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gerrit-public.fairphone.software / fp2-dev / platform / external / libxml2 / 04698d9e1c56467007fcbb9472e5db67cf5938f5 / . / doc / xml.html
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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 Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]6 <meta name="GENERATOR" content="amaya V3.2.1">
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]7 <meta http-equiv="Content-Type" content="text/html">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]8</head>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]9
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]10<body bgcolor="#ffffff">
Daniel 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 Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]23 <li><a href="#Downloads">Downloads</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]24 <li><a href="#News">News</a></li>
25 <li><a href="#XML">XML</a></li>
26 <li><a href="#tree">The tree output</a></li>
27 <li><a href="#interface">The SAX interface</a></li>
28 <li><a href="#library">The XML library interfaces</a>
29 <ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]30 <li><a href="#Invoking">Invoking the parser: the pull way</a></li>
31 <li><a href="#Invoking">Invoking the parser: the push way</a></li>
32 <li><a href="#Invoking2">Invoking the parser: the SAX interface</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]33 <li><a href="#Building">Building a tree from scratch</a></li>
34 <li><a href="#Traversing">Traversing the tree</a></li>
35 <li><a href="#Modifying">Modifying the tree</a></li>
36 <li><a href="#Saving">Saving the tree</a></li>
37 <li><a href="#Compressio">Compression</a></li>
38 </ul>
39 </li>
40 <li><a href="#Entities">Entities or no entities</a></li>
41 <li><a href="#Namespaces">Namespaces</a></li>
42 <li><a href="#Validation">Validation</a></li>
43 <li><a href="#Principles">DOM principles</a></li>
44 <li><a href="#real">A real example</a></li>
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]45 <li><a href="#Contributi">Contributions</a></li>
46</ul>
47
48<p>Separate documents:</p>
49<ul>
50 <li><a href="upgrade.html">upgrade instructions for migrating to
51 libxml2</a></li>
52 <li><a href="encoding.html">libxml Internationalization support</a></li>
53 <li><a href="xmlio.html">libxml Input/Output interfaces</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]54</ul>
55
56<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]57
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]58<p>This document describes libxml, the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]59href="http://www.w3.org/XML/">XML</a> C library developped for the <a
60href="http://www.gnome.org/">Gnome</a> project. <a
61href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
62structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]63
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]64<p>Here are some key points about libxml:</p>
65<ul>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]66 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]67 sticking closely to ANSI C for easy embedding.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]68 <li>The internal document repesentation is as close as possible to the <a
69 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
70 <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]71 like interface</a>; the interface is designed to be compatible with <a
72 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]73 <li>Libxml now includes a nearly complete <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]74 href="http://www.w3.org/TR/xpath">XPath</a> implementation.</li>
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]75 <li>Libxml exports Push and Pull type parser interfaces for both XML and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]76 HTML.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]77 <li>This library is released both under the <a
78 href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C
79 IPR</a> and the GNU LGPL. Use either at your convenience, basically this
80 should make everybody happy, if not, drop me a mail.</li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]81 <li>There is <a href="upgrade.html">a first set of instructions</a>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]82 concerning upgrade from libxml-1.x to libxml-2.x</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]83</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]84
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]85<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]86
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]87<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]88<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]89 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]90 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]91 documentation</a> automatically extracted from code comments (using <a
92 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
93 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000[diff] [blame]94 <li>Look at the documentation about <a href="encoding.html">libxml
95 internationalization support</a></li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]96 <li>This page provides a global overview and <a href="#real">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]97 examples</a> on how to use libxml.</li>
98 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
99 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
100 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]101 <li>George Lebl wrote <a
102 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]103 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]104 <li>It is also a good idea to check to <a href="mailto:raph@levien.com">Raph
105 Levien</a> <a href="http://levien.com/gnome/">web site</a> since he is
106 building the <a href="http://levien.com/gnome/gdome.html">DOM interface
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]107 gdome</a> on top of libxml result tree and an implementation of <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]108 href="http://www.w3.org/Graphics/SVG/">SVG</a> called <a
109 href="http://www.levien.com/svg/">gill</a>. Check his <a
110 href="http://www.levien.com/gnome/domination.html">DOMination
111 paper</a>.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]112 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
113 file</a></li>
114 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
115 starting a new project using libxml you should really use the 2.x
116 version.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]117 <li>And don't forget to look at the <a href="/messages/">mailing-list
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]118 archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]119</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]120
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]121<h3>Reporting bugs and getting help</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]122
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]123<p>Well, bugs or missing features are always possible, and I will make a point
124of fixing them in a timely fashion. The best way to report a bug is to <a
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]125href="http://bugs.gnome.org/db/pa/lgnome-xml.html">use the Gnome bug tracking
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]126database</a>. I look at reports there regularly and it's good to have a
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]127reminder when a bug is still open. Check the <a
128href="http://bugs.gnome.org/Reporting.html">instructions on reporting bugs</a>
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]129and be sure to specify that the bug is for the package gnome-xml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]130
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]131<p>There is also a mailing-list <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]132href="mailto:xml@rpmfind.net">xml@rpmfind.net</a> for libxml, with an <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]133href="http://xmlsoft.org/messages">on-line archive</a>. To subscribe to this
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]134majordomo based list, send a mail message to <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]135href="mailto:majordomo@rpmfind.net">majordomo@rpmfind.net</a> with "subscribe
136xml" in the <strong>content</strong> of the message.</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]137
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]138<p>Alternatively, you can just send the bug to the <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]139href="mailto:xml@rpmfind.net">xml@rpmfind.net</a> list, if it's really libxml
140related I will approve it..</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]141
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]142<p>Of course, bugs reports with a suggested patch for fixing them will
143probably be processed faster.</p>
144
145<p>If you're looking for help, a quick look at <a
146href="http://xmlsoft.org/messages/#407">the list archive</a> may actually
147provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]148questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]149documentantion</a> is not as polished as I would like (i need to learn more
150about Docbook), but it's a good starting point.</p>
151
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]152<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]153
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]154<p>The latest versions of libxml can be found on <a
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]155href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]156href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]157as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]158archive</a> or <a
159href="ftp://ftp.gnome.org/pub/GNOME/contrib/redhat/SRPMS/">RPM packages</a>.
160(NOTE that you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]161href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
162href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]163packages installed to compile applications using libxml.)</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]164
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]165<p><a name="Snapshot">Snapshot:</a></p>
166<ul>
167 <li>Code from the W3C cvs base libxml <a
168 href="ftp://rpmfind.net/pub/libxml/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
169 <li>Docs, content of the web site, the list archive included <a
170 href="ftp://rpmfind.net/pub/libxml/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
171</ul>
172
173<p><a name="Contribs">Contribs:</a></p>
174
175<p>I do accept external contributions, especially if compiling on another
176platform, get in touch with me to upload the package. I will keep them in the
177<a href="ftp://rpmfind.net/pub/libxml/contribs/">contrib directory</a></p>
178
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]179<p>Libxml is also available from 2 CVS bases:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]180<ul>
181 <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]182 available read-only using the CVS pserver authentification (I tend to use
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]183 this base for my own development, so it's updated more regularly, but the
184 content may not be as stable):</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]185 <pre>CVSROOT=:pserver:anonymous@dev.w3.org:/sources/public
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]186 password: anonymous
187 module: XML</pre>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]188 </li>
189 <li><p>The <a
190 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]191 CVS base</a>. Check the <a
192 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a> page;
193 the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]194 </li>
195</ul>
196
197<h2><a name="News">News</a></h2>
198
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]199<h3>CVS only : check the <a
200href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
201for really accurate description</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]202<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]203 <li>working on HTML and XML links recognition layers, get in touch with me
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]204 if you want to test those.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]205</ul>
206
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]207<h2>2.2.2: August 12 2000</h2>
208<ul>
209 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]210 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]211</ul>
212
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]213<h2>2.2.1: July 21 2000</h2>
214<ul>
215 <li>a purely bug fixes release</li>
216 <li>fixed an encoding support problem when parsing from a memory block</li>
217 <li>fixed a DOCTYPE parsing problem</li>
218 <li>removed a bug in the function allowing to override the memory allocation
219 routines</li>
220</ul>
221
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]222<h2>2.2.0: July 14 2000</h2>
223<ul>
224 <li>applied a lot of portability fixes</li>
225 <li>better encoding support/cleanup and saving (content is now always
226 encoded in UTF-8)</li>
227 <li>the HTML parser now correctly handles encodings</li>
228 <li>added xmlHasProp()</li>
229 <li>fixed a serious problem with &amp;#38;</li>
230 <li>propagated the fix to FTP client</li>
231 <li>cleanup, bugfixes, etc ...</li>
232 <li>Added a page about <a href="encoding.html">libxml Internationalization
233 support</a></li>
234</ul>
235
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]236<h3>1.8.9: July 9 2000</h3>
237<ul>
238 <li>fixed the spec the RPMs should be better</li>
239 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
240 rpmfind users problem</li>
241</ul>
242
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]243<h3>2.1.1: July 1 2000</h3>
244<ul>
245 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
246 <li>improvements on the HTML parser</li>
247</ul>
248
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]249<h3>2.1.0 and 1.8.8: June 29 2000</h3>
250<ul>
251 <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to
252 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
253 about &amp;#38; charref parsing</li>
254 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
255 also contains numerous fixes and enhancements:
256 <ul>
257 <li>added xmlStopParser() to stop parsing</li>
258 <li>improved a lot parsing speed when there is large CDATA blocs</li>
259 <li>includes XPath patches provided by Picdar Technology</li>
260 <li>tried to fix as much as possible DtD validation and namespace
261 related problems</li>
262 <li>output to a given encoding has been added/tested</li>
263 <li>lot of various fixes</li>
264 </ul>
265 </li>
266</ul>
267
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]268<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]269<ul>
270 <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]271 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally
272 scheduled for Apr 3 the relase occured only on Apr 12 due to massive
273 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]274 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]275 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]276 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]277 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]278 <pre>#include "xxx.h"</pre>
279 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]280 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
281 <li>the memory allocation routines used by libxml can now be overloaded
282 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]283 <li>The previously CVS only tool tester has been renamed
284 <strong>xmllint</strong> and is now installed as part of the libxml2
285 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]286 <li>The I/O interface has been revamped. There is now ways to plug in
287 specific I/O modules, either at the URI scheme detection level using
288 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
289 parser context using xmlCreateIOParserCtxt()</li>
290 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
291 number of the libxml module in use</li>
292 <li>a number of optional features of libxml can now be excluded at configure
293 time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]294</ul>
295
296<h3>2.0.0beta: Mar 14 2000</h3>
297<ul>
298 <li>This is a first Beta release of libxml version 2</li>
299 <li>It's available only from<a href="ftp://rpmfind.net/pub/libxml/">
300 rpmfind.net FTP</a>, it's packaged as libxml2-2.0.0beta and available as
301 tar and RPMs</li>
302 <li>This version is now the head in the Gnome CVS base, the old one is
303 available under the tag LIB_XML_1_X</li>
304 <li>This includes a very large set of changes. Froma programmatic point of
305 view applications should not have to be modified too much, check the <a
306 href="upgrade.html">upgrade page</a></li>
307 <li>Some interfaces may changes (especially a bit about encoding).</li>
308 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]309 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]310 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
311 handled now</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]312 <li>Better handling of entities, especially well formedness checking and
313 proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]314 <li>DTD conditional sections</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]315 <li>Validation now correcly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]316 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
317 structures to accomodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]318 </ul>
319 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]320 <li>Serious progress were made toward compliance, <a
321 href="conf/result.html">here are the result of the test</a> against the
322 OASIS testsuite (except the japanese tests since I don't support that
323 encoding yet). This URL is rebuilt every couple of hours using the CVS
324 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]325</ul>
326
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]327<h3>1.8.7: Mar 6 2000</h3>
328<ul>
329 <li>This is a bug fix release:</li>
330 <li>It is possible to disable the ignorable blanks heuristic used by
331 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
332 that for adherence to XML spec, this behaviour will be disabled by default
333 in 2.x . The same function will allow to keep compatibility for old
334 code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]335 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
336 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]337 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
338 compilation on some platforms has been fixed</li>
339 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
340 URIs</li>
341</ul>
342
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]343<h3>1.8.6: Jan 31 2000</h3>
344<ul>
345 <li>added a nanoFTP transport module, debugged until the new version of <a
346 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
347 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]348</ul>
349
350<h3>1.8.5: Jan 21 2000</h3>
351<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]352 <li>adding APIs to parse a well balanced chunk of XML (production <a
353 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the XML
354 spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]355 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]356 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
357 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]358 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
359 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]360</ul>
361
362<h3>1.8.4: Jan 13 2000</h3>
363<ul>
364 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
365 <li>all exit() call should have been removed from libxml</li>
366 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
367 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]368</ul>
369
370<h3>1.8.3: Jan 5 2000</h3>
371<ul>
372 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]373 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillarddbfd6411999-12-28 16:35:14 +0000[diff] [blame]374 <li>lots of bug fixes and improvement added over XMas hollidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]375 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]376 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
377 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]378 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]379 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]380 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]381</ul>
382
383<h3>1.8.2: Dec 21 1999</h3>
384<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]385 <li>I got another problem with includes and C++, I hope this issue is fixed
386 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]387 <li>Added a few tree modification functions: xmlReplaceNode,
388 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
389 xmlDocSetRootElement</li>
390 <li>Tried to improve the HTML output with help from <a
391 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]392</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]393
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]394<h3>1.8.1: Dec 18 1999</h3>
395<ul>
396 <li>various patches to avoid troubles when using libxml with C++ compilers
397 the "namespace" keyword and C escaping in include files</li>
398 <li>a problem in one of the core macros IS_CHAR was corrected</li>
399 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
400 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]401 <li>fixed a posteriori validation (validation after parsing, or by using a
402 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]403 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]404</ul>
405
406<h3>1.8.0: Dec 12 1999</h3>
407<ul>
408 <li>cleanup, especially memory wise</li>
409 <li>the parser should be more reliable, especially the HTML one, it should
410 not crash, whatever the input !</li>
411 <li>Integrated various patches, especially a speedup improvement for large
412 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
413 configure with --with-buffers to enable them.</li>
414 <li>attribute normalization, oops should have been added long ago !</li>
415 <li>attributes defaulted from Dtds should be available, xmlSetProp() now
416 does entities escapting by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]417</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]418
419<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]420<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]421 <li>Lots of HTML improvement</li>
422 <li>Fixed some errors when saving both XML and HTML</li>
423 <li>More examples, the regression tests should now look clean</li>
424 <li>Fixed a bug with contiguous charref</li>
425</ul>
426
427<h3>1.7.3: Sep 29 1999</h3>
428<ul>
429 <li>portability problems fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]430 <li>snprintf was used unconditionnally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]431 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]432</ul>
433
434<h3>1.7.1: Sep 24 1999</h3>
435<ul>
436 <li>The basic type for strings manipulated by libxml has been renamed in
437 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
438 is that CHAR was conflicting with a predefined type on Windows. However on
439 non WIN32 environment, compatibility is provided by the way of a
440 <strong>#define </strong>.</li>
441 <li>Changed another error : the use of a structure field called errno, and
442 leading to troubles on platforms where it's a macro</li>
443</ul>
444
445<h3>1.7.0: sep 23 1999</h3>
446<ul>
447 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]448 href="html/gnome-xml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]449 <li>Added an errno to report errors by another mean than a simple printf
450 like callback</li>
451 <li>Finished ID/IDREF support and checking when validation</li>
452 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]453 href="html/gnome-xml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]454 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
455 implementation</li>
456 <li>Added an HTML parser front-end</li>
457</ul>
458
459<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]460
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]461<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]462markup-based structured documents. Here is <a name="example">an example XML
463document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]464<pre>&lt;?xml version="1.0"?&gt;
465&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
466 &lt;head&gt;
467 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
468 &lt;/head&gt;
469 &lt;chapter&gt;
470 &lt;title&gt;The Linux adventure&lt;/title&gt;
471 &lt;p&gt;bla bla bla ...&lt;/p&gt;
472 &lt;image href="linus.gif"/&gt;
473 &lt;p&gt;...&lt;/p&gt;
474 &lt;/chapter&gt;
475&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]476
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]477<p>The first line specifies that it's an XML document and gives useful
478information about its encoding. Then the document is a text format whose
479structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]480to be closed</strong>. XML is pedantic about this. However, if a tag is empty
481(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]482ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note that,
483for example, the image tag has no content (just an attribute) and is closed by
484ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]485
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]486<p>XML can be applied sucessfully to a wide range of uses, from long term
487structured document maintenance (where it follows the steps of SGML) to simple
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]488data encoding mechanisms like configuration file formatting (glade),
489spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
490it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]491
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]492<h2>An overview of libxml architecture</h2>
493
494<p>Libxml is made of multiple components, some of them optionals, and most of
495the block interfaces are public. The main components are:</p>
496<ul>
497 <li>an Input/Output layer</li>
498 <li>FTP and HTTP client layers (optionnal)</li>
499 <li>an Internationalization layer managing the encodings support</li>
500 <li>an URI module</li>
501 <li>the XML parser and its basic SAX interface</li>
502 <li>an HTML parser using the same SAX interface (optionnal)</li>
503 <li>a SAX tree module to build an in-memory DOM representation</li>
504 <li>a tree module to manipulate the DOM representation</li>
505 <li>a validation module using the DOM representation (optionnal)</li>
506 <li>an XPath module for global lookup in a DOM representation
507 (optionnal)</li>
508 <li>a debug module (optionnal)</li>
509</ul>
510
511<p>Graphically this gives the following:</p>
512
513<p><img src="libxml.gif" alt="a graphical view of the various"></p>
514
515<p></p>
516
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]517<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]518
519<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]520returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]521<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]522as the file name, the document type, and a <strong>children</strong> pointer
523which is the root of the document (or more exactly the first child under the
524root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]525chained in double-linked lists of siblings and with children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]526relationship. An xmlNode can also carry properties (a chain of xmlAttr
527structures). An attribute may have a value which is a list of TEXT or
528ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]529
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]530<p>Here is an example (erroneous with respect to the XML spec since there
531should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]532
533<p><img src="structure.gif" alt=" structure.gif "></p>
534
535<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]536called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]537prints them back as parsed. This is useful for detecting errors both in XML
538code and in the XML parser itself. It has an option <strong>--debug</strong>
539which prints the actual in-memory structure of the document, here is the
540result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]541<pre>DOCUMENT
542version=1.0
543standalone=true
544 ELEMENT EXAMPLE
545 ATTRIBUTE prop1
546 TEXT
547 content=gnome is great
548 ATTRIBUTE prop2
549 ENTITY_REF
550 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]551 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]552 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]553 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]554 TEXT
555 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]556 ELEMENT chapter
557 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]558 TEXT
559 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]560 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]561 TEXT
562 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]563 ELEMENT image
564 ATTRIBUTE href
565 TEXT
566 content=linus.gif
567 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]568 TEXT
569 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]570
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]571<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]572
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]573<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]574
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]575<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]576memory. In that case (and if you don't expect to save back the XML document
577loaded 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]578<strong>callback-based interface</strong> to the parser. Before parsing, the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]579application layer registers a customized set of callbacks which are called by
580the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]581
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]582<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]583libxml, see the <a
584href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
585documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]586Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]587
588<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
589program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]590binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]591distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]592testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]593<pre>SAX.setDocumentLocator()
594SAX.startDocument()
595SAX.getEntity(amp)
596SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
597SAX.characters( , 3)
598SAX.startElement(head)
599SAX.characters( , 4)
600SAX.startElement(title)
601SAX.characters(Welcome to Gnome, 16)
602SAX.endElement(title)
603SAX.characters( , 3)
604SAX.endElement(head)
605SAX.characters( , 3)
606SAX.startElement(chapter)
607SAX.characters( , 4)
608SAX.startElement(title)
609SAX.characters(The Linux adventure, 19)
610SAX.endElement(title)
611SAX.characters( , 4)
612SAX.startElement(p)
613SAX.characters(bla bla bla ..., 15)
614SAX.endElement(p)
615SAX.characters( , 4)
616SAX.startElement(image, href='linus.gif')
617SAX.endElement(image)
618SAX.characters( , 4)
619SAX.startElement(p)
620SAX.characters(..., 3)
621SAX.endElement(p)
622SAX.characters( , 3)
623SAX.endElement(chapter)
624SAX.characters( , 1)
625SAX.endElement(EXAMPLE)
626SAX.endDocument()</pre>
627
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]628<p>Most of the other functionalities of libxml are based on the DOM
629tree-building facility, so nearly everything up to the end of this document
630presupposes the use of the standard DOM tree build. Note that the DOM tree
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]631itself is built by a set of registered default callbacks, without internal
632specific interface.</p>
633
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]634<h2><a name="library">The XML library interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]635
636<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]637using the XML library from the C language. It is not intended to be extensive.
638I hope the automatically generated documents will provide the completeness
639required, but as a separate set of documents. The interfaces of the XML
640library are by principle low level, there is nearly zero abstraction. Those
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]641interested in a higher level API should <a href="#DOM">look at DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]642
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]643<p>The <a href="html/gnome-xml-parser.html">parser interfaces for XML</a> are
644separated from the <a href="html/gnome-xml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]645interfaces</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]646
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]647<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]648
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]649<p>Usually, the first thing to do is to read an XML input. The parser accepts
650documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]651defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]652<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]653 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]654 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]655 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]656</dl>
657<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]658 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]659 <dd><p>Parse an XML document contained in a (possibly compressed)
660 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]661 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]662</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]663
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]664<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]665failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]666
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]667<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]668
669<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]670fetched (which is common for GUI based programs) libxml provides a push
671interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]672<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
673 void *user_data,
674 const char *chunk,
675 int size,
676 const char *filename);
677int xmlParseChunk (xmlParserCtxtPtr ctxt,
678 const char *chunk,
679 int size,
680 int terminate);</pre>
681
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]682<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]683<pre> FILE *f;
684
685 f = fopen(filename, "r");
686 if (f != NULL) {
687 int res, size = 1024;
688 char chars[1024];
689 xmlParserCtxtPtr ctxt;
690
691 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]692 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]693 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
694 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]695 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]696 xmlParseChunk(ctxt, chars, res, 0);
697 }
698 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]699 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]700 xmlFreeParserCtxt(ctxt);
701 }
702 }</pre>
703
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]704<p>Also note that the HTML parser embedded into libxml also has a push
705interface; the functions are just prefixed by "html" rather than "xml"</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]706
707<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
708
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]709<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]710memory-hungry, first to load the document in memory, second to build the tree.
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]711Reading a document without building the tree is possible using the SAX
712interfaces (see SAX.h and <a
713href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]714Henstridge's documentation</a>). Note also that the push interface can be
715limited to SAX. Just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]716<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]717
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]718<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]719
720<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]721there is a set of functions dedicated to building new elements. (These are
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]722also 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]723that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]724<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]725 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]726 xmlNodePtr tree, subtree;
727
728 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]729 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
730 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
731 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
732 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]733 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]734 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]735 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
736 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
737 subtree = xmlNewChild(tree, NULL, "image", NULL);
738 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]739
740<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]741
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]742<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]743
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]744<p>Basically by <a href="html/gnome-xml-tree.html">including "tree.h"</a> your
745code has access to the internal structure of all the elements of the tree. The
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]746names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]747<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]748<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]749example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]750<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]751
752<p>points to the title element,</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]753<pre>doc-&gt;children-&gt;children-&gt;next-&gt;child-&gt;child</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]754
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]755<p>points to the text node containing the chapter title "The Linux
756adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]757
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]758<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]759present before the document root, so <code>doc-&gt;children</code> may point
760to an element which is not the document Root Element, a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]761<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]762
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]763<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]764
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]765<p>Functions are provided for reading and writing the document content. Here
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]766is 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]767<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]768 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
769 xmlChar *value);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]770 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node. The
771 value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]772 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]773</dl>
774<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]775 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]776 *name);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]777 <dd><p>This function returns a pointer to the property content. Note that
778 no extra copy is made.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]779 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]780</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]781
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]782<p>Two functions are provided for reading and writing the text associated with
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]783elements:</p>
784<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]785 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]786 *value);</code></dt>
787 <dd><p>This function takes an "external" string and convert it to one text
788 node or possibly to a list of entity and text nodes. All non-predefined
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]789 entity references like &amp;Gnome; will be stored internally as entity
790 nodes, hence the result of the function may not be a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]791 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]792</dl>
793<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]794 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]795 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]796 <dd><p>This function is the inverse of
797 <code>xmlStringGetNodeList()</code>. It generates a new string
798 containing the content of the text and entity nodes. Note the extra
799 argument inLine. If this argument is set to 1, the function will expand
800 entity references. For example, instead of returning the &amp;Gnome;
801 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]802 "GNU Network Object Model Environment"). Set this argument if you want
803 to use the string for non-XML usage like User Interface.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]804 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]805</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]806
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]807<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]808
809<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]810<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]811 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]812 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]813 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]814 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]815</dl>
816<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]817 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]818 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]819 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]820</dl>
821<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]822 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]823 <dd><p>Saves the document to a file. In this case, the compression
824 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]825 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]826</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]827
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]828<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]829
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]830<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]831accesses. The level of compression on saves can be turned on either globally
832or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]833<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]834 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]835 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]836 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]837</dl>
838<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]839 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]840 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]841 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]842</dl>
843<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]844 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]845 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]846 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]847</dl>
848<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]849 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]850 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]851 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]852</dl>
853
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]854<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]855
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]856<p>Entities in principle are similar to simple C macros. An entity defines an
857abbreviation for a given string that you can reuse many times throughout the
858content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]859may occur frequently within a document, or to confine the change needed to a
860document to a restricted area in the internal subset of the document (at the
861beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]862<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]8632 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]8643 &lt;!ENTITY xml "Extensible Markup Language"&gt;
8654 ]&gt;
8665 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]8676 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]8687 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]869
870<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]871it's name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]872are 5 predefined entities in libxml allowing you to escape charaters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]873predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]874<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]875for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]876<strong>&amp;quot;</strong> for the character '"', and
877<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]878
879<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]880substitute an entity's content so that you can see the replacement text in
881your application. Or you may prefer to keep entity references as such in the
882content to be able to save the document back without losing this usually
883precious information (if the user went through the pain of explicitly defining
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]884entities, he may have a a rather negative attitude if you blindly susbtitute
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]885them as saving time). The <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]886href="html/gnome-xml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]887function allows you to check and change the behaviour, which is to not
888substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]889
890<p>Here is the DOM tree built by libxml for the previous document in the
891default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]892<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]893DOCUMENT
894version=1.0
895 ELEMENT EXAMPLE
896 TEXT
897 content=
898 ENTITY_REF
899 INTERNAL_GENERAL_ENTITY xml
900 content=Extensible Markup Language
901 TEXT
902 content=</pre>
903
904<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]905<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]906DOCUMENT
907version=1.0
908 ELEMENT EXAMPLE
909 TEXT
910 content= Extensible Markup Language</pre>
911
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]912<p>So, entities or no entities? Basically, it depends on your use case. I
913suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]914entities in your XML document or data if you are not willing to handle the
915entity references elements in the DOM tree.</p>
916
917<p>Note that at save time libxml enforce the conversion of the predefined
918entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]919transparently replace those with chars (i.e., it will not generate entity
920reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]921finding them in the input).</p>
922
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]923<p><span style="background-color: #FF0000">WARNING</span>: handling entities
924on top of libxml SAX interface is difficult !!! If you plan to use
925non-predefined entities in your documents, then the learning cuvre to handle
926then using the SAX API may be long. If you plan to use complex document, I
927strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]928deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]929
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]930<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]931
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]932<p>The libxml library implements <a
933href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
934recognizing namespace contructs in the input, and does namespace lookup
935automatically when building the DOM tree. A namespace declaration is
936associated with an in-memory structure and all elements or attributes within
937that namespace point to it. Hence testing the namespace is a simple and fast
938equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]939
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]940<p>I suggest that people using libxml use a namespace, and declare it in the
941root element of their document as the default namespace. Then they don't need
942to use the prefix in the content but we will have a basis for future semantic
943refinement and merging of data from different sources. This doesn't augment
944significantly the size of the XML output, but significantly increase its value
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]945in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]946<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
947 &lt;elem1&gt;...&lt;/elem1&gt;
948 &lt;elem2&gt;...&lt;/elem2&gt;
949&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]950
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]951<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]952have to point to any existing resource on the Web. It will bind all the
953element and atributes with that URL. I suggest to use an URL within a domain
954you control, and that the URL should contain some kind of version information
955if possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]956a good namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]957
958<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]959version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]960and if the version information don't match something you know, warn the user
961and 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]962namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
963same as &lt;bar:text&gt; in another document. What really matter is the URI
964associated with the element or the attribute, not the prefix string (which is
965just a shortcut for the full URI). In libxml element and attributes have a
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]966<code>ns</code> field pointing to an xmlNs structure detailing the namespace
967prefix and it's URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]968
969<p>@@Interfaces@@</p>
970
971<p>@@Examples@@</p>
972
973<p>Usually people object using namespace in the case of validation, I object
974this and will make sure that using namespaces won't break validity checking,
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]975so even is you plan to use or currently are using validation I strongly
976suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]977<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]978flexible parsers. Now using namespace to mix and differentiate content coming
979from multiple DTDs will certainly break current validation schemes. I will try
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]980to provide ways to do this, but this may not be portable or standardized.</p>
981
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]982<h2><a name="Validation">Validation, or are you afraid of DTDs ?</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]983
984<p>Well what is validation and what is a DTD ?</p>
985
986<p>Validation is the process of checking a document against a set of
987construction rules, a <strong>DTD</strong> (Document Type Definition) is such
988a set of rules.</p>
989
990<p>The validation process and building DTDs are the two most difficult parts
991of XML life cycle. Briefly a DTD defines all the possibles element to be
992found within your document, what is the formal shape of your document tree (by
993defining the allowed content of an element, either text, a regular expression
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]994for the allowed list of children, or mixed content i.e. both text and
995children). The DTD also defines the allowed attributes for all elements and
996the types of the attributes. For more detailed informations, I suggest to read
997the related parts of the XML specification, the examples found under
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]998gnome-xml/test/valid/dtd and the large amount of books available on XML. The
999dia example in gnome-xml/test/valid should be both simple and complete enough
1000to allow you to build your own.</p>
1001
1002<p>A word of warning, building a good DTD which will fit your needs of your
1003application in the long-term is far from trivial, however the extra level of
1004quality it can insure is well worth the price for some sets of applications or
1005if you already have already a DTD defined for your application field.</p>
1006
1007<p>The validation is not completely finished but in a (very IMHO) usable
1008state. Until a real validation interface is defined the way to do it is to
1009define and set the <strong>xmlDoValidityCheckingDefaultValue</strong> external
1010variable to 1, this will of course be changed at some point:</p>
1011
1012<p>extern int xmlDoValidityCheckingDefaultValue;</p>
1013
1014<p>...</p>
1015
1016<p>xmlDoValidityCheckingDefaultValue = 1;</p>
1017
1018<p></p>
1019
1020<p>To handle external entities, use the function
1021<strong>xmlSetExternalEntityLoader</strong>(xmlExternalEntityLoader f); to
1022link in you HTTP/FTP/Entities database library to the standard libxml
1023core.</p>
1024
1025<p>@@interfaces@@</p>
1026
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1027<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1028
1029<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]1030Model</em> this is an API for accessing XML or HTML structured documents.
1031Native 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]1032be based on gnome-xml. This will be a far cleaner interface to manipulate XML
Daniel Veillardc08a2c61999-09-08 21:35:25 +0000[diff] [blame]1033files within Gnome since it won't expose the internal structure. DOM defines a
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1034set of IDL (or Java) interfaces allowing to traverse and manipulate a
1035document. The DOM library will allow accessing and modifying "live" documents
1036presents on other programs like this:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1037
1038<p><img src="DOM.gif" alt=" DOM.gif "></p>
1039
1040<p>This should help greatly doing things like modifying a gnumeric spreadsheet
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1041embedded in a GWP document for example.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1042
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1043<p>The current DOM implementation on top of libxml is the <a
1044href="http://cvs.gnome.org/lxr/source/gdome/">gdome Gnome module</a>, this is
1045a full DOM interface, thanks to <a href="mailto:raph@levien.com">Raph
1046Levien</a>.</p>
1047
1048<p>The gnome-dom module in the Gnome CVS base is obsolete</p>
1049
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1050<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1051
1052<p>Here is a real size example, where the actual content of the application
1053data 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]1054a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1055storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
1056base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1057<pre>&lt;?xml version="1.0"?&gt;
1058&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
1059 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1060
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1061 &lt;gjob:Job&gt;
1062 &lt;gjob:Project ID="3"/&gt;
1063 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
1064 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1065
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1066 &lt;gjob:Update&gt;
1067 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
1068 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
1069 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
1070 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1071
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1072 &lt;gjob:Developers&gt;
1073 &lt;gjob:Developer&gt;
1074 &lt;/gjob:Developer&gt;
1075 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1076
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1077 &lt;gjob:Contact&gt;
1078 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
1079 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
1080 &lt;gjob:Company&gt;
1081 &lt;/gjob:Company&gt;
1082 &lt;gjob:Organisation&gt;
1083 &lt;/gjob:Organisation&gt;
1084 &lt;gjob:Webpage&gt;
1085 &lt;/gjob:Webpage&gt;
1086 &lt;gjob:Snailmail&gt;
1087 &lt;/gjob:Snailmail&gt;
1088 &lt;gjob:Phone&gt;
1089 &lt;/gjob:Phone&gt;
1090 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1091
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1092 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1093 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1094 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1095
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1096 &lt;gjob:Skills&gt;
1097 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1098
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1099 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1100 A GNOME based system that will allow a superuser to configure
1101 compressed and uncompressed files and/or file systems to be backed
1102 up with a supported media in the system. This should be able to
1103 perform via find commands generating a list of files that are passed
1104 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
1105 or via operations performed on the filesystem itself. Email
1106 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1107 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1108
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1109 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1110
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1111 &lt;/gjob:Jobs&gt;
1112&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1113
1114<p>While loading the XML file into an internal DOM tree is a matter of calling
1115only a couple of functions, browsing the tree to gather the informations and
1116generate the internals structures is harder, and more error prone.</p>
1117
1118<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1119structure. For example, the ordering of the attributes is not significant,
1120Cthe 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]1121be dependent of the orders of the children of a given node, unless it really
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1122makes things harder. Here is some code to parse the informations for a
1123person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1124<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1125 * A person record
1126 */
1127typedef struct person {
1128 char *name;
1129 char *email;
1130 char *company;
1131 char *organisation;
1132 char *smail;
1133 char *webPage;
1134 char *phone;
1135} person, *personPtr;
1136
1137/*
1138 * And the code needed to parse it
1139 */
1140personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1141 personPtr ret = NULL;
1142
1143DEBUG("parsePerson\n");
1144 /*
1145 * allocate the struct
1146 */
1147 ret = (personPtr) malloc(sizeof(person));
1148 if (ret == NULL) {
1149 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1150 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1151 }
1152 memset(ret, 0, sizeof(person));
1153
1154 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1155 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1156 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1157 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
1158 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1159 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
1160 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1161 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1162 }
1163
1164 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1165}</pre>
1166
1167<p>Here is a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1168<ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1169 <li>Usually a recursive parsing style is the more convenient one, XML data
1170 being by nature subject to repetitive constructs and usualy exibit highly
1171 stuctured patterns.</li>
1172 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>, i.e.
1173 the pointer to the global XML document and the namespace reserved to the
1174 application. Document wide information are needed for example to decode
1175 entities and it's a good coding practice to define a namespace for your
1176 application set of data and test that the element and attributes you're
1177 analyzing actually pertains to your application space. This is done by a
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1178 simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1179 <li>To retrieve text and attributes value, it is suggested to use the
1180 function <em>xmlNodeListGetString</em> to gather all the text and entity
1181 reference nodes generated by the DOM output and produce an single text
1182 string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1183</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1184
1185<p>Here is another piece of code used to parse another level of the
1186structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1187<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1188/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1189 * a Description for a Job
1190 */
1191typedef struct job {
1192 char *projectID;
1193 char *application;
1194 char *category;
1195 personPtr contact;
1196 int nbDevelopers;
1197 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
1198} job, *jobPtr;
1199
1200/*
1201 * And the code needed to parse it
1202 */
1203jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1204 jobPtr ret = NULL;
1205
1206DEBUG("parseJob\n");
1207 /*
1208 * allocate the struct
1209 */
1210 ret = (jobPtr) malloc(sizeof(job));
1211 if (ret == NULL) {
1212 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1213 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1214 }
1215 memset(ret, 0, sizeof(job));
1216
1217 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1218 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1219 while (cur != NULL) {
1220
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1221 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
1222 ret-&gt;projectID = xmlGetProp(cur, "ID");
1223 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1224 fprintf(stderr, "Project has no ID\n");
1225 }
1226 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1227 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
1228 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1229 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
1230 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1231 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
1232 ret-&gt;contact = parsePerson(doc, ns, cur);
1233 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1234 }
1235
1236 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1237}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1238
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1239<p>One can notice that once used to it, writing this kind of code is quite
1240simple, but boring. Ultimately, it could be possble to write stubbers taking
1241either C data structure definitions, a set of XML examples or an XML DTD and
1242produce the code needed to import and export the content between C data and
1243XML storage. This is left as an exercise to the reader :-)</p>
1244
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]1245<p>Feel free to use <a href="example/gjobread.c">the code for the full C
1246parsing example</a> as a template, it is also available with Makefile in the
1247Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1248
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1249<h2><a name="Contributi">Contributions</a></h2>
1250<ul>
1251 <li><a href="mailto:ari@btigate.com">Ari Johnson</a> provides a C++ wrapper
1252 for libxml:
1253 <p>Website: <a
1254 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
1255 <p>Download: <a
1256 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
1257 </li>
1258 <li><a href="mailto:doolin@cs.utk.edu">David Doolin</a> provides a
1259 precompiled Windows version
1260 <p><a
1261 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
1262 </li>
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1263 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> provided <a
1264 href="libxml-doc.el">an emacs module</a> to lookup libxml functions
1265 documentation</li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1266 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
1267 href="http://xmlsoft.org/messages/0488.html">man pages</a> (not yet
1268 integrated in the distribution)</li>
1269</ul>
1270
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1271<p></p>
1272
1273<p><a href="mailto:Daniel.Veillard@w3.org">Daniel Veillard</a></p>
1274
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]1275<p>$Id: xml.html,v 1.50 2000/08/29 23:40:42 veillard Exp $</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1276</body>
1277</html>