
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]15<h1 align="center">The XML C library for Gnome</h1>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]16
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]17<h2 style="text-align: center">libxml, a.k.a. gnome-xml</h2>
18
19<p></p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]20<ul>
21 <li><a href="#Introducti">Introduction</a></li>
22 <li><a href="#Documentat">Documentation</a></li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]23 <li><a href="#Reporting">Reporting bugs and getting help</a></li>
24 <li><a href="#help">how to help</a></li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]25 <li><a href="#Downloads">Downloads</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]26 <li><a href="#News">News</a></li>
27 <li><a href="#XML">XML</a></li>
28 <li><a href="#tree">The tree output</a></li>
29 <li><a href="#interface">The SAX interface</a></li>
30 <li><a href="#library">The XML library interfaces</a>
31 <ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]32 <li><a href="#Invoking">Invoking the parser: the pull way</a></li>
33 <li><a href="#Invoking">Invoking the parser: the push way</a></li>
34 <li><a href="#Invoking2">Invoking the parser: the SAX interface</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]35 <li><a href="#Building">Building a tree from scratch</a></li>
36 <li><a href="#Traversing">Traversing the tree</a></li>
37 <li><a href="#Modifying">Modifying the tree</a></li>
38 <li><a href="#Saving">Saving the tree</a></li>
39 <li><a href="#Compressio">Compression</a></li>
40 </ul>
41 </li>
42 <li><a href="#Entities">Entities or no entities</a></li>
43 <li><a href="#Namespaces">Namespaces</a></li>
44 <li><a href="#Validation">Validation</a></li>
45 <li><a href="#Principles">DOM principles</a></li>
46 <li><a href="#real">A real example</a></li>
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]47 <li><a href="#Contributi">Contributions</a></li>
48</ul>
49
50<p>Separate documents:</p>
51<ul>
52 <li><a href="upgrade.html">upgrade instructions for migrating to
53 libxml2</a></li>
54 <li><a href="encoding.html">libxml Internationalization support</a></li>
55 <li><a href="xmlio.html">libxml Input/Output interfaces</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]56</ul>
57
58<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]59
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]60<p>This document describes libxml, the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]61href="http://www.w3.org/XML/">XML</a> C library developped for the <a
62href="http://www.gnome.org/">Gnome</a> project. <a
63href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
64structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]65
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]66<p>Here are some key points about libxml:</p>
67<ul>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]68 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]69 sticking closely to ANSI C for easy embedding.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]70 <li>The internal document repesentation is as close as possible to the <a
71 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
72 <li>Libxml also has a <a href="http://www.megginson.com/SAX/index.html">SAX
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]73 like interface</a>; the interface is designed to be compatible with <a
74 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]75 <li>Libxml now includes a nearly complete <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]76 href="http://www.w3.org/TR/xpath">XPath</a> implementation.</li>
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]77 <li>Libxml exports Push and Pull type parser interfaces for both XML and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]78 HTML.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]79 <li>This library is released both under the <a
80 href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C
81 IPR</a> and the GNU LGPL. Use either at your convenience, basically this
82 should make everybody happy, if not, drop me a mail.</li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]83 <li>There is <a href="upgrade.html">a first set of instructions</a>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]84 concerning upgrade from libxml-1.x to libxml-2.x</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]85</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]86
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]87<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]88
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]89<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]90<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]91 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]92 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]93 documentation</a> automatically extracted from code comments (using <a
94 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
95 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000[diff] [blame]96 <li>Look at the documentation about <a href="encoding.html">libxml
97 internationalization support</a></li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]98 <li>This page provides a global overview and <a href="#real">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]99 examples</a> on how to use libxml.</li>
100 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
101 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
102 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]103 <li>George Lebl wrote <a
104 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]105 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]106 <li>It is also a good idea to check to <a href="mailto:raph@levien.com">Raph
107 Levien</a> <a href="http://levien.com/gnome/">web site</a> since he is
108 building the <a href="http://levien.com/gnome/gdome.html">DOM interface
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]109 gdome</a> on top of libxml result tree and an implementation of <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]110 href="http://www.w3.org/Graphics/SVG/">SVG</a> called <a
111 href="http://www.levien.com/svg/">gill</a>. Check his <a
112 href="http://www.levien.com/gnome/domination.html">DOMination
113 paper</a>.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]114 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
115 file</a></li>
116 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
117 starting a new project using libxml you should really use the 2.x
118 version.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]119 <li>And don't forget to look at the <a href="/messages/">mailing-list
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]120 archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]121</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]122
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]123<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]124
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]125<p>Well, bugs or missing features are always possible, and I will make a point
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]126of fixing them in a timely fashion. The best way to report a bug is to use the
127<a href="http://bugs.gnome.org/db/pa/lgnome-xml.html">Gnome bug tracking
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]128database</a>. I look at reports there regularly and it's good to have a
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]129reminder when a bug is still open. Check the <a
130href="http://bugs.gnome.org/Reporting.html">instructions on reporting bugs</a>
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]131and be sure to specify that the bug is for the package gnome-xml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]132
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]133<p>There is also a mailing-list <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]134href="mailto:xml@rpmfind.net">xml@rpmfind.net</a> for libxml, with an <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]135href="http://xmlsoft.org/messages">on-line archive</a>. To subscribe to this
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]136majordomo based list, send a mail message to <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]137href="mailto:majordomo@rpmfind.net">majordomo@rpmfind.net</a> with "subscribe
138xml" in the <strong>content</strong> of the message.</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]139
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]140<p>Alternatively, you can just send the bug to the <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]141href="mailto:xml@rpmfind.net">xml@rpmfind.net</a> list, if it's really libxml
142related I will approve it..</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]143
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]144<p>Of course, bugs reports with a suggested patch for fixing them will
145probably be processed faster.</p>
146
147<p>If you're looking for help, a quick look at <a
148href="http://xmlsoft.org/messages/#407">the list archive</a> may actually
149provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]150questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]151documentantion</a> is not as polished as I would like (i need to learn more
152about Docbook), but it's a good starting point.</p>
153
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]154<h2><a name="help">How to help</a></h2>
155
156<p>You can help the project in various ways, the best thing to do first is to
157subscribe to the mailing-list as explained before, check the <a
158href="http://xmlsoft.org/messages/">archives </a>and the <a
159href="http://bugs.gnome.org/db/pa/lgnome-xml.html">Gnome bug
160database:</a>:</p>
161<ol>
162 <li>provide patches when you find problems</li>
163 <li>provice documentation fixes (either as patches to the code comments or
164 as HTML diffs).</li>
165 <li>provide new documentations pieces (translations, examples, etc ...)</li>
166 <li>Check the TODO file and try to close one of the items</li>
167 <li>take one of the points raised in the archive or the bug database and
168 provide a fix. <a href="mailto:Daniel.Veillard@w3.org">Get in touch with
169 me </a>before to avoid synchronization problems and check that the
170 suggested fix will fit in nicely :-)</li>
171</ol>
172
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]173<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]174
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]175<p>The latest versions of libxml can be found on <a
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]176href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]177href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]178as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]179archive</a> or <a
180href="ftp://ftp.gnome.org/pub/GNOME/contrib/redhat/SRPMS/">RPM packages</a>.
181(NOTE that you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]182href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
183href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]184packages installed to compile applications using libxml.)</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]185
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]186<p><a name="Snapshot">Snapshot:</a></p>
187<ul>
188 <li>Code from the W3C cvs base libxml <a
189 href="ftp://rpmfind.net/pub/libxml/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
190 <li>Docs, content of the web site, the list archive included <a
191 href="ftp://rpmfind.net/pub/libxml/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
192</ul>
193
194<p><a name="Contribs">Contribs:</a></p>
195
196<p>I do accept external contributions, especially if compiling on another
197platform, get in touch with me to upload the package. I will keep them in the
198<a href="ftp://rpmfind.net/pub/libxml/contribs/">contrib directory</a></p>
199
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]200<p>Libxml is also available from 2 CVS bases:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]201<ul>
202 <li><p>The <a href="http://dev.w3.org/cvsweb/XML/">W3C CVS base</a>,
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]203 available read-only using the CVS pserver authentification (I tend to use
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]204 this base for my own development, so it's updated more regularly, but the
205 content may not be as stable):</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]206 <pre>CVSROOT=:pserver:anonymous@dev.w3.org:/sources/public
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]207 password: anonymous
208 module: XML</pre>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]209 </li>
210 <li><p>The <a
211 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Gnome
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]212 CVS base</a>. Check the <a
213 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a> page;
214 the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]215 </li>
216</ul>
217
218<h2><a name="News">News</a></h2>
219
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]220<h3>CVS only : check the <a
221href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
222for really accurate description</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]223<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]224 <li>working on HTML and XML links recognition layers, get in touch with me
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]225 if you want to test those.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]226</ul>
227
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]228<h3>2.2.3: Sep 17 2000</h3>
229<ul>
230 <li>bug fixes</li>
231 <li>cleanup of entity handling code</li>
232 <li>overall review of all loops in the parsers, all sprintf usage has been
233 checked too</li>
234 <li>Far better handling of larges Dtd. Validating against Docbook XML Dtd
235 works smoothly now.</li>
236</ul>
237
238<h3>1.8.10: Sep 6 2000</h3>
239<ul>
240 <li>bug fix release for some Gnome projects</li>
241</ul>
242
243<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]244<ul>
245 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]246 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]247</ul>
248
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]249<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]250<ul>
251 <li>a purely bug fixes release</li>
252 <li>fixed an encoding support problem when parsing from a memory block</li>
253 <li>fixed a DOCTYPE parsing problem</li>
254 <li>removed a bug in the function allowing to override the memory allocation
255 routines</li>
256</ul>
257
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]258<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]259<ul>
260 <li>applied a lot of portability fixes</li>
261 <li>better encoding support/cleanup and saving (content is now always
262 encoded in UTF-8)</li>
263 <li>the HTML parser now correctly handles encodings</li>
264 <li>added xmlHasProp()</li>
265 <li>fixed a serious problem with &amp;#38;</li>
266 <li>propagated the fix to FTP client</li>
267 <li>cleanup, bugfixes, etc ...</li>
268 <li>Added a page about <a href="encoding.html">libxml Internationalization
269 support</a></li>
270</ul>
271
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]272<h3>1.8.9: July 9 2000</h3>
273<ul>
274 <li>fixed the spec the RPMs should be better</li>
275 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
276 rpmfind users problem</li>
277</ul>
278
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]279<h3>2.1.1: July 1 2000</h3>
280<ul>
281 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
282 <li>improvements on the HTML parser</li>
283</ul>
284
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]285<h3>2.1.0 and 1.8.8: June 29 2000</h3>
286<ul>
287 <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to
288 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
289 about &amp;#38; charref parsing</li>
290 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
291 also contains numerous fixes and enhancements:
292 <ul>
293 <li>added xmlStopParser() to stop parsing</li>
294 <li>improved a lot parsing speed when there is large CDATA blocs</li>
295 <li>includes XPath patches provided by Picdar Technology</li>
296 <li>tried to fix as much as possible DtD validation and namespace
297 related problems</li>
298 <li>output to a given encoding has been added/tested</li>
299 <li>lot of various fixes</li>
300 </ul>
301 </li>
302</ul>
303
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]304<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]305<ul>
306 <li>First public release of libxml2. If you are using libxml, it's a good
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]307 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally
308 scheduled for Apr 3 the relase occured only on Apr 12 due to massive
309 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]310 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]311 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]312 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]313 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]314 <pre>#include "xxx.h"</pre>
315 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]316 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
317 <li>the memory allocation routines used by libxml can now be overloaded
318 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]319 <li>The previously CVS only tool tester has been renamed
320 <strong>xmllint</strong> and is now installed as part of the libxml2
321 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]322 <li>The I/O interface has been revamped. There is now ways to plug in
323 specific I/O modules, either at the URI scheme detection level using
324 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
325 parser context using xmlCreateIOParserCtxt()</li>
326 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
327 number of the libxml module in use</li>
328 <li>a number of optional features of libxml can now be excluded at configure
329 time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]330</ul>
331
332<h3>2.0.0beta: Mar 14 2000</h3>
333<ul>
334 <li>This is a first Beta release of libxml version 2</li>
335 <li>It's available only from<a href="ftp://rpmfind.net/pub/libxml/">
336 rpmfind.net FTP</a>, it's packaged as libxml2-2.0.0beta and available as
337 tar and RPMs</li>
338 <li>This version is now the head in the Gnome CVS base, the old one is
339 available under the tag LIB_XML_1_X</li>
340 <li>This includes a very large set of changes. Froma programmatic point of
341 view applications should not have to be modified too much, check the <a
342 href="upgrade.html">upgrade page</a></li>
343 <li>Some interfaces may changes (especially a bit about encoding).</li>
344 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]345 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]346 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
347 handled now</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]348 <li>Better handling of entities, especially well formedness checking and
349 proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]350 <li>DTD conditional sections</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]351 <li>Validation now correcly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]352 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
353 structures to accomodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]354 </ul>
355 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]356 <li>Serious progress were made toward compliance, <a
357 href="conf/result.html">here are the result of the test</a> against the
358 OASIS testsuite (except the japanese tests since I don't support that
359 encoding yet). This URL is rebuilt every couple of hours using the CVS
360 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]361</ul>
362
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]363<h3>1.8.7: Mar 6 2000</h3>
364<ul>
365 <li>This is a bug fix release:</li>
366 <li>It is possible to disable the ignorable blanks heuristic used by
367 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
368 that for adherence to XML spec, this behaviour will be disabled by default
369 in 2.x . The same function will allow to keep compatibility for old
370 code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]371 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
372 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]373 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
374 compilation on some platforms has been fixed</li>
375 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
376 URIs</li>
377</ul>
378
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]379<h3>1.8.6: Jan 31 2000</h3>
380<ul>
381 <li>added a nanoFTP transport module, debugged until the new version of <a
382 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
383 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]384</ul>
385
386<h3>1.8.5: Jan 21 2000</h3>
387<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]388 <li>adding APIs to parse a well balanced chunk of XML (production <a
389 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the XML
390 spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]391 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]392 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
393 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]394 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
395 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]396</ul>
397
398<h3>1.8.4: Jan 13 2000</h3>
399<ul>
400 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
401 <li>all exit() call should have been removed from libxml</li>
402 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
403 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]404</ul>
405
406<h3>1.8.3: Jan 5 2000</h3>
407<ul>
408 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]409 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillarddbfd6411999-12-28 16:35:14 +0000[diff] [blame]410 <li>lots of bug fixes and improvement added over XMas hollidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]411 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]412 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
413 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]414 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]415 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]416 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]417</ul>
418
419<h3>1.8.2: Dec 21 1999</h3>
420<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]421 <li>I got another problem with includes and C++, I hope this issue is fixed
422 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]423 <li>Added a few tree modification functions: xmlReplaceNode,
424 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
425 xmlDocSetRootElement</li>
426 <li>Tried to improve the HTML output with help from <a
427 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]428</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]429
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]430<h3>1.8.1: Dec 18 1999</h3>
431<ul>
432 <li>various patches to avoid troubles when using libxml with C++ compilers
433 the "namespace" keyword and C escaping in include files</li>
434 <li>a problem in one of the core macros IS_CHAR was corrected</li>
435 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
436 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]437 <li>fixed a posteriori validation (validation after parsing, or by using a
438 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]439 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]440</ul>
441
442<h3>1.8.0: Dec 12 1999</h3>
443<ul>
444 <li>cleanup, especially memory wise</li>
445 <li>the parser should be more reliable, especially the HTML one, it should
446 not crash, whatever the input !</li>
447 <li>Integrated various patches, especially a speedup improvement for large
448 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
449 configure with --with-buffers to enable them.</li>
450 <li>attribute normalization, oops should have been added long ago !</li>
451 <li>attributes defaulted from Dtds should be available, xmlSetProp() now
452 does entities escapting by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]453</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]454
455<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]456<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]457 <li>Lots of HTML improvement</li>
458 <li>Fixed some errors when saving both XML and HTML</li>
459 <li>More examples, the regression tests should now look clean</li>
460 <li>Fixed a bug with contiguous charref</li>
461</ul>
462
463<h3>1.7.3: Sep 29 1999</h3>
464<ul>
465 <li>portability problems fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]466 <li>snprintf was used unconditionnally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]467 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]468</ul>
469
470<h3>1.7.1: Sep 24 1999</h3>
471<ul>
472 <li>The basic type for strings manipulated by libxml has been renamed in
473 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
474 is that CHAR was conflicting with a predefined type on Windows. However on
475 non WIN32 environment, compatibility is provided by the way of a
476 <strong>#define </strong>.</li>
477 <li>Changed another error : the use of a structure field called errno, and
478 leading to troubles on platforms where it's a macro</li>
479</ul>
480
481<h3>1.7.0: sep 23 1999</h3>
482<ul>
483 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]484 href="html/gnome-xml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]485 <li>Added an errno to report errors by another mean than a simple printf
486 like callback</li>
487 <li>Finished ID/IDREF support and checking when validation</li>
488 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]489 href="html/gnome-xml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]490 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
491 implementation</li>
492 <li>Added an HTML parser front-end</li>
493</ul>
494
495<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]496
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]497<p><a href="http://www.w3.org/TR/REC-xml">XML is a standard</a> for
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]498markup-based structured documents. Here is <a name="example">an example XML
499document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]500<pre>&lt;?xml version="1.0"?&gt;
501&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
502 &lt;head&gt;
503 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
504 &lt;/head&gt;
505 &lt;chapter&gt;
506 &lt;title&gt;The Linux adventure&lt;/title&gt;
507 &lt;p&gt;bla bla bla ...&lt;/p&gt;
508 &lt;image href="linus.gif"/&gt;
509 &lt;p&gt;...&lt;/p&gt;
510 &lt;/chapter&gt;
511&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]512
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]513<p>The first line specifies that it's an XML document and gives useful
514information about its encoding. Then the document is a text format whose
515structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]516to be closed</strong>. XML is pedantic about this. However, if a tag is empty
517(no content), a single tag can serve as both the opening and closing tag if it
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]518ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note that,
519for example, the image tag has no content (just an attribute) and is closed by
520ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]521
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]522<p>XML can be applied sucessfully to a wide range of uses, from long term
523structured document maintenance (where it follows the steps of SGML) to simple
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]524data encoding mechanisms like configuration file formatting (glade),
525spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
526it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]527
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]528<h2>An overview of libxml architecture</h2>
529
530<p>Libxml is made of multiple components, some of them optionals, and most of
531the block interfaces are public. The main components are:</p>
532<ul>
533 <li>an Input/Output layer</li>
534 <li>FTP and HTTP client layers (optionnal)</li>
535 <li>an Internationalization layer managing the encodings support</li>
536 <li>an URI module</li>
537 <li>the XML parser and its basic SAX interface</li>
538 <li>an HTML parser using the same SAX interface (optionnal)</li>
539 <li>a SAX tree module to build an in-memory DOM representation</li>
540 <li>a tree module to manipulate the DOM representation</li>
541 <li>a validation module using the DOM representation (optionnal)</li>
542 <li>an XPath module for global lookup in a DOM representation
543 (optionnal)</li>
544 <li>a debug module (optionnal)</li>
545</ul>
546
547<p>Graphically this gives the following:</p>
548
549<p><img src="libxml.gif" alt="a graphical view of the various"></p>
550
551<p></p>
552
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]553<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]554
555<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]556returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]557<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]558as the file name, the document type, and a <strong>children</strong> pointer
559which is the root of the document (or more exactly the first child under the
560root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]561chained in double-linked lists of siblings and with children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]562relationship. An xmlNode can also carry properties (a chain of xmlAttr
563structures). An attribute may have a value which is a list of TEXT or
564ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]565
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]566<p>Here is an example (erroneous with respect to the XML spec since there
567should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]568
569<p><img src="structure.gif" alt=" structure.gif "></p>
570
571<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]572called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]573prints them back as parsed. This is useful for detecting errors both in XML
574code and in the XML parser itself. It has an option <strong>--debug</strong>
575which prints the actual in-memory structure of the document, here is the
576result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]577<pre>DOCUMENT
578version=1.0
579standalone=true
580 ELEMENT EXAMPLE
581 ATTRIBUTE prop1
582 TEXT
583 content=gnome is great
584 ATTRIBUTE prop2
585 ENTITY_REF
586 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]587 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]588 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]589 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]590 TEXT
591 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]592 ELEMENT chapter
593 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]594 TEXT
595 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]596 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]597 TEXT
598 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]599 ELEMENT image
600 ATTRIBUTE href
601 TEXT
602 content=linus.gif
603 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]604 TEXT
605 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]606
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]607<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]608
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]609<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]610
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]611<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]612memory. In that case (and if you don't expect to save back the XML document
613loaded using libxml), it's better to use the SAX interface of libxml. SAX is a
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]614<strong>callback-based interface</strong> to the parser. Before parsing, the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]615application layer registers a customized set of callbacks which are called by
616the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]617
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]618<p>To get more detailed step-by-step guidance on using the SAX interface of
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]619libxml, see the <a
620href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
621documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]622Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]623
624<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
625program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]626binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]627distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]628testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]629<pre>SAX.setDocumentLocator()
630SAX.startDocument()
631SAX.getEntity(amp)
632SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
633SAX.characters( , 3)
634SAX.startElement(head)
635SAX.characters( , 4)
636SAX.startElement(title)
637SAX.characters(Welcome to Gnome, 16)
638SAX.endElement(title)
639SAX.characters( , 3)
640SAX.endElement(head)
641SAX.characters( , 3)
642SAX.startElement(chapter)
643SAX.characters( , 4)
644SAX.startElement(title)
645SAX.characters(The Linux adventure, 19)
646SAX.endElement(title)
647SAX.characters( , 4)
648SAX.startElement(p)
649SAX.characters(bla bla bla ..., 15)
650SAX.endElement(p)
651SAX.characters( , 4)
652SAX.startElement(image, href='linus.gif')
653SAX.endElement(image)
654SAX.characters( , 4)
655SAX.startElement(p)
656SAX.characters(..., 3)
657SAX.endElement(p)
658SAX.characters( , 3)
659SAX.endElement(chapter)
660SAX.characters( , 1)
661SAX.endElement(EXAMPLE)
662SAX.endDocument()</pre>
663
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]664<p>Most of the other functionalities of libxml are based on the DOM
665tree-building facility, so nearly everything up to the end of this document
666presupposes the use of the standard DOM tree build. Note that the DOM tree
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]667itself is built by a set of registered default callbacks, without internal
668specific interface.</p>
669
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]670<h2><a name="library">The XML library interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]671
672<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]673using the XML library from the C language. It is not intended to be extensive.
674I hope the automatically generated documents will provide the completeness
675required, but as a separate set of documents. The interfaces of the XML
676library are by principle low level, there is nearly zero abstraction. Those
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]677interested in a higher level API should <a href="#DOM">look at DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]678
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]679<p>The <a href="html/gnome-xml-parser.html">parser interfaces for XML</a> are
680separated from the <a href="html/gnome-xml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]681interfaces</a>. Let's have a look at how the XML parser can be called:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]682
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]683<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]684
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]685<p>Usually, the first thing to do is to read an XML input. The parser accepts
686documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]687defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]688<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]689 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]690 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]691 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]692</dl>
693<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]694 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]695 <dd><p>Parse an XML document contained in a (possibly compressed)
696 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]697 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]698</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]699
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]700<p>The parser returns a pointer to the document structure (or NULL in case of
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]701failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]702
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]703<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]704
705<p>In order for the application to keep the control when the document is been
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]706fetched (which is common for GUI based programs) libxml provides a push
707interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]708<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
709 void *user_data,
710 const char *chunk,
711 int size,
712 const char *filename);
713int xmlParseChunk (xmlParserCtxtPtr ctxt,
714 const char *chunk,
715 int size,
716 int terminate);</pre>
717
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]718<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]719<pre> FILE *f;
720
721 f = fopen(filename, "r");
722 if (f != NULL) {
723 int res, size = 1024;
724 char chars[1024];
725 xmlParserCtxtPtr ctxt;
726
727 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]728 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]729 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
730 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]731 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]732 xmlParseChunk(ctxt, chars, res, 0);
733 }
734 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]735 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]736 xmlFreeParserCtxt(ctxt);
737 }
738 }</pre>
739
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]740<p>Also note that the HTML parser embedded into libxml also has a push
741interface; the functions are just prefixed by "html" rather than "xml"</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]742
743<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
744
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]745<p>A couple of comments can be made, first this mean that the parser is
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]746memory-hungry, first to load the document in memory, second to build the tree.
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]747Reading a document without building the tree is possible using the SAX
748interfaces (see SAX.h and <a
749href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]750Henstridge's documentation</a>). Note also that the push interface can be
751limited to SAX. Just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]752<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]753
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]754<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]755
756<p>The other way to get an XML tree in memory is by building it. Basically
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]757there is a set of functions dedicated to building new elements. (These are
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]758also described in &lt;libxml/tree.h&gt;.) For example, here is a piece of code
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]759that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]760<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]761 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]762 xmlNodePtr tree, subtree;
763
764 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]765 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
766 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
767 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
768 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]769 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]770 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]771 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
772 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
773 subtree = xmlNewChild(tree, NULL, "image", NULL);
774 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]775
776<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]777
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]778<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]779
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]780<p>Basically by <a href="html/gnome-xml-tree.html">including "tree.h"</a> your
781code has access to the internal structure of all the elements of the tree. The
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]782names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]783<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]784<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]785example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]786<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]787
788<p>points to the title element,</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]789<pre>doc-&gt;children-&gt;children-&gt;next-&gt;child-&gt;child</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]790
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]791<p>points to the text node containing the chapter title "The Linux
792adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]793
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]794<p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em> to be
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]795present before the document root, so <code>doc-&gt;children</code> may point
796to an element which is not the document Root Element, a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]797<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]798
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]799<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]800
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]801<p>Functions are provided for reading and writing the document content. Here
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]802is an excerpt from the <a href="html/gnome-xml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]803<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]804 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
805 xmlChar *value);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]806 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node. The
807 value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]808 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]809</dl>
810<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]811 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]812 *name);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]813 <dd><p>This function returns a pointer to the property content. Note that
814 no extra copy is made.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]815 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]816</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]817
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]818<p>Two functions are provided for reading and writing the text associated with
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]819elements:</p>
820<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]821 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]822 *value);</code></dt>
823 <dd><p>This function takes an "external" string and convert it to one text
824 node or possibly to a list of entity and text nodes. All non-predefined
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]825 entity references like &amp;Gnome; will be stored internally as entity
826 nodes, hence the result of the function may not be a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]827 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]828</dl>
829<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]830 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]831 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]832 <dd><p>This function is the inverse of
833 <code>xmlStringGetNodeList()</code>. It generates a new string
834 containing the content of the text and entity nodes. Note the extra
835 argument inLine. If this argument is set to 1, the function will expand
836 entity references. For example, instead of returning the &amp;Gnome;
837 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]838 "GNU Network Object Model Environment"). Set this argument if you want
839 to use the string for non-XML usage like User Interface.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]840 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]841</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]842
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]843<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]844
845<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]846<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]847 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]848 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]849 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]850 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]851</dl>
852<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]853 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]854 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]855 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]856</dl>
857<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]858 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]859 <dd><p>Saves the document to a file. In this case, the compression
860 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]861 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]862</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]863
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]864<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]865
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]866<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]867accesses. The level of compression on saves can be turned on either globally
868or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]869<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]870 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]871 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]872 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]873</dl>
874<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]875 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]876 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]877 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]878</dl>
879<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]880 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]881 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]882 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]883</dl>
884<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]885 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]886 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]887 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]888</dl>
889
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]890<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]891
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]892<p>Entities in principle are similar to simple C macros. An entity defines an
893abbreviation for a given string that you can reuse many times throughout the
894content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]895may occur frequently within a document, or to confine the change needed to a
896document to a restricted area in the internal subset of the document (at the
897beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]898<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]8992 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]9003 &lt;!ENTITY xml "Extensible Markup Language"&gt;
9014 ]&gt;
9025 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]9036 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]9047 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]905
906<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]907it's name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]908are 5 predefined entities in libxml allowing you to escape charaters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]909predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]910<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]911for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]912<strong>&amp;quot;</strong> for the character '"', and
913<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]914
915<p>One of the problems related to entities is that you may want the parser to
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]916substitute an entity's content so that you can see the replacement text in
917your application. Or you may prefer to keep entity references as such in the
918content to be able to save the document back without losing this usually
919precious information (if the user went through the pain of explicitly defining
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]920entities, he may have a a rather negative attitude if you blindly susbtitute
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]921them as saving time). The <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]922href="html/gnome-xml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]923function allows you to check and change the behaviour, which is to not
924substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]925
926<p>Here is the DOM tree built by libxml for the previous document in the
927default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]928<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]929DOCUMENT
930version=1.0
931 ELEMENT EXAMPLE
932 TEXT
933 content=
934 ENTITY_REF
935 INTERNAL_GENERAL_ENTITY xml
936 content=Extensible Markup Language
937 TEXT
938 content=</pre>
939
940<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]941<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]942DOCUMENT
943version=1.0
944 ELEMENT EXAMPLE
945 TEXT
946 content= Extensible Markup Language</pre>
947
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]948<p>So, entities or no entities? Basically, it depends on your use case. I
949suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]950entities in your XML document or data if you are not willing to handle the
951entity references elements in the DOM tree.</p>
952
953<p>Note that at save time libxml enforce the conversion of the predefined
954entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]955transparently replace those with chars (i.e., it will not generate entity
956reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]957finding them in the input).</p>
958
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]959<p><span style="background-color: #FF0000">WARNING</span>: handling entities
960on top of libxml SAX interface is difficult !!! If you plan to use
961non-predefined entities in your documents, then the learning cuvre to handle
962then using the SAX API may be long. If you plan to use complex document, I
963strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]964deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]965
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]966<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]967
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]968<p>The libxml library implements <a
969href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
970recognizing namespace contructs in the input, and does namespace lookup
971automatically when building the DOM tree. A namespace declaration is
972associated with an in-memory structure and all elements or attributes within
973that namespace point to it. Hence testing the namespace is a simple and fast
974equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]975
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]976<p>I suggest that people using libxml use a namespace, and declare it in the
977root element of their document as the default namespace. Then they don't need
978to use the prefix in the content but we will have a basis for future semantic
979refinement and merging of data from different sources. This doesn't augment
980significantly the size of the XML output, but significantly increase its value
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]981in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]982<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
983 &lt;elem1&gt;...&lt;/elem1&gt;
984 &lt;elem2&gt;...&lt;/elem2&gt;
985&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]986
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]987<p>Concerning the namespace value, this has to be an URL, but the URL doesn't
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]988have to point to any existing resource on the Web. It will bind all the
989element and atributes with that URL. I suggest to use an URL within a domain
990you control, and that the URL should contain some kind of version information
991if possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]992a good namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]993
994<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]995version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]996and if the version information don't match something you know, warn the user
997and be liberal in what you accept as the input. Also do *not* try to base
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]998namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
999same as &lt;bar:text&gt; in another document. What really matter is the URI
1000associated with the element or the attribute, not the prefix string (which is
1001just a shortcut for the full URI). In libxml element and attributes have a
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1002<code>ns</code> field pointing to an xmlNs structure detailing the namespace
1003prefix and it's URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1004
1005<p>@@Interfaces@@</p>
1006
1007<p>@@Examples@@</p>
1008
1009<p>Usually people object using namespace in the case of validation, I object
1010this and will make sure that using namespaces won't break validity checking,
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1011so even is you plan to use or currently are using validation I strongly
1012suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1013<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1014flexible parsers. Now using namespace to mix and differentiate content coming
1015from multiple DTDs will certainly break current validation schemes. I will try
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1016to provide ways to do this, but this may not be portable or standardized.</p>
1017
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1018<h2><a name="Validation">Validation, or are you afraid of DTDs ?</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1019
1020<p>Well what is validation and what is a DTD ?</p>
1021
1022<p>Validation is the process of checking a document against a set of
1023construction rules, a <strong>DTD</strong> (Document Type Definition) is such
1024a set of rules.</p>
1025
1026<p>The validation process and building DTDs are the two most difficult parts
1027of XML life cycle. Briefly a DTD defines all the possibles element to be
1028found within your document, what is the formal shape of your document tree (by
1029defining the allowed content of an element, either text, a regular expression
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1030for the allowed list of children, or mixed content i.e. both text and
1031children). The DTD also defines the allowed attributes for all elements and
1032the types of the attributes. For more detailed informations, I suggest to read
1033the related parts of the XML specification, the examples found under
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1034gnome-xml/test/valid/dtd and the large amount of books available on XML. The
1035dia example in gnome-xml/test/valid should be both simple and complete enough
1036to allow you to build your own.</p>
1037
1038<p>A word of warning, building a good DTD which will fit your needs of your
1039application in the long-term is far from trivial, however the extra level of
1040quality it can insure is well worth the price for some sets of applications or
1041if you already have already a DTD defined for your application field.</p>
1042
1043<p>The validation is not completely finished but in a (very IMHO) usable
1044state. Until a real validation interface is defined the way to do it is to
1045define and set the <strong>xmlDoValidityCheckingDefaultValue</strong> external
1046variable to 1, this will of course be changed at some point:</p>
1047
1048<p>extern int xmlDoValidityCheckingDefaultValue;</p>
1049
1050<p>...</p>
1051
1052<p>xmlDoValidityCheckingDefaultValue = 1;</p>
1053
1054<p></p>
1055
1056<p>To handle external entities, use the function
1057<strong>xmlSetExternalEntityLoader</strong>(xmlExternalEntityLoader f); to
1058link in you HTTP/FTP/Entities database library to the standard libxml
1059core.</p>
1060
1061<p>@@interfaces@@</p>
1062
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1063<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1064
1065<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document Object
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1066Model</em> this is an API for accessing XML or HTML structured documents.
1067Native support for DOM in Gnome is on the way (module gnome-dom), and it will
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1068be based on gnome-xml. This will be a far cleaner interface to manipulate XML
Daniel Veillardc08a2c61999-09-08 21:35:25 +0000[diff] [blame]1069files within Gnome since it won't expose the internal structure. DOM defines a
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1070set of IDL (or Java) interfaces allowing to traverse and manipulate a
1071document. The DOM library will allow accessing and modifying "live" documents
1072presents on other programs like this:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1073
1074<p><img src="DOM.gif" alt=" DOM.gif "></p>
1075
1076<p>This should help greatly doing things like modifying a gnumeric spreadsheet
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1077embedded in a GWP document for example.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1078
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1079<p>The current DOM implementation on top of libxml is the <a
1080href="http://cvs.gnome.org/lxr/source/gdome/">gdome Gnome module</a>, this is
1081a full DOM interface, thanks to <a href="mailto:raph@levien.com">Raph
1082Levien</a>.</p>
1083
1084<p>The gnome-dom module in the Gnome CVS base is obsolete</p>
1085
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1086<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1087
1088<p>Here is a real size example, where the actual content of the application
1089data is not kept in the DOM tree but uses internal structures. It is based on
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1090a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1091storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
1092base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1093<pre>&lt;?xml version="1.0"?&gt;
1094&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
1095 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1096
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1097 &lt;gjob:Job&gt;
1098 &lt;gjob:Project ID="3"/&gt;
1099 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
1100 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1101
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1102 &lt;gjob:Update&gt;
1103 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
1104 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
1105 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
1106 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1107
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1108 &lt;gjob:Developers&gt;
1109 &lt;gjob:Developer&gt;
1110 &lt;/gjob:Developer&gt;
1111 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1112
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1113 &lt;gjob:Contact&gt;
1114 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
1115 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
1116 &lt;gjob:Company&gt;
1117 &lt;/gjob:Company&gt;
1118 &lt;gjob:Organisation&gt;
1119 &lt;/gjob:Organisation&gt;
1120 &lt;gjob:Webpage&gt;
1121 &lt;/gjob:Webpage&gt;
1122 &lt;gjob:Snailmail&gt;
1123 &lt;/gjob:Snailmail&gt;
1124 &lt;gjob:Phone&gt;
1125 &lt;/gjob:Phone&gt;
1126 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1127
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1128 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1129 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1130 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1131
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1132 &lt;gjob:Skills&gt;
1133 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1134
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1135 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1136 A GNOME based system that will allow a superuser to configure
1137 compressed and uncompressed files and/or file systems to be backed
1138 up with a supported media in the system. This should be able to
1139 perform via find commands generating a list of files that are passed
1140 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
1141 or via operations performed on the filesystem itself. Email
1142 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1143 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1144
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1145 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1146
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1147 &lt;/gjob:Jobs&gt;
1148&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1149
1150<p>While loading the XML file into an internal DOM tree is a matter of calling
1151only a couple of functions, browsing the tree to gather the informations and
1152generate the internals structures is harder, and more error prone.</p>
1153
1154<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1155structure. For example, the ordering of the attributes is not significant,
1156Cthe XML specification is clear about it. It's also usually a good idea to not
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1157be dependent of the orders of the children of a given node, unless it really
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1158makes things harder. Here is some code to parse the informations for a
1159person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1160<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1161 * A person record
1162 */
1163typedef struct person {
1164 char *name;
1165 char *email;
1166 char *company;
1167 char *organisation;
1168 char *smail;
1169 char *webPage;
1170 char *phone;
1171} person, *personPtr;
1172
1173/*
1174 * And the code needed to parse it
1175 */
1176personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1177 personPtr ret = NULL;
1178
1179DEBUG("parsePerson\n");
1180 /*
1181 * allocate the struct
1182 */
1183 ret = (personPtr) malloc(sizeof(person));
1184 if (ret == NULL) {
1185 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1186 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1187 }
1188 memset(ret, 0, sizeof(person));
1189
1190 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1191 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1192 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1193 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
1194 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1195 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
1196 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1197 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1198 }
1199
1200 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1201}</pre>
1202
1203<p>Here is a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1204<ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1205 <li>Usually a recursive parsing style is the more convenient one, XML data
1206 being by nature subject to repetitive constructs and usualy exibit highly
1207 stuctured patterns.</li>
1208 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>, i.e.
1209 the pointer to the global XML document and the namespace reserved to the
1210 application. Document wide information are needed for example to decode
1211 entities and it's a good coding practice to define a namespace for your
1212 application set of data and test that the element and attributes you're
1213 analyzing actually pertains to your application space. This is done by a
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1214 simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1215 <li>To retrieve text and attributes value, it is suggested to use the
1216 function <em>xmlNodeListGetString</em> to gather all the text and entity
1217 reference nodes generated by the DOM output and produce an single text
1218 string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1219</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1220
1221<p>Here is another piece of code used to parse another level of the
1222structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1223<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1224/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1225 * a Description for a Job
1226 */
1227typedef struct job {
1228 char *projectID;
1229 char *application;
1230 char *category;
1231 personPtr contact;
1232 int nbDevelopers;
1233 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
1234} job, *jobPtr;
1235
1236/*
1237 * And the code needed to parse it
1238 */
1239jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1240 jobPtr ret = NULL;
1241
1242DEBUG("parseJob\n");
1243 /*
1244 * allocate the struct
1245 */
1246 ret = (jobPtr) malloc(sizeof(job));
1247 if (ret == NULL) {
1248 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1249 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1250 }
1251 memset(ret, 0, sizeof(job));
1252
1253 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1254 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1255 while (cur != NULL) {
1256
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1257 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
1258 ret-&gt;projectID = xmlGetProp(cur, "ID");
1259 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1260 fprintf(stderr, "Project has no ID\n");
1261 }
1262 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1263 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
1264 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1265 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
1266 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1267 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
1268 ret-&gt;contact = parsePerson(doc, ns, cur);
1269 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1270 }
1271
1272 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1273}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1274
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1275<p>One can notice that once used to it, writing this kind of code is quite
1276simple, but boring. Ultimately, it could be possble to write stubbers taking
1277either C data structure definitions, a set of XML examples or an XML DTD and
1278produce the code needed to import and export the content between C data and
1279XML storage. This is left as an exercise to the reader :-)</p>
1280
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]1281<p>Feel free to use <a href="example/gjobread.c">the code for the full C
1282parsing example</a> as a template, it is also available with Makefile in the
1283Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1284
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1285<h2><a name="Contributi">Contributions</a></h2>
1286<ul>
1287 <li><a href="mailto:ari@btigate.com">Ari Johnson</a> provides a C++ wrapper
1288 for libxml:
1289 <p>Website: <a
1290 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
1291 <p>Download: <a
1292 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
1293 </li>
1294 <li><a href="mailto:doolin@cs.utk.edu">David Doolin</a> provides a
1295 precompiled Windows version
1296 <p><a
1297 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
1298 </li>
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1299 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> provided <a
1300 href="libxml-doc.el">an emacs module</a> to lookup libxml functions
1301 documentation</li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1302 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
1303 href="http://xmlsoft.org/messages/0488.html">man pages</a> (not yet
1304 integrated in the distribution)</li>
1305</ul>
1306
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1307<p></p>
1308
1309<p><a href="mailto:Daniel.Veillard@w3.org">Daniel Veillard</a></p>
1310
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1311<p>$Id: xml.html,v 1.51 2000/08/31 13:50:12 veillard Exp $</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1312</body>
1313</html>