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blob: fece34f1a6db31d2e35749fee42c5a28bc584bfc [file] [log] [blame]
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000[diff] [blame]1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
2 "http://www.w3.org/TR/html4/loose.dtd">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3<html>
4<head>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]5 <title>The XML C library for Gnome</title>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]6 <meta name="GENERATOR" content="amaya V4.1">
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]7 <meta http-equiv="Content-Type" content="text/html">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]8</head>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]9
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]10<body bgcolor="#ffffff">
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]11<p><a href="http://www.gnome.org/"><img src="smallfootonly.gif"
12alt="Gnome Logo"></a><a href="http://www.w3.org/Status"><img src="w3c.png"
13alt="W3C Logo"></a></p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]14
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]15<h1 align="center">The XML C library for Gnome</h1>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]16
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]17<h2 style="text-align: center">libxml, a.k.a. gnome-xml</h2>
18
19<p></p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]20<ul>
21 <li><a href="#Introducti">Introduction</a></li>
22 <li><a href="#Documentat">Documentation</a></li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]23 <li><a href="#Reporting">Reporting bugs and getting help</a></li>
24 <li><a href="#help">how to help</a></li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]25 <li><a href="#Downloads">Downloads</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]26 <li><a href="#News">News</a></li>
27 <li><a href="#XML">XML</a></li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]28 <li><a href="#XSLT">XSLT</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]29 <li><a href="#tree">The tree output</a></li>
30 <li><a href="#interface">The SAX interface</a></li>
31 <li><a href="#library">The XML library interfaces</a>
32 <ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]33 <li><a href="#Invoking">Invoking the parser: the pull way</a></li>
34 <li><a href="#Invoking">Invoking the parser: the push way</a></li>
35 <li><a href="#Invoking2">Invoking the parser: the SAX interface</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]36 <li><a href="#Building">Building a tree from scratch</a></li>
37 <li><a href="#Traversing">Traversing the tree</a></li>
38 <li><a href="#Modifying">Modifying the tree</a></li>
39 <li><a href="#Saving">Saving the tree</a></li>
40 <li><a href="#Compressio">Compression</a></li>
41 </ul>
42 </li>
43 <li><a href="#Entities">Entities or no entities</a></li>
44 <li><a href="#Namespaces">Namespaces</a></li>
45 <li><a href="#Validation">Validation</a></li>
46 <li><a href="#Principles">DOM principles</a></li>
47 <li><a href="#real">A real example</a></li>
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]48 <li><a href="#Contributi">Contributions</a></li>
49</ul>
50
51<p>Separate documents:</p>
52<ul>
53 <li><a href="upgrade.html">upgrade instructions for migrating to
54 libxml2</a></li>
55 <li><a href="encoding.html">libxml Internationalization support</a></li>
56 <li><a href="xmlio.html">libxml Input/Output interfaces</a></li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]57 <li><a href="xmlmem.html">libxml Memory interfaces</a></li>
Daniel Veillard300f7d62000-11-24 13:04:04 +0000[diff] [blame]58 <li><a href="xmldtd.html">a short introduction about DTDs and
59 libxml</a></li>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]60 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a></li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]61</ul>
62
63<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]64
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]65<p>This document describes libxml, the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]66href="http://www.w3.org/XML/">XML</a> C library developped for the <a
67href="http://www.gnome.org/">Gnome</a> project. <a
68href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
69structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]70
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]71<p>Here are some key points about libxml:</p>
72<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]73 <li>Libxml exports Push and Pull type parser interfaces for both XML and
74 HTML.</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]75 <li>Libxml can do DTD validation at parse time, using a parsed document
76 instance, or with an arbitrary DTD.</li>
77 <li>Libxml now includes nearly complete <a
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]78 href="http://www.w3.org/TR/xpath">XPath</a> and <a
Daniel Veillard0c069222000-10-21 09:25:52 +0000[diff] [blame]79 href="http://www.w3.org/TR/xptr">XPointer</a> implementations.</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]80 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]81 sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]82 Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]83 <li>Basic support for HTTP and FTP client allowing aplications to fetch
84 remote resources</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]85 <li>The design is modular, most of the extensions can be compiled out.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]86 <li>The internal document repesentation is as close as possible to the <a
87 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
88 <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]89 like interface</a>; the interface is designed to be compatible with <a
90 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]91 <li>This library is released both under the <a
92 href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]93 IPR</a> and the <a href="http://www.gnu.org/copyleft/lesser.html">GNU
94 LGPL</a>. Use either at your convenience, basically this should make
95 everybody happy, if not, drop me a mail.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]96</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]97
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000[diff] [blame]98<p>Warning: unless you are forced to because your application links with a
99Gnome library requiring it, <strong><span
100style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use
101libxml2</p>
102
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]103<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]104
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]105<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]106<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]107 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]108 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]109 documentation</a> automatically extracted from code comments (using <a
110 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
111 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000[diff] [blame]112 <li>Look at the documentation about <a href="encoding.html">libxml
113 internationalization support</a></li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]114 <li>This page provides a global overview and <a href="#real">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]115 examples</a> on how to use libxml.</li>
116 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
117 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
118 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]119 <li>George Lebl wrote <a
120 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]121 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]122 <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]123 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]124 building the <a href="http://levien.com/gnome/gdome.html">DOM interface
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]125 gdome</a> on top of libxml result tree and an implementation of <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]126 href="http://www.w3.org/Graphics/SVG/">SVG</a> called <a
127 href="http://www.levien.com/svg/">gill</a>. Check his <a
128 href="http://www.levien.com/gnome/domination.html">DOMination
129 paper</a>.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]130 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
131 file</a></li>
132 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
133 starting a new project using libxml you should really use the 2.x
134 version.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]135 <li>And don't forget to look at the <a href="/messages/">mailing-list
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]136 archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]137</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]138
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]139<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]140
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]141<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]142of fixing them in a timely fashion. The best way to report a bug is to use the
Daniel Veillard81781102001-03-07 09:31:47 +0000[diff] [blame]143<a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome bug
144tracking database</a> (make sure to use the "libxml" module name). I look at
145reports there regularly and it's good to have a reminder when a bug is still
146open. Check the <a href="http://bugs.gnome.org/Reporting.html">instructions on
147reporting bugs</a> and be sure to specify that the bug is for the package
148libxml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]149
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]150<p>There is also a mailing-list <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]151href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]152href="http://xmlsoft.org/messages">on-line archive</a>. To subscribe to this
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]153list, please visit the <a
154href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and
155follow the instructions.</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]156
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]157<p>Alternatively, you can just send the bug to the <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]158href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml
Daniel Veillardf121ab72000-08-29 23:40:42 +0000[diff] [blame]159related I will approve it..</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]160
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]161<p>Of course, bugs reported with a suggested patch for fixing them will
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]162probably be processed faster.</p>
163
164<p>If you're looking for help, a quick look at <a
165href="http://xmlsoft.org/messages/#407">the list archive</a> may actually
166provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]167questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]168documentantion</a> is not as polished as I would like (i need to learn more
169about Docbook), but it's a good starting point.</p>
170
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]171<h2><a name="help">How to help</a></h2>
172
173<p>You can help the project in various ways, the best thing to do first is to
174subscribe to the mailing-list as explained before, check the <a
175href="http://xmlsoft.org/messages/">archives </a>and the <a
176href="http://bugs.gnome.org/db/pa/lgnome-xml.html">Gnome bug
177database:</a>:</p>
178<ol>
179 <li>provide patches when you find problems</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]180 <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]181 be integrated in all cases but help pinpointing portability problems
182 and</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]183 <li>provide documentation fixes (either as patches to the code comments or
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]184 as HTML diffs).</li>
185 <li>provide new documentations pieces (translations, examples, etc ...)</li>
186 <li>Check the TODO file and try to close one of the items</li>
187 <li>take one of the points raised in the archive or the bug database and
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]188 provide a fix. <a href="mailto:Daniel.Veillard@imag.fr">Get in touch with
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]189 me </a>before to avoid synchronization problems and check that the
190 suggested fix will fit in nicely :-)</li>
191</ol>
192
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]193<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]194
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]195<p>The latest versions of libxml can be found on <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]196href="ftp://xmlsoft.org/">xmlsoft.org</a> or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]197href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]198as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]199archive</a> or <a
200href="ftp://ftp.gnome.org/pub/GNOME/contrib/redhat/SRPMS/">RPM packages</a>.
201(NOTE that you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]202href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
203href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]204packages installed to compile applications using libxml.)</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]205
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]206<p><a name="Snapshot">Snapshot:</a></p>
207<ul>
208 <li>Code from the W3C cvs base libxml <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]209 href="ftp://xmlsoft.org/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]210 <li>Docs, content of the web site, the list archive included <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]211 href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]212</ul>
213
214<p><a name="Contribs">Contribs:</a></p>
215
216<p>I do accept external contributions, especially if compiling on another
217platform, get in touch with me to upload the package. I will keep them in the
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]218<a href="ftp://xmlsoft.org/contribs/">contrib directory</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]219
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]220<p>Libxml is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]221<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]222 <li><p>The <a
223 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]224 CVS base</a>. Check the <a
225 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a> page;
226 the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]227 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]228 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]229</ul>
230
231<h2><a name="News">News</a></h2>
232
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]233<h3>CVS only : check the <a
234href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]235for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]236
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]237<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]238you want to test those</p>
239<ul>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]240 <li>Implementing <a href="http://xmlsoft.org/XSLT">XSLT</a>, this is done as
241 a separate C library on top of libxml called libxslt, not released yet but
242 available from CVS</li>
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]243 <li>Finishing up <a href="http://www.w3.org/TR/xptr">XPointer</a> and <a
244 href="http://www.w3.org/TR/xinclude">XInclude</a></li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]245 <li>(seeems working but delayed from release) parsing/import of Docbook SGML
246 docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]247</ul>
248
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]249<h3>2.3.4: Mar 10 2001</h3>
250<ul>
251 <li>Fixed bugs #51860 and #51861</li>
252 <li>Added a global variable xmlDefaultBufferSize to allow default buffer
253 size to be application tunable.</li>
254 <li>Some cleanup in the validation code, still a bug left and this part
255 should probably be rewritten to support ambiguous content model :-\</li>
256 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3
257 parser</li>
258 <li>Fixed another bug in xmlNodeGetContent()</li>
259 <li>Bjorn fixed XPath node collection and Number formatting</li>
260 <li>Fixed a loop reported in the HTML parsing</li>
261 <li>blank space are reported even if the Dtd content model proves that they
262 are formatting spaces, this is for XmL conformance</li>
263</ul>
264
Daniel Veillardb402c072001-03-01 17:28:58 +0000[diff] [blame]265<h3>2.3.3: Mar 1 2001</h3>
266<ul>
267 <li>small change in XPath for XSLT</li>
268 <li>documentation cleanups</li>
269 <li>fix in validation by Gary Pennington</li>
270 <li>serious parsing performances improvements</li>
271</ul>
272
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]273<h3>2.3.2: Feb 24 2001</h3>
Daniel Veillard71681102001-02-24 17:48:53 +0000[diff] [blame]274<ul>
275 <li>chasing XPath bugs, found a bunch, completed some TODO</li>
276 <li>fixed a Dtd parsing bug</li>
277 <li>fixed a bug in xmlNodeGetContent</li>
278 <li>ID/IDREF support partly rewritten by Gary Pennington</li>
279</ul>
280
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]281<h3>2.3.1: Feb 15 2001</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]282<ul>
283 <li>some XPath and HTML bug fixes for XSLT</li>
284 <li>small extension of the hash table interfaces for DOM gdome2
285 implementation</li>
286 <li>A few bug fixes</li>
287</ul>
288
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]289<h3>2.3.0: Feb 8 2001 (2.2.12 was on 25 Jan but I didn't kept track)</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]290<ul>
291 <li>Lots of XPath bug fixes</li>
292 <li>Add a mode with Dtd lookup but without validation error reporting for
293 XSLT</li>
294 <li>Add support for text node without escaping (XSLT)</li>
295 <li>bug fixes for xmlCheckFilename</li>
296 <li>validation code bug fixes from Gary Pennington</li>
297 <li>Patch from Paul D. Smith correcting URI path normalization</li>
298 <li>Patch to allow simultaneous install of libxml-devel and
299 libxml2-devel</li>
300 <li>the example Makefile is now fixed</li>
301 <li>added HTML to the RPM packages</li>
302 <li>tree copying bugfixes</li>
303 <li>updates to Windows makefiles</li>
304 <li>optimisation patch from Bjorn Reese</li>
305</ul>
306
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]307<h3>2.2.11: Jan 4 2001</h3>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]308<ul>
309 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
310 <li>added htmlHandleOmittedElem()</li>
311 <li>Applied Bjorn Reese's IPV6 first patch</li>
312 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]313 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]314</ul>
315
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]316<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000[diff] [blame]317<ul>
318 <li>Fix the Windows problems of 2.2.8</li>
319 <li>integrate OpenVMS patches</li>
320 <li>better handling of some nasty HTML input</li>
321 <li>Improved the XPointer implementation</li>
322 <li>integrate a number of provided patches</li>
323</ul>
324
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]325<h3>2.2.9: Nov 25 2000</h3>
326<ul>
327 <li>erroneous release :-(</li>
328</ul>
329
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]330<h3>2.2.8: Nov 13 2000</h3>
331<ul>
332 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
333 support</li>
334 <li>Patch in conditional section handling</li>
335 <li>updated MS compiler project</li>
336 <li>fixed some XPath problems</li>
337 <li>added an URI escaping function</li>
338 <li>some other bug fixes</li>
339</ul>
340
341<h3>2.2.7: Oct 31 2000</h3>
342<ul>
343 <li>added message redirection</li>
344 <li>XPath improvements (thanks TOM !)</li>
345 <li>xmlIOParseDTD() added</li>
346 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
347 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
348</ul>
349
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000[diff] [blame]350<h3>2.2.6: Oct 25 2000:</h3>
351<ul>
352 <li>Added an hash table module, migrated a number of internal structure to
353 those</li>
354 <li>Fixed a posteriori validation problems</li>
355 <li>HTTP module cleanups</li>
356 <li>HTML parser improvements (tag errors, script/style handling, attribute
357 normalization)</li>
358 <li>coalescing of adjacent text nodes</li>
359 <li>couple of XPath bug fixes, exported the internal API</li>
360</ul>
361
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]362<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]363<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]364 <li>XPointer implementation and testsuite</li>
365 <li>Lot of XPath fixes, added variable and functions registration, more
366 tests</li>
367 <li>Portability fixes, lots of enhancements toward an easy Windows build and
368 release</li>
369 <li>Late validation fixes</li>
370 <li>Integrated a lot of contributed patches</li>
371 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]372 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]373</ul>
374
375<h3>2.2.4: Oct 1 2000:</h3>
376<ul>
377 <li>main XPath problem fixed</li>
378 <li>Integrated portability patches for Windows</li>
379 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]380</ul>
381
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]382<h3>2.2.3: Sep 17 2000</h3>
383<ul>
384 <li>bug fixes</li>
385 <li>cleanup of entity handling code</li>
386 <li>overall review of all loops in the parsers, all sprintf usage has been
387 checked too</li>
388 <li>Far better handling of larges Dtd. Validating against Docbook XML Dtd
389 works smoothly now.</li>
390</ul>
391
392<h3>1.8.10: Sep 6 2000</h3>
393<ul>
394 <li>bug fix release for some Gnome projects</li>
395</ul>
396
397<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]398<ul>
399 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]400 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]401</ul>
402
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]403<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]404<ul>
405 <li>a purely bug fixes release</li>
406 <li>fixed an encoding support problem when parsing from a memory block</li>
407 <li>fixed a DOCTYPE parsing problem</li>
408 <li>removed a bug in the function allowing to override the memory allocation
409 routines</li>
410</ul>
411
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]412<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]413<ul>
414 <li>applied a lot of portability fixes</li>
415 <li>better encoding support/cleanup and saving (content is now always
416 encoded in UTF-8)</li>
417 <li>the HTML parser now correctly handles encodings</li>
418 <li>added xmlHasProp()</li>
419 <li>fixed a serious problem with &amp;#38;</li>
420 <li>propagated the fix to FTP client</li>
421 <li>cleanup, bugfixes, etc ...</li>
422 <li>Added a page about <a href="encoding.html">libxml Internationalization
423 support</a></li>
424</ul>
425
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]426<h3>1.8.9: July 9 2000</h3>
427<ul>
428 <li>fixed the spec the RPMs should be better</li>
429 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
430 rpmfind users problem</li>
431</ul>
432
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]433<h3>2.1.1: July 1 2000</h3>
434<ul>
435 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
436 <li>improvements on the HTML parser</li>
437</ul>
438
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]439<h3>2.1.0 and 1.8.8: June 29 2000</h3>
440<ul>
441 <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to
442 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
443 about &amp;#38; charref parsing</li>
444 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
445 also contains numerous fixes and enhancements:
446 <ul>
447 <li>added xmlStopParser() to stop parsing</li>
448 <li>improved a lot parsing speed when there is large CDATA blocs</li>
449 <li>includes XPath patches provided by Picdar Technology</li>
450 <li>tried to fix as much as possible DtD validation and namespace
451 related problems</li>
452 <li>output to a given encoding has been added/tested</li>
453 <li>lot of various fixes</li>
454 </ul>
455 </li>
456</ul>
457
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]458<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]459<ul>
460 <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]461 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally
462 scheduled for Apr 3 the relase occured only on Apr 12 due to massive
463 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]464 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]465 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]466 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]467 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]468 <pre>#include "xxx.h"</pre>
469 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]470 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
471 <li>the memory allocation routines used by libxml can now be overloaded
472 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]473 <li>The previously CVS only tool tester has been renamed
474 <strong>xmllint</strong> and is now installed as part of the libxml2
475 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]476 <li>The I/O interface has been revamped. There is now ways to plug in
477 specific I/O modules, either at the URI scheme detection level using
478 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
479 parser context using xmlCreateIOParserCtxt()</li>
480 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
481 number of the libxml module in use</li>
482 <li>a number of optional features of libxml can now be excluded at configure
483 time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]484</ul>
485
486<h3>2.0.0beta: Mar 14 2000</h3>
487<ul>
488 <li>This is a first Beta release of libxml version 2</li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]489 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org
490 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and
491 RPMs</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]492 <li>This version is now the head in the Gnome CVS base, the old one is
493 available under the tag LIB_XML_1_X</li>
494 <li>This includes a very large set of changes. Froma programmatic point of
495 view applications should not have to be modified too much, check the <a
496 href="upgrade.html">upgrade page</a></li>
497 <li>Some interfaces may changes (especially a bit about encoding).</li>
498 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]499 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]500 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
501 handled now</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]502 <li>Better handling of entities, especially well formedness checking and
503 proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]504 <li>DTD conditional sections</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]505 <li>Validation now correcly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]506 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
507 structures to accomodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]508 </ul>
509 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]510 <li>Serious progress were made toward compliance, <a
511 href="conf/result.html">here are the result of the test</a> against the
512 OASIS testsuite (except the japanese tests since I don't support that
513 encoding yet). This URL is rebuilt every couple of hours using the CVS
514 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]515</ul>
516
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]517<h3>1.8.7: Mar 6 2000</h3>
518<ul>
519 <li>This is a bug fix release:</li>
520 <li>It is possible to disable the ignorable blanks heuristic used by
521 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
522 that for adherence to XML spec, this behaviour will be disabled by default
523 in 2.x . The same function will allow to keep compatibility for old
524 code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]525 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
526 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]527 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
528 compilation on some platforms has been fixed</li>
529 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
530 URIs</li>
531</ul>
532
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]533<h3>1.8.6: Jan 31 2000</h3>
534<ul>
535 <li>added a nanoFTP transport module, debugged until the new version of <a
536 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
537 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]538</ul>
539
540<h3>1.8.5: Jan 21 2000</h3>
541<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]542 <li>adding APIs to parse a well balanced chunk of XML (production <a
543 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the XML
544 spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]545 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]546 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
547 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]548 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
549 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]550</ul>
551
552<h3>1.8.4: Jan 13 2000</h3>
553<ul>
554 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
555 <li>all exit() call should have been removed from libxml</li>
556 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
557 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]558</ul>
559
560<h3>1.8.3: Jan 5 2000</h3>
561<ul>
562 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]563 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillarddbfd6411999-12-28 16:35:14 +0000[diff] [blame]564 <li>lots of bug fixes and improvement added over XMas hollidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]565 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]566 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
567 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]568 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]569 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]570 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]571</ul>
572
573<h3>1.8.2: Dec 21 1999</h3>
574<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]575 <li>I got another problem with includes and C++, I hope this issue is fixed
576 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]577 <li>Added a few tree modification functions: xmlReplaceNode,
578 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
579 xmlDocSetRootElement</li>
580 <li>Tried to improve the HTML output with help from <a
581 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]582</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]583
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]584<h3>1.8.1: Dec 18 1999</h3>
585<ul>
586 <li>various patches to avoid troubles when using libxml with C++ compilers
587 the "namespace" keyword and C escaping in include files</li>
588 <li>a problem in one of the core macros IS_CHAR was corrected</li>
589 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
590 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]591 <li>fixed a posteriori validation (validation after parsing, or by using a
592 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]593 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]594</ul>
595
596<h3>1.8.0: Dec 12 1999</h3>
597<ul>
598 <li>cleanup, especially memory wise</li>
599 <li>the parser should be more reliable, especially the HTML one, it should
600 not crash, whatever the input !</li>
601 <li>Integrated various patches, especially a speedup improvement for large
602 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
603 configure with --with-buffers to enable them.</li>
604 <li>attribute normalization, oops should have been added long ago !</li>
605 <li>attributes defaulted from Dtds should be available, xmlSetProp() now
606 does entities escapting by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]607</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]608
609<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]610<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]611 <li>Lots of HTML improvement</li>
612 <li>Fixed some errors when saving both XML and HTML</li>
613 <li>More examples, the regression tests should now look clean</li>
614 <li>Fixed a bug with contiguous charref</li>
615</ul>
616
617<h3>1.7.3: Sep 29 1999</h3>
618<ul>
619 <li>portability problems fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]620 <li>snprintf was used unconditionnally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]621 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]622</ul>
623
624<h3>1.7.1: Sep 24 1999</h3>
625<ul>
626 <li>The basic type for strings manipulated by libxml has been renamed in
627 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
628 is that CHAR was conflicting with a predefined type on Windows. However on
629 non WIN32 environment, compatibility is provided by the way of a
630 <strong>#define </strong>.</li>
631 <li>Changed another error : the use of a structure field called errno, and
632 leading to troubles on platforms where it's a macro</li>
633</ul>
634
635<h3>1.7.0: sep 23 1999</h3>
636<ul>
637 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]638 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]639 <li>Added an errno to report errors by another mean than a simple printf
640 like callback</li>
641 <li>Finished ID/IDREF support and checking when validation</li>
642 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]643 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]644 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
645 implementation</li>
646 <li>Added an HTML parser front-end</li>
647</ul>
648
649<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]650
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]651<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]652markup-based structured documents. Here is <a name="example">an example XML
653document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]654<pre>&lt;?xml version="1.0"?&gt;
655&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
656 &lt;head&gt;
657 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
658 &lt;/head&gt;
659 &lt;chapter&gt;
660 &lt;title&gt;The Linux adventure&lt;/title&gt;
661 &lt;p&gt;bla bla bla ...&lt;/p&gt;
662 &lt;image href="linus.gif"/&gt;
663 &lt;p&gt;...&lt;/p&gt;
664 &lt;/chapter&gt;
665&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]666
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]667<p>The first line specifies that it's an XML document and gives useful
668information about its encoding. Then the document is a text format whose
669structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]670to be closed</strong>. XML is pedantic about this. However, if a tag is empty
671(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]672ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note that,
673for example, the image tag has no content (just an attribute) and is closed by
674ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]675
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]676<p>XML can be applied sucessfully to a wide range of uses, from long term
677structured document maintenance (where it follows the steps of SGML) to simple
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]678data encoding mechanisms like configuration file formatting (glade),
679spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
680it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]681
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]682<h2><a name="XSLT">XSLT</a></h2>
683
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]684<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
685
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]686<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a language
687for transforming XML documents into other XML documents (or HTML/textual
688output).</p>
689
690<p>A separate library called libxslt is being built on top of libxml2. This
691module "libxslt" can be found in the Gnome CVS base too.</p>
692
Daniel Veillard383b1472001-01-23 11:39:52 +0000[diff] [blame]693<p>You can check the <a
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]694href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a> supported
695and the progresses on the <a
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]696href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog">Changelog</a></p>
697
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]698<h2>An overview of libxml architecture</h2>
699
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]700<p>Libxml is made of multiple components; some of them are optional, and most
701of the block interfaces are public. The main components are:</p>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]702<ul>
703 <li>an Input/Output layer</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]704 <li>FTP and HTTP client layers (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]705 <li>an Internationalization layer managing the encodings support</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]706 <li>a URI module</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]707 <li>the XML parser and its basic SAX interface</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]708 <li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]709 <li>a SAX tree module to build an in-memory DOM representation</li>
710 <li>a tree module to manipulate the DOM representation</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]711 <li>a validation module using the DOM representation (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]712 <li>an XPath module for global lookup in a DOM representation
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]713 (optional)</li>
714 <li>a debug module (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]715</ul>
716
717<p>Graphically this gives the following:</p>
718
719<p><img src="libxml.gif" alt="a graphical view of the various"></p>
720
721<p></p>
722
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]723<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]724
725<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]726returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]727<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]728as the file name, the document type, and a <strong>children</strong> pointer
729which is the root of the document (or more exactly the first child under the
730root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]731chained in double-linked lists of siblings and with a children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]732relationship. An xmlNode can also carry properties (a chain of xmlAttr
733structures). An attribute may have a value which is a list of TEXT or
734ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]735
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]736<p>Here is an example (erroneous with respect to the XML spec since there
737should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]738
739<p><img src="structure.gif" alt=" structure.gif "></p>
740
741<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]742called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]743prints them back as parsed. This is useful for detecting errors both in XML
744code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]745which prints the actual in-memory structure of the document; here is the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]746result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]747<pre>DOCUMENT
748version=1.0
749standalone=true
750 ELEMENT EXAMPLE
751 ATTRIBUTE prop1
752 TEXT
753 content=gnome is great
754 ATTRIBUTE prop2
755 ENTITY_REF
756 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]757 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]758 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]759 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]760 TEXT
761 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]762 ELEMENT chapter
763 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]764 TEXT
765 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]766 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]767 TEXT
768 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]769 ELEMENT image
770 ATTRIBUTE href
771 TEXT
772 content=linus.gif
773 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]774 TEXT
775 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]776
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]777<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]778
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]779<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]780
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]781<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]782memory. In that case (and if you don't expect to save back the XML document
783loaded 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]784<strong>callback-based interface</strong> to the parser. Before parsing, the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]785application layer registers a customized set of callbacks which are called by
786the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]787
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]788<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]789libxml, see the <a
790href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
791documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]792Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]793
794<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
795program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]796binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]797distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]798testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]799<pre>SAX.setDocumentLocator()
800SAX.startDocument()
801SAX.getEntity(amp)
802SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
803SAX.characters( , 3)
804SAX.startElement(head)
805SAX.characters( , 4)
806SAX.startElement(title)
807SAX.characters(Welcome to Gnome, 16)
808SAX.endElement(title)
809SAX.characters( , 3)
810SAX.endElement(head)
811SAX.characters( , 3)
812SAX.startElement(chapter)
813SAX.characters( , 4)
814SAX.startElement(title)
815SAX.characters(The Linux adventure, 19)
816SAX.endElement(title)
817SAX.characters( , 4)
818SAX.startElement(p)
819SAX.characters(bla bla bla ..., 15)
820SAX.endElement(p)
821SAX.characters( , 4)
822SAX.startElement(image, href='linus.gif')
823SAX.endElement(image)
824SAX.characters( , 4)
825SAX.startElement(p)
826SAX.characters(..., 3)
827SAX.endElement(p)
828SAX.characters( , 3)
829SAX.endElement(chapter)
830SAX.characters( , 1)
831SAX.endElement(EXAMPLE)
832SAX.endDocument()</pre>
833
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]834<p>Most of the other interfaces of libxml are based on the DOM tree-building
835facility, so nearly everything up to the end of this document presupposes the
836use of the standard DOM tree build. Note that the DOM tree itself is built by
837a set of registered default callbacks, without internal specific
838interface.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]839
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]840<h2><a name="library">The XML library interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]841
842<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]843using the XML library from the C language. It is not intended to be extensive.
844I hope the automatically generated documents will provide the completeness
845required, but as a separate set of documents. The interfaces of the XML
846library are by principle low level, there is nearly zero abstraction. Those
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]847interested in a higher level API should <a href="#DOM">look at DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]848
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]849<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
850separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]851interfaces</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]852
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]853<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]854
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]855<p>Usually, the first thing to do is to read an XML input. The parser accepts
856documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]857defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]858<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]859 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]860 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]861 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]862</dl>
863<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]864 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]865 <dd><p>Parse an XML document contained in a (possibly compressed)
866 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]867 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]868</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]869
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]870<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]871failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]872
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]873<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]874
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]875<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]876fetched (which is common for GUI based programs) libxml provides a push
877interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]878<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
879 void *user_data,
880 const char *chunk,
881 int size,
882 const char *filename);
883int xmlParseChunk (xmlParserCtxtPtr ctxt,
884 const char *chunk,
885 int size,
886 int terminate);</pre>
887
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]888<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]889<pre> FILE *f;
890
891 f = fopen(filename, "r");
892 if (f != NULL) {
893 int res, size = 1024;
894 char chars[1024];
895 xmlParserCtxtPtr ctxt;
896
897 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]898 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]899 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
900 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]901 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]902 xmlParseChunk(ctxt, chars, res, 0);
903 }
904 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]905 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]906 xmlFreeParserCtxt(ctxt);
907 }
908 }</pre>
909
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]910<p>The HTML parser embedded into libxml also has a push interface; the
911functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]912
913<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
914
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]915<p>The tree-building interface makes the parser memory-hungry, first loading
916the document in memory and then building the tree itself. Reading a document
917without building the tree is possible using the SAX interfaces (see SAX.h and
918<a href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]919Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]920limited to SAX: just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]921<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]922
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]923<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]924
925<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]926there is a set of functions dedicated to building new elements. (These are
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]927also 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]928that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]929<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]930 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]931 xmlNodePtr tree, subtree;
932
933 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]934 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
935 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
936 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
937 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]938 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]939 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]940 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
941 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
942 subtree = xmlNewChild(tree, NULL, "image", NULL);
943 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]944
945<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]946
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]947<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]948
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]949<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]950code has access to the internal structure of all the elements of the tree. The
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]951names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]952<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]953<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]954example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]955<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]956
957<p>points to the title element,</p>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]958<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]959
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]960<p>points to the text node containing the chapter title "The Linux
961adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]962
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]963<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]964present before the document root, so <code>doc-&gt;children</code> may point
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]965to an element which is not the document Root Element; a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]966<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]967
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]968<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]969
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]970<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]971is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]972<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]973 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
974 xmlChar *value);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]975 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node. The
976 value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]977 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]978</dl>
979<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]980 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]981 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +0000[diff] [blame]982 <dd><p>This function returns a pointer to new copy of the property
983 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]984 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]985</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]986
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]987<p>Two functions are provided for reading and writing the text associated with
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]988elements:</p>
989<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]990 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]991 *value);</code></dt>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]992 <dd><p>This function takes an "external" string and converts it to one
993 text node or possibly to a list of entity and text nodes. All
994 non-predefined entity references like &amp;Gnome; will be stored
995 internally as entity nodes, hence the result of the function may not be
996 a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]997 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]998</dl>
999<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]1000 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1001 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1002 <dd><p>This function is the inverse of
1003 <code>xmlStringGetNodeList()</code>. It generates a new string
1004 containing the content of the text and entity nodes. Note the extra
1005 argument inLine. If this argument is set to 1, the function will expand
1006 entity references. For example, instead of returning the &amp;Gnome;
1007 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1008 "GNU Network Object Model Environment").</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1009 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1010</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1011
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1012<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1013
1014<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1015<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]1016 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1017 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1018 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1019 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1020</dl>
1021<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1022 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1023 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1024 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1025</dl>
1026<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1027 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1028 <dd><p>Saves the document to a file. In this case, the compression
1029 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1030 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1031</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1032
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1033<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1034
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1035<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1036accesses. The level of compression on saves can be turned on either globally
1037or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1038<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1039 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1040 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1041 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1042</dl>
1043<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1044 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1045 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1046 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1047</dl>
1048<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1049 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1050 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1051 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1052</dl>
1053<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1054 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1055 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1056 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1057</dl>
1058
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1059<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1060
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1061<p>Entities in principle are similar to simple C macros. An entity defines an
1062abbreviation for a given string that you can reuse many times throughout the
1063content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1064may occur frequently within a document, or to confine the change needed to a
1065document to a restricted area in the internal subset of the document (at the
1066beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1067<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]10682 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]10693 &lt;!ENTITY xml "Extensible Markup Language"&gt;
10704 ]&gt;
10715 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]10726 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]10737 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1074
1075<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]1076its name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1077are 5 predefined entities in libxml allowing you to escape charaters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1078predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1079<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1080for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1081<strong>&amp;quot;</strong> for the character '"', and
1082<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1083
1084<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]1085substitute an entity's content so that you can see the replacement text in
1086your application. Or you may prefer to keep entity references as such in the
1087content to be able to save the document back without losing this usually
1088precious information (if the user went through the pain of explicitly defining
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1089entities, he may have a a rather negative attitude if you blindly susbtitute
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1090them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1091href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1092function allows you to check and change the behaviour, which is to not
1093substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1094
1095<p>Here is the DOM tree built by libxml for the previous document in the
1096default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1097<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1098DOCUMENT
1099version=1.0
1100 ELEMENT EXAMPLE
1101 TEXT
1102 content=
1103 ENTITY_REF
1104 INTERNAL_GENERAL_ENTITY xml
1105 content=Extensible Markup Language
1106 TEXT
1107 content=</pre>
1108
1109<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1110<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1111DOCUMENT
1112version=1.0
1113 ELEMENT EXAMPLE
1114 TEXT
1115 content= Extensible Markup Language</pre>
1116
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1117<p>So, entities or no entities? Basically, it depends on your use case. I
1118suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1119entities in your XML document or data if you are not willing to handle the
1120entity references elements in the DOM tree.</p>
1121
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1122<p>Note that at save time libxml enforces the conversion of the predefined
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1123entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1124transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1125reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1126finding them in the input).</p>
1127
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]1128<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1129on top of the libxml SAX interface is difficult!!! If you plan to use
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]1130non-predefined entities in your documents, then the learning cuvre to handle
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1131then 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]1132strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]1133deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]1134
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1135<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1136
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1137<p>The libxml library implements <a
1138href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
1139recognizing namespace contructs in the input, and does namespace lookup
1140automatically when building the DOM tree. A namespace declaration is
1141associated with an in-memory structure and all elements or attributes within
1142that namespace point to it. Hence testing the namespace is a simple and fast
1143equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1144
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1145<p>I suggest that people using libxml use a namespace, and declare it in the
1146root element of their document as the default namespace. Then they don't need
1147to 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]1148refinement and merging of data from different sources. This doesn't increase
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1149the size of the XML output significantly, but significantly increases its
1150value in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1151<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
1152 &lt;elem1&gt;...&lt;/elem1&gt;
1153 &lt;elem2&gt;...&lt;/elem2&gt;
1154&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1155
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1156<p>The namespace value has to be an absolute URL, but the URL doesn't have to
1157point to any existing resource on the Web. It will bind all the element and
1158atributes with that URL. I suggest to use an URL within a domain you control,
1159and that the URL should contain some kind of version information if possible.
1160For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a good
1161namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1162
1163<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1164version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1165and if the version information don't match something you know, warn the user
1166and 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]1167namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1168same as &lt;bar:text&gt; in another document. What really matters is the URI
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1169associated with the element or the attribute, not the prefix string (which is
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1170just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]1171<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1172prefix and its URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1173
1174<p>@@Interfaces@@</p>
1175
1176<p>@@Examples@@</p>
1177
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1178<p>Usually people object to using namespaces together with validity checking.
1179I will try to make sure that using namespaces won't break validity checking,
1180so even if you plan to use or currently are using validation I strongly
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1181suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1182<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1183flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1184from multiple DTDs will certainly break current validation schemes. I will try
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1185to provide ways to do this, but this may not be portable or standardized.</p>
1186
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1187<h2><a name="Validation">Validation, or are you afraid of DTDs ?</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1188
1189<p>Well what is validation and what is a DTD ?</p>
1190
1191<p>Validation is the process of checking a document against a set of
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1192construction rules; a <strong>DTD</strong> (Document Type Definition) is such
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1193a set of rules.</p>
1194
1195<p>The validation process and building DTDs are the two most difficult parts
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1196of the XML life cycle. Briefly a DTD defines all the possibles element to be
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1197found within your document, what is the formal shape of your document tree (by
1198defining the allowed content of an element, either text, a regular expression
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1199for the allowed list of children, or mixed content i.e. both text and
1200children). The DTD also defines the allowed attributes for all elements and
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1201the types of the attributes. For more detailed information, I suggest that you
Daniel Veillard81781102001-03-07 09:31:47 +0000[diff] [blame]1202read the related parts of the XML specification, the examples found under
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1203gnome-xml/test/valid/dtd and any of the large number of books available on
1204XML. The dia example in gnome-xml/test/valid should be both simple and
1205complete enough to allow you to build your own.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1206
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1207<p>A word of warning, building a good DTD which will fit the needs of your
1208application in the long-term is far from trivial; however, the extra level of
1209quality it can ensure is well worth the price for some sets of applications or
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1210if you already have already a DTD defined for your application field.</p>
1211
1212<p>The validation is not completely finished but in a (very IMHO) usable
1213state. Until a real validation interface is defined the way to do it is to
1214define and set the <strong>xmlDoValidityCheckingDefaultValue</strong> external
1215variable to 1, this will of course be changed at some point:</p>
1216
1217<p>extern int xmlDoValidityCheckingDefaultValue;</p>
1218
1219<p>...</p>
1220
1221<p>xmlDoValidityCheckingDefaultValue = 1;</p>
1222
1223<p></p>
1224
1225<p>To handle external entities, use the function
1226<strong>xmlSetExternalEntityLoader</strong>(xmlExternalEntityLoader f); to
1227link in you HTTP/FTP/Entities database library to the standard libxml
1228core.</p>
1229
1230<p>@@interfaces@@</p>
1231
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1232<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1233
1234<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]1235Model</em>; this is an API for accessing XML or HTML structured documents.
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1236Native support for DOM in Gnome is on the way (module gnome-dom), and will be
1237based on gnome-xml. This will be a far cleaner interface to manipulate XML
Daniel Veillardc08a2c61999-09-08 21:35:25 +0000[diff] [blame]1238files within Gnome since it won't expose the internal structure. DOM defines a
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1239set of IDL (or Java) interfaces allowing you to traverse and manipulate a
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1240document. The DOM library will allow accessing and modifying "live" documents
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1241present in other programs like this:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1242
1243<p><img src="DOM.gif" alt=" DOM.gif "></p>
1244
1245<p>This should help greatly doing things like modifying a gnumeric spreadsheet
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1246embedded in a GWP document for example.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1247
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1248<p>The current DOM implementation on top of libxml is the <a
1249href="http://cvs.gnome.org/lxr/source/gdome/">gdome Gnome module</a>, this is
1250a full DOM interface, thanks to <a href="mailto:raph@levien.com">Raph
1251Levien</a>.</p>
1252
1253<p>The gnome-dom module in the Gnome CVS base is obsolete</p>
1254
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1255<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1256
1257<p>Here is a real size example, where the actual content of the application
1258data 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]1259a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1260storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
1261base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1262<pre>&lt;?xml version="1.0"?&gt;
1263&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
1264 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1265
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1266 &lt;gjob:Job&gt;
1267 &lt;gjob:Project ID="3"/&gt;
1268 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
1269 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1270
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1271 &lt;gjob:Update&gt;
1272 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
1273 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
1274 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
1275 &lt;/gjob:Update&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:Developers&gt;
1278 &lt;gjob:Developer&gt;
1279 &lt;/gjob:Developer&gt;
1280 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1281
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1282 &lt;gjob:Contact&gt;
1283 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
1284 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
1285 &lt;gjob:Company&gt;
1286 &lt;/gjob:Company&gt;
1287 &lt;gjob:Organisation&gt;
1288 &lt;/gjob:Organisation&gt;
1289 &lt;gjob:Webpage&gt;
1290 &lt;/gjob:Webpage&gt;
1291 &lt;gjob:Snailmail&gt;
1292 &lt;/gjob:Snailmail&gt;
1293 &lt;gjob:Phone&gt;
1294 &lt;/gjob:Phone&gt;
1295 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1296
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1297 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1298 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1299 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1300
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1301 &lt;gjob:Skills&gt;
1302 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1303
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1304 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1305 A GNOME based system that will allow a superuser to configure
1306 compressed and uncompressed files and/or file systems to be backed
1307 up with a supported media in the system. This should be able to
1308 perform via find commands generating a list of files that are passed
1309 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
1310 or via operations performed on the filesystem itself. Email
1311 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1312 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1313
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1314 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1315
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1316 &lt;/gjob:Jobs&gt;
1317&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1318
1319<p>While loading the XML file into an internal DOM tree is a matter of calling
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1320only a couple of functions, browsing the tree to gather the ata and generate
1321the internal structures is harder, and more error prone.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1322
1323<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1324structure. For example, the ordering of the attributes is not significant, the
1325XML specification is clear about it. It's also usually a good idea not to
1326depend on the order of the children of a given node, unless it really makes
1327things harder. Here is some code to parse the information for a person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1328<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1329 * A person record
1330 */
1331typedef struct person {
1332 char *name;
1333 char *email;
1334 char *company;
1335 char *organisation;
1336 char *smail;
1337 char *webPage;
1338 char *phone;
1339} person, *personPtr;
1340
1341/*
1342 * And the code needed to parse it
1343 */
1344personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1345 personPtr ret = NULL;
1346
1347DEBUG("parsePerson\n");
1348 /*
1349 * allocate the struct
1350 */
1351 ret = (personPtr) malloc(sizeof(person));
1352 if (ret == NULL) {
1353 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1354 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1355 }
1356 memset(ret, 0, sizeof(person));
1357
1358 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1359 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1360 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1361 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
1362 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1363 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
1364 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1365 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1366 }
1367
1368 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1369}</pre>
1370
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1371<p>Here are a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1372<ul>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1373 <li>Usually a recursive parsing style is the more convenient one: XML data
1374 is by nature subject to repetitive constructs and usually exibits highly
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1375 stuctured patterns.</li>
1376 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>, i.e.
1377 the pointer to the global XML document and the namespace reserved to the
1378 application. Document wide information are needed for example to decode
1379 entities and it's a good coding practice to define a namespace for your
1380 application set of data and test that the element and attributes you're
1381 analyzing actually pertains to your application space. This is done by a
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1382 simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1383 <li>To retrieve text and attributes value, you can use the function
1384 <em>xmlNodeListGetString</em> to gather all the text and entity reference
1385 nodes generated by the DOM output and produce an single text string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1386</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1387
1388<p>Here is another piece of code used to parse another level of the
1389structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1390<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1391/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1392 * a Description for a Job
1393 */
1394typedef struct job {
1395 char *projectID;
1396 char *application;
1397 char *category;
1398 personPtr contact;
1399 int nbDevelopers;
1400 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
1401} job, *jobPtr;
1402
1403/*
1404 * And the code needed to parse it
1405 */
1406jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
1407 jobPtr ret = NULL;
1408
1409DEBUG("parseJob\n");
1410 /*
1411 * allocate the struct
1412 */
1413 ret = (jobPtr) malloc(sizeof(job));
1414 if (ret == NULL) {
1415 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1416 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1417 }
1418 memset(ret, 0, sizeof(job));
1419
1420 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1421 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1422 while (cur != NULL) {
1423
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1424 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
1425 ret-&gt;projectID = xmlGetProp(cur, "ID");
1426 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1427 fprintf(stderr, "Project has no ID\n");
1428 }
1429 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1430 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
1431 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1432 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
1433 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
1434 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
1435 ret-&gt;contact = parsePerson(doc, ns, cur);
1436 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1437 }
1438
1439 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1440}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]1441
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1442<p>Once you are used to it, writing this kind of code is quite simple, but
1443boring. Ultimately, it could be possble to write stubbers taking either C data
1444structure definitions, a set of XML examples or an XML DTD and produce the
1445code needed to import and export the content between C data and XML storage.
1446This is left as an exercise to the reader :-)</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1447
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]1448<p>Feel free to use <a href="example/gjobread.c">the code for the full C
1449parsing example</a> as a template, it is also available with Makefile in the
1450Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1451
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1452<h2><a name="Contributi">Contributions</a></h2>
1453<ul>
Daniel Veillard851c59c2000-11-24 16:06:22 +0000[diff] [blame]1454 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1455 for libxml:
1456 <p>Website: <a
1457 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
1458 <p>Download: <a
1459 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
1460 </li>
1461 <li><a href="mailto:doolin@cs.utk.edu">David Doolin</a> provides a
1462 precompiled Windows version
1463 <p><a
1464 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
1465 </li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]1466 <li><a
1467 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
1468 Sergeant</a> developped <a
1469 href="http://axkit.org/download/">XML::LibXSLT</a>, a perl wrapper for
1470 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
1471 application server</a></li>
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1472 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> provided <a
1473 href="libxml-doc.el">an emacs module</a> to lookup libxml functions
1474 documentation</li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]1475 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
1476 href="http://xmlsoft.org/messages/0488.html">man pages</a> (not yet
1477 integrated in the distribution)</li>
1478</ul>
1479
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1480<p></p>
1481
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]1482<p><a href="mailto:Daniel.Veillard@imag.fr">Daniel Veillard</a></p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1483
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000[diff] [blame]1484<p>$Id: xml.html,v 1.74 2001/03/10 12:32:02 veillard Exp $</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1485</body>
1486</html>