Gitiles
Code Review Sign In
gerrit-public.fairphone.software / platform / external / libxml2 / f121ab729552eb7059b2e148c3ef9d078b0fd736 / . / doc / xml.html
blob: e747b1938a8f804898d5a015f3806504a4c173ab [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 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 Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]45 <li><a href="#Contributi">Contribution</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]46</ul>
47
48<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]49
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]50<p>This document describes libxml, the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]51href="http://www.w3.org/XML/">XML</a> C library developped for the <a
52href="http://www.gnome.org/">Gnome</a> project. <a
53href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
54structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]55
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]56<p>Here are some key points about libxml:</p>
57<ul>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]58 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]59 sticking closely to ANSI C for easy embedding.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]60 <li>The internal document repesentation is as close as possible to the <a
61 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
62 <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]63 like interface</a>; the interface is designed to be compatible with <a
64 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]65 <li>Libxml now includes a nearly complete <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]66 href="http://www.w3.org/TR/xpath">XPath</a> implementation.</li>
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]67 <li>Libxml exports Push and Pull type parser interfaces for both XML and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]68 HTML.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]69 <li>This library is released both under the <a
70 href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C
71 IPR</a> and the GNU LGPL. Use either at your convenience, basically this
72 should make everybody happy, if not, drop me a mail.</li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]73 <li>There is <a href="upgrade.html">a first set of instructions</a>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]74 concerning upgrade from libxml-1.x to libxml-2.x</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]75</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]76
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]77<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]78
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]79<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]80<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]81 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]82 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]83 documentation</a> automatically extracted from code comments (using <a
84 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
85 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000[diff] [blame]86 <li>Look at the documentation about <a href="encoding.html">libxml
87 internationalization support</a></li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]88 <li>This page provides a global overview and <a href="#real">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]89 examples</a> on how to use libxml.</li>
90 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
91 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
92 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]93 <li>George Lebl wrote <a
94 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]95 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]96 <li>It is also a good idea to check to <a href="mailto:raph@levien.com">Raph
97 Levien</a> <a href="http://levien.com/gnome/">web site</a> since he is
98 building the <a href="http://levien.com/gnome/gdome.html">DOM interface
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]99 gdome</a> on top of libxml result tree and an implementation of <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]100 href="http://www.w3.org/Graphics/SVG/">SVG</a> called <a
101 href="http://www.levien.com/svg/">gill</a>. Check his <a
102 href="http://www.levien.com/gnome/domination.html">DOMination
103 paper</a>.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]104 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
105 file</a></li>
106 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
107 starting a new project using libxml you should really use the 2.x
108 version.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]109 <li>And don't forget to look at the <a href="/messages/">mailing-list
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]110 archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]111</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]112
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]113<h3>Reporting bugs and getting help</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]114
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]115<p>Well, bugs or missing features are always possible, and I will make a point
116of 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]117href="http://bugs.gnome.org/db/pa/lgnome-xml.html">use the Gnome bug tracking
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]118database</a>. I look at reports there regularly and it's good to have a
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]119reminder when a bug is still open. Check the <a
120href="http://bugs.gnome.org/Reporting.html">instructions on reporting bugs</a>
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]121and be sure to specify that the bug is for the package gnome-xml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]122
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]123<p>There is also a mailing-list <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame^]124href="mailto:xml@rpmfind.net">xml@rpmfind.net</a> for libxml, with an <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]125href="http://xmlsoft.org/messages">on-line archive</a>. To subscribe to this
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]126majordomo based list, send a mail message to <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame^]127href="mailto:majordomo@rpmfind.net">majordomo@rpmfind.net</a> with "subscribe
128xml" in the <strong>content</strong> of the message.</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]129
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]130<p>Alternatively, you can just send the bug to the <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame^]131href="mailto:xml@rpmfind.net">xml@rpmfind.net</a> list, if it's really libxml
132related I will approve it..</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]133
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]134<p>Of course, bugs reports with a suggested patch for fixing them will
135probably be processed faster.</p>
136
137<p>If you're looking for help, a quick look at <a
138href="http://xmlsoft.org/messages/#407">the list archive</a> may actually
139provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]140questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]141documentantion</a> is not as polished as I would like (i need to learn more
142about Docbook), but it's a good starting point.</p>
143
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]144<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]145
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]146<p>The latest versions of libxml can be found on <a
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]147href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]148href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]149as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]150archive</a> or <a
151href="ftp://ftp.gnome.org/pub/GNOME/contrib/redhat/SRPMS/">RPM packages</a>.
152(NOTE that you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]153href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
154href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]155packages installed to compile applications using libxml.)</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]156
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]157<p><a name="Snapshot">Snapshot:</a></p>
158<ul>
159 <li>Code from the W3C cvs base libxml <a
160 href="ftp://rpmfind.net/pub/libxml/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
161 <li>Docs, content of the web site, the list archive included <a
162 href="ftp://rpmfind.net/pub/libxml/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
163</ul>
164
165<p><a name="Contribs">Contribs:</a></p>
166
167<p>I do accept external contributions, especially if compiling on another
168platform, get in touch with me to upload the package. I will keep them in the
169<a href="ftp://rpmfind.net/pub/libxml/contribs/">contrib directory</a></p>
170
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]171<p>Libxml is also available from 2 CVS bases:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]172<ul>
173 <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]174 available read-only using the CVS pserver authentification (I tend to use
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]175 this base for my own development, so it's updated more regularly, but the
176 content may not be as stable):</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]177 <pre>CVSROOT=:pserver:anonymous@dev.w3.org:/sources/public
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]178 password: anonymous
179 module: XML</pre>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]180 </li>
181 <li><p>The <a
182 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]183 CVS base</a>. Check the <a
184 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a> page;
185 the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]186 </li>
187</ul>
188
189<h2><a name="News">News</a></h2>
190
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]191<h3>CVS only : check the <a
192href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
193for really accurate description</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]194<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]195 <li>working on HTML and XML links recognition layers, get in touch with me
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]196 if you want to test those.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]197</ul>
198
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]199<h2>2.2.2: August 12 2000</h2>
200<ul>
201 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]202 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]203</ul>
204
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]205<h2>2.2.1: July 21 2000</h2>
206<ul>
207 <li>a purely bug fixes release</li>
208 <li>fixed an encoding support problem when parsing from a memory block</li>
209 <li>fixed a DOCTYPE parsing problem</li>
210 <li>removed a bug in the function allowing to override the memory allocation
211 routines</li>
212</ul>
213
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]214<h2>2.2.0: July 14 2000</h2>
215<ul>
216 <li>applied a lot of portability fixes</li>
217 <li>better encoding support/cleanup and saving (content is now always
218 encoded in UTF-8)</li>
219 <li>the HTML parser now correctly handles encodings</li>
220 <li>added xmlHasProp()</li>
221 <li>fixed a serious problem with &amp;#38;</li>
222 <li>propagated the fix to FTP client</li>
223 <li>cleanup, bugfixes, etc ...</li>
224 <li>Added a page about <a href="encoding.html">libxml Internationalization
225 support</a></li>
226</ul>
227
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]228<h3>1.8.9: July 9 2000</h3>
229<ul>
230 <li>fixed the spec the RPMs should be better</li>
231 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
232 rpmfind users problem</li>
233</ul>
234
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]235<h3>2.1.1: July 1 2000</h3>
236<ul>
237 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
238 <li>improvements on the HTML parser</li>
239</ul>
240
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]241<h3>2.1.0 and 1.8.8: June 29 2000</h3>
242<ul>
243 <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to
244 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
245 about &amp;#38; charref parsing</li>
246 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
247 also contains numerous fixes and enhancements:
248 <ul>
249 <li>added xmlStopParser() to stop parsing</li>
250 <li>improved a lot parsing speed when there is large CDATA blocs</li>
251 <li>includes XPath patches provided by Picdar Technology</li>
252 <li>tried to fix as much as possible DtD validation and namespace
253 related problems</li>
254 <li>output to a given encoding has been added/tested</li>
255 <li>lot of various fixes</li>
256 </ul>
257 </li>
258</ul>
259
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]260<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]261<ul>
262 <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]263 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally
264 scheduled for Apr 3 the relase occured only on Apr 12 due to massive
265 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]266 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]267 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]268 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]269 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]270 <pre>#include "xxx.h"</pre>
271 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]272 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
273 <li>the memory allocation routines used by libxml can now be overloaded
274 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]275 <li>The previously CVS only tool tester has been renamed
276 <strong>xmllint</strong> and is now installed as part of the libxml2
277 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]278 <li>The I/O interface has been revamped. There is now ways to plug in
279 specific I/O modules, either at the URI scheme detection level using
280 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
281 parser context using xmlCreateIOParserCtxt()</li>
282 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
283 number of the libxml module in use</li>
284 <li>a number of optional features of libxml can now be excluded at configure
285 time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]286</ul>
287
288<h3>2.0.0beta: Mar 14 2000</h3>
289<ul>
290 <li>This is a first Beta release of libxml version 2</li>
291 <li>It's available only from<a href="ftp://rpmfind.net/pub/libxml/">
292 rpmfind.net FTP</a>, it's packaged as libxml2-2.0.0beta and available as
293 tar and RPMs</li>
294 <li>This version is now the head in the Gnome CVS base, the old one is
295 available under the tag LIB_XML_1_X</li>
296 <li>This includes a very large set of changes. Froma programmatic point of
297 view applications should not have to be modified too much, check the <a
298 href="upgrade.html">upgrade page</a></li>
299 <li>Some interfaces may changes (especially a bit about encoding).</li>
300 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]301 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]302 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
303 handled now</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]304 <li>Better handling of entities, especially well formedness checking and
305 proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]306 <li>DTD conditional sections</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]307 <li>Validation now correcly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]308 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
309 structures to accomodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]310 </ul>
311 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]312 <li>Serious progress were made toward compliance, <a
313 href="conf/result.html">here are the result of the test</a> against the
314 OASIS testsuite (except the japanese tests since I don't support that
315 encoding yet). This URL is rebuilt every couple of hours using the CVS
316 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]317</ul>
318
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]319<h3>1.8.7: Mar 6 2000</h3>
320<ul>
321 <li>This is a bug fix release:</li>
322 <li>It is possible to disable the ignorable blanks heuristic used by
323 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
324 that for adherence to XML spec, this behaviour will be disabled by default
325 in 2.x . The same function will allow to keep compatibility for old
326 code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]327 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
328 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]329 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
330 compilation on some platforms has been fixed</li>
331 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
332 URIs</li>
333</ul>
334
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]335<h3>1.8.6: Jan 31 2000</h3>
336<ul>
337 <li>added a nanoFTP transport module, debugged until the new version of <a
338 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
339 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]340</ul>
341
342<h3>1.8.5: Jan 21 2000</h3>
343<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]344 <li>adding APIs to parse a well balanced chunk of XML (production <a
345 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the XML
346 spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]347 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]348 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
349 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]350 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
351 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]352</ul>
353
354<h3>1.8.4: Jan 13 2000</h3>
355<ul>
356 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
357 <li>all exit() call should have been removed from libxml</li>
358 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
359 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]360</ul>
361
362<h3>1.8.3: Jan 5 2000</h3>
363<ul>
364 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]365 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillarddbfd6411999-12-28 16:35:14 +0000[diff] [blame]366 <li>lots of bug fixes and improvement added over XMas hollidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]367 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]368 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
369 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]370 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]371 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]372 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]373</ul>
374
375<h3>1.8.2: Dec 21 1999</h3>
376<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]377 <li>I got another problem with includes and C++, I hope this issue is fixed
378 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]379 <li>Added a few tree modification functions: xmlReplaceNode,
380 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
381 xmlDocSetRootElement</li>
382 <li>Tried to improve the HTML output with help from <a
383 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]384</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]385
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]386<h3>1.8.1: Dec 18 1999</h3>
387<ul>
388 <li>various patches to avoid troubles when using libxml with C++ compilers
389 the "namespace" keyword and C escaping in include files</li>
390 <li>a problem in one of the core macros IS_CHAR was corrected</li>
391 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
392 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]393 <li>fixed a posteriori validation (validation after parsing, or by using a
394 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]395 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]396</ul>
397
398<h3>1.8.0: Dec 12 1999</h3>
399<ul>
400 <li>cleanup, especially memory wise</li>
401 <li>the parser should be more reliable, especially the HTML one, it should
402 not crash, whatever the input !</li>
403 <li>Integrated various patches, especially a speedup improvement for large
404 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
405 configure with --with-buffers to enable them.</li>
406 <li>attribute normalization, oops should have been added long ago !</li>
407 <li>attributes defaulted from Dtds should be available, xmlSetProp() now
408 does entities escapting by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]409</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]410
411<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]412<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]413 <li>Lots of HTML improvement</li>
414 <li>Fixed some errors when saving both XML and HTML</li>
415 <li>More examples, the regression tests should now look clean</li>
416 <li>Fixed a bug with contiguous charref</li>
417</ul>
418
419<h3>1.7.3: Sep 29 1999</h3>
420<ul>
421 <li>portability problems fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]422 <li>snprintf was used unconditionnally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]423 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]424</ul>
425
426<h3>1.7.1: Sep 24 1999</h3>
427<ul>
428 <li>The basic type for strings manipulated by libxml has been renamed in
429 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
430 is that CHAR was conflicting with a predefined type on Windows. However on
431 non WIN32 environment, compatibility is provided by the way of a
432 <strong>#define </strong>.</li>
433 <li>Changed another error : the use of a structure field called errno, and
434 leading to troubles on platforms where it's a macro</li>
435</ul>
436
437<h3>1.7.0: sep 23 1999</h3>
438<ul>
439 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]440 href="html/gnome-xml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]441 <li>Added an errno to report errors by another mean than a simple printf
442 like callback</li>
443 <li>Finished ID/IDREF support and checking when validation</li>
444 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]445 href="html/gnome-xml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]446 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
447 implementation</li>
448 <li>Added an HTML parser front-end</li>
449</ul>
450
451<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]452
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]453<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]454markup-based structured documents. Here is <a name="example">an example XML
455document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]456<pre>&lt;?xml version="1.0"?&gt;
457&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
458 &lt;head&gt;
459 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
460 &lt;/head&gt;
461 &lt;chapter&gt;
462 &lt;title&gt;The Linux adventure&lt;/title&gt;
463 &lt;p&gt;bla bla bla ...&lt;/p&gt;
464 &lt;image href="linus.gif"/&gt;
465 &lt;p&gt;...&lt;/p&gt;
466 &lt;/chapter&gt;
467&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]468
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]469<p>The first line specifies that it's an XML document and gives useful
470information about its encoding. Then the document is a text format whose
471structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]472to be closed</strong>. XML is pedantic about this. However, if a tag is empty
473(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]474ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note that,
475for example, the image tag has no content (just an attribute) and is closed by
476ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]477
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]478<p>XML can be applied sucessfully to a wide range of uses, from long term
479structured document maintenance (where it follows the steps of SGML) to simple
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]480data encoding mechanisms like configuration file formatting (glade),
481spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
482it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]483
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]484<h2>An overview of libxml architecture</h2>
485
486<p>Libxml is made of multiple components, some of them optionals, and most of
487the block interfaces are public. The main components are:</p>
488<ul>
489 <li>an Input/Output layer</li>
490 <li>FTP and HTTP client layers (optionnal)</li>
491 <li>an Internationalization layer managing the encodings support</li>
492 <li>an URI module</li>
493 <li>the XML parser and its basic SAX interface</li>
494 <li>an HTML parser using the same SAX interface (optionnal)</li>
495 <li>a SAX tree module to build an in-memory DOM representation</li>
496 <li>a tree module to manipulate the DOM representation</li>
497 <li>a validation module using the DOM representation (optionnal)</li>
498 <li>an XPath module for global lookup in a DOM representation
499 (optionnal)</li>
500 <li>a debug module (optionnal)</li>
501</ul>
502
503<p>Graphically this gives the following:</p>
504
505<p><img src="libxml.gif" alt="a graphical view of the various"></p>
506
507<p></p>
508
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]509<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]510
511<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]512returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]513<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]514as the file name, the document type, and a <strong>children</strong> pointer
515which is the root of the document (or more exactly the first child under the
516root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]517chained in double-linked lists of siblings and with children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]518relationship. An xmlNode can also carry properties (a chain of xmlAttr
519structures). An attribute may have a value which is a list of TEXT or
520ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]521
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]522<p>Here is an example (erroneous with respect to the XML spec since there
523should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]524
525<p><img src="structure.gif" alt=" structure.gif "></p>
526
527<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]528called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]529prints them back as parsed. This is useful for detecting errors both in XML
530code and in the XML parser itself. It has an option <strong>--debug</strong>
531which prints the actual in-memory structure of the document, here is the
532result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]533<pre>DOCUMENT
534version=1.0
535standalone=true
536 ELEMENT EXAMPLE
537 ATTRIBUTE prop1
538 TEXT
539 content=gnome is great
540 ATTRIBUTE prop2
541 ENTITY_REF
542 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]543 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]544 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]545 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]546 TEXT
547 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]548 ELEMENT chapter
549 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]550 TEXT
551 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]552 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]553 TEXT
554 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]555 ELEMENT image
556 ATTRIBUTE href
557 TEXT
558 content=linus.gif
559 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]560 TEXT
561 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]562
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]563<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]564
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]565<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]566
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]567<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]568memory. In that case (and if you don't expect to save back the XML document
569loaded 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]570<strong>callback-based interface</strong> to the parser. Before parsing, the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]571application layer registers a customized set of callbacks which are called by
572the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]573
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]574<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]575libxml, see the <a
576href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
577documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]578Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]579
580<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
581program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]582binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]583distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]584testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]585<pre>SAX.setDocumentLocator()
586SAX.startDocument()
587SAX.getEntity(amp)
588SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
589SAX.characters( , 3)
590SAX.startElement(head)
591SAX.characters( , 4)
592SAX.startElement(title)
593SAX.characters(Welcome to Gnome, 16)
594SAX.endElement(title)
595SAX.characters( , 3)
596SAX.endElement(head)
597SAX.characters( , 3)
598SAX.startElement(chapter)
599SAX.characters( , 4)
600SAX.startElement(title)
601SAX.characters(The Linux adventure, 19)
602SAX.endElement(title)
603SAX.characters( , 4)
604SAX.startElement(p)
605SAX.characters(bla bla bla ..., 15)
606SAX.endElement(p)
607SAX.characters( , 4)
608SAX.startElement(image, href='linus.gif')
609SAX.endElement(image)
610SAX.characters( , 4)
611SAX.startElement(p)
612SAX.characters(..., 3)
613SAX.endElement(p)
614SAX.characters( , 3)
615SAX.endElement(chapter)
616SAX.characters( , 1)
617SAX.endElement(EXAMPLE)
618SAX.endDocument()</pre>
619
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]620<p>Most of the other functionalities of libxml are based on the DOM
621tree-building facility, so nearly everything up to the end of this document
622presupposes the use of the standard DOM tree build. Note that the DOM tree
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]623itself is built by a set of registered default callbacks, without internal
624specific interface.</p>
625
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]626<h2><a name="library">The XML library interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]627
628<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]629using the XML library from the C language. It is not intended to be extensive.
630I hope the automatically generated documents will provide the completeness
631required, but as a separate set of documents. The interfaces of the XML
632library are by principle low level, there is nearly zero abstraction. Those
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]633interested in a higher level API should <a href="#DOM">look at DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]634
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]635<p>The <a href="html/gnome-xml-parser.html">parser interfaces for XML</a> are
636separated from the <a href="html/gnome-xml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]637interfaces</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]638
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]639<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]640
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]641<p>Usually, the first thing to do is to read an XML input. The parser accepts
642documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]643defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]644<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]645 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]646 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]647 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]648</dl>
649<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]650 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]651 <dd><p>Parse an XML document contained in a (possibly compressed)
652 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]653 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]654</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]655
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]656<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]657failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]658
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]659<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]660
661<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]662fetched (which is common for GUI based programs) libxml provides a push
663interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]664<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
665 void *user_data,
666 const char *chunk,
667 int size,
668 const char *filename);
669int xmlParseChunk (xmlParserCtxtPtr ctxt,
670 const char *chunk,
671 int size,
672 int terminate);</pre>
673
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]674<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]675<pre> FILE *f;
676
677 f = fopen(filename, "r");
678 if (f != NULL) {
679 int res, size = 1024;
680 char chars[1024];
681 xmlParserCtxtPtr ctxt;
682
683 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]684 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]685 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
686 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]687 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]688 xmlParseChunk(ctxt, chars, res, 0);
689 }
690 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]691 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]692 xmlFreeParserCtxt(ctxt);
693 }
694 }</pre>
695
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]696<p>Also note that the HTML parser embedded into libxml also has a push
697interface; the functions are just prefixed by "html" rather than "xml"</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]698
699<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
700
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]701<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]702memory-hungry, first to load the document in memory, second to build the tree.
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]703Reading a document without building the tree is possible using the SAX
704interfaces (see SAX.h and <a
705href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]706Henstridge's documentation</a>). Note also that the push interface can be
707limited to SAX. Just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]708<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]709
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]710<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]711
712<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]713there is a set of functions dedicated to building new elements. (These are
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]714also 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]715that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]716<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]717 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]718 xmlNodePtr tree, subtree;
719
720 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]721 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
722 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
723 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
724 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]725 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]726 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]727 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
728 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
729 subtree = xmlNewChild(tree, NULL, "image", NULL);
730 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]731
732<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]733
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]734<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]735
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]736<p>Basically by <a href="html/gnome-xml-tree.html">including "tree.h"</a> your
737code has access to the internal structure of all the elements of the tree. The
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]738names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]739<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]740<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]741example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]742<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]743
744<p>points to the title element,</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]745<pre>doc-&gt;children-&gt;children-&gt;next-&gt;child-&gt;child</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]746
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]747<p>points to the text node containing the chapter title "The Linux
748adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]749
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]750<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]751present before the document root, so <code>doc-&gt;children</code> may point
752to an element which is not the document Root Element, a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]753<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]754
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]755<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]756
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]757<p>Functions are provided for reading and writing the document content. Here
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]758is 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]759<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]760 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
761 xmlChar *value);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]762 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node. The
763 value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]764 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]765</dl>
766<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]767 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]768 *name);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]769 <dd><p>This function returns a pointer to the property content. Note that
770 no extra copy is made.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]771 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]772</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]773
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]774<p>Two functions are provided for reading and writing the text associated with
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]775elements:</p>
776<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]777 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]778 *value);</code></dt>
779 <dd><p>This function takes an "external" string and convert it to one text
780 node or possibly to a list of entity and text nodes. All non-predefined
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]781 entity references like &amp;Gnome; will be stored internally as entity
782 nodes, hence the result of the function may not be a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]783 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]784</dl>
785<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]786 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]787 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]788 <dd><p>This function is the inverse of
789 <code>xmlStringGetNodeList()</code>. It generates a new string
790 containing the content of the text and entity nodes. Note the extra
791 argument inLine. If this argument is set to 1, the function will expand
792 entity references. For example, instead of returning the &amp;Gnome;
793 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]794 "GNU Network Object Model Environment"). Set this argument if you want
795 to use the string for non-XML usage like User Interface.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]796 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]797</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]798
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]799<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]800
801<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]802<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]803 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]804 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]805 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]806 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]807</dl>
808<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]809 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]810 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]811 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]812</dl>
813<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]814 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]815 <dd><p>Saves the document to a file. In this case, the compression
816 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]817 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]818</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]819
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]820<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]821
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]822<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]823accesses. The level of compression on saves can be turned on either globally
824or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]825<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]826 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]827 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]828 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]829</dl>
830<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]831 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]832 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]833 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]834</dl>
835<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]836 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]837 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]838 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]839</dl>
840<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]841 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]842 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]843 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]844</dl>
845
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]846<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]847
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]848<p>Entities in principle are similar to simple C macros. An entity defines an
849abbreviation for a given string that you can reuse many times throughout the
850content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]851may occur frequently within a document, or to confine the change needed to a
852document to a restricted area in the internal subset of the document (at the
853beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]854<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]8552 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]8563 &lt;!ENTITY xml "Extensible Markup Language"&gt;
8574 ]&gt;
8585 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]8596 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]8607 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]861
862<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]863it's name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]864are 5 predefined entities in libxml allowing you to escape charaters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]865predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]866<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]867for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]868<strong>&amp;quot;</strong> for the character '"', and
869<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]870
871<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]872substitute an entity's content so that you can see the replacement text in
873your application. Or you may prefer to keep entity references as such in the
874content to be able to save the document back without losing this usually
875precious information (if the user went through the pain of explicitly defining
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]876entities, he may have a a rather negative attitude if you blindly susbtitute
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]877them as saving time). The <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]878href="html/gnome-xml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]879function allows you to check and change the behaviour, which is to not
880substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]881
882<p>Here is the DOM tree built by libxml for the previous document in the
883default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]884<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]885DOCUMENT
886version=1.0
887 ELEMENT EXAMPLE
888 TEXT
889 content=
890 ENTITY_REF
891 INTERNAL_GENERAL_ENTITY xml
892 content=Extensible Markup Language
893 TEXT
894 content=</pre>
895
896<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]897<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]898DOCUMENT
899version=1.0
900 ELEMENT EXAMPLE
901 TEXT
902 content= Extensible Markup Language</pre>
903
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]904<p>So, entities or no entities? Basically, it depends on your use case. I
905suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]906entities in your XML document or data if you are not willing to handle the
907entity references elements in the DOM tree.</p>
908
909<p>Note that at save time libxml enforce the conversion of the predefined
910entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]911transparently replace those with chars (i.e., it will not generate entity
912reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]913finding them in the input).</p>
914
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]915<p><span style="background-color: #FF0000">WARNING</span>: handling entities
916on top of libxml SAX interface is difficult !!! If you plan to use
917non-predefined entities in your documents, then the learning cuvre to handle
918then using the SAX API may be long. If you plan to use complex document, I
919strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]920deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]921
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]922<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]923
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]924<p>The libxml library implements <a
925href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
926recognizing namespace contructs in the input, and does namespace lookup
927automatically when building the DOM tree. A namespace declaration is
928associated with an in-memory structure and all elements or attributes within
929that namespace point to it. Hence testing the namespace is a simple and fast
930equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]931
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]932<p>I suggest that people using libxml use a namespace, and declare it in the
933root element of their document as the default namespace. Then they don't need
934to use the prefix in the content but we will have a basis for future semantic
935refinement and merging of data from different sources. This doesn't augment
936significantly the size of the XML output, but significantly increase its value
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]937in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]938<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
939 &lt;elem1&gt;...&lt;/elem1&gt;
940 &lt;elem2&gt;...&lt;/elem2&gt;
941&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]942
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]943<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]944have to point to any existing resource on the Web. It will bind all the
945element and atributes with that URL. I suggest to use an URL within a domain
946you control, and that the URL should contain some kind of version information
947if possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]948a good namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]949
950<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]951version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]952and if the version information don't match something you know, warn the user
953and 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]954namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
955same as &lt;bar:text&gt; in another document. What really matter is the URI
956associated with the element or the attribute, not the prefix string (which is
957just a shortcut for the full URI). In libxml element and attributes have a
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]958<code>ns</code> field pointing to an xmlNs structure detailing the namespace
959prefix and it's URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]960
961<p>@@Interfaces@@</p>
962
963<p>@@Examples@@</p>
964
965<p>Usually people object using namespace in the case of validation, I object
966this and will make sure that using namespaces won't break validity checking,
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]967so even is you plan to use or currently are using validation I strongly
968suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]969<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]970flexible parsers. Now using namespace to mix and differentiate content coming
971from multiple DTDs will certainly break current validation schemes. I will try
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]972to provide ways to do this, but this may not be portable or standardized.</p>
973
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]974<h2><a name="Validation">Validation, or are you afraid of DTDs ?</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]975
976<p>Well what is validation and what is a DTD ?</p>
977
978<p>Validation is the process of checking a document against a set of
979construction rules, a <strong>DTD</strong> (Document Type Definition) is such
980a set of rules.</p>
981
982<p>The validation process and building DTDs are the two most difficult parts
983of XML life cycle. Briefly a DTD defines all the possibles element to be
984found within your document, what is the formal shape of your document tree (by
985defining the allowed content of an element, either text, a regular expression
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]986for the allowed list of children, or mixed content i.e. both text and
987children). The DTD also defines the allowed attributes for all elements and
988the types of the attributes. For more detailed informations, I suggest to read
989the related parts of the XML specification, the examples found under
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]990gnome-xml/test/valid/dtd and the large amount of books available on XML. The
991dia example in gnome-xml/test/valid should be both simple and complete enough
992to allow you to build your own.</p>
993
994<p>A word of warning, building a good DTD which will fit your needs of your
995application in the long-term is far from trivial, however the extra level of
996quality it can insure is well worth the price for some sets of applications or
997if you already have already a DTD defined for your application field.</p>
998
999<p>The validation is not completely finished but in a (very IMHO) usable
1000state. Until a real validation interface is defined the way to do it is to
1001define and set the <strong>xmlDoValidityCheckingDefaultValue</strong> external
1002variable to 1, this will of course be changed at some point:</p>
1003
1004<p>extern int xmlDoValidityCheckingDefaultValue;</p>
1005
1006<p>...</p>
1007
1008<p>xmlDoValidityCheckingDefaultValue = 1;</p>
1009
1010<p></p>
1011
1012<p>To handle external entities, use the function
1013<strong>xmlSetExternalEntityLoader</strong>(xmlExternalEntityLoader f); to
1014link in you HTTP/FTP/Entities database library to the standard libxml
1015core.</p>
1016
1017<p>@@interfaces@@</p>
1018
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1019<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1020
1021<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]1022Model</em> this is an API for accessing XML or HTML structured documents.
1023Native 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]1024be based on gnome-xml. This will be a far cleaner interface to manipulate XML
Daniel Veillardc08a2c61999-09-08 21:35:25 +0000[diff] [blame]1025files within Gnome since it won't expose the internal structure. DOM defines a
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1026set of IDL (or Java) interfaces allowing to traverse and manipulate a
1027document. The DOM library will allow accessing and modifying "live" documents
1028presents on other programs like this:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1029
1030<p><img src="DOM.gif" alt=" DOM.gif "></p>
1031
1032<p>This should help greatly doing things like modifying a gnumeric spreadsheet
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1033embedded in a GWP document for example.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1034
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1035<p>The current DOM implementation on top of libxml is the <a
1036href="http://cvs.gnome.org/lxr/source/gdome/">gdome Gnome module</a>, this is
1037a full DOM interface, thanks to <a href="mailto:raph@levien.com">Raph
1038Levien</a>.</p>
1039
1040<p>The gnome-dom module in the Gnome CVS base is obsolete</p>
1041
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1042<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1043
1044<p>Here is a real size example, where the actual content of the application
1045data 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]1046a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1047storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
1048base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1049<pre>&lt;?xml version="1.0"?&gt;
1050&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
1051 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1052
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1053 &lt;gjob:Job&gt;
1054 &lt;gjob:Project ID="3"/&gt;
1055 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
1056 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1057
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1058 &lt;gjob:Update&gt;
1059 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
1060 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
1061 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
1062 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1063
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1064 &lt;gjob:Developers&gt;
1065 &lt;gjob:Developer&gt;
1066 &lt;/gjob:Developer&gt;
1067 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1068
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1069 &lt;gjob:Contact&gt;
1070 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
1071 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
1072 &lt;gjob:Company&gt;
1073 &lt;/gjob:Company&gt;
1074 &lt;gjob:Organisation&gt;
1075 &lt;/gjob:Organisation&gt;
1076 &lt;gjob:Webpage&gt;
1077 &lt;/gjob:Webpage&gt;
1078 &lt;gjob:Snailmail&gt;
1079 &lt;/gjob:Snailmail&gt;
1080 &lt;gjob:Phone&gt;
1081 &lt;/gjob:Phone&gt;
1082 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1083
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1084 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1085 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1086 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1087
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1088 &lt;gjob:Skills&gt;
1089 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1090
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1091 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1092 A GNOME based system that will allow a superuser to configure
1093 compressed and uncompressed files and/or file systems to be backed
1094 up with a supported media in the system. This should be able to
1095 perform via find commands generating a list of files that are passed
1096 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
1097 or via operations performed on the filesystem itself. Email
1098 notification and GUI status display very important.
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
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1101 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1102
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1103 &lt;/gjob:Jobs&gt;
1104&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1105
1106<p>While loading the XML file into an internal DOM tree is a matter of calling
1107only a couple of functions, browsing the tree to gather the informations and
1108generate the internals structures is harder, and more error prone.</p>
1109
1110<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1111structure. For example, the ordering of the attributes is not significant,
1112Cthe 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]1113be dependent of the orders of the children of a given node, unless it really
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1114makes things harder. Here is some code to parse the informations for a
1115person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1116<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1117 * A person record
1118 */
1119typedef struct person {
1120 char *name;
1121 char *email;
1122 char *company;
1123 char *organisation;
1124 char *smail;
1125 char *webPage;
1126 char *phone;
1127} person, *personPtr;
1128
1129/*
1130 * And the code needed to parse it
1131 */
1132personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1133 personPtr ret = NULL;
1134
1135DEBUG("parsePerson\n");
1136 /*
1137 * allocate the struct
1138 */
1139 ret = (personPtr) malloc(sizeof(person));
1140 if (ret == NULL) {
1141 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1142 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1143 }
1144 memset(ret, 0, sizeof(person));
1145
1146 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1147 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1148 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1149 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
1150 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1151 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
1152 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1153 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1154 }
1155
1156 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1157}</pre>
1158
1159<p>Here is a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1160<ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1161 <li>Usually a recursive parsing style is the more convenient one, XML data
1162 being by nature subject to repetitive constructs and usualy exibit highly
1163 stuctured patterns.</li>
1164 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>, i.e.
1165 the pointer to the global XML document and the namespace reserved to the
1166 application. Document wide information are needed for example to decode
1167 entities and it's a good coding practice to define a namespace for your
1168 application set of data and test that the element and attributes you're
1169 analyzing actually pertains to your application space. This is done by a
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1170 simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1171 <li>To retrieve text and attributes value, it is suggested to use the
1172 function <em>xmlNodeListGetString</em> to gather all the text and entity
1173 reference nodes generated by the DOM output and produce an single text
1174 string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1175</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1176
1177<p>Here is another piece of code used to parse another level of the
1178structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1179<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1180/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1181 * a Description for a Job
1182 */
1183typedef struct job {
1184 char *projectID;
1185 char *application;
1186 char *category;
1187 personPtr contact;
1188 int nbDevelopers;
1189 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
1190} job, *jobPtr;
1191
1192/*
1193 * And the code needed to parse it
1194 */
1195jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1196 jobPtr ret = NULL;
1197
1198DEBUG("parseJob\n");
1199 /*
1200 * allocate the struct
1201 */
1202 ret = (jobPtr) malloc(sizeof(job));
1203 if (ret == NULL) {
1204 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1205 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1206 }
1207 memset(ret, 0, sizeof(job));
1208
1209 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1210 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1211 while (cur != NULL) {
1212
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1213 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
1214 ret-&gt;projectID = xmlGetProp(cur, "ID");
1215 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1216 fprintf(stderr, "Project has no ID\n");
1217 }
1218 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1219 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
1220 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1221 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
1222 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1223 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
1224 ret-&gt;contact = parsePerson(doc, ns, cur);
1225 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1226 }
1227
1228 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1229}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1230
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1231<p>One can notice that once used to it, writing this kind of code is quite
1232simple, but boring. Ultimately, it could be possble to write stubbers taking
1233either C data structure definitions, a set of XML examples or an XML DTD and
1234produce the code needed to import and export the content between C data and
1235XML storage. This is left as an exercise to the reader :-)</p>
1236
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]1237<p>Feel free to use <a href="example/gjobread.c">the code for the full C
1238parsing example</a> as a template, it is also available with Makefile in the
1239Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1240
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1241<h2><a name="Contributi">Contributions</a></h2>
1242<ul>
1243 <li><a href="mailto:ari@btigate.com">Ari Johnson</a> provides a C++ wrapper
1244 for libxml:
1245 <p>Website: <a
1246 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
1247 <p>Download: <a
1248 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
1249 </li>
1250 <li><a href="mailto:doolin@cs.utk.edu">David Doolin</a> provides a
1251 precompiled Windows version
1252 <p><a
1253 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
1254 </li>
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1255 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> provided <a
1256 href="libxml-doc.el">an emacs module</a> to lookup libxml functions
1257 documentation</li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1258 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
1259 href="http://xmlsoft.org/messages/0488.html">man pages</a> (not yet
1260 integrated in the distribution)</li>
1261</ul>
1262
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1263<p></p>
1264
1265<p><a href="mailto:Daniel.Veillard@w3.org">Daniel Veillard</a></p>
1266
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame^]1267<p>$Id: xml.html,v 1.49 2000/08/25 17:14:13 veillard Exp $</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1268</body>
1269</html>