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blob: edc55044947b82e5f400d4182c1ce38de77ee8a4 [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 Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]58</ul>
59
60<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]61
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]62<p>This document describes libxml, the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]63href="http://www.w3.org/XML/">XML</a> C library developped for the <a
64href="http://www.gnome.org/">Gnome</a> project. <a
65href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
66structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]67
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]68<p>Here are some key points about libxml:</p>
69<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]70 <li>Libxml exports Push and Pull type parser interfaces for both XML and
71 HTML.</li>
72 <li>Libxml can do Dtd validation at parse time, using a parsed document
73 instance, or with an arbitrary Dtd.</li>
74 <li>Libxml now includes a nearly complete <a
75 href="http://www.w3.org/TR/xpath">XPath</a> and <a
Daniel Veillard0c069222000-10-21 09:25:52 +0000[diff] [blame]76 href="http://www.w3.org/TR/xptr">XPointer</a> implementations.</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]77 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]78 sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]79 Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]80 <li>Basic support for HTTP and FTP client allowing to fetch remote
81 resources</li>
82 <li>The design of modular, most of the extensions can be compiled out.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]83 <li>The internal document repesentation is as close as possible to the <a
84 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
85 <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]86 like interface</a>; the interface is designed to be compatible with <a
87 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]88 <li>This library is released both under the <a
89 href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]90 IPR</a> and the <a href="http://www.gnu.org/copyleft/lesser.html">GNU
91 LGPL</a>. Use either at your convenience, basically this should make
92 everybody happy, if not, drop me a mail.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]93</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]94
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]95<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]96
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]97<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]98<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]99 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]100 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]101 documentation</a> automatically extracted from code comments (using <a
102 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
103 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000[diff] [blame]104 <li>Look at the documentation about <a href="encoding.html">libxml
105 internationalization support</a></li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]106 <li>This page provides a global overview and <a href="#real">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]107 examples</a> on how to use libxml.</li>
108 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
109 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
110 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]111 <li>George Lebl wrote <a
112 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]113 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]114 <li>It is also a good idea to check to <a href="mailto:raph@levien.com">Raph
115 Levien</a> <a href="http://levien.com/gnome/">web site</a> since he is
116 building the <a href="http://levien.com/gnome/gdome.html">DOM interface
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]117 gdome</a> on top of libxml result tree and an implementation of <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]118 href="http://www.w3.org/Graphics/SVG/">SVG</a> called <a
119 href="http://www.levien.com/svg/">gill</a>. Check his <a
120 href="http://www.levien.com/gnome/domination.html">DOMination
121 paper</a>.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]122 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
123 file</a></li>
124 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
125 starting a new project using libxml you should really use the 2.x
126 version.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]127 <li>And don't forget to look at the <a href="/messages/">mailing-list
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]128 archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]129</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]130
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]131<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]132
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]133<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]134of fixing them in a timely fashion. The best way to report a bug is to use the
135<a href="http://bugs.gnome.org/db/pa/lgnome-xml.html">Gnome bug tracking
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]136database</a> (make sure to use the "gnome-xml" module name, not libxml or
137libxml2). I look at reports there regularly and it's good to have a reminder
138when a bug is still open. Check the <a
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]139href="http://bugs.gnome.org/Reporting.html">instructions on reporting bugs</a>
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]140and be sure to specify that the bug is for the package gnome-xml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]141
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]142<p>There is also a mailing-list <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]143href="mailto:xml@rpmfind.net">xml@rpmfind.net</a> for libxml, with an <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]144href="http://xmlsoft.org/messages">on-line archive</a>. To subscribe to this
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]145majordomo based list, send a mail message to <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]146href="mailto:majordomo@rpmfind.net">majordomo@rpmfind.net</a> with "subscribe
147xml" in the <strong>content</strong> of the message.</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]148
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]149<p>Alternatively, you can just send the bug to the <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]150href="mailto:xml@rpmfind.net">xml@rpmfind.net</a> list, if it's really libxml
151related I will approve it..</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]152
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]153<p>Of course, bugs reports with a suggested patch for fixing them will
154probably be processed faster.</p>
155
156<p>If you're looking for help, a quick look at <a
157href="http://xmlsoft.org/messages/#407">the list archive</a> may actually
158provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]159questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]160documentantion</a> is not as polished as I would like (i need to learn more
161about Docbook), but it's a good starting point.</p>
162
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]163<h2><a name="help">How to help</a></h2>
164
165<p>You can help the project in various ways, the best thing to do first is to
166subscribe to the mailing-list as explained before, check the <a
167href="http://xmlsoft.org/messages/">archives </a>and the <a
168href="http://bugs.gnome.org/db/pa/lgnome-xml.html">Gnome bug
169database:</a>:</p>
170<ol>
171 <li>provide patches when you find problems</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]172 <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]173 be integrated in all cases but help pinpointing portability problems
174 and</li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]175 <li>provice documentation fixes (either as patches to the code comments or
176 as HTML diffs).</li>
177 <li>provide new documentations pieces (translations, examples, etc ...)</li>
178 <li>Check the TODO file and try to close one of the items</li>
179 <li>take one of the points raised in the archive or the bug database and
180 provide a fix. <a href="mailto:Daniel.Veillard@w3.org">Get in touch with
181 me </a>before to avoid synchronization problems and check that the
182 suggested fix will fit in nicely :-)</li>
183</ol>
184
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]185<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]186
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]187<p>The latest versions of libxml can be found on <a
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]188href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]189href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]190as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]191archive</a> or <a
192href="ftp://ftp.gnome.org/pub/GNOME/contrib/redhat/SRPMS/">RPM packages</a>.
193(NOTE that you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]194href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
195href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]196packages installed to compile applications using libxml.)</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]197
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]198<p><a name="Snapshot">Snapshot:</a></p>
199<ul>
200 <li>Code from the W3C cvs base libxml <a
201 href="ftp://rpmfind.net/pub/libxml/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
202 <li>Docs, content of the web site, the list archive included <a
203 href="ftp://rpmfind.net/pub/libxml/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
204</ul>
205
206<p><a name="Contribs">Contribs:</a></p>
207
208<p>I do accept external contributions, especially if compiling on another
209platform, get in touch with me to upload the package. I will keep them in the
210<a href="ftp://rpmfind.net/pub/libxml/contribs/">contrib directory</a></p>
211
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]212<p>Libxml is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]213<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]214 <li><p>The <a
215 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]216 CVS base</a>. Check the <a
217 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a> page;
218 the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]219 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]220 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]221</ul>
222
223<h2><a name="News">News</a></h2>
224
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]225<h3>CVS only : check the <a
226href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]227for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]228
229<p>Item floating around but not actively worked on, get in touch with me if
230you want to test those</p>
231<ul>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]232 <li>Implementing <a href="http://www.w3.org/TR/xslt">XSLT</a>, this is done
233 as a separate C library on top of libxml called libxslt, not released yet
234 but available from CVS</li>
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]235 <li>Finishing up <a href="http://www.w3.org/TR/xptr">XPointer</a> and <a
236 href="http://www.w3.org/TR/xinclude">XInclude</a></li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]237 <li>(seeems working but delayed from release) parsing/import of Docbook SGML
238 docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]239</ul>
240
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]241<h3>2.2.11: Jan 4 2000</h3>
242<ul>
243 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
244 <li>added htmlHandleOmittedElem()</li>
245 <li>Applied Bjorn Reese's IPV6 first patch</li>
246 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]247 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]248</ul>
249
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]250<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000[diff] [blame]251<ul>
252 <li>Fix the Windows problems of 2.2.8</li>
253 <li>integrate OpenVMS patches</li>
254 <li>better handling of some nasty HTML input</li>
255 <li>Improved the XPointer implementation</li>
256 <li>integrate a number of provided patches</li>
257</ul>
258
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]259<h3>2.2.9: Nov 25 2000</h3>
260<ul>
261 <li>erroneous release :-(</li>
262</ul>
263
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]264<h3>2.2.8: Nov 13 2000</h3>
265<ul>
266 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
267 support</li>
268 <li>Patch in conditional section handling</li>
269 <li>updated MS compiler project</li>
270 <li>fixed some XPath problems</li>
271 <li>added an URI escaping function</li>
272 <li>some other bug fixes</li>
273</ul>
274
275<h3>2.2.7: Oct 31 2000</h3>
276<ul>
277 <li>added message redirection</li>
278 <li>XPath improvements (thanks TOM !)</li>
279 <li>xmlIOParseDTD() added</li>
280 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
281 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
282</ul>
283
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000[diff] [blame]284<h3>2.2.6: Oct 25 2000:</h3>
285<ul>
286 <li>Added an hash table module, migrated a number of internal structure to
287 those</li>
288 <li>Fixed a posteriori validation problems</li>
289 <li>HTTP module cleanups</li>
290 <li>HTML parser improvements (tag errors, script/style handling, attribute
291 normalization)</li>
292 <li>coalescing of adjacent text nodes</li>
293 <li>couple of XPath bug fixes, exported the internal API</li>
294</ul>
295
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]296<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]297<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]298 <li>XPointer implementation and testsuite</li>
299 <li>Lot of XPath fixes, added variable and functions registration, more
300 tests</li>
301 <li>Portability fixes, lots of enhancements toward an easy Windows build and
302 release</li>
303 <li>Late validation fixes</li>
304 <li>Integrated a lot of contributed patches</li>
305 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]306 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]307</ul>
308
309<h3>2.2.4: Oct 1 2000:</h3>
310<ul>
311 <li>main XPath problem fixed</li>
312 <li>Integrated portability patches for Windows</li>
313 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]314</ul>
315
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]316<h3>2.2.3: Sep 17 2000</h3>
317<ul>
318 <li>bug fixes</li>
319 <li>cleanup of entity handling code</li>
320 <li>overall review of all loops in the parsers, all sprintf usage has been
321 checked too</li>
322 <li>Far better handling of larges Dtd. Validating against Docbook XML Dtd
323 works smoothly now.</li>
324</ul>
325
326<h3>1.8.10: Sep 6 2000</h3>
327<ul>
328 <li>bug fix release for some Gnome projects</li>
329</ul>
330
331<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]332<ul>
333 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]334 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]335</ul>
336
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]337<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]338<ul>
339 <li>a purely bug fixes release</li>
340 <li>fixed an encoding support problem when parsing from a memory block</li>
341 <li>fixed a DOCTYPE parsing problem</li>
342 <li>removed a bug in the function allowing to override the memory allocation
343 routines</li>
344</ul>
345
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]346<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]347<ul>
348 <li>applied a lot of portability fixes</li>
349 <li>better encoding support/cleanup and saving (content is now always
350 encoded in UTF-8)</li>
351 <li>the HTML parser now correctly handles encodings</li>
352 <li>added xmlHasProp()</li>
353 <li>fixed a serious problem with &amp;#38;</li>
354 <li>propagated the fix to FTP client</li>
355 <li>cleanup, bugfixes, etc ...</li>
356 <li>Added a page about <a href="encoding.html">libxml Internationalization
357 support</a></li>
358</ul>
359
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]360<h3>1.8.9: July 9 2000</h3>
361<ul>
362 <li>fixed the spec the RPMs should be better</li>
363 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
364 rpmfind users problem</li>
365</ul>
366
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]367<h3>2.1.1: July 1 2000</h3>
368<ul>
369 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
370 <li>improvements on the HTML parser</li>
371</ul>
372
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]373<h3>2.1.0 and 1.8.8: June 29 2000</h3>
374<ul>
375 <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to
376 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
377 about &amp;#38; charref parsing</li>
378 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
379 also contains numerous fixes and enhancements:
380 <ul>
381 <li>added xmlStopParser() to stop parsing</li>
382 <li>improved a lot parsing speed when there is large CDATA blocs</li>
383 <li>includes XPath patches provided by Picdar Technology</li>
384 <li>tried to fix as much as possible DtD validation and namespace
385 related problems</li>
386 <li>output to a given encoding has been added/tested</li>
387 <li>lot of various fixes</li>
388 </ul>
389 </li>
390</ul>
391
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]392<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]393<ul>
394 <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]395 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally
396 scheduled for Apr 3 the relase occured only on Apr 12 due to massive
397 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]398 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]399 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]400 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]401 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]402 <pre>#include "xxx.h"</pre>
403 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]404 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
405 <li>the memory allocation routines used by libxml can now be overloaded
406 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]407 <li>The previously CVS only tool tester has been renamed
408 <strong>xmllint</strong> and is now installed as part of the libxml2
409 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]410 <li>The I/O interface has been revamped. There is now ways to plug in
411 specific I/O modules, either at the URI scheme detection level using
412 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
413 parser context using xmlCreateIOParserCtxt()</li>
414 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
415 number of the libxml module in use</li>
416 <li>a number of optional features of libxml can now be excluded at configure
417 time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]418</ul>
419
420<h3>2.0.0beta: Mar 14 2000</h3>
421<ul>
422 <li>This is a first Beta release of libxml version 2</li>
423 <li>It's available only from<a href="ftp://rpmfind.net/pub/libxml/">
424 rpmfind.net FTP</a>, it's packaged as libxml2-2.0.0beta and available as
425 tar and RPMs</li>
426 <li>This version is now the head in the Gnome CVS base, the old one is
427 available under the tag LIB_XML_1_X</li>
428 <li>This includes a very large set of changes. Froma programmatic point of
429 view applications should not have to be modified too much, check the <a
430 href="upgrade.html">upgrade page</a></li>
431 <li>Some interfaces may changes (especially a bit about encoding).</li>
432 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]433 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]434 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
435 handled now</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]436 <li>Better handling of entities, especially well formedness checking and
437 proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]438 <li>DTD conditional sections</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]439 <li>Validation now correcly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]440 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
441 structures to accomodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]442 </ul>
443 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]444 <li>Serious progress were made toward compliance, <a
445 href="conf/result.html">here are the result of the test</a> against the
446 OASIS testsuite (except the japanese tests since I don't support that
447 encoding yet). This URL is rebuilt every couple of hours using the CVS
448 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]449</ul>
450
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]451<h3>1.8.7: Mar 6 2000</h3>
452<ul>
453 <li>This is a bug fix release:</li>
454 <li>It is possible to disable the ignorable blanks heuristic used by
455 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
456 that for adherence to XML spec, this behaviour will be disabled by default
457 in 2.x . The same function will allow to keep compatibility for old
458 code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]459 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
460 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]461 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
462 compilation on some platforms has been fixed</li>
463 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
464 URIs</li>
465</ul>
466
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]467<h3>1.8.6: Jan 31 2000</h3>
468<ul>
469 <li>added a nanoFTP transport module, debugged until the new version of <a
470 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
471 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]472</ul>
473
474<h3>1.8.5: Jan 21 2000</h3>
475<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]476 <li>adding APIs to parse a well balanced chunk of XML (production <a
477 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the XML
478 spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]479 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]480 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
481 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]482 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
483 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]484</ul>
485
486<h3>1.8.4: Jan 13 2000</h3>
487<ul>
488 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
489 <li>all exit() call should have been removed from libxml</li>
490 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
491 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]492</ul>
493
494<h3>1.8.3: Jan 5 2000</h3>
495<ul>
496 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]497 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillarddbfd6411999-12-28 16:35:14 +0000[diff] [blame]498 <li>lots of bug fixes and improvement added over XMas hollidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]499 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]500 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
501 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]502 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]503 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]504 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]505</ul>
506
507<h3>1.8.2: Dec 21 1999</h3>
508<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]509 <li>I got another problem with includes and C++, I hope this issue is fixed
510 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]511 <li>Added a few tree modification functions: xmlReplaceNode,
512 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
513 xmlDocSetRootElement</li>
514 <li>Tried to improve the HTML output with help from <a
515 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]516</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]517
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]518<h3>1.8.1: Dec 18 1999</h3>
519<ul>
520 <li>various patches to avoid troubles when using libxml with C++ compilers
521 the "namespace" keyword and C escaping in include files</li>
522 <li>a problem in one of the core macros IS_CHAR was corrected</li>
523 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
524 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]525 <li>fixed a posteriori validation (validation after parsing, or by using a
526 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]527 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]528</ul>
529
530<h3>1.8.0: Dec 12 1999</h3>
531<ul>
532 <li>cleanup, especially memory wise</li>
533 <li>the parser should be more reliable, especially the HTML one, it should
534 not crash, whatever the input !</li>
535 <li>Integrated various patches, especially a speedup improvement for large
536 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
537 configure with --with-buffers to enable them.</li>
538 <li>attribute normalization, oops should have been added long ago !</li>
539 <li>attributes defaulted from Dtds should be available, xmlSetProp() now
540 does entities escapting by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]541</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]542
543<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]544<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]545 <li>Lots of HTML improvement</li>
546 <li>Fixed some errors when saving both XML and HTML</li>
547 <li>More examples, the regression tests should now look clean</li>
548 <li>Fixed a bug with contiguous charref</li>
549</ul>
550
551<h3>1.7.3: Sep 29 1999</h3>
552<ul>
553 <li>portability problems fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]554 <li>snprintf was used unconditionnally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]555 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]556</ul>
557
558<h3>1.7.1: Sep 24 1999</h3>
559<ul>
560 <li>The basic type for strings manipulated by libxml has been renamed in
561 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
562 is that CHAR was conflicting with a predefined type on Windows. However on
563 non WIN32 environment, compatibility is provided by the way of a
564 <strong>#define </strong>.</li>
565 <li>Changed another error : the use of a structure field called errno, and
566 leading to troubles on platforms where it's a macro</li>
567</ul>
568
569<h3>1.7.0: sep 23 1999</h3>
570<ul>
571 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]572 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]573 <li>Added an errno to report errors by another mean than a simple printf
574 like callback</li>
575 <li>Finished ID/IDREF support and checking when validation</li>
576 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]577 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]578 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
579 implementation</li>
580 <li>Added an HTML parser front-end</li>
581</ul>
582
583<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]584
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]585<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]586markup-based structured documents. Here is <a name="example">an example XML
587document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]588<pre>&lt;?xml version="1.0"?&gt;
589&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
590 &lt;head&gt;
591 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
592 &lt;/head&gt;
593 &lt;chapter&gt;
594 &lt;title&gt;The Linux adventure&lt;/title&gt;
595 &lt;p&gt;bla bla bla ...&lt;/p&gt;
596 &lt;image href="linus.gif"/&gt;
597 &lt;p&gt;...&lt;/p&gt;
598 &lt;/chapter&gt;
599&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]600
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]601<p>The first line specifies that it's an XML document and gives useful
602information about its encoding. Then the document is a text format whose
603structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]604to be closed</strong>. XML is pedantic about this. However, if a tag is empty
605(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]606ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note that,
607for example, the image tag has no content (just an attribute) and is closed by
608ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]609
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]610<p>XML can be applied sucessfully to a wide range of uses, from long term
611structured document maintenance (where it follows the steps of SGML) to simple
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]612data encoding mechanisms like configuration file formatting (glade),
613spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
614it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]615
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]616<h2><a name="XSLT">XSLT</a></h2>
617
618<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a language
619for transforming XML documents into other XML documents (or HTML/textual
620output).</p>
621
622<p>A separate library called libxslt is being built on top of libxml2. This
623module "libxslt" can be found in the Gnome CVS base too.</p>
624
Daniel Veillard383b1472001-01-23 11:39:52 +0000[diff] [blame]625<p>You can check the <a
626href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a>
627supported and the progresses on the <a
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]628href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog">Changelog</a></p>
629
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]630<h2>An overview of libxml architecture</h2>
631
632<p>Libxml is made of multiple components, some of them optionals, and most of
633the block interfaces are public. The main components are:</p>
634<ul>
635 <li>an Input/Output layer</li>
636 <li>FTP and HTTP client layers (optionnal)</li>
637 <li>an Internationalization layer managing the encodings support</li>
638 <li>an URI module</li>
639 <li>the XML parser and its basic SAX interface</li>
640 <li>an HTML parser using the same SAX interface (optionnal)</li>
641 <li>a SAX tree module to build an in-memory DOM representation</li>
642 <li>a tree module to manipulate the DOM representation</li>
643 <li>a validation module using the DOM representation (optionnal)</li>
644 <li>an XPath module for global lookup in a DOM representation
645 (optionnal)</li>
646 <li>a debug module (optionnal)</li>
647</ul>
648
649<p>Graphically this gives the following:</p>
650
651<p><img src="libxml.gif" alt="a graphical view of the various"></p>
652
653<p></p>
654
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]655<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]656
657<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]658returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]659<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]660as the file name, the document type, and a <strong>children</strong> pointer
661which is the root of the document (or more exactly the first child under the
662root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]663chained in double-linked lists of siblings and with children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]664relationship. An xmlNode can also carry properties (a chain of xmlAttr
665structures). An attribute may have a value which is a list of TEXT or
666ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]667
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]668<p>Here is an example (erroneous with respect to the XML spec since there
669should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]670
671<p><img src="structure.gif" alt=" structure.gif "></p>
672
673<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]674called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]675prints them back as parsed. This is useful for detecting errors both in XML
676code and in the XML parser itself. It has an option <strong>--debug</strong>
677which prints the actual in-memory structure of the document, here is the
678result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]679<pre>DOCUMENT
680version=1.0
681standalone=true
682 ELEMENT EXAMPLE
683 ATTRIBUTE prop1
684 TEXT
685 content=gnome is great
686 ATTRIBUTE prop2
687 ENTITY_REF
688 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]689 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]690 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]691 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]692 TEXT
693 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]694 ELEMENT chapter
695 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]696 TEXT
697 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]698 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]699 TEXT
700 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]701 ELEMENT image
702 ATTRIBUTE href
703 TEXT
704 content=linus.gif
705 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]706 TEXT
707 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]708
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]709<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]710
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]711<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]712
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]713<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]714memory. In that case (and if you don't expect to save back the XML document
715loaded 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]716<strong>callback-based interface</strong> to the parser. Before parsing, the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]717application layer registers a customized set of callbacks which are called by
718the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]719
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]720<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]721libxml, see the <a
722href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
723documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]724Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]725
726<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
727program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]728binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]729distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]730testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]731<pre>SAX.setDocumentLocator()
732SAX.startDocument()
733SAX.getEntity(amp)
734SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
735SAX.characters( , 3)
736SAX.startElement(head)
737SAX.characters( , 4)
738SAX.startElement(title)
739SAX.characters(Welcome to Gnome, 16)
740SAX.endElement(title)
741SAX.characters( , 3)
742SAX.endElement(head)
743SAX.characters( , 3)
744SAX.startElement(chapter)
745SAX.characters( , 4)
746SAX.startElement(title)
747SAX.characters(The Linux adventure, 19)
748SAX.endElement(title)
749SAX.characters( , 4)
750SAX.startElement(p)
751SAX.characters(bla bla bla ..., 15)
752SAX.endElement(p)
753SAX.characters( , 4)
754SAX.startElement(image, href='linus.gif')
755SAX.endElement(image)
756SAX.characters( , 4)
757SAX.startElement(p)
758SAX.characters(..., 3)
759SAX.endElement(p)
760SAX.characters( , 3)
761SAX.endElement(chapter)
762SAX.characters( , 1)
763SAX.endElement(EXAMPLE)
764SAX.endDocument()</pre>
765
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]766<p>Most of the other functionalities of libxml are based on the DOM
767tree-building facility, so nearly everything up to the end of this document
768presupposes the use of the standard DOM tree build. Note that the DOM tree
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]769itself is built by a set of registered default callbacks, without internal
770specific interface.</p>
771
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]772<h2><a name="library">The XML library interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]773
774<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]775using the XML library from the C language. It is not intended to be extensive.
776I hope the automatically generated documents will provide the completeness
777required, but as a separate set of documents. The interfaces of the XML
778library are by principle low level, there is nearly zero abstraction. Those
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]779interested in a higher level API should <a href="#DOM">look at DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]780
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]781<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
782separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]783interfaces</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]784
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]785<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]786
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]787<p>Usually, the first thing to do is to read an XML input. The parser accepts
788documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]789defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]790<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]791 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]792 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]793 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]794</dl>
795<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]796 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]797 <dd><p>Parse an XML document contained in a (possibly compressed)
798 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]799 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]800</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]801
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]802<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]803failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]804
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]805<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]806
807<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]808fetched (which is common for GUI based programs) libxml provides a push
809interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]810<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
811 void *user_data,
812 const char *chunk,
813 int size,
814 const char *filename);
815int xmlParseChunk (xmlParserCtxtPtr ctxt,
816 const char *chunk,
817 int size,
818 int terminate);</pre>
819
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]820<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]821<pre> FILE *f;
822
823 f = fopen(filename, "r");
824 if (f != NULL) {
825 int res, size = 1024;
826 char chars[1024];
827 xmlParserCtxtPtr ctxt;
828
829 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]830 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]831 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
832 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]833 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]834 xmlParseChunk(ctxt, chars, res, 0);
835 }
836 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]837 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]838 xmlFreeParserCtxt(ctxt);
839 }
840 }</pre>
841
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]842<p>Also note that the HTML parser embedded into libxml also has a push
843interface; the functions are just prefixed by "html" rather than "xml"</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]844
845<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
846
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]847<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]848memory-hungry, first to load the document in memory, second to build the tree.
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]849Reading a document without building the tree is possible using the SAX
850interfaces (see SAX.h and <a
851href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]852Henstridge's documentation</a>). Note also that the push interface can be
853limited to SAX. Just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]854<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]855
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]856<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]857
858<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]859there is a set of functions dedicated to building new elements. (These are
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]860also 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]861that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]862<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]863 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]864 xmlNodePtr tree, subtree;
865
866 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]867 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
868 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
869 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
870 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]871 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]872 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]873 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
874 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
875 subtree = xmlNewChild(tree, NULL, "image", NULL);
876 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]877
878<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]879
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]880<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]881
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]882<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]883code has access to the internal structure of all the elements of the tree. The
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]884names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]885<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]886<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]887example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]888<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]889
890<p>points to the title element,</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]891<pre>doc-&gt;children-&gt;children-&gt;next-&gt;child-&gt;child</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]892
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]893<p>points to the text node containing the chapter title "The Linux
894adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]895
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]896<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]897present before the document root, so <code>doc-&gt;children</code> may point
898to an element which is not the document Root Element, a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]899<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]900
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]901<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]902
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]903<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]904is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]905<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]906 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
907 xmlChar *value);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]908 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node. The
909 value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]910 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]911</dl>
912<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]913 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]914 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +0000[diff] [blame]915 <dd><p>This function returns a pointer to new copy of the property
916 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]917 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]918</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]919
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]920<p>Two functions are provided for reading and writing the text associated with
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]921elements:</p>
922<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]923 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]924 *value);</code></dt>
925 <dd><p>This function takes an "external" string and convert it to one text
926 node or possibly to a list of entity and text nodes. All non-predefined
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]927 entity references like &amp;Gnome; will be stored internally as entity
928 nodes, hence the result of the function may not be a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]929 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]930</dl>
931<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]932 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]933 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]934 <dd><p>This function is the inverse of
935 <code>xmlStringGetNodeList()</code>. It generates a new string
936 containing the content of the text and entity nodes. Note the extra
937 argument inLine. If this argument is set to 1, the function will expand
938 entity references. For example, instead of returning the &amp;Gnome;
939 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]940 "GNU Network Object Model Environment"). Set this argument if you want
941 to use the string for non-XML usage like User Interface.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]942 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]943</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]944
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]945<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]946
947<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]948<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]949 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]950 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]951 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]952 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]953</dl>
954<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]955 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]956 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]957 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]958</dl>
959<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]960 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]961 <dd><p>Saves the document to a file. In this case, the compression
962 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]963 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]964</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]965
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]966<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]967
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]968<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]969accesses. The level of compression on saves can be turned on either globally
970or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]971<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]972 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]973 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]974 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]975</dl>
976<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]977 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]978 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]979 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]980</dl>
981<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]982 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]983 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]984 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]985</dl>
986<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]987 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]988 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]989 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]990</dl>
991
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]992<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]993
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]994<p>Entities in principle are similar to simple C macros. An entity defines an
995abbreviation for a given string that you can reuse many times throughout the
996content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]997may occur frequently within a document, or to confine the change needed to a
998document to a restricted area in the internal subset of the document (at the
999beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1000<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]10012 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]10023 &lt;!ENTITY xml "Extensible Markup Language"&gt;
10034 ]&gt;
10045 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]10056 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]10067 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1007
1008<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]1009it's name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1010are 5 predefined entities in libxml allowing you to escape charaters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1011predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1012<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1013for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1014<strong>&amp;quot;</strong> for the character '"', and
1015<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1016
1017<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]1018substitute an entity's content so that you can see the replacement text in
1019your application. Or you may prefer to keep entity references as such in the
1020content to be able to save the document back without losing this usually
1021precious information (if the user went through the pain of explicitly defining
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1022entities, he may have a a rather negative attitude if you blindly susbtitute
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1023them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1024href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1025function allows you to check and change the behaviour, which is to not
1026substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1027
1028<p>Here is the DOM tree built by libxml for the previous document in the
1029default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1030<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1031DOCUMENT
1032version=1.0
1033 ELEMENT EXAMPLE
1034 TEXT
1035 content=
1036 ENTITY_REF
1037 INTERNAL_GENERAL_ENTITY xml
1038 content=Extensible Markup Language
1039 TEXT
1040 content=</pre>
1041
1042<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1043<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1044DOCUMENT
1045version=1.0
1046 ELEMENT EXAMPLE
1047 TEXT
1048 content= Extensible Markup Language</pre>
1049
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1050<p>So, entities or no entities? Basically, it depends on your use case. I
1051suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1052entities in your XML document or data if you are not willing to handle the
1053entity references elements in the DOM tree.</p>
1054
1055<p>Note that at save time libxml enforce the conversion of the predefined
1056entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1057transparently replace those with chars (i.e., it will not generate entity
1058reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1059finding them in the input).</p>
1060
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]1061<p><span style="background-color: #FF0000">WARNING</span>: handling entities
1062on top of libxml SAX interface is difficult !!! If you plan to use
1063non-predefined entities in your documents, then the learning cuvre to handle
1064then using the SAX API may be long. If you plan to use complex document, I
1065strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]1066deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]1067
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1068<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1069
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1070<p>The libxml library implements <a
1071href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
1072recognizing namespace contructs in the input, and does namespace lookup
1073automatically when building the DOM tree. A namespace declaration is
1074associated with an in-memory structure and all elements or attributes within
1075that namespace point to it. Hence testing the namespace is a simple and fast
1076equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1077
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1078<p>I suggest that people using libxml use a namespace, and declare it in the
1079root element of their document as the default namespace. Then they don't need
1080to use the prefix in the content but we will have a basis for future semantic
1081refinement and merging of data from different sources. This doesn't augment
1082significantly the size of the XML output, but significantly increase its value
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1083in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1084<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
1085 &lt;elem1&gt;...&lt;/elem1&gt;
1086 &lt;elem2&gt;...&lt;/elem2&gt;
1087&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1088
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1089<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]1090have to point to any existing resource on the Web. It will bind all the
1091element and atributes with that URL. I suggest to use an URL within a domain
1092you control, and that the URL should contain some kind of version information
1093if possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1094a good namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1095
1096<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1097version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1098and if the version information don't match something you know, warn the user
1099and 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]1100namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
1101same as &lt;bar:text&gt; in another document. What really matter is the URI
1102associated with the element or the attribute, not the prefix string (which is
1103just a shortcut for the full URI). In libxml element and attributes have a
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1104<code>ns</code> field pointing to an xmlNs structure detailing the namespace
1105prefix and it's URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1106
1107<p>@@Interfaces@@</p>
1108
1109<p>@@Examples@@</p>
1110
1111<p>Usually people object using namespace in the case of validation, I object
1112this and will make sure that using namespaces won't break validity checking,
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1113so even is you plan to use or currently are using validation I strongly
1114suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1115<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1116flexible parsers. Now using namespace to mix and differentiate content coming
1117from multiple DTDs will certainly break current validation schemes. I will try
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1118to provide ways to do this, but this may not be portable or standardized.</p>
1119
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1120<h2><a name="Validation">Validation, or are you afraid of DTDs ?</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1121
1122<p>Well what is validation and what is a DTD ?</p>
1123
1124<p>Validation is the process of checking a document against a set of
1125construction rules, a <strong>DTD</strong> (Document Type Definition) is such
1126a set of rules.</p>
1127
1128<p>The validation process and building DTDs are the two most difficult parts
1129of XML life cycle. Briefly a DTD defines all the possibles element to be
1130found within your document, what is the formal shape of your document tree (by
1131defining the allowed content of an element, either text, a regular expression
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1132for the allowed list of children, or mixed content i.e. both text and
1133children). The DTD also defines the allowed attributes for all elements and
1134the types of the attributes. For more detailed informations, I suggest to read
1135the related parts of the XML specification, the examples found under
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1136gnome-xml/test/valid/dtd and the large amount of books available on XML. The
1137dia example in gnome-xml/test/valid should be both simple and complete enough
1138to allow you to build your own.</p>
1139
1140<p>A word of warning, building a good DTD which will fit your needs of your
1141application in the long-term is far from trivial, however the extra level of
1142quality it can insure is well worth the price for some sets of applications or
1143if you already have already a DTD defined for your application field.</p>
1144
1145<p>The validation is not completely finished but in a (very IMHO) usable
1146state. Until a real validation interface is defined the way to do it is to
1147define and set the <strong>xmlDoValidityCheckingDefaultValue</strong> external
1148variable to 1, this will of course be changed at some point:</p>
1149
1150<p>extern int xmlDoValidityCheckingDefaultValue;</p>
1151
1152<p>...</p>
1153
1154<p>xmlDoValidityCheckingDefaultValue = 1;</p>
1155
1156<p></p>
1157
1158<p>To handle external entities, use the function
1159<strong>xmlSetExternalEntityLoader</strong>(xmlExternalEntityLoader f); to
1160link in you HTTP/FTP/Entities database library to the standard libxml
1161core.</p>
1162
1163<p>@@interfaces@@</p>
1164
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1165<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1166
1167<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]1168Model</em> this is an API for accessing XML or HTML structured documents.
1169Native 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]1170be based on gnome-xml. This will be a far cleaner interface to manipulate XML
Daniel Veillardc08a2c61999-09-08 21:35:25 +0000[diff] [blame]1171files within Gnome since it won't expose the internal structure. DOM defines a
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1172set of IDL (or Java) interfaces allowing to traverse and manipulate a
1173document. The DOM library will allow accessing and modifying "live" documents
1174presents on other programs like this:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1175
1176<p><img src="DOM.gif" alt=" DOM.gif "></p>
1177
1178<p>This should help greatly doing things like modifying a gnumeric spreadsheet
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1179embedded in a GWP document for example.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1180
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1181<p>The current DOM implementation on top of libxml is the <a
1182href="http://cvs.gnome.org/lxr/source/gdome/">gdome Gnome module</a>, this is
1183a full DOM interface, thanks to <a href="mailto:raph@levien.com">Raph
1184Levien</a>.</p>
1185
1186<p>The gnome-dom module in the Gnome CVS base is obsolete</p>
1187
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1188<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1189
1190<p>Here is a real size example, where the actual content of the application
1191data 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]1192a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1193storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
1194base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1195<pre>&lt;?xml version="1.0"?&gt;
1196&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
1197 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1198
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1199 &lt;gjob:Job&gt;
1200 &lt;gjob:Project ID="3"/&gt;
1201 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
1202 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1203
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1204 &lt;gjob:Update&gt;
1205 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
1206 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
1207 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
1208 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1209
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1210 &lt;gjob:Developers&gt;
1211 &lt;gjob:Developer&gt;
1212 &lt;/gjob:Developer&gt;
1213 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1214
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1215 &lt;gjob:Contact&gt;
1216 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
1217 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
1218 &lt;gjob:Company&gt;
1219 &lt;/gjob:Company&gt;
1220 &lt;gjob:Organisation&gt;
1221 &lt;/gjob:Organisation&gt;
1222 &lt;gjob:Webpage&gt;
1223 &lt;/gjob:Webpage&gt;
1224 &lt;gjob:Snailmail&gt;
1225 &lt;/gjob:Snailmail&gt;
1226 &lt;gjob:Phone&gt;
1227 &lt;/gjob:Phone&gt;
1228 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1229
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1230 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1231 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1232 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1233
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1234 &lt;gjob:Skills&gt;
1235 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1236
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1237 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1238 A GNOME based system that will allow a superuser to configure
1239 compressed and uncompressed files and/or file systems to be backed
1240 up with a supported media in the system. This should be able to
1241 perform via find commands generating a list of files that are passed
1242 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
1243 or via operations performed on the filesystem itself. Email
1244 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1245 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1246
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1247 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1248
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1249 &lt;/gjob:Jobs&gt;
1250&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1251
1252<p>While loading the XML file into an internal DOM tree is a matter of calling
1253only a couple of functions, browsing the tree to gather the informations and
1254generate the internals structures is harder, and more error prone.</p>
1255
1256<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1257structure. For example, the ordering of the attributes is not significant,
1258Cthe 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]1259be dependent of the orders of the children of a given node, unless it really
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1260makes things harder. Here is some code to parse the informations for a
1261person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1262<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1263 * A person record
1264 */
1265typedef struct person {
1266 char *name;
1267 char *email;
1268 char *company;
1269 char *organisation;
1270 char *smail;
1271 char *webPage;
1272 char *phone;
1273} person, *personPtr;
1274
1275/*
1276 * And the code needed to parse it
1277 */
1278personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1279 personPtr ret = NULL;
1280
1281DEBUG("parsePerson\n");
1282 /*
1283 * allocate the struct
1284 */
1285 ret = (personPtr) malloc(sizeof(person));
1286 if (ret == NULL) {
1287 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1288 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1289 }
1290 memset(ret, 0, sizeof(person));
1291
1292 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1293 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1294 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1295 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
1296 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1297 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
1298 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1299 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1300 }
1301
1302 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1303}</pre>
1304
1305<p>Here is a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1306<ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1307 <li>Usually a recursive parsing style is the more convenient one, XML data
1308 being by nature subject to repetitive constructs and usualy exibit highly
1309 stuctured patterns.</li>
1310 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>, i.e.
1311 the pointer to the global XML document and the namespace reserved to the
1312 application. Document wide information are needed for example to decode
1313 entities and it's a good coding practice to define a namespace for your
1314 application set of data and test that the element and attributes you're
1315 analyzing actually pertains to your application space. This is done by a
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1316 simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1317 <li>To retrieve text and attributes value, it is suggested to use the
1318 function <em>xmlNodeListGetString</em> to gather all the text and entity
1319 reference nodes generated by the DOM output and produce an single text
1320 string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1321</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1322
1323<p>Here is another piece of code used to parse another level of the
1324structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1325<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1326/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1327 * a Description for a Job
1328 */
1329typedef struct job {
1330 char *projectID;
1331 char *application;
1332 char *category;
1333 personPtr contact;
1334 int nbDevelopers;
1335 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
1336} job, *jobPtr;
1337
1338/*
1339 * And the code needed to parse it
1340 */
1341jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1342 jobPtr ret = NULL;
1343
1344DEBUG("parseJob\n");
1345 /*
1346 * allocate the struct
1347 */
1348 ret = (jobPtr) malloc(sizeof(job));
1349 if (ret == NULL) {
1350 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1351 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1352 }
1353 memset(ret, 0, sizeof(job));
1354
1355 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1356 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1357 while (cur != NULL) {
1358
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1359 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
1360 ret-&gt;projectID = xmlGetProp(cur, "ID");
1361 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1362 fprintf(stderr, "Project has no ID\n");
1363 }
1364 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1365 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
1366 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1367 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
1368 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1369 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
1370 ret-&gt;contact = parsePerson(doc, ns, cur);
1371 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1372 }
1373
1374 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1375}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1376
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1377<p>One can notice that once used to it, writing this kind of code is quite
1378simple, but boring. Ultimately, it could be possble to write stubbers taking
1379either C data structure definitions, a set of XML examples or an XML DTD and
1380produce the code needed to import and export the content between C data and
1381XML storage. This is left as an exercise to the reader :-)</p>
1382
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]1383<p>Feel free to use <a href="example/gjobread.c">the code for the full C
1384parsing example</a> as a template, it is also available with Makefile in the
1385Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1386
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1387<h2><a name="Contributi">Contributions</a></h2>
1388<ul>
Daniel Veillard851c59c2000-11-24 16:06:22 +0000[diff] [blame]1389 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1390 for libxml:
1391 <p>Website: <a
1392 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
1393 <p>Download: <a
1394 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
1395 </li>
1396 <li><a href="mailto:doolin@cs.utk.edu">David Doolin</a> provides a
1397 precompiled Windows version
1398 <p><a
1399 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
1400 </li>
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1401 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> provided <a
1402 href="libxml-doc.el">an emacs module</a> to lookup libxml functions
1403 documentation</li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1404 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
1405 href="http://xmlsoft.org/messages/0488.html">man pages</a> (not yet
1406 integrated in the distribution)</li>
1407</ul>
1408
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1409<p></p>
1410
1411<p><a href="mailto:Daniel.Veillard@w3.org">Daniel Veillard</a></p>
1412
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1413<p>$Id: xml.html,v 1.65 2001/01/23 11:39:52 veillard Exp $</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1414</body>
1415</html>