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gerrit-public.fairphone.software / fp2-dev / platform / external / libxml2 / 91e9d589eac436536e781c95f474f99c2f39d6f7 / . / doc / xml.html
blob: d546ed16c7b9ef2cce87465c05fe440c4fd3af17 [file] [log] [blame]
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1<html>
2<head>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]3 <title>The XML C library for Gnome</title>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]4 <meta name="GENERATOR" content="amaya V4.1">
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]6</head>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]7
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]8<body bgcolor="#ffffff">
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]9<p><a href="http://www.gnome.org/"><img src="smallfootonly.gif"
10alt="Gnome Logo"></a><a href="http://www.w3.org/Status"><img src="w3c.png"
11alt="W3C Logo"></a></p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]12
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]13<h1 align="center">The XML C library for Gnome</h1>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]14
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]15<h2 style="text-align: center">libxml, a.k.a. gnome-xml</h2>
16
17<p></p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]18<ul>
19 <li><a href="#Introducti">Introduction</a></li>
20 <li><a href="#Documentat">Documentation</a></li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]21 <li><a href="#Reporting">Reporting bugs and getting help</a></li>
22 <li><a href="#help">how to help</a></li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]23 <li><a href="#Downloads">Downloads</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]24 <li><a href="#News">News</a></li>
25 <li><a href="#XML">XML</a></li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]26 <li><a href="#XSLT">XSLT</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]27 <li><a href="#tree">The tree output</a></li>
28 <li><a href="#interface">The SAX interface</a></li>
29 <li><a href="#library">The XML library interfaces</a>
30 <ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]31 <li><a href="#Invoking">Invoking the parser: the pull way</a></li>
32 <li><a href="#Invoking">Invoking the parser: the push way</a></li>
33 <li><a href="#Invoking2">Invoking the parser: the SAX interface</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]34 <li><a href="#Building">Building a tree from scratch</a></li>
35 <li><a href="#Traversing">Traversing the tree</a></li>
36 <li><a href="#Modifying">Modifying the tree</a></li>
37 <li><a href="#Saving">Saving the tree</a></li>
38 <li><a href="#Compressio">Compression</a></li>
39 </ul>
40 </li>
41 <li><a href="#Entities">Entities or no entities</a></li>
42 <li><a href="#Namespaces">Namespaces</a></li>
43 <li><a href="#Validation">Validation</a></li>
44 <li><a href="#Principles">DOM principles</a></li>
45 <li><a href="#real">A real example</a></li>
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]46 <li><a href="#Contributi">Contributions</a></li>
47</ul>
48
49<p>Separate documents:</p>
50<ul>
51 <li><a href="upgrade.html">upgrade instructions for migrating to
52 libxml2</a></li>
53 <li><a href="encoding.html">libxml Internationalization support</a></li>
54 <li><a href="xmlio.html">libxml Input/Output interfaces</a></li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]55 <li><a href="xmlmem.html">libxml Memory interfaces</a></li>
Daniel Veillard300f7d62000-11-24 13:04:04 +0000[diff] [blame]56 <li><a href="xmldtd.html">a short introduction about DTDs and
57 libxml</a></li>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]58 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]59</ul>
60
61<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]62
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]63<p>This document describes libxml, the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]64href="http://www.w3.org/XML/">XML</a> C library developped for the <a
65href="http://www.gnome.org/">Gnome</a> project. <a
66href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
67structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]68
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]69<p>Here are some key points about libxml:</p>
70<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]71 <li>Libxml exports Push and Pull type parser interfaces for both XML and
72 HTML.</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]73 <li>Libxml can do DTD validation at parse time, using a parsed document
74 instance, or with an arbitrary DTD.</li>
75 <li>Libxml now includes nearly complete <a
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]76 href="http://www.w3.org/TR/xpath">XPath</a> and <a
Daniel Veillard0c069222000-10-21 09:25:52 +0000[diff] [blame]77 href="http://www.w3.org/TR/xptr">XPointer</a> implementations.</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]78 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]79 sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]80 Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]81 <li>Basic support for HTTP and FTP client allowing aplications to fetch remote
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]82 resources</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]83 <li>The design is modular, most of the extensions can be compiled out.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]84 <li>The internal document repesentation is as close as possible to the <a
85 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
86 <li>Libxml also has a <a href="http://www.megginson.com/SAX/index.html">SAX
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]87 like interface</a>; the interface is designed to be compatible with <a
88 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]89 <li>This library is released both under the <a
90 href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]91 IPR</a> and the <a href="http://www.gnu.org/copyleft/lesser.html">GNU
92 LGPL</a>. Use either at your convenience, basically this should make
93 everybody happy, if not, drop me a mail.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]94</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]95
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]96<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]97
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]98<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]99<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]100 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]101 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]102 documentation</a> automatically extracted from code comments (using <a
103 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
104 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000[diff] [blame]105 <li>Look at the documentation about <a href="encoding.html">libxml
106 internationalization support</a></li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]107 <li>This page provides a global overview and <a href="#real">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]108 examples</a> on how to use libxml.</li>
109 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
110 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
111 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]112 <li>George Lebl wrote <a
113 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]114 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]115 <li>It is also a good idea to check to <a href="mailto:raph@levien.com">Raph
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]116 Levien</a>'s <a href="http://levien.com/gnome/">web site</a> since he is
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]117 building the <a href="http://levien.com/gnome/gdome.html">DOM interface
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]118 gdome</a> on top of libxml result tree and an implementation of <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]119 href="http://www.w3.org/Graphics/SVG/">SVG</a> called <a
120 href="http://www.levien.com/svg/">gill</a>. Check his <a
121 href="http://www.levien.com/gnome/domination.html">DOMination
122 paper</a>.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]123 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
124 file</a></li>
125 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
126 starting a new project using libxml you should really use the 2.x
127 version.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]128 <li>And don't forget to look at the <a href="/messages/">mailing-list
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]129 archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]130</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]131
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]132<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]133
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]134<p>Well, bugs or missing features are always possible, and I will make a point
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]135of fixing them in a timely fashion. The best way to report a bug is to use the
136<a href="http://bugs.gnome.org/db/pa/lgnome-xml.html">Gnome bug tracking
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]137database</a> (make sure to use the "gnome-xml" module name, not libxml or
138libxml2). I look at reports there regularly and it's good to have a reminder
139when a bug is still open. Check the <a
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]140href="http://bugs.gnome.org/Reporting.html">instructions on reporting bugs</a>
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]141and be sure to specify that the bug is for the package gnome-xml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]142
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]143<p>There is also a mailing-list <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]144href="mailto:xml@rpmfind.net">xml@rpmfind.net</a> for libxml, with an <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]145href="http://xmlsoft.org/messages">on-line archive</a>. To subscribe to this
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]146majordomo based list, send a mail message to <a
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]147href="mailto:majordomo@rpmfind.net">majordomo@rpmfind.net</a> with "subscribe
148xml" in the <strong>content</strong> of the message.</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]149
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]150<p>Alternatively, you can just send the bug to the <a
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]151href="mailto:xml@rpmfind.net">xml@rpmfind.net</a> list; if it's really libxml
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]152related I will approve it..</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]153
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]154<p>Of course, bugs reported with a suggested patch for fixing them will
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]155probably be processed faster.</p>
156
157<p>If you're looking for help, a quick look at <a
158href="http://xmlsoft.org/messages/#407">the list archive</a> may actually
159provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]160questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]161documentantion</a> is not as polished as I would like (i need to learn more
162about Docbook), but it's a good starting point.</p>
163
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]164<h2><a name="help">How to help</a></h2>
165
166<p>You can help the project in various ways, the best thing to do first is to
167subscribe to the mailing-list as explained before, check the <a
168href="http://xmlsoft.org/messages/">archives </a>and the <a
169href="http://bugs.gnome.org/db/pa/lgnome-xml.html">Gnome bug
170database:</a>:</p>
171<ol>
172 <li>provide patches when you find problems</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]173 <li>provide the diffs when you port libxml to a new platform. They may not
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]174 be integrated in all cases but help pinpointing portability problems
175 and</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]176 <li>provide documentation fixes (either as patches to the code comments or
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]177 as HTML diffs).</li>
178 <li>provide new documentations pieces (translations, examples, etc ...)</li>
179 <li>Check the TODO file and try to close one of the items</li>
180 <li>take one of the points raised in the archive or the bug database and
181 provide a fix. <a href="mailto:Daniel.Veillard@w3.org">Get in touch with
182 me </a>before to avoid synchronization problems and check that the
183 suggested fix will fit in nicely :-)</li>
184</ol>
185
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]186<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]187
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]188<p>The latest versions of libxml can be found on <a
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]189href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]190href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]191as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]192archive</a> or <a
193href="ftp://ftp.gnome.org/pub/GNOME/contrib/redhat/SRPMS/">RPM packages</a>.
194(NOTE that you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]195href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
196href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]197packages installed to compile applications using libxml.)</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]198
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]199<p><a name="Snapshot">Snapshot:</a></p>
200<ul>
201 <li>Code from the W3C cvs base libxml <a
202 href="ftp://rpmfind.net/pub/libxml/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
203 <li>Docs, content of the web site, the list archive included <a
204 href="ftp://rpmfind.net/pub/libxml/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
205</ul>
206
207<p><a name="Contribs">Contribs:</a></p>
208
209<p>I do accept external contributions, especially if compiling on another
210platform, get in touch with me to upload the package. I will keep them in the
211<a href="ftp://rpmfind.net/pub/libxml/contribs/">contrib directory</a></p>
212
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]213<p>Libxml is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]214<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]215 <li><p>The <a
216 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Gnome
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]217 CVS base</a>. Check the <a
218 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a> page;
219 the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]220 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]221 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]222</ul>
223
224<h2><a name="News">News</a></h2>
225
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]226<h3>CVS only : check the <a
227href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]228for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]229
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]230<p>Items floating around but not actively worked on, get in touch with me if
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]231you want to test those</p>
232<ul>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]233 <li>Implementing <a href="http://xmlsoft.org/XSLT">XSLT</a>, this is done as
234 a separate C library on top of libxml called libxslt, not released yet but
235 available from CVS</li>
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]236 <li>Finishing up <a href="http://www.w3.org/TR/xptr">XPointer</a> and <a
237 href="http://www.w3.org/TR/xinclude">XInclude</a></li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]238 <li>(seeems working but delayed from release) parsing/import of Docbook SGML
239 docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]240</ul>
241
Daniel Veillard71681102001-02-24 17:48:53 +0000[diff] [blame]242<h3>2.3.2: Feb 24 2000</h3>
243<ul>
244 <li>chasing XPath bugs, found a bunch, completed some TODO</li>
245 <li>fixed a Dtd parsing bug</li>
246 <li>fixed a bug in xmlNodeGetContent</li>
247 <li>ID/IDREF support partly rewritten by Gary Pennington</li>
248</ul>
249
250<h3>2.3.1: Feb 15 2000</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]251<ul>
252 <li>some XPath and HTML bug fixes for XSLT</li>
253 <li>small extension of the hash table interfaces for DOM gdome2
254 implementation</li>
255 <li>A few bug fixes</li>
256</ul>
257
Daniel Veillard71681102001-02-24 17:48:53 +0000[diff] [blame]258<h3>2.3.0: Feb 8 2000 (2.2.12 was on 25 Jan but I didn't kept track)</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]259<ul>
260 <li>Lots of XPath bug fixes</li>
261 <li>Add a mode with Dtd lookup but without validation error reporting for
262 XSLT</li>
263 <li>Add support for text node without escaping (XSLT)</li>
264 <li>bug fixes for xmlCheckFilename</li>
265 <li>validation code bug fixes from Gary Pennington</li>
266 <li>Patch from Paul D. Smith correcting URI path normalization</li>
267 <li>Patch to allow simultaneous install of libxml-devel and
268 libxml2-devel</li>
269 <li>the example Makefile is now fixed</li>
270 <li>added HTML to the RPM packages</li>
271 <li>tree copying bugfixes</li>
272 <li>updates to Windows makefiles</li>
273 <li>optimisation patch from Bjorn Reese</li>
274</ul>
275
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]276<h3>2.2.11: Jan 4 2000</h3>
277<ul>
278 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
279 <li>added htmlHandleOmittedElem()</li>
280 <li>Applied Bjorn Reese's IPV6 first patch</li>
281 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]282 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]283</ul>
284
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]285<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000[diff] [blame]286<ul>
287 <li>Fix the Windows problems of 2.2.8</li>
288 <li>integrate OpenVMS patches</li>
289 <li>better handling of some nasty HTML input</li>
290 <li>Improved the XPointer implementation</li>
291 <li>integrate a number of provided patches</li>
292</ul>
293
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]294<h3>2.2.9: Nov 25 2000</h3>
295<ul>
296 <li>erroneous release :-(</li>
297</ul>
298
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]299<h3>2.2.8: Nov 13 2000</h3>
300<ul>
301 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
302 support</li>
303 <li>Patch in conditional section handling</li>
304 <li>updated MS compiler project</li>
305 <li>fixed some XPath problems</li>
306 <li>added an URI escaping function</li>
307 <li>some other bug fixes</li>
308</ul>
309
310<h3>2.2.7: Oct 31 2000</h3>
311<ul>
312 <li>added message redirection</li>
313 <li>XPath improvements (thanks TOM !)</li>
314 <li>xmlIOParseDTD() added</li>
315 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
316 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
317</ul>
318
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000[diff] [blame]319<h3>2.2.6: Oct 25 2000:</h3>
320<ul>
321 <li>Added an hash table module, migrated a number of internal structure to
322 those</li>
323 <li>Fixed a posteriori validation problems</li>
324 <li>HTTP module cleanups</li>
325 <li>HTML parser improvements (tag errors, script/style handling, attribute
326 normalization)</li>
327 <li>coalescing of adjacent text nodes</li>
328 <li>couple of XPath bug fixes, exported the internal API</li>
329</ul>
330
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]331<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]332<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]333 <li>XPointer implementation and testsuite</li>
334 <li>Lot of XPath fixes, added variable and functions registration, more
335 tests</li>
336 <li>Portability fixes, lots of enhancements toward an easy Windows build and
337 release</li>
338 <li>Late validation fixes</li>
339 <li>Integrated a lot of contributed patches</li>
340 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]341 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]342</ul>
343
344<h3>2.2.4: Oct 1 2000:</h3>
345<ul>
346 <li>main XPath problem fixed</li>
347 <li>Integrated portability patches for Windows</li>
348 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]349</ul>
350
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]351<h3>2.2.3: Sep 17 2000</h3>
352<ul>
353 <li>bug fixes</li>
354 <li>cleanup of entity handling code</li>
355 <li>overall review of all loops in the parsers, all sprintf usage has been
356 checked too</li>
357 <li>Far better handling of larges Dtd. Validating against Docbook XML Dtd
358 works smoothly now.</li>
359</ul>
360
361<h3>1.8.10: Sep 6 2000</h3>
362<ul>
363 <li>bug fix release for some Gnome projects</li>
364</ul>
365
366<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]367<ul>
368 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]369 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]370</ul>
371
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]372<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]373<ul>
374 <li>a purely bug fixes release</li>
375 <li>fixed an encoding support problem when parsing from a memory block</li>
376 <li>fixed a DOCTYPE parsing problem</li>
377 <li>removed a bug in the function allowing to override the memory allocation
378 routines</li>
379</ul>
380
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]381<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]382<ul>
383 <li>applied a lot of portability fixes</li>
384 <li>better encoding support/cleanup and saving (content is now always
385 encoded in UTF-8)</li>
386 <li>the HTML parser now correctly handles encodings</li>
387 <li>added xmlHasProp()</li>
388 <li>fixed a serious problem with &amp;#38;</li>
389 <li>propagated the fix to FTP client</li>
390 <li>cleanup, bugfixes, etc ...</li>
391 <li>Added a page about <a href="encoding.html">libxml Internationalization
392 support</a></li>
393</ul>
394
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]395<h3>1.8.9: July 9 2000</h3>
396<ul>
397 <li>fixed the spec the RPMs should be better</li>
398 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
399 rpmfind users problem</li>
400</ul>
401
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]402<h3>2.1.1: July 1 2000</h3>
403<ul>
404 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
405 <li>improvements on the HTML parser</li>
406</ul>
407
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]408<h3>2.1.0 and 1.8.8: June 29 2000</h3>
409<ul>
410 <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to
411 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
412 about &amp;#38; charref parsing</li>
413 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
414 also contains numerous fixes and enhancements:
415 <ul>
416 <li>added xmlStopParser() to stop parsing</li>
417 <li>improved a lot parsing speed when there is large CDATA blocs</li>
418 <li>includes XPath patches provided by Picdar Technology</li>
419 <li>tried to fix as much as possible DtD validation and namespace
420 related problems</li>
421 <li>output to a given encoding has been added/tested</li>
422 <li>lot of various fixes</li>
423 </ul>
424 </li>
425</ul>
426
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]427<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]428<ul>
429 <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]430 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally
431 scheduled for Apr 3 the relase occured only on Apr 12 due to massive
432 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]433 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]434 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]435 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]436 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]437 <pre>#include "xxx.h"</pre>
438 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]439 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
440 <li>the memory allocation routines used by libxml can now be overloaded
441 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]442 <li>The previously CVS only tool tester has been renamed
443 <strong>xmllint</strong> and is now installed as part of the libxml2
444 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]445 <li>The I/O interface has been revamped. There is now ways to plug in
446 specific I/O modules, either at the URI scheme detection level using
447 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
448 parser context using xmlCreateIOParserCtxt()</li>
449 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
450 number of the libxml module in use</li>
451 <li>a number of optional features of libxml can now be excluded at configure
452 time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]453</ul>
454
455<h3>2.0.0beta: Mar 14 2000</h3>
456<ul>
457 <li>This is a first Beta release of libxml version 2</li>
458 <li>It's available only from<a href="ftp://rpmfind.net/pub/libxml/">
459 rpmfind.net FTP</a>, it's packaged as libxml2-2.0.0beta and available as
460 tar and RPMs</li>
461 <li>This version is now the head in the Gnome CVS base, the old one is
462 available under the tag LIB_XML_1_X</li>
463 <li>This includes a very large set of changes. Froma programmatic point of
464 view applications should not have to be modified too much, check the <a
465 href="upgrade.html">upgrade page</a></li>
466 <li>Some interfaces may changes (especially a bit about encoding).</li>
467 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]468 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]469 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
470 handled now</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]471 <li>Better handling of entities, especially well formedness checking and
472 proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]473 <li>DTD conditional sections</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]474 <li>Validation now correcly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]475 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
476 structures to accomodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]477 </ul>
478 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]479 <li>Serious progress were made toward compliance, <a
480 href="conf/result.html">here are the result of the test</a> against the
481 OASIS testsuite (except the japanese tests since I don't support that
482 encoding yet). This URL is rebuilt every couple of hours using the CVS
483 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]484</ul>
485
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]486<h3>1.8.7: Mar 6 2000</h3>
487<ul>
488 <li>This is a bug fix release:</li>
489 <li>It is possible to disable the ignorable blanks heuristic used by
490 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
491 that for adherence to XML spec, this behaviour will be disabled by default
492 in 2.x . The same function will allow to keep compatibility for old
493 code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]494 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
495 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]496 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
497 compilation on some platforms has been fixed</li>
498 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
499 URIs</li>
500</ul>
501
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]502<h3>1.8.6: Jan 31 2000</h3>
503<ul>
504 <li>added a nanoFTP transport module, debugged until the new version of <a
505 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
506 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]507</ul>
508
509<h3>1.8.5: Jan 21 2000</h3>
510<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]511 <li>adding APIs to parse a well balanced chunk of XML (production <a
512 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the XML
513 spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]514 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]515 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
516 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]517 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
518 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]519</ul>
520
521<h3>1.8.4: Jan 13 2000</h3>
522<ul>
523 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
524 <li>all exit() call should have been removed from libxml</li>
525 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
526 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]527</ul>
528
529<h3>1.8.3: Jan 5 2000</h3>
530<ul>
531 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]532 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillarddbfd6411999-12-28 16:35:14 +0000[diff] [blame]533 <li>lots of bug fixes and improvement added over XMas hollidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]534 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]535 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
536 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]537 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]538 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]539 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]540</ul>
541
542<h3>1.8.2: Dec 21 1999</h3>
543<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]544 <li>I got another problem with includes and C++, I hope this issue is fixed
545 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]546 <li>Added a few tree modification functions: xmlReplaceNode,
547 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
548 xmlDocSetRootElement</li>
549 <li>Tried to improve the HTML output with help from <a
550 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]551</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]552
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]553<h3>1.8.1: Dec 18 1999</h3>
554<ul>
555 <li>various patches to avoid troubles when using libxml with C++ compilers
556 the "namespace" keyword and C escaping in include files</li>
557 <li>a problem in one of the core macros IS_CHAR was corrected</li>
558 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
559 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]560 <li>fixed a posteriori validation (validation after parsing, or by using a
561 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]562 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]563</ul>
564
565<h3>1.8.0: Dec 12 1999</h3>
566<ul>
567 <li>cleanup, especially memory wise</li>
568 <li>the parser should be more reliable, especially the HTML one, it should
569 not crash, whatever the input !</li>
570 <li>Integrated various patches, especially a speedup improvement for large
571 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
572 configure with --with-buffers to enable them.</li>
573 <li>attribute normalization, oops should have been added long ago !</li>
574 <li>attributes defaulted from Dtds should be available, xmlSetProp() now
575 does entities escapting by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]576</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]577
578<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]579<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]580 <li>Lots of HTML improvement</li>
581 <li>Fixed some errors when saving both XML and HTML</li>
582 <li>More examples, the regression tests should now look clean</li>
583 <li>Fixed a bug with contiguous charref</li>
584</ul>
585
586<h3>1.7.3: Sep 29 1999</h3>
587<ul>
588 <li>portability problems fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]589 <li>snprintf was used unconditionnally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]590 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]591</ul>
592
593<h3>1.7.1: Sep 24 1999</h3>
594<ul>
595 <li>The basic type for strings manipulated by libxml has been renamed in
596 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
597 is that CHAR was conflicting with a predefined type on Windows. However on
598 non WIN32 environment, compatibility is provided by the way of a
599 <strong>#define </strong>.</li>
600 <li>Changed another error : the use of a structure field called errno, and
601 leading to troubles on platforms where it's a macro</li>
602</ul>
603
604<h3>1.7.0: sep 23 1999</h3>
605<ul>
606 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]607 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]608 <li>Added an errno to report errors by another mean than a simple printf
609 like callback</li>
610 <li>Finished ID/IDREF support and checking when validation</li>
611 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]612 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]613 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
614 implementation</li>
615 <li>Added an HTML parser front-end</li>
616</ul>
617
618<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]619
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]620<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]621markup-based structured documents. Here is <a name="example">an example XML
622document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]623<pre>&lt;?xml version="1.0"?&gt;
624&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
625 &lt;head&gt;
626 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
627 &lt;/head&gt;
628 &lt;chapter&gt;
629 &lt;title&gt;The Linux adventure&lt;/title&gt;
630 &lt;p&gt;bla bla bla ...&lt;/p&gt;
631 &lt;image href="linus.gif"/&gt;
632 &lt;p&gt;...&lt;/p&gt;
633 &lt;/chapter&gt;
634&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]635
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]636<p>The first line specifies that it's an XML document and gives useful
637information about its encoding. Then the document is a text format whose
638structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]639to be closed</strong>. XML is pedantic about this. However, if a tag is empty
640(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]641ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note that,
642for example, the image tag has no content (just an attribute) and is closed by
643ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]644
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]645<p>XML can be applied sucessfully to a wide range of uses, from long term
646structured document maintenance (where it follows the steps of SGML) to simple
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]647data encoding mechanisms like configuration file formatting (glade),
648spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
649it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]650
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]651<h2><a name="XSLT">XSLT</a></h2>
652
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]653<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
654
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]655<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a language
656for transforming XML documents into other XML documents (or HTML/textual
657output).</p>
658
659<p>A separate library called libxslt is being built on top of libxml2. This
660module "libxslt" can be found in the Gnome CVS base too.</p>
661
Daniel Veillard383b1472001-01-23 11:39:52 +0000[diff] [blame]662<p>You can check the <a
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]663href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a> supported
664and the progresses on the <a
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]665href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog">Changelog</a></p>
666
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]667<h2>An overview of libxml architecture</h2>
668
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]669<p>Libxml is made of multiple components; some of them are optional,
670and most of
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]671the block interfaces are public. The main components are:</p>
672<ul>
673 <li>an Input/Output layer</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]674 <li>FTP and HTTP client layers (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]675 <li>an Internationalization layer managing the encodings support</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]676 <li>a URI module</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]677 <li>the XML parser and its basic SAX interface</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]678 <li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]679 <li>a SAX tree module to build an in-memory DOM representation</li>
680 <li>a tree module to manipulate the DOM representation</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]681 <li>a validation module using the DOM representation (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]682 <li>an XPath module for global lookup in a DOM representation
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]683 (optional)</li>
684 <li>a debug module (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]685</ul>
686
687<p>Graphically this gives the following:</p>
688
689<p><img src="libxml.gif" alt="a graphical view of the various"></p>
690
691<p></p>
692
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]693<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]694
695<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]696returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]697<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]698as the file name, the document type, and a <strong>children</strong> pointer
699which is the root of the document (or more exactly the first child under the
700root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]701chained in double-linked lists of siblings and with a children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]702relationship. An xmlNode can also carry properties (a chain of xmlAttr
703structures). An attribute may have a value which is a list of TEXT or
704ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]705
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]706<p>Here is an example (erroneous with respect to the XML spec since there
707should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]708
709<p><img src="structure.gif" alt=" structure.gif "></p>
710
711<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]712called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]713prints them back as parsed. This is useful for detecting errors both in XML
714code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]715which prints the actual in-memory structure of the document; here is the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]716result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]717<pre>DOCUMENT
718version=1.0
719standalone=true
720 ELEMENT EXAMPLE
721 ATTRIBUTE prop1
722 TEXT
723 content=gnome is great
724 ATTRIBUTE prop2
725 ENTITY_REF
726 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]727 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]728 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]729 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]730 TEXT
731 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]732 ELEMENT chapter
733 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]734 TEXT
735 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]736 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]737 TEXT
738 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]739 ELEMENT image
740 ATTRIBUTE href
741 TEXT
742 content=linus.gif
743 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]744 TEXT
745 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]746
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]747<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]748
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]749<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]750
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]751<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]752memory. In that case (and if you don't expect to save back the XML document
753loaded 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]754<strong>callback-based interface</strong> to the parser. Before parsing, the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]755application layer registers a customized set of callbacks which are called by
756the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]757
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]758<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]759libxml, see the <a
760href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
761documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]762Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]763
764<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
765program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]766binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]767distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]768testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]769<pre>SAX.setDocumentLocator()
770SAX.startDocument()
771SAX.getEntity(amp)
772SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
773SAX.characters( , 3)
774SAX.startElement(head)
775SAX.characters( , 4)
776SAX.startElement(title)
777SAX.characters(Welcome to Gnome, 16)
778SAX.endElement(title)
779SAX.characters( , 3)
780SAX.endElement(head)
781SAX.characters( , 3)
782SAX.startElement(chapter)
783SAX.characters( , 4)
784SAX.startElement(title)
785SAX.characters(The Linux adventure, 19)
786SAX.endElement(title)
787SAX.characters( , 4)
788SAX.startElement(p)
789SAX.characters(bla bla bla ..., 15)
790SAX.endElement(p)
791SAX.characters( , 4)
792SAX.startElement(image, href='linus.gif')
793SAX.endElement(image)
794SAX.characters( , 4)
795SAX.startElement(p)
796SAX.characters(..., 3)
797SAX.endElement(p)
798SAX.characters( , 3)
799SAX.endElement(chapter)
800SAX.characters( , 1)
801SAX.endElement(EXAMPLE)
802SAX.endDocument()</pre>
803
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]804<p>Most of the other interfaces of libxml are based on the DOM
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]805tree-building facility, so nearly everything up to the end of this document
806presupposes the use of the standard DOM tree build. Note that the DOM tree
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]807itself is built by a set of registered default callbacks, without internal
808specific interface.</p>
809
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]810<h2><a name="library">The XML library interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]811
812<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]813using the XML library from the C language. It is not intended to be extensive.
814I hope the automatically generated documents will provide the completeness
815required, but as a separate set of documents. The interfaces of the XML
816library are by principle low level, there is nearly zero abstraction. Those
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]817interested in a higher level API should <a href="#DOM">look at DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]818
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]819<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
820separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]821interfaces</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]822
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]823<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]824
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]825<p>Usually, the first thing to do is to read an XML input. The parser accepts
826documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]827defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]828<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]829 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]830 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]831 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]832</dl>
833<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]834 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]835 <dd><p>Parse an XML document contained in a (possibly compressed)
836 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]837 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]838</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]839
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]840<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]841failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]842
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]843<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]844
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]845<p>In order for the application to keep the control when the document is being
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]846fetched (which is common for GUI based programs) libxml provides a push
847interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]848<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
849 void *user_data,
850 const char *chunk,
851 int size,
852 const char *filename);
853int xmlParseChunk (xmlParserCtxtPtr ctxt,
854 const char *chunk,
855 int size,
856 int terminate);</pre>
857
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]858<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]859<pre> FILE *f;
860
861 f = fopen(filename, "r");
862 if (f != NULL) {
863 int res, size = 1024;
864 char chars[1024];
865 xmlParserCtxtPtr ctxt;
866
867 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]868 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]869 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
870 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]871 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]872 xmlParseChunk(ctxt, chars, res, 0);
873 }
874 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]875 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]876 xmlFreeParserCtxt(ctxt);
877 }
878 }</pre>
879
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]880<p>The HTML parser embedded into libxml also has a push
881interface; the functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]882
883<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
884
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]885<p>The tree-building interface makes the parser
886memory-hungry, first loading the document in memory and then building
887the tree itself.
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]888Reading a document without building the tree is possible using the SAX
889interfaces (see SAX.h and <a
890href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]891Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]892limited to SAX: just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]893<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]894
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]895<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]896
897<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]898there is a set of functions dedicated to building new elements. (These are
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]899also 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]900that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]901<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]902 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]903 xmlNodePtr tree, subtree;
904
905 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]906 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
907 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
908 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
909 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]910 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]911 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]912 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
913 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
914 subtree = xmlNewChild(tree, NULL, "image", NULL);
915 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]916
917<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]918
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]919<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]920
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]921<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]922code has access to the internal structure of all the elements of the tree. The
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]923names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]924<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]925<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]926example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]927<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]928
929<p>points to the title element,</p>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]930<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]931
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]932<p>points to the text node containing the chapter title "The Linux
933adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]934
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]935<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]936present before the document root, so <code>doc-&gt;children</code> may point
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]937to an element which is not the document Root Element; a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]938<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]939
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]940<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]941
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]942<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]943is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]944<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]945 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
946 xmlChar *value);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]947 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node. The
948 value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]949 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]950</dl>
951<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]952 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]953 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +0000[diff] [blame]954 <dd><p>This function returns a pointer to new copy of the property
955 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]956 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]957</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]958
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]959<p>Two functions are provided for reading and writing the text associated with
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]960elements:</p>
961<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]962 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]963 *value);</code></dt>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]964 <dd><p>This function takes an "external" string and converts it to one text
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]965 node or possibly to a list of entity and text nodes. All non-predefined
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]966 entity references like &amp;Gnome; will be stored internally as entity
967 nodes, hence the result of the function may not be a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]968 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]969</dl>
970<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]971 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]972 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]973 <dd><p>This function is the inverse of
974 <code>xmlStringGetNodeList()</code>. It generates a new string
975 containing the content of the text and entity nodes. Note the extra
976 argument inLine. If this argument is set to 1, the function will expand
977 entity references. For example, instead of returning the &amp;Gnome;
978 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]979 "GNU Network Object Model Environment").</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]980 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]981</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]982
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]983<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]984
985<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]986<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]987 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]988 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]989 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]990 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]991</dl>
992<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]993 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]994 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]995 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]996</dl>
997<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]998 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]999 <dd><p>Saves the document to a file. In this case, the compression
1000 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1001 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1002</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1003
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1004<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1005
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1006<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1007accesses. The level of compression on saves can be turned on either globally
1008or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1009<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1010 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1011 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1012 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1013</dl>
1014<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1015 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1016 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1017 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1018</dl>
1019<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1020 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1021 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1022 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1023</dl>
1024<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1025 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1026 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1027 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1028</dl>
1029
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1030<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1031
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1032<p>Entities in principle are similar to simple C macros. An entity defines an
1033abbreviation for a given string that you can reuse many times throughout the
1034content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1035may occur frequently within a document, or to confine the change needed to a
1036document to a restricted area in the internal subset of the document (at the
1037beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1038<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]10392 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]10403 &lt;!ENTITY xml "Extensible Markup Language"&gt;
10414 ]&gt;
10425 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]10436 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]10447 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1045
1046<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1047its name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1048are 5 predefined entities in libxml allowing you to escape charaters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1049predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1050<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1051for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1052<strong>&amp;quot;</strong> for the character '"', and
1053<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1054
1055<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]1056substitute an entity's content so that you can see the replacement text in
1057your application. Or you may prefer to keep entity references as such in the
1058content to be able to save the document back without losing this usually
1059precious information (if the user went through the pain of explicitly defining
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1060entities, he may have a a rather negative attitude if you blindly susbtitute
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1061them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1062href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1063function allows you to check and change the behaviour, which is to not
1064substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1065
1066<p>Here is the DOM tree built by libxml for the previous document in the
1067default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1068<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1069DOCUMENT
1070version=1.0
1071 ELEMENT EXAMPLE
1072 TEXT
1073 content=
1074 ENTITY_REF
1075 INTERNAL_GENERAL_ENTITY xml
1076 content=Extensible Markup Language
1077 TEXT
1078 content=</pre>
1079
1080<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1081<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1082DOCUMENT
1083version=1.0
1084 ELEMENT EXAMPLE
1085 TEXT
1086 content= Extensible Markup Language</pre>
1087
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1088<p>So, entities or no entities? Basically, it depends on your use case. I
1089suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1090entities in your XML document or data if you are not willing to handle the
1091entity references elements in the DOM tree.</p>
1092
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1093<p>Note that at save time libxml enforces the conversion of the predefined
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1094entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1095transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1096reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1097finding them in the input).</p>
1098
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]1099<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1100on top of the libxml SAX interface is difficult!!! If you plan to use
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]1101non-predefined entities in your documents, then the learning cuvre to handle
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1102then using the SAX API may be long. If you plan to use complex documents, I
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]1103strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]1104deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]1105
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1106<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1107
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1108<p>The libxml library implements <a
1109href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
1110recognizing namespace contructs in the input, and does namespace lookup
1111automatically when building the DOM tree. A namespace declaration is
1112associated with an in-memory structure and all elements or attributes within
1113that namespace point to it. Hence testing the namespace is a simple and fast
1114equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1115
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1116<p>I suggest that people using libxml use a namespace, and declare it in the
1117root element of their document as the default namespace. Then they don't need
1118to use the prefix in the content but we will have a basis for future semantic
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1119refinement and merging of data from different sources. This doesn't increase
1120the size of the XML output significantly, but significantly increases its value
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1121in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1122<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
1123 &lt;elem1&gt;...&lt;/elem1&gt;
1124 &lt;elem2&gt;...&lt;/elem2&gt;
1125&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1126
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1127<p>The namespace value has to be an absolute URL, but the URL doesn't
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1128have to point to any existing resource on the Web. It will bind all the
1129element and atributes with that URL. I suggest to use an URL within a domain
1130you control, and that the URL should contain some kind of version information
1131if possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1132a good namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1133
1134<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1135version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1136and if the version information don't match something you know, warn the user
1137and 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]1138namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1139same as &lt;bar:text&gt; in another document. What really matters is the URI
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1140associated with the element or the attribute, not the prefix string (which is
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1141just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1142<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1143prefix and its URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1144
1145<p>@@Interfaces@@</p>
1146
1147<p>@@Examples@@</p>
1148
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1149<p>Usually people object to using namespaces together with validity checking.
1150I will try to make sure that using namespaces won't break validity checking,
1151so even if you plan to use or currently are using validation I strongly
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1152suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1153<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1154flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1155from multiple DTDs will certainly break current validation schemes. I will try
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1156to provide ways to do this, but this may not be portable or standardized.</p>
1157
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1158<h2><a name="Validation">Validation, or are you afraid of DTDs ?</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1159
1160<p>Well what is validation and what is a DTD ?</p>
1161
1162<p>Validation is the process of checking a document against a set of
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1163construction rules; a <strong>DTD</strong> (Document Type Definition) is such
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1164a set of rules.</p>
1165
1166<p>The validation process and building DTDs are the two most difficult parts
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1167of the XML life cycle. Briefly a DTD defines all the possibles element to be
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1168found within your document, what is the formal shape of your document tree (by
1169defining the allowed content of an element, either text, a regular expression
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1170for the allowed list of children, or mixed content i.e. both text and
1171children). The DTD also defines the allowed attributes for all elements and
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1172the types of the attributes. For more detailed information,
1173I suggest that you read
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1174the related parts of the XML specification, the examples found under
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1175gnome-xml/test/valid/dtd and any of the
1176large number of books available on XML. The
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1177dia example in gnome-xml/test/valid should be both simple and complete enough
1178to allow you to build your own.</p>
1179
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1180<p>A word of warning, building a good DTD which will fit the needs of your
1181application in the long-term is far from trivial; however, the extra level of
1182quality it can ensure is well worth the price for some sets of applications or
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1183if you already have already a DTD defined for your application field.</p>
1184
1185<p>The validation is not completely finished but in a (very IMHO) usable
1186state. Until a real validation interface is defined the way to do it is to
1187define and set the <strong>xmlDoValidityCheckingDefaultValue</strong> external
1188variable to 1, this will of course be changed at some point:</p>
1189
1190<p>extern int xmlDoValidityCheckingDefaultValue;</p>
1191
1192<p>...</p>
1193
1194<p>xmlDoValidityCheckingDefaultValue = 1;</p>
1195
1196<p></p>
1197
1198<p>To handle external entities, use the function
1199<strong>xmlSetExternalEntityLoader</strong>(xmlExternalEntityLoader f); to
1200link in you HTTP/FTP/Entities database library to the standard libxml
1201core.</p>
1202
1203<p>@@interfaces@@</p>
1204
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1205<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1206
1207<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document Object
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1208Model</em>; this is an API for accessing XML or HTML structured documents.
1209Native support for DOM in Gnome is on the way (module gnome-dom), and will
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1210be based on gnome-xml. This will be a far cleaner interface to manipulate XML
Daniel Veillardc08a2c61999-09-08 21:35:25 +0000[diff] [blame]1211files within Gnome since it won't expose the internal structure. DOM defines a
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1212set of IDL (or Java) interfaces allowing you to traverse and manipulate a
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1213document. The DOM library will allow accessing and modifying "live" documents
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1214present in other programs like this:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1215
1216<p><img src="DOM.gif" alt=" DOM.gif "></p>
1217
1218<p>This should help greatly doing things like modifying a gnumeric spreadsheet
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1219embedded in a GWP document for example.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1220
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1221<p>The current DOM implementation on top of libxml is the <a
1222href="http://cvs.gnome.org/lxr/source/gdome/">gdome Gnome module</a>, this is
1223a full DOM interface, thanks to <a href="mailto:raph@levien.com">Raph
1224Levien</a>.</p>
1225
1226<p>The gnome-dom module in the Gnome CVS base is obsolete</p>
1227
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1228<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1229
1230<p>Here is a real size example, where the actual content of the application
1231data 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]1232a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1233storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
1234base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1235<pre>&lt;?xml version="1.0"?&gt;
1236&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
1237 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1238
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1239 &lt;gjob:Job&gt;
1240 &lt;gjob:Project ID="3"/&gt;
1241 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
1242 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1243
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1244 &lt;gjob:Update&gt;
1245 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
1246 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
1247 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
1248 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1249
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1250 &lt;gjob:Developers&gt;
1251 &lt;gjob:Developer&gt;
1252 &lt;/gjob:Developer&gt;
1253 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1254
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1255 &lt;gjob:Contact&gt;
1256 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
1257 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
1258 &lt;gjob:Company&gt;
1259 &lt;/gjob:Company&gt;
1260 &lt;gjob:Organisation&gt;
1261 &lt;/gjob:Organisation&gt;
1262 &lt;gjob:Webpage&gt;
1263 &lt;/gjob:Webpage&gt;
1264 &lt;gjob:Snailmail&gt;
1265 &lt;/gjob:Snailmail&gt;
1266 &lt;gjob:Phone&gt;
1267 &lt;/gjob:Phone&gt;
1268 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1269
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1270 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1271 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1272 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1273
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1274 &lt;gjob:Skills&gt;
1275 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1276
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1277 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1278 A GNOME based system that will allow a superuser to configure
1279 compressed and uncompressed files and/or file systems to be backed
1280 up with a supported media in the system. This should be able to
1281 perform via find commands generating a list of files that are passed
1282 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
1283 or via operations performed on the filesystem itself. Email
1284 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1285 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1286
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1287 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1288
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1289 &lt;/gjob:Jobs&gt;
1290&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1291
1292<p>While loading the XML file into an internal DOM tree is a matter of calling
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1293only a couple of functions, browsing the tree to gather the ata and
1294generate the internal structures is harder, and more error prone.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1295
1296<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1297structure. For example, the ordering of the attributes is not significant,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1298the XML specification is clear about it. It's also usually a good idea not to
1299depend on the order of the children of a given node, unless it really
1300makes things harder. Here is some code to parse the information for a
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1301person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1302<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1303 * A person record
1304 */
1305typedef struct person {
1306 char *name;
1307 char *email;
1308 char *company;
1309 char *organisation;
1310 char *smail;
1311 char *webPage;
1312 char *phone;
1313} person, *personPtr;
1314
1315/*
1316 * And the code needed to parse it
1317 */
1318personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1319 personPtr ret = NULL;
1320
1321DEBUG("parsePerson\n");
1322 /*
1323 * allocate the struct
1324 */
1325 ret = (personPtr) malloc(sizeof(person));
1326 if (ret == NULL) {
1327 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1328 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1329 }
1330 memset(ret, 0, sizeof(person));
1331
1332 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1333 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1334 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1335 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
1336 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1337 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
1338 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1339 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1340 }
1341
1342 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1343}</pre>
1344
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1345<p>Here are a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1346<ul>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1347 <li>Usually a recursive parsing style is the more convenient one: XML data
1348 is by nature subject to repetitive constructs and usually exibits highly
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1349 stuctured patterns.</li>
1350 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>, i.e.
1351 the pointer to the global XML document and the namespace reserved to the
1352 application. Document wide information are needed for example to decode
1353 entities and it's a good coding practice to define a namespace for your
1354 application set of data and test that the element and attributes you're
1355 analyzing actually pertains to your application space. This is done by a
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1356 simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1357 <li>To retrieve text and attributes value, you can use the
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1358 function <em>xmlNodeListGetString</em> to gather all the text and entity
1359 reference nodes generated by the DOM output and produce an single text
1360 string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1361</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1362
1363<p>Here is another piece of code used to parse another level of the
1364structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1365<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1366/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1367 * a Description for a Job
1368 */
1369typedef struct job {
1370 char *projectID;
1371 char *application;
1372 char *category;
1373 personPtr contact;
1374 int nbDevelopers;
1375 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
1376} job, *jobPtr;
1377
1378/*
1379 * And the code needed to parse it
1380 */
1381jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1382 jobPtr ret = NULL;
1383
1384DEBUG("parseJob\n");
1385 /*
1386 * allocate the struct
1387 */
1388 ret = (jobPtr) malloc(sizeof(job));
1389 if (ret == NULL) {
1390 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1391 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1392 }
1393 memset(ret, 0, sizeof(job));
1394
1395 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1396 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1397 while (cur != NULL) {
1398
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1399 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
1400 ret-&gt;projectID = xmlGetProp(cur, "ID");
1401 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1402 fprintf(stderr, "Project has no ID\n");
1403 }
1404 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1405 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
1406 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1407 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
1408 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1409 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
1410 ret-&gt;contact = parsePerson(doc, ns, cur);
1411 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1412 }
1413
1414 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1415}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1416
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1417<p>Once you are used to it, writing this kind of code is quite
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1418simple, but boring. Ultimately, it could be possble to write stubbers taking
1419either C data structure definitions, a set of XML examples or an XML DTD and
1420produce the code needed to import and export the content between C data and
1421XML storage. This is left as an exercise to the reader :-)</p>
1422
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]1423<p>Feel free to use <a href="example/gjobread.c">the code for the full C
1424parsing example</a> as a template, it is also available with Makefile in the
1425Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1426
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1427<h2><a name="Contributi">Contributions</a></h2>
1428<ul>
Daniel Veillard851c59c2000-11-24 16:06:22 +0000[diff] [blame]1429 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1430 for libxml:
1431 <p>Website: <a
1432 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
1433 <p>Download: <a
1434 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
1435 </li>
1436 <li><a href="mailto:doolin@cs.utk.edu">David Doolin</a> provides a
1437 precompiled Windows version
1438 <p><a
1439 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
1440 </li>
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1441 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> provided <a
1442 href="libxml-doc.el">an emacs module</a> to lookup libxml functions
1443 documentation</li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1444 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
1445 href="http://xmlsoft.org/messages/0488.html">man pages</a> (not yet
1446 integrated in the distribution)</li>
1447</ul>
1448
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1449<p></p>
1450
1451<p><a href="mailto:Daniel.Veillard@w3.org">Daniel Veillard</a></p>
1452
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame^]1453<p>$Id: xml.html,v 1.68 2001/02/24 17:48:53 veillard Exp $</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1454</body>
1455</html>