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blob: 700b8512e1453e806ce6b13715a0fa485c287fcb [file] [log] [blame]
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1<html>
2<head>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]3 <title>The XML C library for Gnome</title>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]4 <meta name="GENERATOR" content="amaya V4.1">
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]6</head>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]7
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]8<body bgcolor="#ffffff">
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]9<p><a href="http://www.gnome.org/"><img src="smallfootonly.gif"
10alt="Gnome Logo"></a><a href="http://www.w3.org/Status"><img src="w3c.png"
11alt="W3C Logo"></a></p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]12
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]13<h1 align="center">The XML C library for Gnome</h1>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]14
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]15<h2 style="text-align: center">libxml, a.k.a. gnome-xml</h2>
16
17<p></p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]18<ul>
19 <li><a href="#Introducti">Introduction</a></li>
20 <li><a href="#Documentat">Documentation</a></li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]21 <li><a href="#Reporting">Reporting bugs and getting help</a></li>
22 <li><a href="#help">how to help</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>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]26 <li><a href="#XSLT">XSLT</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]27 <li><a href="#tree">The tree output</a></li>
28 <li><a href="#interface">The SAX interface</a></li>
29 <li><a href="#library">The XML library interfaces</a>
30 <ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]31 <li><a href="#Invoking">Invoking the parser: the pull way</a></li>
32 <li><a href="#Invoking">Invoking the parser: the push way</a></li>
33 <li><a href="#Invoking2">Invoking the parser: the SAX interface</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]34 <li><a href="#Building">Building a tree from scratch</a></li>
35 <li><a href="#Traversing">Traversing the tree</a></li>
36 <li><a href="#Modifying">Modifying the tree</a></li>
37 <li><a href="#Saving">Saving the tree</a></li>
38 <li><a href="#Compressio">Compression</a></li>
39 </ul>
40 </li>
41 <li><a href="#Entities">Entities or no entities</a></li>
42 <li><a href="#Namespaces">Namespaces</a></li>
43 <li><a href="#Validation">Validation</a></li>
44 <li><a href="#Principles">DOM principles</a></li>
45 <li><a href="#real">A real example</a></li>
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]46 <li><a href="#Contributi">Contributions</a></li>
47</ul>
48
49<p>Separate documents:</p>
50<ul>
51 <li><a href="upgrade.html">upgrade instructions for migrating to
52 libxml2</a></li>
53 <li><a href="encoding.html">libxml Internationalization support</a></li>
54 <li><a href="xmlio.html">libxml Input/Output interfaces</a></li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]55 <li><a href="xmlmem.html">libxml Memory interfaces</a></li>
Daniel Veillard300f7d62000-11-24 13:04:04 +0000[diff] [blame]56 <li><a href="xmldtd.html">a short introduction about DTDs and
57 libxml</a></li>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame^]58 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]59</ul>
60
61<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]62
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]63<p>This document describes libxml, the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]64href="http://www.w3.org/XML/">XML</a> C library developped for the <a
65href="http://www.gnome.org/">Gnome</a> project. <a
66href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
67structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]68
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]69<p>Here are some key points about libxml:</p>
70<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]71 <li>Libxml exports Push and Pull type parser interfaces for both XML and
72 HTML.</li>
73 <li>Libxml can do Dtd validation at parse time, using a parsed document
74 instance, or with an arbitrary Dtd.</li>
75 <li>Libxml now includes a nearly complete <a
76 href="http://www.w3.org/TR/xpath">XPath</a> and <a
Daniel Veillard0c069222000-10-21 09:25:52 +0000[diff] [blame]77 href="http://www.w3.org/TR/xptr">XPointer</a> implementations.</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]78 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]79 sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]80 Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]81 <li>Basic support for HTTP and FTP client allowing to fetch remote
82 resources</li>
83 <li>The design of modular, most of the extensions can be compiled out.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]84 <li>The internal document repesentation is as close as possible to the <a
85 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
86 <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]87 like interface</a>; the interface is designed to be compatible with <a
88 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]89 <li>This library is released both under the <a
90 href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]91 IPR</a> and the <a href="http://www.gnu.org/copyleft/lesser.html">GNU
92 LGPL</a>. Use either at your convenience, basically this should make
93 everybody happy, if not, drop me a mail.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]94</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]95
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]96<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]97
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]98<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]99<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]100 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]101 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]102 documentation</a> automatically extracted from code comments (using <a
103 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
104 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000[diff] [blame]105 <li>Look at the documentation about <a href="encoding.html">libxml
106 internationalization support</a></li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]107 <li>This page provides a global overview and <a href="#real">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]108 examples</a> on how to use libxml.</li>
109 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
110 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
111 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]112 <li>George Lebl wrote <a
113 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]114 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]115 <li>It is also a good idea to check to <a href="mailto:raph@levien.com">Raph
116 Levien</a> <a href="http://levien.com/gnome/">web site</a> since he is
117 building the <a href="http://levien.com/gnome/gdome.html">DOM interface
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]118 gdome</a> on top of libxml result tree and an implementation of <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]119 href="http://www.w3.org/Graphics/SVG/">SVG</a> called <a
120 href="http://www.levien.com/svg/">gill</a>. Check his <a
121 href="http://www.levien.com/gnome/domination.html">DOMination
122 paper</a>.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]123 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
124 file</a></li>
125 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
126 starting a new project using libxml you should really use the 2.x
127 version.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]128 <li>And don't forget to look at the <a href="/messages/">mailing-list
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]129 archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]130</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]131
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]132<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]133
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]134<p>Well, bugs or missing features are always possible, and I will make a point
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]135of fixing them in a timely fashion. The best way to report a bug is to use the
136<a href="http://bugs.gnome.org/db/pa/lgnome-xml.html">Gnome bug tracking
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]137database</a> (make sure to use the "gnome-xml" module name, not libxml or
138libxml2). I look at reports there regularly and it's good to have a reminder
139when a bug is still open. Check the <a
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]140href="http://bugs.gnome.org/Reporting.html">instructions on reporting bugs</a>
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]141and be sure to specify that the bug is for the package gnome-xml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]142
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]143<p>There is also a mailing-list <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]144href="mailto:xml@rpmfind.net">xml@rpmfind.net</a> for libxml, with an <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]145href="http://xmlsoft.org/messages">on-line archive</a>. To subscribe to this
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]146majordomo based list, send a mail message to <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]147href="mailto:majordomo@rpmfind.net">majordomo@rpmfind.net</a> with "subscribe
148xml" in the <strong>content</strong> of the message.</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]149
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]150<p>Alternatively, you can just send the bug to the <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]151href="mailto:xml@rpmfind.net">xml@rpmfind.net</a> list, if it's really libxml
152related I will approve it..</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]153
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]154<p>Of course, bugs reports with a suggested patch for fixing them will
155probably be processed faster.</p>
156
157<p>If you're looking for help, a quick look at <a
158href="http://xmlsoft.org/messages/#407">the list archive</a> may actually
159provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]160questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]161documentantion</a> is not as polished as I would like (i need to learn more
162about Docbook), but it's a good starting point.</p>
163
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]164<h2><a name="help">How to help</a></h2>
165
166<p>You can help the project in various ways, the best thing to do first is to
167subscribe to the mailing-list as explained before, check the <a
168href="http://xmlsoft.org/messages/">archives </a>and the <a
169href="http://bugs.gnome.org/db/pa/lgnome-xml.html">Gnome bug
170database:</a>:</p>
171<ol>
172 <li>provide patches when you find problems</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]173 <li>provide the diffs when you port libxml to a new platform. They may not
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]174 be integrated in all cases but help pinpointing portability problems
175 and</li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]176 <li>provice documentation fixes (either as patches to the code comments or
177 as HTML diffs).</li>
178 <li>provide new documentations pieces (translations, examples, etc ...)</li>
179 <li>Check the TODO file and try to close one of the items</li>
180 <li>take one of the points raised in the archive or the bug database and
181 provide a fix. <a href="mailto:Daniel.Veillard@w3.org">Get in touch with
182 me </a>before to avoid synchronization problems and check that the
183 suggested fix will fit in nicely :-)</li>
184</ol>
185
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]186<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]187
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]188<p>The latest versions of libxml can be found on <a
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]189href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]190href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]191as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]192archive</a> or <a
193href="ftp://ftp.gnome.org/pub/GNOME/contrib/redhat/SRPMS/">RPM packages</a>.
194(NOTE that you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]195href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
196href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]197packages installed to compile applications using libxml.)</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]198
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]199<p><a name="Snapshot">Snapshot:</a></p>
200<ul>
201 <li>Code from the W3C cvs base libxml <a
202 href="ftp://rpmfind.net/pub/libxml/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
203 <li>Docs, content of the web site, the list archive included <a
204 href="ftp://rpmfind.net/pub/libxml/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
205</ul>
206
207<p><a name="Contribs">Contribs:</a></p>
208
209<p>I do accept external contributions, especially if compiling on another
210platform, get in touch with me to upload the package. I will keep them in the
211<a href="ftp://rpmfind.net/pub/libxml/contribs/">contrib directory</a></p>
212
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]213<p>Libxml is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]214<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]215 <li><p>The <a
216 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]217 CVS base</a>. Check the <a
218 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a> page;
219 the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]220 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]221 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]222</ul>
223
224<h2><a name="News">News</a></h2>
225
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]226<h3>CVS only : check the <a
227href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]228for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]229
230<p>Item floating around but not actively worked on, get in touch with me if
231you want to test those</p>
232<ul>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame^]233 <li>Implementing <a href="http://xmlsoft.org/XSLT">XSLT</a>, this is done as
234 a separate C library on top of libxml called libxslt, not released yet but
235 available from CVS</li>
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]236 <li>Finishing up <a href="http://www.w3.org/TR/xptr">XPointer</a> and <a
237 href="http://www.w3.org/TR/xinclude">XInclude</a></li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]238 <li>(seeems working but delayed from release) parsing/import of Docbook SGML
239 docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]240</ul>
241
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame^]242<p>2.3.1: Feb 15 2000</p>
243<ul>
244 <li>some XPath and HTML bug fixes for XSLT</li>
245 <li>small extension of the hash table interfaces for DOM gdome2
246 implementation</li>
247 <li>A few bug fixes</li>
248</ul>
249
250<p>2.3.0: Feb 8 2000 (2.2.12 was on 25 Jan but I didn't kept track)</p>
251<ul>
252 <li>Lots of XPath bug fixes</li>
253 <li>Add a mode with Dtd lookup but without validation error reporting for
254 XSLT</li>
255 <li>Add support for text node without escaping (XSLT)</li>
256 <li>bug fixes for xmlCheckFilename</li>
257 <li>validation code bug fixes from Gary Pennington</li>
258 <li>Patch from Paul D. Smith correcting URI path normalization</li>
259 <li>Patch to allow simultaneous install of libxml-devel and
260 libxml2-devel</li>
261 <li>the example Makefile is now fixed</li>
262 <li>added HTML to the RPM packages</li>
263 <li>tree copying bugfixes</li>
264 <li>updates to Windows makefiles</li>
265 <li>optimisation patch from Bjorn Reese</li>
266</ul>
267
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]268<h3>2.2.11: Jan 4 2000</h3>
269<ul>
270 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
271 <li>added htmlHandleOmittedElem()</li>
272 <li>Applied Bjorn Reese's IPV6 first patch</li>
273 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]274 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]275</ul>
276
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]277<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000[diff] [blame]278<ul>
279 <li>Fix the Windows problems of 2.2.8</li>
280 <li>integrate OpenVMS patches</li>
281 <li>better handling of some nasty HTML input</li>
282 <li>Improved the XPointer implementation</li>
283 <li>integrate a number of provided patches</li>
284</ul>
285
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]286<h3>2.2.9: Nov 25 2000</h3>
287<ul>
288 <li>erroneous release :-(</li>
289</ul>
290
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]291<h3>2.2.8: Nov 13 2000</h3>
292<ul>
293 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
294 support</li>
295 <li>Patch in conditional section handling</li>
296 <li>updated MS compiler project</li>
297 <li>fixed some XPath problems</li>
298 <li>added an URI escaping function</li>
299 <li>some other bug fixes</li>
300</ul>
301
302<h3>2.2.7: Oct 31 2000</h3>
303<ul>
304 <li>added message redirection</li>
305 <li>XPath improvements (thanks TOM !)</li>
306 <li>xmlIOParseDTD() added</li>
307 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
308 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
309</ul>
310
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000[diff] [blame]311<h3>2.2.6: Oct 25 2000:</h3>
312<ul>
313 <li>Added an hash table module, migrated a number of internal structure to
314 those</li>
315 <li>Fixed a posteriori validation problems</li>
316 <li>HTTP module cleanups</li>
317 <li>HTML parser improvements (tag errors, script/style handling, attribute
318 normalization)</li>
319 <li>coalescing of adjacent text nodes</li>
320 <li>couple of XPath bug fixes, exported the internal API</li>
321</ul>
322
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]323<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]324<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]325 <li>XPointer implementation and testsuite</li>
326 <li>Lot of XPath fixes, added variable and functions registration, more
327 tests</li>
328 <li>Portability fixes, lots of enhancements toward an easy Windows build and
329 release</li>
330 <li>Late validation fixes</li>
331 <li>Integrated a lot of contributed patches</li>
332 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]333 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]334</ul>
335
336<h3>2.2.4: Oct 1 2000:</h3>
337<ul>
338 <li>main XPath problem fixed</li>
339 <li>Integrated portability patches for Windows</li>
340 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]341</ul>
342
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]343<h3>2.2.3: Sep 17 2000</h3>
344<ul>
345 <li>bug fixes</li>
346 <li>cleanup of entity handling code</li>
347 <li>overall review of all loops in the parsers, all sprintf usage has been
348 checked too</li>
349 <li>Far better handling of larges Dtd. Validating against Docbook XML Dtd
350 works smoothly now.</li>
351</ul>
352
353<h3>1.8.10: Sep 6 2000</h3>
354<ul>
355 <li>bug fix release for some Gnome projects</li>
356</ul>
357
358<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]359<ul>
360 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]361 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]362</ul>
363
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]364<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]365<ul>
366 <li>a purely bug fixes release</li>
367 <li>fixed an encoding support problem when parsing from a memory block</li>
368 <li>fixed a DOCTYPE parsing problem</li>
369 <li>removed a bug in the function allowing to override the memory allocation
370 routines</li>
371</ul>
372
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]373<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]374<ul>
375 <li>applied a lot of portability fixes</li>
376 <li>better encoding support/cleanup and saving (content is now always
377 encoded in UTF-8)</li>
378 <li>the HTML parser now correctly handles encodings</li>
379 <li>added xmlHasProp()</li>
380 <li>fixed a serious problem with &amp;#38;</li>
381 <li>propagated the fix to FTP client</li>
382 <li>cleanup, bugfixes, etc ...</li>
383 <li>Added a page about <a href="encoding.html">libxml Internationalization
384 support</a></li>
385</ul>
386
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]387<h3>1.8.9: July 9 2000</h3>
388<ul>
389 <li>fixed the spec the RPMs should be better</li>
390 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
391 rpmfind users problem</li>
392</ul>
393
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]394<h3>2.1.1: July 1 2000</h3>
395<ul>
396 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
397 <li>improvements on the HTML parser</li>
398</ul>
399
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]400<h3>2.1.0 and 1.8.8: June 29 2000</h3>
401<ul>
402 <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to
403 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
404 about &amp;#38; charref parsing</li>
405 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
406 also contains numerous fixes and enhancements:
407 <ul>
408 <li>added xmlStopParser() to stop parsing</li>
409 <li>improved a lot parsing speed when there is large CDATA blocs</li>
410 <li>includes XPath patches provided by Picdar Technology</li>
411 <li>tried to fix as much as possible DtD validation and namespace
412 related problems</li>
413 <li>output to a given encoding has been added/tested</li>
414 <li>lot of various fixes</li>
415 </ul>
416 </li>
417</ul>
418
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]419<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]420<ul>
421 <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]422 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally
423 scheduled for Apr 3 the relase occured only on Apr 12 due to massive
424 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]425 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]426 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]427 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]428 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]429 <pre>#include "xxx.h"</pre>
430 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]431 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
432 <li>the memory allocation routines used by libxml can now be overloaded
433 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]434 <li>The previously CVS only tool tester has been renamed
435 <strong>xmllint</strong> and is now installed as part of the libxml2
436 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]437 <li>The I/O interface has been revamped. There is now ways to plug in
438 specific I/O modules, either at the URI scheme detection level using
439 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
440 parser context using xmlCreateIOParserCtxt()</li>
441 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
442 number of the libxml module in use</li>
443 <li>a number of optional features of libxml can now be excluded at configure
444 time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]445</ul>
446
447<h3>2.0.0beta: Mar 14 2000</h3>
448<ul>
449 <li>This is a first Beta release of libxml version 2</li>
450 <li>It's available only from<a href="ftp://rpmfind.net/pub/libxml/">
451 rpmfind.net FTP</a>, it's packaged as libxml2-2.0.0beta and available as
452 tar and RPMs</li>
453 <li>This version is now the head in the Gnome CVS base, the old one is
454 available under the tag LIB_XML_1_X</li>
455 <li>This includes a very large set of changes. Froma programmatic point of
456 view applications should not have to be modified too much, check the <a
457 href="upgrade.html">upgrade page</a></li>
458 <li>Some interfaces may changes (especially a bit about encoding).</li>
459 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]460 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]461 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
462 handled now</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]463 <li>Better handling of entities, especially well formedness checking and
464 proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]465 <li>DTD conditional sections</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]466 <li>Validation now correcly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]467 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
468 structures to accomodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]469 </ul>
470 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]471 <li>Serious progress were made toward compliance, <a
472 href="conf/result.html">here are the result of the test</a> against the
473 OASIS testsuite (except the japanese tests since I don't support that
474 encoding yet). This URL is rebuilt every couple of hours using the CVS
475 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]476</ul>
477
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]478<h3>1.8.7: Mar 6 2000</h3>
479<ul>
480 <li>This is a bug fix release:</li>
481 <li>It is possible to disable the ignorable blanks heuristic used by
482 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
483 that for adherence to XML spec, this behaviour will be disabled by default
484 in 2.x . The same function will allow to keep compatibility for old
485 code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]486 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
487 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]488 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
489 compilation on some platforms has been fixed</li>
490 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
491 URIs</li>
492</ul>
493
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]494<h3>1.8.6: Jan 31 2000</h3>
495<ul>
496 <li>added a nanoFTP transport module, debugged until the new version of <a
497 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
498 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]499</ul>
500
501<h3>1.8.5: Jan 21 2000</h3>
502<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]503 <li>adding APIs to parse a well balanced chunk of XML (production <a
504 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the XML
505 spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]506 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]507 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
508 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]509 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
510 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]511</ul>
512
513<h3>1.8.4: Jan 13 2000</h3>
514<ul>
515 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
516 <li>all exit() call should have been removed from libxml</li>
517 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
518 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]519</ul>
520
521<h3>1.8.3: Jan 5 2000</h3>
522<ul>
523 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]524 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillarddbfd6411999-12-28 16:35:14 +0000[diff] [blame]525 <li>lots of bug fixes and improvement added over XMas hollidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]526 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]527 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
528 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]529 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]530 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]531 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]532</ul>
533
534<h3>1.8.2: Dec 21 1999</h3>
535<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]536 <li>I got another problem with includes and C++, I hope this issue is fixed
537 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]538 <li>Added a few tree modification functions: xmlReplaceNode,
539 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
540 xmlDocSetRootElement</li>
541 <li>Tried to improve the HTML output with help from <a
542 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]543</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]544
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]545<h3>1.8.1: Dec 18 1999</h3>
546<ul>
547 <li>various patches to avoid troubles when using libxml with C++ compilers
548 the "namespace" keyword and C escaping in include files</li>
549 <li>a problem in one of the core macros IS_CHAR was corrected</li>
550 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
551 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]552 <li>fixed a posteriori validation (validation after parsing, or by using a
553 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]554 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]555</ul>
556
557<h3>1.8.0: Dec 12 1999</h3>
558<ul>
559 <li>cleanup, especially memory wise</li>
560 <li>the parser should be more reliable, especially the HTML one, it should
561 not crash, whatever the input !</li>
562 <li>Integrated various patches, especially a speedup improvement for large
563 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
564 configure with --with-buffers to enable them.</li>
565 <li>attribute normalization, oops should have been added long ago !</li>
566 <li>attributes defaulted from Dtds should be available, xmlSetProp() now
567 does entities escapting by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]568</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]569
570<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]571<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]572 <li>Lots of HTML improvement</li>
573 <li>Fixed some errors when saving both XML and HTML</li>
574 <li>More examples, the regression tests should now look clean</li>
575 <li>Fixed a bug with contiguous charref</li>
576</ul>
577
578<h3>1.7.3: Sep 29 1999</h3>
579<ul>
580 <li>portability problems fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]581 <li>snprintf was used unconditionnally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]582 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]583</ul>
584
585<h3>1.7.1: Sep 24 1999</h3>
586<ul>
587 <li>The basic type for strings manipulated by libxml has been renamed in
588 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
589 is that CHAR was conflicting with a predefined type on Windows. However on
590 non WIN32 environment, compatibility is provided by the way of a
591 <strong>#define </strong>.</li>
592 <li>Changed another error : the use of a structure field called errno, and
593 leading to troubles on platforms where it's a macro</li>
594</ul>
595
596<h3>1.7.0: sep 23 1999</h3>
597<ul>
598 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]599 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]600 <li>Added an errno to report errors by another mean than a simple printf
601 like callback</li>
602 <li>Finished ID/IDREF support and checking when validation</li>
603 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]604 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]605 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
606 implementation</li>
607 <li>Added an HTML parser front-end</li>
608</ul>
609
610<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]611
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]612<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]613markup-based structured documents. Here is <a name="example">an example XML
614document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]615<pre>&lt;?xml version="1.0"?&gt;
616&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
617 &lt;head&gt;
618 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
619 &lt;/head&gt;
620 &lt;chapter&gt;
621 &lt;title&gt;The Linux adventure&lt;/title&gt;
622 &lt;p&gt;bla bla bla ...&lt;/p&gt;
623 &lt;image href="linus.gif"/&gt;
624 &lt;p&gt;...&lt;/p&gt;
625 &lt;/chapter&gt;
626&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]627
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]628<p>The first line specifies that it's an XML document and gives useful
629information about its encoding. Then the document is a text format whose
630structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]631to be closed</strong>. XML is pedantic about this. However, if a tag is empty
632(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]633ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note that,
634for example, the image tag has no content (just an attribute) and is closed by
635ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]636
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]637<p>XML can be applied sucessfully to a wide range of uses, from long term
638structured document maintenance (where it follows the steps of SGML) to simple
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]639data encoding mechanisms like configuration file formatting (glade),
640spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
641it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]642
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]643<h2><a name="XSLT">XSLT</a></h2>
644
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame^]645<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
646
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]647<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a language
648for transforming XML documents into other XML documents (or HTML/textual
649output).</p>
650
651<p>A separate library called libxslt is being built on top of libxml2. This
652module "libxslt" can be found in the Gnome CVS base too.</p>
653
Daniel Veillard383b1472001-01-23 11:39:52 +0000[diff] [blame]654<p>You can check the <a
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame^]655href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a> supported
656and the progresses on the <a
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]657href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog">Changelog</a></p>
658
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]659<h2>An overview of libxml architecture</h2>
660
661<p>Libxml is made of multiple components, some of them optionals, and most of
662the block interfaces are public. The main components are:</p>
663<ul>
664 <li>an Input/Output layer</li>
665 <li>FTP and HTTP client layers (optionnal)</li>
666 <li>an Internationalization layer managing the encodings support</li>
667 <li>an URI module</li>
668 <li>the XML parser and its basic SAX interface</li>
669 <li>an HTML parser using the same SAX interface (optionnal)</li>
670 <li>a SAX tree module to build an in-memory DOM representation</li>
671 <li>a tree module to manipulate the DOM representation</li>
672 <li>a validation module using the DOM representation (optionnal)</li>
673 <li>an XPath module for global lookup in a DOM representation
674 (optionnal)</li>
675 <li>a debug module (optionnal)</li>
676</ul>
677
678<p>Graphically this gives the following:</p>
679
680<p><img src="libxml.gif" alt="a graphical view of the various"></p>
681
682<p></p>
683
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]684<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]685
686<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]687returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]688<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]689as the file name, the document type, and a <strong>children</strong> pointer
690which is the root of the document (or more exactly the first child under the
691root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]692chained in double-linked lists of siblings and with children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]693relationship. An xmlNode can also carry properties (a chain of xmlAttr
694structures). An attribute may have a value which is a list of TEXT or
695ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]696
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]697<p>Here is an example (erroneous with respect to the XML spec since there
698should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]699
700<p><img src="structure.gif" alt=" structure.gif "></p>
701
702<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]703called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]704prints them back as parsed. This is useful for detecting errors both in XML
705code and in the XML parser itself. It has an option <strong>--debug</strong>
706which prints the actual in-memory structure of the document, here is the
707result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]708<pre>DOCUMENT
709version=1.0
710standalone=true
711 ELEMENT EXAMPLE
712 ATTRIBUTE prop1
713 TEXT
714 content=gnome is great
715 ATTRIBUTE prop2
716 ENTITY_REF
717 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]718 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]719 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]720 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]721 TEXT
722 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]723 ELEMENT chapter
724 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]725 TEXT
726 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]727 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]728 TEXT
729 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]730 ELEMENT image
731 ATTRIBUTE href
732 TEXT
733 content=linus.gif
734 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]735 TEXT
736 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]737
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]738<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]739
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]740<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]741
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]742<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]743memory. In that case (and if you don't expect to save back the XML document
744loaded 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]745<strong>callback-based interface</strong> to the parser. Before parsing, the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]746application layer registers a customized set of callbacks which are called by
747the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]748
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]749<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]750libxml, see the <a
751href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
752documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]753Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]754
755<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
756program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]757binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]758distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]759testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]760<pre>SAX.setDocumentLocator()
761SAX.startDocument()
762SAX.getEntity(amp)
763SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
764SAX.characters( , 3)
765SAX.startElement(head)
766SAX.characters( , 4)
767SAX.startElement(title)
768SAX.characters(Welcome to Gnome, 16)
769SAX.endElement(title)
770SAX.characters( , 3)
771SAX.endElement(head)
772SAX.characters( , 3)
773SAX.startElement(chapter)
774SAX.characters( , 4)
775SAX.startElement(title)
776SAX.characters(The Linux adventure, 19)
777SAX.endElement(title)
778SAX.characters( , 4)
779SAX.startElement(p)
780SAX.characters(bla bla bla ..., 15)
781SAX.endElement(p)
782SAX.characters( , 4)
783SAX.startElement(image, href='linus.gif')
784SAX.endElement(image)
785SAX.characters( , 4)
786SAX.startElement(p)
787SAX.characters(..., 3)
788SAX.endElement(p)
789SAX.characters( , 3)
790SAX.endElement(chapter)
791SAX.characters( , 1)
792SAX.endElement(EXAMPLE)
793SAX.endDocument()</pre>
794
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]795<p>Most of the other functionalities of libxml are based on the DOM
796tree-building facility, so nearly everything up to the end of this document
797presupposes the use of the standard DOM tree build. Note that the DOM tree
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]798itself is built by a set of registered default callbacks, without internal
799specific interface.</p>
800
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]801<h2><a name="library">The XML library interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]802
803<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]804using the XML library from the C language. It is not intended to be extensive.
805I hope the automatically generated documents will provide the completeness
806required, but as a separate set of documents. The interfaces of the XML
807library are by principle low level, there is nearly zero abstraction. Those
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]808interested in a higher level API should <a href="#DOM">look at DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]809
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]810<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
811separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]812interfaces</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]813
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]814<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]815
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]816<p>Usually, the first thing to do is to read an XML input. The parser accepts
817documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]818defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]819<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]820 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]821 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]822 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]823</dl>
824<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]825 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]826 <dd><p>Parse an XML document contained in a (possibly compressed)
827 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]828 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]829</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]830
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]831<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]832failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]833
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]834<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]835
836<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]837fetched (which is common for GUI based programs) libxml provides a push
838interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]839<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
840 void *user_data,
841 const char *chunk,
842 int size,
843 const char *filename);
844int xmlParseChunk (xmlParserCtxtPtr ctxt,
845 const char *chunk,
846 int size,
847 int terminate);</pre>
848
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]849<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]850<pre> FILE *f;
851
852 f = fopen(filename, "r");
853 if (f != NULL) {
854 int res, size = 1024;
855 char chars[1024];
856 xmlParserCtxtPtr ctxt;
857
858 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]859 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]860 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
861 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]862 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]863 xmlParseChunk(ctxt, chars, res, 0);
864 }
865 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]866 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]867 xmlFreeParserCtxt(ctxt);
868 }
869 }</pre>
870
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]871<p>Also note that the HTML parser embedded into libxml also has a push
872interface; the functions are just prefixed by "html" rather than "xml"</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]873
874<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
875
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]876<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]877memory-hungry, first to load the document in memory, second to build the tree.
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]878Reading a document without building the tree is possible using the SAX
879interfaces (see SAX.h and <a
880href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]881Henstridge's documentation</a>). Note also that the push interface can be
882limited to SAX. Just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]883<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]884
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]885<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]886
887<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]888there is a set of functions dedicated to building new elements. (These are
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]889also 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]890that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]891<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]892 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]893 xmlNodePtr tree, subtree;
894
895 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]896 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
897 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
898 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
899 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]900 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]901 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]902 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
903 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
904 subtree = xmlNewChild(tree, NULL, "image", NULL);
905 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]906
907<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]908
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]909<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]910
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]911<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]912code has access to the internal structure of all the elements of the tree. The
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]913names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]914<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]915<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]916example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]917<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]918
919<p>points to the title element,</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]920<pre>doc-&gt;children-&gt;children-&gt;next-&gt;child-&gt;child</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]921
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]922<p>points to the text node containing the chapter title "The Linux
923adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]924
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]925<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]926present before the document root, so <code>doc-&gt;children</code> may point
927to an element which is not the document Root Element, a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]928<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]929
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]930<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]931
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]932<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]933is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]934<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]935 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
936 xmlChar *value);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]937 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node. The
938 value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]939 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]940</dl>
941<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]942 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]943 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +0000[diff] [blame]944 <dd><p>This function returns a pointer to new copy of the property
945 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]946 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]947</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]948
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]949<p>Two functions are provided for reading and writing the text associated with
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]950elements:</p>
951<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]952 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]953 *value);</code></dt>
954 <dd><p>This function takes an "external" string and convert it to one text
955 node or possibly to a list of entity and text nodes. All non-predefined
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]956 entity references like &amp;Gnome; will be stored internally as entity
957 nodes, hence the result of the function may not be a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]958 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]959</dl>
960<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]961 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]962 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]963 <dd><p>This function is the inverse of
964 <code>xmlStringGetNodeList()</code>. It generates a new string
965 containing the content of the text and entity nodes. Note the extra
966 argument inLine. If this argument is set to 1, the function will expand
967 entity references. For example, instead of returning the &amp;Gnome;
968 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]969 "GNU Network Object Model Environment"). Set this argument if you want
970 to use the string for non-XML usage like User Interface.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]971 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]972</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]973
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]974<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]975
976<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]977<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]978 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]979 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]980 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]981 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]982</dl>
983<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]984 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]985 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]986 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]987</dl>
988<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]989 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]990 <dd><p>Saves the document to a file. In this case, the compression
991 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]992 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]993</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]994
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]995<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]996
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]997<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]998accesses. The level of compression on saves can be turned on either globally
999or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1000<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1001 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1002 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1003 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1004</dl>
1005<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1006 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1007 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1008 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1009</dl>
1010<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1011 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1012 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1013 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1014</dl>
1015<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1016 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1017 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1018 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1019</dl>
1020
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1021<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1022
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1023<p>Entities in principle are similar to simple C macros. An entity defines an
1024abbreviation for a given string that you can reuse many times throughout the
1025content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1026may occur frequently within a document, or to confine the change needed to a
1027document to a restricted area in the internal subset of the document (at the
1028beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1029<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]10302 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]10313 &lt;!ENTITY xml "Extensible Markup Language"&gt;
10324 ]&gt;
10335 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]10346 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]10357 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1036
1037<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]1038it's name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1039are 5 predefined entities in libxml allowing you to escape charaters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1040predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1041<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1042for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1043<strong>&amp;quot;</strong> for the character '"', and
1044<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1045
1046<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]1047substitute an entity's content so that you can see the replacement text in
1048your application. Or you may prefer to keep entity references as such in the
1049content to be able to save the document back without losing this usually
1050precious information (if the user went through the pain of explicitly defining
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1051entities, he may have a a rather negative attitude if you blindly susbtitute
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1052them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1053href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1054function allows you to check and change the behaviour, which is to not
1055substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1056
1057<p>Here is the DOM tree built by libxml for the previous document in the
1058default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1059<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1060DOCUMENT
1061version=1.0
1062 ELEMENT EXAMPLE
1063 TEXT
1064 content=
1065 ENTITY_REF
1066 INTERNAL_GENERAL_ENTITY xml
1067 content=Extensible Markup Language
1068 TEXT
1069 content=</pre>
1070
1071<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1072<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1073DOCUMENT
1074version=1.0
1075 ELEMENT EXAMPLE
1076 TEXT
1077 content= Extensible Markup Language</pre>
1078
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1079<p>So, entities or no entities? Basically, it depends on your use case. I
1080suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1081entities in your XML document or data if you are not willing to handle the
1082entity references elements in the DOM tree.</p>
1083
1084<p>Note that at save time libxml enforce the conversion of the predefined
1085entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1086transparently replace those with chars (i.e., it will not generate entity
1087reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1088finding them in the input).</p>
1089
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]1090<p><span style="background-color: #FF0000">WARNING</span>: handling entities
1091on top of libxml SAX interface is difficult !!! If you plan to use
1092non-predefined entities in your documents, then the learning cuvre to handle
1093then using the SAX API may be long. If you plan to use complex document, I
1094strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]1095deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]1096
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1097<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1098
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1099<p>The libxml library implements <a
1100href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
1101recognizing namespace contructs in the input, and does namespace lookup
1102automatically when building the DOM tree. A namespace declaration is
1103associated with an in-memory structure and all elements or attributes within
1104that namespace point to it. Hence testing the namespace is a simple and fast
1105equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1106
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1107<p>I suggest that people using libxml use a namespace, and declare it in the
1108root element of their document as the default namespace. Then they don't need
1109to use the prefix in the content but we will have a basis for future semantic
1110refinement and merging of data from different sources. This doesn't augment
1111significantly the size of the XML output, but significantly increase its value
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1112in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1113<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
1114 &lt;elem1&gt;...&lt;/elem1&gt;
1115 &lt;elem2&gt;...&lt;/elem2&gt;
1116&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1117
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1118<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]1119have to point to any existing resource on the Web. It will bind all the
1120element and atributes with that URL. I suggest to use an URL within a domain
1121you control, and that the URL should contain some kind of version information
1122if possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1123a good namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1124
1125<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1126version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1127and if the version information don't match something you know, warn the user
1128and 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]1129namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
1130same as &lt;bar:text&gt; in another document. What really matter is the URI
1131associated with the element or the attribute, not the prefix string (which is
1132just a shortcut for the full URI). In libxml element and attributes have a
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1133<code>ns</code> field pointing to an xmlNs structure detailing the namespace
1134prefix and it's URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1135
1136<p>@@Interfaces@@</p>
1137
1138<p>@@Examples@@</p>
1139
1140<p>Usually people object using namespace in the case of validation, I object
1141this and will make sure that using namespaces won't break validity checking,
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1142so even is you plan to use or currently are using validation I strongly
1143suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1144<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1145flexible parsers. Now using namespace to mix and differentiate content coming
1146from multiple DTDs will certainly break current validation schemes. I will try
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1147to provide ways to do this, but this may not be portable or standardized.</p>
1148
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1149<h2><a name="Validation">Validation, or are you afraid of DTDs ?</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1150
1151<p>Well what is validation and what is a DTD ?</p>
1152
1153<p>Validation is the process of checking a document against a set of
1154construction rules, a <strong>DTD</strong> (Document Type Definition) is such
1155a set of rules.</p>
1156
1157<p>The validation process and building DTDs are the two most difficult parts
1158of XML life cycle. Briefly a DTD defines all the possibles element to be
1159found within your document, what is the formal shape of your document tree (by
1160defining the allowed content of an element, either text, a regular expression
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1161for the allowed list of children, or mixed content i.e. both text and
1162children). The DTD also defines the allowed attributes for all elements and
1163the types of the attributes. For more detailed informations, I suggest to read
1164the related parts of the XML specification, the examples found under
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1165gnome-xml/test/valid/dtd and the large amount of books available on XML. The
1166dia example in gnome-xml/test/valid should be both simple and complete enough
1167to allow you to build your own.</p>
1168
1169<p>A word of warning, building a good DTD which will fit your needs of your
1170application in the long-term is far from trivial, however the extra level of
1171quality it can insure is well worth the price for some sets of applications or
1172if you already have already a DTD defined for your application field.</p>
1173
1174<p>The validation is not completely finished but in a (very IMHO) usable
1175state. Until a real validation interface is defined the way to do it is to
1176define and set the <strong>xmlDoValidityCheckingDefaultValue</strong> external
1177variable to 1, this will of course be changed at some point:</p>
1178
1179<p>extern int xmlDoValidityCheckingDefaultValue;</p>
1180
1181<p>...</p>
1182
1183<p>xmlDoValidityCheckingDefaultValue = 1;</p>
1184
1185<p></p>
1186
1187<p>To handle external entities, use the function
1188<strong>xmlSetExternalEntityLoader</strong>(xmlExternalEntityLoader f); to
1189link in you HTTP/FTP/Entities database library to the standard libxml
1190core.</p>
1191
1192<p>@@interfaces@@</p>
1193
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1194<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1195
1196<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]1197Model</em> this is an API for accessing XML or HTML structured documents.
1198Native 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]1199be based on gnome-xml. This will be a far cleaner interface to manipulate XML
Daniel Veillardc08a2c61999-09-08 21:35:25 +0000[diff] [blame]1200files within Gnome since it won't expose the internal structure. DOM defines a
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1201set of IDL (or Java) interfaces allowing to traverse and manipulate a
1202document. The DOM library will allow accessing and modifying "live" documents
1203presents on other programs like this:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1204
1205<p><img src="DOM.gif" alt=" DOM.gif "></p>
1206
1207<p>This should help greatly doing things like modifying a gnumeric spreadsheet
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1208embedded in a GWP document for example.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1209
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1210<p>The current DOM implementation on top of libxml is the <a
1211href="http://cvs.gnome.org/lxr/source/gdome/">gdome Gnome module</a>, this is
1212a full DOM interface, thanks to <a href="mailto:raph@levien.com">Raph
1213Levien</a>.</p>
1214
1215<p>The gnome-dom module in the Gnome CVS base is obsolete</p>
1216
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1217<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1218
1219<p>Here is a real size example, where the actual content of the application
1220data 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]1221a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1222storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
1223base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1224<pre>&lt;?xml version="1.0"?&gt;
1225&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
1226 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1227
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1228 &lt;gjob:Job&gt;
1229 &lt;gjob:Project ID="3"/&gt;
1230 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
1231 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1232
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1233 &lt;gjob:Update&gt;
1234 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
1235 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
1236 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
1237 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1238
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1239 &lt;gjob:Developers&gt;
1240 &lt;gjob:Developer&gt;
1241 &lt;/gjob:Developer&gt;
1242 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1243
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1244 &lt;gjob:Contact&gt;
1245 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
1246 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
1247 &lt;gjob:Company&gt;
1248 &lt;/gjob:Company&gt;
1249 &lt;gjob:Organisation&gt;
1250 &lt;/gjob:Organisation&gt;
1251 &lt;gjob:Webpage&gt;
1252 &lt;/gjob:Webpage&gt;
1253 &lt;gjob:Snailmail&gt;
1254 &lt;/gjob:Snailmail&gt;
1255 &lt;gjob:Phone&gt;
1256 &lt;/gjob:Phone&gt;
1257 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1258
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1259 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1260 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1261 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1262
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1263 &lt;gjob:Skills&gt;
1264 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1265
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1266 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1267 A GNOME based system that will allow a superuser to configure
1268 compressed and uncompressed files and/or file systems to be backed
1269 up with a supported media in the system. This should be able to
1270 perform via find commands generating a list of files that are passed
1271 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
1272 or via operations performed on the filesystem itself. Email
1273 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1274 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1275
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1276 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1277
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1278 &lt;/gjob:Jobs&gt;
1279&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1280
1281<p>While loading the XML file into an internal DOM tree is a matter of calling
1282only a couple of functions, browsing the tree to gather the informations and
1283generate the internals structures is harder, and more error prone.</p>
1284
1285<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1286structure. For example, the ordering of the attributes is not significant,
1287Cthe 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]1288be dependent of the orders of the children of a given node, unless it really
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1289makes things harder. Here is some code to parse the informations for a
1290person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1291<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1292 * A person record
1293 */
1294typedef struct person {
1295 char *name;
1296 char *email;
1297 char *company;
1298 char *organisation;
1299 char *smail;
1300 char *webPage;
1301 char *phone;
1302} person, *personPtr;
1303
1304/*
1305 * And the code needed to parse it
1306 */
1307personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1308 personPtr ret = NULL;
1309
1310DEBUG("parsePerson\n");
1311 /*
1312 * allocate the struct
1313 */
1314 ret = (personPtr) malloc(sizeof(person));
1315 if (ret == NULL) {
1316 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1317 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1318 }
1319 memset(ret, 0, sizeof(person));
1320
1321 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1322 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1323 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1324 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
1325 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1326 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
1327 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1328 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1329 }
1330
1331 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1332}</pre>
1333
1334<p>Here is a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1335<ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1336 <li>Usually a recursive parsing style is the more convenient one, XML data
1337 being by nature subject to repetitive constructs and usualy exibit highly
1338 stuctured patterns.</li>
1339 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>, i.e.
1340 the pointer to the global XML document and the namespace reserved to the
1341 application. Document wide information are needed for example to decode
1342 entities and it's a good coding practice to define a namespace for your
1343 application set of data and test that the element and attributes you're
1344 analyzing actually pertains to your application space. This is done by a
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1345 simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1346 <li>To retrieve text and attributes value, it is suggested to use the
1347 function <em>xmlNodeListGetString</em> to gather all the text and entity
1348 reference nodes generated by the DOM output and produce an single text
1349 string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1350</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1351
1352<p>Here is another piece of code used to parse another level of the
1353structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1354<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1355/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1356 * a Description for a Job
1357 */
1358typedef struct job {
1359 char *projectID;
1360 char *application;
1361 char *category;
1362 personPtr contact;
1363 int nbDevelopers;
1364 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
1365} job, *jobPtr;
1366
1367/*
1368 * And the code needed to parse it
1369 */
1370jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1371 jobPtr ret = NULL;
1372
1373DEBUG("parseJob\n");
1374 /*
1375 * allocate the struct
1376 */
1377 ret = (jobPtr) malloc(sizeof(job));
1378 if (ret == NULL) {
1379 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1380 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1381 }
1382 memset(ret, 0, sizeof(job));
1383
1384 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1385 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1386 while (cur != NULL) {
1387
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1388 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
1389 ret-&gt;projectID = xmlGetProp(cur, "ID");
1390 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1391 fprintf(stderr, "Project has no ID\n");
1392 }
1393 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1394 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
1395 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1396 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
1397 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1398 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
1399 ret-&gt;contact = parsePerson(doc, ns, cur);
1400 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1401 }
1402
1403 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1404}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1405
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1406<p>One can notice that once used to it, writing this kind of code is quite
1407simple, but boring. Ultimately, it could be possble to write stubbers taking
1408either C data structure definitions, a set of XML examples or an XML DTD and
1409produce the code needed to import and export the content between C data and
1410XML storage. This is left as an exercise to the reader :-)</p>
1411
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]1412<p>Feel free to use <a href="example/gjobread.c">the code for the full C
1413parsing example</a> as a template, it is also available with Makefile in the
1414Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1415
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1416<h2><a name="Contributi">Contributions</a></h2>
1417<ul>
Daniel Veillard851c59c2000-11-24 16:06:22 +0000[diff] [blame]1418 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1419 for libxml:
1420 <p>Website: <a
1421 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
1422 <p>Download: <a
1423 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
1424 </li>
1425 <li><a href="mailto:doolin@cs.utk.edu">David Doolin</a> provides a
1426 precompiled Windows version
1427 <p><a
1428 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
1429 </li>
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1430 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> provided <a
1431 href="libxml-doc.el">an emacs module</a> to lookup libxml functions
1432 documentation</li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1433 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
1434 href="http://xmlsoft.org/messages/0488.html">man pages</a> (not yet
1435 integrated in the distribution)</li>
1436</ul>
1437
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1438<p></p>
1439
1440<p><a href="mailto:Daniel.Veillard@w3.org">Daniel Veillard</a></p>
1441
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame^]1442<p>$Id: xml.html,v 1.66 2001/01/29 08:22:12 veillard Exp $</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1443</body>
1444</html>