Blame - doc/xml.html - platform/external/libxml2

blob: bd9e672b9058fd0ca8dca03dbf741063b5eddf38 [file] [log] [blame]

Daniel Veillard	09ab7e1	2001-07-10 15:49:44 +0000	[diff] [blame]	1	<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
				2	"http://www.w3.org/TR/html4/loose.dtd">
Daniel Veillard	ccb0963	1998-10-27 06:21:04 +0000	[diff] [blame]	3	<html>
				4	<head>
Daniel Veillard	ec78c0f	2000-08-25 10:25:23 +0000	[diff] [blame]	5	<title>The XML C library for Gnome</title>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	6	<meta name="GENERATOR" content="amaya 5.1">
Daniel Veillard	b24054a	1999-12-18 15:32:46 +0000	[diff] [blame]	7	<meta http-equiv="Content-Type" content="text/html">
Daniel Veillard	ccb0963	1998-10-27 06:21:04 +0000	[diff] [blame]	8	</head>
Daniel Veillard	ccb0963	1998-10-27 06:21:04 +0000	[diff] [blame]	9
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	10	<body bgcolor="#ffffff">
Daniel Veillard	ec78c0f	2000-08-25 10:25:23 +0000	[diff] [blame]	11	<h1 align="center">The XML C library for Gnome</h1>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	12
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	13	<h1>Note: this is the flat content of the <a href="index.html">web
				14	site</a></h1>
				15
Daniel Veillard	c948420	2001-10-24 12:35:52 +0000	[diff] [blame]	16	<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	17
				18	<p></p>
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	19
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	20	<p>Libxml is the XML C library developed for the Gnome project. XML itself
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	21	is a metalanguage to design markup languages, i.e. text language where
				22	semantic and structure are added to the content using extra "markup"
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	23	information enclosed between angle brackets. HTML is the most well-known
Daniel Veillard	1eb2424	2002-03-18 11:33:03 +0000	[diff] [blame]	24	markup language. Though the library is written in C <a href="python.html">a
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	25	variety of language bindings</a> make it available in other environments.</p>
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	26
				27	<p>Libxml2 implements a number of existing standards related to markup
				28	languages:</p>
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	29	<ul>
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	30	<li>the XML standard: <a
				31	href="http://www.w3.org/TR/REC-xml">http://www.w3.org/TR/REC-xml</a></li>
				32	<li>Namespaces in XML: <a
				33	href="http://www.w3.org/TR/REC-xml-names/">http://www.w3.org/TR/REC-xml-names/</a></li>
				34	<li>XML Base: <a
				35	href="http://www.w3.org/TR/xmlbase/">http://www.w3.org/TR/xmlbase/</a></li>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	36	<li><a href="http://www.cis.ohio-state.edu/rfc/rfc2396.txt">RFC 2396</a> :
				37	Uniform Resource Identifiers <a
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	38	href="http://www.ietf.org/rfc/rfc2396.txt">http://www.ietf.org/rfc/rfc2396.txt</a></li>
				39	<li>XML Path Language (XPath) 1.0: <a
				40	href="http://www.w3.org/TR/xpath">http://www.w3.org/TR/xpath</a></li>
				41	<li>HTML4 parser: <a
				42	href="http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</a></li>
				43	<li>most of XML Pointer Language (XPointer) Version 1.0: <a
				44	href="http://www.w3.org/TR/xptr">http://www.w3.org/TR/xptr</a></li>
				45	<li>XML Inclusions (XInclude) Version 1.0: <a
				46	href="http://www.w3.org/TR/xinclude/">http://www.w3.org/TR/xinclude/</a></li>
				47	<li>[ISO-8859-1], <a
				48	href="http://www.cis.ohio-state.edu/rfc/rfc2044.txt">rfc2044</a> [UTF-8]
				49	and <a href="http://www.cis.ohio-state.edu/rfc/rfc2781.txt">rfc2781</a>
				50	[UTF-16] core encodings</li>
				51	<li>part of SGML Open Technical Resolution TR9401:1997</li>
				52	<li>XML Catalogs Working Draft 06 August 2001: <a
				53	href="http://www.oasis-open.org/committees/entity/spec-2001-08-06.html">http://www.oasis-open.org/committees/entity/spec-2001-08-06.html</a></li>
Daniel Veillard	5c39654	2002-03-15 07:57:50 +0000	[diff] [blame]	54	<li>Canonical XML Version 1.0: <a
				55	href="http://www.w3.org/TR/xml-c14n">http://www.w3.org/TR/xml-c14n</a>
Daniel Veillard	2d347fa	2002-03-17 10:34:11 +0000	[diff] [blame]	56	and the Exclusive XML Canonicalization CR draft <a
				57	href="http://www.w3.org/TR/xml-exc-c14n">http://www.w3.org/TR/xml-exc-c14n</a></li>
Daniel Veillard	9698445	2000-08-31 13:50:12 +0000	[diff] [blame]	58	</ul>
				59
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	60	<p>In most cases libxml tries to implement the specifications in a relatively
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	61	strictly compliant way. As of release 2.4.16, libxml2 passes all 1800+ tests
				62	from the <a
Daniel Veillard	a539356	2002-02-20 11:40:49 +0000	[diff] [blame]	63	href="http://www.oasis-open.org/committees/xml-conformance/">OASIS XML Tests
				64	Suite</a>.</p>
Daniel Veillard	5b16f58	2002-02-20 11:38:46 +0000	[diff] [blame]	65
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	66	<p>To some extent libxml2 provides support for the following additional
				67	specifications but doesn't claim to implement them completely:</p>
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	68	<ul>
				69	<li>Document Object Model (DOM) <a
				70	href="http://www.w3.org/TR/DOM-Level-2-Core/">http://www.w3.org/TR/DOM-Level-2-Core/</a>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	71	it doesn't implement the API itself, gdome2 does this on top of
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	72	libxml2</li>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	73	<li><a href="http://www.cis.ohio-state.edu/rfc/rfc959.txt">RFC 959</a> :
				74	libxml implements a basic FTP client code</li>
				75	<li><a href="http://www.cis.ohio-state.edu/rfc/rfc1945.txt">RFC 1945</a> :
				76	HTTP/1.0, again a basic HTTP client code</li>
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	77	<li>SAX: a minimal SAX implementation compatible with early expat
				78	versions</li>
				79	<li>DocBook SGML v4: libxml2 includes a hackish parser to transition to
				80	XML</li>
				81	</ul>
				82
Daniel Veillard	e6d8e20	2002-05-02 06:11:10 +0000	[diff] [blame]	83	<p>XML Schemas is being worked on but it would be far too early to make any
				84	conformance statement about it at the moment.</p>
				85
Daniel Veillard	2d347fa	2002-03-17 10:34:11 +0000	[diff] [blame]	86	<p>Libxml2 is known to be very portable, the library should build and work
				87	without serious troubles on a variety of systems (Linux, Unix, Windows,
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	88	CygWin, MacOS, MacOS X, RISC Os, OS/2, VMS, QNX, MVS, ...)</p>
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	89
Daniel Veillard	9698445	2000-08-31 13:50:12 +0000	[diff] [blame]	90	<p>Separate documents:</p>
				91	<ul>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	92	<li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a> providing an
Daniel Veillard	2d347fa	2002-03-17 10:34:11 +0000	[diff] [blame]	93	implementation of XSLT 1.0 and common extensions like EXSLT for
				94	libxml2</li>
Daniel Veillard	c6271d2	2001-10-27 07:50:58 +0000	[diff] [blame]	95	<li><a href="http://www.cs.unibo.it/~casarini/gdome2/">the gdome2 page</a>
Daniel Veillard	2d347fa	2002-03-17 10:34:11 +0000	[diff] [blame]	96	: a standard DOM2 implementation for libxml2</li>
				97	<li><a href="http://www.aleksey.com/xmlsec/">the XMLSec page</a>: an
				98	implementation of <a href="http://www.w3.org/TR/xmldsig-core/">W3C XML
				99	Digital Signature</a> for libxml2</li>
Daniel Veillard	e6d8e20	2002-05-02 06:11:10 +0000	[diff] [blame]	100	<li>also check the related links section below for more related and active
				101	projects.</li>
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	102	</ul>
				103
Daniel Veillard	e166254	2002-08-28 11:50:59 +0000	[diff] [blame]	104	<p>Logo designed by <a href="mailto:liyanage@access.ch">Marc Liyanage</a>.</p>
				105
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	106	<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	107
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	108	<p>This document describes libxml, the <a
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	109	href="http://www.w3.org/XML/">XML</a> C library developed for the <a
Daniel Veillard	ec78c0f	2000-08-25 10:25:23 +0000	[diff] [blame]	110	href="http://www.gnome.org/">Gnome</a> project. <a
				111	href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
				112	structured documents/data.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	113
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	114	<p>Here are some key points about libxml:</p>
				115	<ul>
Daniel Veillard	2d347fa	2002-03-17 10:34:11 +0000	[diff] [blame]	116	<li>Libxml exports Push (progressive) and Pull (blocking) type parser
				117	interfaces for both XML and HTML.</li>
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	118	<li>Libxml can do DTD validation at parse time, using a parsed document
				119	instance, or with an arbitrary DTD.</li>
Daniel Veillard	2d347fa	2002-03-17 10:34:11 +0000	[diff] [blame]	120	<li>Libxml includes complete <a
Daniel Veillard	8c2ecaf	2001-07-10 17:53:07 +0000	[diff] [blame]	121	href="http://www.w3.org/TR/xpath">XPath</a>, <a
				122	href="http://www.w3.org/TR/xptr">XPointer</a> and <a
				123	href="http://www.w3.org/TR/xinclude">XInclude</a> implementations.</li>
Daniel Veillard	ec78c0f	2000-08-25 10:25:23 +0000	[diff] [blame]	124	<li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard	189446d	2000-10-13 10:23:06 +0000	[diff] [blame]	125	sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillard	ab8500d	2000-10-15 21:06:19 +0000	[diff] [blame]	126	Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	127	<li>Basic support for HTTP and FTP client allowing applications to fetch
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	128	remote resources.</li>
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	129	<li>The design is modular, most of the extensions can be compiled out.</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	130	<li>The internal document representation is as close as possible to the <a
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	131	href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
				132	<li>Libxml also has a <a href="http://www.megginson.com/SAX/index.html">SAX
Daniel Veillard	402e8c8	2000-02-29 22:57:47 +0000	[diff] [blame]	133	like interface</a>; the interface is designed to be compatible with <a
				134	href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillard	c575b99	2002-02-08 13:28:40 +0000	[diff] [blame]	135	<li>This library is released under the <a
				136	href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	137	License</a>. See the Copyright file in the distribution for the precise
Daniel Veillard	c575b99	2002-02-08 13:28:40 +0000	[diff] [blame]	138	wording.</li>
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	139	</ul>
Daniel Veillard	ccb0963	1998-10-27 06:21:04 +0000	[diff] [blame]	140
Daniel Veillard	e0c1d72	2001-03-21 10:28:36 +0000	[diff] [blame]	141	<p>Warning: unless you are forced to because your application links with a
Daniel Veillard	2d347fa	2002-03-17 10:34:11 +0000	[diff] [blame]	142	Gnome-1.X library requiring it, <strong><span
Daniel Veillard	e0c1d72	2001-03-21 10:28:36 +0000	[diff] [blame]	143	style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use
				144	libxml2</p>
				145
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	146	<h2><a name="FAQ">FAQ</a></h2>
				147
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	148	<p>Table of Contents:</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	149	<ul>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	150	<li><a href="FAQ.html#License">License(s)</a></li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	151	<li><a href="FAQ.html#Installati">Installation</a></li>
				152	<li><a href="FAQ.html#Compilatio">Compilation</a></li>
				153	<li><a href="FAQ.html#Developer">Developer corner</a></li>
				154	</ul>
				155
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	156	<h3><a name="License">License</a>(s)</h3>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	157	<ol>
				158	<li><em>Licensing Terms for libxml</em>
Daniel Veillard	c575b99	2002-02-08 13:28:40 +0000	[diff] [blame]	159	<p>libxml is released under the <a
				160	href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	161	License</a>; see the file Copyright in the distribution for the precise
Daniel Veillard	c575b99	2002-02-08 13:28:40 +0000	[diff] [blame]	162	wording</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	163	</li>
				164	<li><em>Can I embed libxml in a proprietary application ?</em>
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	165	<p>Yes. The MIT License allows you to keep proprietary the changes you
				166	made to libxml, but it would be graceful to send-back bug fixes and
				167	improvements as patches for possible incorporation in the main
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	168	development tree.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	169	</li>
				170	</ol>
				171
				172	<h3><a name="Installati">Installation</a></h3>
				173	<ol>
				174	<li>Unless you are forced to because your application links with a Gnome
				175	library requiring it, <strong><span style="background-color: #FF0000">Do
				176	Not Use libxml1</span></strong>, use libxml2</li>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	177	<li><em>Where can I get libxml</em> ?
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	178	<p>The original distribution comes from <a
				179	href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a
MDT 2002 John Fleck	30c7054	2002-09-24 14:24:54 +0000	[diff] [blame]	180	href="ftp://ftp.gnome.org/pub/GNOME/sources/libxml2/2.4/">gnome.org</a></p>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	181	<p>Most Linux and BSD distributions include libxml, this is probably the
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	182	safer way for end-users to use libxml.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	183	<p>David Doolin provides precompiled Windows versions at <a
				184	href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
				185	</li>
				186	<li><em>I see libxml and libxml2 releases, which one should I install ?</em>
				187	<ul>
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	188	<li>If you are not constrained by backward compatibility issues with
				189	existing applications, install libxml2 only</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	190	<li>If you are not doing development, you can safely install both.
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	191	Usually the packages <a
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	192	href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a
				193	href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a> are
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	194	compatible (this is not the case for development packages).</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	195	<li>If you are a developer and your system provides separate packaging
				196	for shared libraries and the development components, it is possible
				197	to install libxml and libxml2, and also <a
				198	href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>
				199	and <a
				200	href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>
				201	too for libxml2 >= 2.3.0</li>
				202	<li>If you are developing a new application, please develop against
				203	libxml2(-devel)</li>
				204	</ul>
				205	</li>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	206	<li><em>I can't install the libxml package, it conflicts with libxml0</em>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	207	<p>You probably have an old libxml0 package used to provide the shared
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	208	library for libxml.so.0, you can probably safely remove it. The libxml
				209	packages provided on <a
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	210	href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provide
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	211	libxml.so.0</p>
				212	</li>
				213	<li><em>I can't install the libxml(2) RPM package due to failed
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	214	dependencies</em>
				215	<p>The most generic solution is to re-fetch the latest src.rpm , and
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	216	rebuild it locally with</p>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	217	<p><code>rpm --rebuild libxml(2)-xxx.src.rpm</code>.</p>
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	218	<p>If everything goes well it will generate two binary rpm packages (one
				219	providing the shared libs and xmllint, and the other one, the -devel
				220	package, providing includes, static libraries and scripts needed to build
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	221	applications with libxml(2)) that you can install locally.</p>
				222	</li>
				223	</ol>
				224
				225	<h3><a name="Compilatio">Compilation</a></h3>
				226	<ol>
				227	<li><em>What is the process to compile libxml ?</em>
				228	<p>As most UNIX libraries libxml follows the "standard":</p>
				229	<p><code>gunzip -c xxx.tar.gz \| tar xvf -</code></p>
				230	<p><code>cd libxml-xxxx</code></p>
				231	<p><code>./configure --help</code></p>
				232	<p>to see the options, then the compilation/installation proper</p>
				233	<p><code>./configure [possible options]</code></p>
				234	<p><code>make</code></p>
				235	<p><code>make install</code></p>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	236	<p>At that point you may have to rerun ldconfig or a similar utility to
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	237	update your list of installed shared libs.</p>
				238	</li>
				239	<li><em>What other libraries are needed to compile/install libxml ?</em>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	240	<p>Libxml does not require any other library, the normal C ANSI API
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	241	should be sufficient (please report any violation to this rule you may
				242	find).</p>
				243	<p>However if found at configuration time libxml will detect and use the
				244	following libs:</p>
				245	<ul>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	246	<li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a> : a
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	247	highly portable and available widely compression library.</li>
				248	<li>iconv: a powerful character encoding conversion library. It is
				249	included by default in recent glibc libraries, so it doesn't need to
				250	be installed specifically on Linux. It now seems a <a
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	251	href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part
				252	of the official UNIX</a> specification. Here is one <a
Daniel Veillard	dad3f68	2002-11-17 16:47:27 +0000	[diff] [blame]	253	href="http://www.gnu.org/software/libiconv/">implementation of the
				254	library</a> which source can be found <a
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	255	href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>.</li>
				256	</ul>
				257	</li>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	258	<li><em>Make check fails on some platforms</em>
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	259	<p>Sometimes the regression tests' results don't completely match the
				260	value produced by the parser, and the makefile uses diff to print the
				261	delta. On some platforms the diff return breaks the compilation process;
				262	if the diff is small this is probably not a serious problem.</p>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	263	<p>Sometimes (especially on Solaris) make checks fail due to limitations
Daniel Veillard	e46182c	2002-02-12 14:29:11 +0000	[diff] [blame]	264	in make. Try using GNU-make instead.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	265	</li>
				266	<li><em>I use the CVS version and there is no configure script</em>
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	267	<p>The configure script (and other Makefiles) are generated. Use the
				268	autogen.sh script to regenerate the configure script and Makefiles,
				269	like:</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	270	<p><code>./autogen.sh --prefix=/usr --disable-shared</code></p>
				271	</li>
				272	<li><em>I have troubles when running make tests with gcc-3.0</em>
				273	<p>It seems the initial release of gcc-3.0 has a problem with the
				274	optimizer which miscompiles the URI module. Please use another
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	275	compiler.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	276	</li>
				277	</ol>
				278
				279	<h3><a name="Developer">Developer</a> corner</h3>
				280	<ol>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	281	<li><em>xmlDocDump() generates output on one line.</em>
				282	<p>Libxml will not <strong>invent</strong> spaces in the content of a
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	283	document since <strong>all spaces in the content of a document are
				284	significant</strong>. If you build a tree from the API and want
				285	indentation:</p>
				286	<ol>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	287	<li>the correct way is to generate those yourself too.</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	288	<li>the dangerous way is to ask libxml to add those blanks to your
				289	content <strong>modifying the content of your document in the
				290	process</strong>. The result may not be what you expect. There is
				291	<strong>NO</strong> way to guarantee that such a modification won't
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	292	affect other parts of the content of your document. See <a
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	293	href="http://xmlsoft.org/html/libxml-parser.html#XMLKEEPBLANKSDEFAULT">xmlKeepBlanksDefault
				294	()</a> and <a
				295	href="http://xmlsoft.org/html/libxml-tree.html#XMLSAVEFORMATFILE">xmlSaveFormatFile
				296	()</a></li>
				297	</ol>
				298	</li>
				299	<li>Extra nodes in the document:
				300	<p><em>For a XML file as below:</em></p>
				301	<pre><?xml version="1.0"?>
				302	<PLAN xmlns="http://www.argus.ca/autotest/1.0/">
				303	<NODE CommFlag="0"/>
				304	<NODE CommFlag="1"/>
				305	</PLAN></pre>
				306	<p><em>after parsing it with the function
				307	pxmlDoc=xmlParseFile(...);</em></p>
				308	<p><em>I want to the get the content of the first node (node with the
				309	CommFlag="0")</em></p>
				310	<p><em>so I did it as following;</em></p>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	311	<pre>xmlNodePtr pnode;
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	312	pnode=pxmlDoc->children->children;</pre>
				313	<p><em>but it does not work. If I change it to</em></p>
				314	<pre>pnode=pxmlDoc->children->children->next;</pre>
				315	<p><em>then it works. Can someone explain it to me.</em></p>
				316	<p></p>
				317	<p>In XML all characters in the content of the document are significant
				318	<strong>including blanks and formatting line breaks</strong>.</p>
				319	<p>The extra nodes you are wondering about are just that, text nodes with
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	320	the formatting spaces which are part of the document but that people tend
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	321	to forget. There is a function <a
				322	href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault
				323	()</a> to remove those at parse time, but that's an heuristic, and its
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	324	use should be limited to cases where you are certain there is no
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	325	mixed-content in the document.</p>
				326	</li>
				327	<li><em>I get compilation errors of existing code like when accessing
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	328	<strong>root</strong> or <strong>child fields</strong> of nodes.</em>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	329	<p>You are compiling code developed for libxml version 1 and using a
				330	libxml2 development environment. Either switch back to libxml v1 devel or
				331	even better fix the code to compile with libxml2 (or both) by <a
				332	href="upgrade.html">following the instructions</a>.</p>
				333	</li>
				334	<li><em>I get compilation errors about non existing
				335	<strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	336	fields.</em>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	337	<p>The source code you are using has been <a
				338	href="upgrade.html">upgraded</a> to be able to compile with both libxml
				339	and libxml2, but you need to install a more recent version:
				340	libxml(-devel) >= 1.8.8 or libxml2(-devel) >= 2.1.0</p>
				341	</li>
				342	<li><em>XPath implementation looks seriously broken</em>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	343	<p>XPath implementation prior to 2.3.0 was really incomplete. Upgrade to
				344	a recent version, there are no known bugs in the current version.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	345	</li>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	346	<li><em>The example provided in the web page does not compile.</em>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	347	<p>It's hard to maintain the documentation in sync with the code
				348	<grin/> ...</p>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	349	<p>Check the previous points 1/ and 2/ raised before, and please send
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	350	patches.</p>
				351	</li>
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	352	<li><em>Where can I get more examples and information than privoded on the
				353	web page?</em>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	354	<p>Ideally a libxml book would be nice. I have no such plan ... But you
				355	can:</p>
				356	<ul>
				357	<li>check more deeply the <a href="html/libxml-lib.html">existing
				358	generated doc</a></li>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	359	<li>look for examples of use for libxml function using the Gnome code.
				360	For example the following will query the full Gnome CVS base for the
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	361	use of the <strong>xmlAddChild()</strong> function:
				362	<p><a
				363	href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p>
				364	<p>This may be slow, a large hardware donation to the gnome project
				365	could cure this :-)</p>
				366	</li>
				367	<li><a
				368	href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&dir=gnome-xml">Browse
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	369	the libxml source</a> , I try to write code as clean and documented
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	370	as possible, so looking at it may be helpful. In particular the code
				371	of xmllint.c and of the various testXXX.c test programs should
				372	provide good examples of how to do things with the library.</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	373	</ul>
				374	</li>
				375	<li>What about C++ ?
				376	<p>libxml is written in pure C in order to allow easy reuse on a number
				377	of platforms, including embedded systems. I don't intend to convert to
				378	C++.</p>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	379	<p>There are however a few C++ wrappers which may fulfill your needs:</p>
Daniel Veillard	9b6fd30	2002-05-13 12:06:47 +0000	[diff] [blame]	380	<ul>
				381	<li>by Ari Johnson <ari@btigate.com>:
				382	<p>Website: <a
				383	href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
				384	<p>Download: <a
				385	href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
				386	</li>
				387	<li>by Peter Jones <pjones@pmade.org>
				388	<p>Website: <a
				389	href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
				390	</li>
				391	</ul>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	392	</li>
				393	<li>How to validate a document a posteriori ?
				394	<p>It is possible to validate documents which had not been validated at
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	395	initial parsing time or documents which have been built from scratch
				396	using the API. Use the <a
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	397	href="http://xmlsoft.org/html/libxml-valid.html#XMLVALIDATEDTD">xmlValidateDtd()</a>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	398	function. It is also possible to simply add a DTD to an existing
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	399	document:</p>
				400	<pre>xmlDocPtr doc; /* your existing document */
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	401	xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */
				402
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	403	dtd->name = xmlStrDup((xmlChar)"root_name"); / use the given root */
				404
				405	doc->intSubset = dtd;
				406	if (doc->children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
				407	else xmlAddPrevSibling(doc->children, (xmlNodePtr)dtd);
				408	</pre>
				409	</li>
Daniel Veillard	dad3f68	2002-11-17 16:47:27 +0000	[diff] [blame]	410	<li>So what is this funky "xmlChar" used all the time?
				411	<p>It is a null terminated sequence of utf-8 characters. And only utf-8!
				412	You need to convert strings encoded in different ways to utf-8 before
				413	passing them to the API. This can be accomplished with the iconv library
				414	for instance.</p>
John Fleck	61f6fb6	2002-10-31 15:23:29 +0000	[diff] [blame]	415	</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	416	<li>etc ...</li>
				417	</ol>
				418
				419	<p></p>
				420
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	421	<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	422
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	423	<p>There are several on-line resources related to using libxml:</p>
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	424	<ol>
Daniel Veillard	321be0c	2002-10-08 21:26:42 +0000	[diff] [blame]	425	<li>Use the <a href="search.php">search engine</a> to lookup
				426	informations.</li>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	427	<li>Check the <a href="FAQ.html">FAQ.</a></li>
Daniel Veillard	c19fccc	2000-07-03 11:52:01 +0000	[diff] [blame]	428	<li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard	8c6d6af	2000-08-25 17:14:13 +0000	[diff] [blame]	429	documentation</a> automatically extracted from code comments (using <a
				430	href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&dir=gtk-doc">gtk
				431	doc</a>).</li>
Daniel Veillard	8d86964	2000-07-14 12:12:59 +0000	[diff] [blame]	432	<li>Look at the documentation about <a href="encoding.html">libxml
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	433	internationalization support</a>.</li>
Daniel Veillard	bc66f85	2002-01-14 09:49:20 +0000	[diff] [blame]	434	<li>This page provides a global overview and <a href="example.html">some
Daniel Veillard	402e8c8	2000-02-29 22:57:47 +0000	[diff] [blame]	435	examples</a> on how to use libxml.</li>
Daniel Veillard	dad3f68	2002-11-17 16:47:27 +0000	[diff] [blame]	436	<li>John Fleck's libxml tutorial: <a href="tutorial/index.html">html</a> or
				437	<a href="tutorial/xmltutorial.pdf">pdf</a>.</li>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	438	<li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
Daniel Veillard	402e8c8	2000-02-29 22:57:47 +0000	[diff] [blame]	439	href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
				440	documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	441	<li>George Lebl wrote <a
				442	href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard	402e8c8	2000-02-29 22:57:47 +0000	[diff] [blame]	443	for IBM developerWorks</a> about using libxml.</li>
Daniel Veillard	ec30341	2000-03-24 13:41:54 +0000	[diff] [blame]	444	<li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	445	file</a>.</li>
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	446	<li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>
				447	description. If you are starting a new project using libxml you should
				448	really use the 2.x version.</li>
Daniel Veillard	845cce4	2002-01-09 11:51:37 +0000	[diff] [blame]	449	<li>And don't forget to look at the <a
				450	href="http://mail.gnome.org/archives/xml/">mailing-list archive</a>.</li>
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	451	</ol>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	452
Daniel Veillard	d5f97f8	2000-09-17 16:38:14 +0000	[diff] [blame]	453	<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard	4c3a203	1999-11-19 17:46:26 +0000	[diff] [blame]	454
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	455	<p>Well, bugs or missing features are always possible, and I will make a
				456	point of fixing them in a timely fashion. The best way to report a bug is to
				457	use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	458	bug tracking database</a> (make sure to use the "libxml2" module name). I
				459	look at reports there regularly and it's good to have a reminder when a bug
				460	is still open. Be sure to specify that the bug is for the package libxml2.</p>
Daniel Veillard	4c3a203	1999-11-19 17:46:26 +0000	[diff] [blame]	461
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	462	<p>There is also a mailing-list <a
Daniel Veillard	3197f16	2001-04-04 00:40:08 +0000	[diff] [blame]	463	href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a
				464	href="http://mail.gnome.org/archives/xml/">on-line archive</a> (<a
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	465	href="http://xmlsoft.org/messages">old</a>). To subscribe to this list,
				466	please visit the <a
				467	href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and
				468	follow the instructions. <strong>Do not send code, I won't debug it</strong>
				469	(but patches are really appreciated!).</p>
Daniel Veillard	234547b	2001-07-05 09:46:10 +0000	[diff] [blame]	470
Daniel Veillard	008186f	2001-09-13 14:24:44 +0000	[diff] [blame]	471	<p>Check the following <strong><span style="color: #FF0000">before
				472	posting</span></strong>:</p>
Daniel Veillard	234547b	2001-07-05 09:46:10 +0000	[diff] [blame]	473	<ul>
Daniel Veillard	321be0c	2002-10-08 21:26:42 +0000	[diff] [blame]	474	<li>Read the <a href="FAQ.html">FAQ</a> and <a href="search.php">use the
				475	search engine</a> to get informations related to your problem.</li>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	476	<li>Make sure you are <a href="ftp://xmlsoft.org/">using a recent
				477	version</a>, and that the problem still shows up in a recent version.</li>
				478	<li>Check the <a href="http://mail.gnome.org/archives/xml/">list
				479	archives</a> to see if the problem was reported already. In this case
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	480	there is probably a fix available, similarly check the <a
Daniel Veillard	e7ead2d	2001-08-22 23:44:09 +0000	[diff] [blame]	481	href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">registered
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	482	open bugs</a>.</li>
				483	<li>Make sure you can reproduce the bug with xmllint or one of the test
				484	programs found in source in the distribution.</li>
Daniel Veillard	234547b	2001-07-05 09:46:10 +0000	[diff] [blame]	485	<li>Please send the command showing the error as well as the input (as an
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	486	attachment)</li>
Daniel Veillard	234547b	2001-07-05 09:46:10 +0000	[diff] [blame]	487	</ul>
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	488
Daniel Veillard	dadd087	2001-09-15 09:21:44 +0000	[diff] [blame]	489	<p>Then send the bug with associated informations to reproduce it to the <a
Daniel Veillard	33a6780	2001-03-07 09:44:02 +0000	[diff] [blame]	490	href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	491	related I will approve it.. Please do not send mail to me directly, it makes
				492	things really hard to track and in some cases I am not the best person to
				493	answer a given question. Ask the list instead.</p>
Daniel Veillard	4c3a203	1999-11-19 17:46:26 +0000	[diff] [blame]	494
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	495	<p>Of course, bugs reported with a suggested patch for fixing them will
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	496	probably be processed faster than those without.</p>
Daniel Veillard	ec30341	2000-03-24 13:41:54 +0000	[diff] [blame]	497
				498	<p>If you're looking for help, a quick look at <a
Daniel Veillard	f7ed336	2001-08-17 12:01:21 +0000	[diff] [blame]	499	href="http://mail.gnome.org/archives/xml/">the list archive</a> may actually
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	500	provide the answer. I usually send source samples when answering libxml usage
Daniel Veillard	6f0adb5	2000-07-03 11:41:26 +0000	[diff] [blame]	501	questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	502	documentation</a> is not as polished as I would like (i need to learn more
				503	about DocBook), but it's a good starting point.</p>
Daniel Veillard	ec30341	2000-03-24 13:41:54 +0000	[diff] [blame]	504
Daniel Veillard	d5f97f8	2000-09-17 16:38:14 +0000	[diff] [blame]	505	<h2><a name="help">How to help</a></h2>
				506
				507	<p>You can help the project in various ways, the best thing to do first is to
				508	subscribe to the mailing-list as explained before, check the <a
Daniel Veillard	f7ed336	2001-08-17 12:01:21 +0000	[diff] [blame]	509	href="http://mail.gnome.org/archives/xml/">archives </a>and the <a
				510	href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome bug
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	511	database</a>:</p>
Daniel Veillard	d5f97f8	2000-09-17 16:38:14 +0000	[diff] [blame]	512	<ol>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	513	<li>Provide patches when you find problems.</li>
				514	<li>Provide the diffs when you port libxml to a new platform. They may not
Daniel Veillard	ab8500d	2000-10-15 21:06:19 +0000	[diff] [blame]	515	be integrated in all cases but help pinpointing portability problems
				516	and</li>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	517	<li>Provide documentation fixes (either as patches to the code comments or
Daniel Veillard	d5f97f8	2000-09-17 16:38:14 +0000	[diff] [blame]	518	as HTML diffs).</li>
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	519	<li>Provide new documentations pieces (translations, examples, etc
				520	...).</li>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	521	<li>Check the TODO file and try to close one of the items.</li>
				522	<li>Take one of the points raised in the archive or the bug database and
Daniel Veillard	e7ead2d	2001-08-22 23:44:09 +0000	[diff] [blame]	523	provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me
				524	</a>before to avoid synchronization problems and check that the suggested
				525	fix will fit in nicely :-)</li>
Daniel Veillard	d5f97f8	2000-09-17 16:38:14 +0000	[diff] [blame]	526	</ol>
				527
Daniel Veillard	10a2c65	1999-12-12 13:03:50 +0000	[diff] [blame]	528	<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	529
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	530	<p>The latest versions of libxml can be found on <a
Daniel Veillard	20c8cf2	2001-06-26 22:47:36 +0000	[diff] [blame]	531	href="ftp://xmlsoft.org/">xmlsoft.org</a> (<a
				532	href="ftp://speakeasy.rpmfind.net/pub/libxml/">Seattle</a>, <a
				533	href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	534	href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
MDT 2002 John Fleck	30c7054	2002-09-24 14:24:54 +0000	[diff] [blame]	535	as a <a href="ftp://ftp.gnome.org/pub/GNOME/sources/libxml2/2.4/">source
				536	archive</a><!-- commenting this out because they seem to have disappeared or <a
Daniel Veillard	a41123c	2001-04-22 19:31:20 +0000	[diff] [blame]	537	href="ftp://ftp.gnome.org/pub/GNOME/stable/redhat/i386/libxml/">RPM
Daniel Veillard	e16b574	2002-09-26 17:50:03 +0000	[diff] [blame]	538	packages</a> -->
Daniel Veillard	321be0c	2002-10-08 21:26:42 +0000	[diff] [blame]	539	, Antonin Sprinzl also provide <a href="ftp://gd.tuwien.ac.at/pub/libxml/">a
Daniel Veillard	e16b574	2002-09-26 17:50:03 +0000	[diff] [blame]	540	mirror in Austria</a>. (NOTE that you need both the <a
Daniel Veillard	c19fccc	2000-07-03 11:52:01 +0000	[diff] [blame]	541	href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
				542	href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard	9518953	2001-07-26 18:30:26 +0000	[diff] [blame]	543	packages installed to compile applications using libxml.) <a
Daniel Veillard	b2fb8ed	2002-04-01 09:33:12 +0000	[diff] [blame]	544	href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now the
				545	maintainer of the Windows port, <a
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	546	href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
Daniel Veillard	c6271d2	2001-10-27 07:50:58 +0000	[diff] [blame]	547	provides binaries</a>. <a href="mailto:Gary.Pennington@sun.com">Gary
Daniel Veillard	1aadc44	2001-11-28 13:10:32 +0000	[diff] [blame]	548	Pennington</a> provides <a href="http://garypennington.net/libxml2/">Solaris
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	549	binaries</a>. <a href="mailto:Steve.Ball@zveno.com">Steve Ball</a> provides
				550	<a href="http://www.zveno.com/open_source/libxml2xslt.html">Mac Os X
				551	binaries</a>.</p>
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	552
Daniel Veillard	6c8b117	2000-03-01 00:40:41 +0000	[diff] [blame]	553	<p><a name="Snapshot">Snapshot:</a></p>
				554	<ul>
				555	<li>Code from the W3C cvs base libxml <a
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	556	href="ftp://xmlsoft.org/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a>.</li>
Daniel Veillard	6c8b117	2000-03-01 00:40:41 +0000	[diff] [blame]	557	<li>Docs, content of the web site, the list archive included <a
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	558	href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a>.</li>
Daniel Veillard	6c8b117	2000-03-01 00:40:41 +0000	[diff] [blame]	559	</ul>
				560
Daniel Veillard	c6271d2	2001-10-27 07:50:58 +0000	[diff] [blame]	561	<p><a name="Contribs">Contributions:</a></p>
Daniel Veillard	6c8b117	2000-03-01 00:40:41 +0000	[diff] [blame]	562
				563	<p>I do accept external contributions, especially if compiling on another
Daniel Veillard	c6271d2	2001-10-27 07:50:58 +0000	[diff] [blame]	564	platform, get in touch with me to upload the package, wrappers for various
Daniel Veillard	5109531	2001-10-28 18:51:57 +0000	[diff] [blame]	565	languages have been provided, and can be found in the <a
				566	href="contribs.html">contrib section</a></p>
Daniel Veillard	6c8b117	2000-03-01 00:40:41 +0000	[diff] [blame]	567
Daniel Veillard	8268716	2001-01-22 15:32:01 +0000	[diff] [blame]	568	<p>Libxml is also available from CVS:</p>
Daniel Veillard	10a2c65	1999-12-12 13:03:50 +0000	[diff] [blame]	569	<ul>
Daniel Veillard	10a2c65	1999-12-12 13:03:50 +0000	[diff] [blame]	570	<li><p>The <a
				571	href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&dir=gnome-xml">Gnome
Daniel Veillard	402e8c8	2000-02-29 22:57:47 +0000	[diff] [blame]	572	CVS base</a>. Check the <a
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	573	href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a>
				574	page; the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard	10a2c65	1999-12-12 13:03:50 +0000	[diff] [blame]	575	</li>
Daniel Veillard	8268716	2001-01-22 15:32:01 +0000	[diff] [blame]	576	<li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard	10a2c65	1999-12-12 13:03:50 +0000	[diff] [blame]	577	</ul>
				578
				579	<h2><a name="News">News</a></h2>
				580
Daniel Veillard	944b5ff	1999-12-15 19:08:24 +0000	[diff] [blame]	581	<h3>CVS only : check the <a
				582	href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard	189446d	2000-10-13 10:23:06 +0000	[diff] [blame]	583	for a really accurate description</h3>
Daniel Veillard	ab8500d	2000-10-15 21:06:19 +0000	[diff] [blame]	584
Daniel Veillard	e6d8e20	2002-05-02 06:11:10 +0000	[diff] [blame]	585	<p>Items not finished and worked on, get in touch with the list if you want
				586	to test those</p>
Daniel Veillard	ab8500d	2000-10-15 21:06:19 +0000	[diff] [blame]	587	<ul>
Daniel Veillard	cf27f7c	2002-04-30 07:12:39 +0000	[diff] [blame]	588	<li>Finishing up <a href="http://www.w3.org/TR/xmlschema-1/">XML
				589	Schemas</a> and <a href="http://www.w3.org/TR/xinclude">XInclude</a></li>
				590	</ul>
				591
Daniel Veillard	f9c4cad	2002-11-22 15:57:07 +0000	[diff] [blame^]	592	<h3>2.4.28: Nov 22 2002</h3>
				593	<ul>
				594	<li>a couple of python binding fixes</li>
				595	<li>2 bug fixes in the XML push parser</li>
				596	<li>potential memory leak removed (Martin Stoilov)</li>
				597	<li>fix to the configure script for Unix (Dimitri Papadopoulos)</li>
				598	<li>added encoding support for XInclude parse="text"</li>
				599	<li>autodetection of XHTML1 and specific serialization rules added</li>
				600	<li>nasty threading bug fixed (William Brack) </li>
				601	</ul>
				602
Daniel Veillard	dad3f68	2002-11-17 16:47:27 +0000	[diff] [blame]	603	<h3>2.4.27: Nov 17 2002</h3>
				604	<ul>
				605	<li>fixes for the Python bindings</li>
				606	<li>a number of bug fixes: SGML catalogs, xmlParseBalancedChunkMemory(),
				607	HTML parser, Schemas (Charles Bozeman), document fragment support
				608	(Christian Glahn), xmlReconciliateNs (Brian Stafford), XPointer,
				609	xmlFreeNode(), xmlSAXParseMemory (Peter Jones), xmlGetNodePath (Petr
				610	Pajas), entities processing</li>
				611	<li>added grep to xmllint --shell</li>
				612	<li>VMS update patch from Craig A. Berry</li>
				613	<li>cleanup of the Windows build with support for more compilers (Igor),
				614	better thread support on Windows</li>
				615	<li>cleanup of Unix Makefiles and spec file</li>
				616	<li>Improvements to the documentation (John Fleck)</li>
				617	</ul>
				618
Daniel Veillard	4826743	2002-10-18 11:21:38 +0000	[diff] [blame]	619	<h3>2.4.26: Oct 18 2002</h3>
				620	<ul>
				621	<li>Patches for Windows CE port, improvements on Windows paths handling</li>
				622	<li>Fixes to the validation code (DTD and Schemas), xmlNodeGetPath() ,
				623	HTML serialization, Namespace compliance, and a number of small
				624	problems</li>
				625	</ul>
				626
Daniel Veillard	e16b574	2002-09-26 17:50:03 +0000	[diff] [blame]	627	<h3>2.4.25: Sep 26 2002</h3>
				628	<ul>
				629	<li>A number of bug fixes: XPath, validation, Python bindings, DOM and
				630	tree, xmlI/O, Html</li>
				631	<li>Serious rewrite of XInclude</li>
				632	<li>Made XML Schemas regexp part of the default build and APIs, small fix
				633	and improvement of the regexp core</li>
				634	<li>Changed the validation code to reuse XML Schemas regexp APIs</li>
				635	<li>Better handling of Windows file paths, improvement of Makefiles (Igor,
				636	Daniel Gehriger, Mark Vakoc)</li>
				637	<li>Improved the python I/O bindings, the tests, added resolver and regexp
Daniel Veillard	321be0c	2002-10-08 21:26:42 +0000	[diff] [blame]	638	APIs</li>
Daniel Veillard	e16b574	2002-09-26 17:50:03 +0000	[diff] [blame]	639	<li>New logos from Marc Liyanage</li>
				640	<li>Tutorial improvements: John Fleck, Christopher Harris</li>
				641	<li>Makefile: Fixes for AMD x86_64 (Mandrake), DESTDIR (Christophe
				642	Merlet)</li>
				643	<li>removal of all stderr/perror use for error reporting</li>
				644	<li>Better error reporting: XPath and DTD validation</li>
				645	<li>update of the trio portability layer (Bjorn Reese)</li>
				646	</ul>
				647
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	648	<p><strong>2.4.24: Aug 22 2002</strong></p>
				649	<ul>
				650	<li>XPath fixes (William), xf:escape-uri() (Wesley Terpstra)</li>
				651	<li>Python binding fixes: makefiles (William), generator, rpm build, x86-64
				652	(fcrozat)</li>
				653	<li>HTML <style> and boolean attributes serializer fixes</li>
				654	<li>C14N improvements by Aleksey</li>
Daniel Veillard	e166254	2002-08-28 11:50:59 +0000	[diff] [blame]	655	<li>doc cleanups: Rick Jones</li>
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	656	<li>Windows compiler makefile updates: Igor and Elizabeth Barham</li>
				657	<li>XInclude: implementation of fallback and xml:base fixup added</li>
				658	</ul>
				659
Daniel Veillard	782afda	2002-07-08 15:12:49 +0000	[diff] [blame]	660	<h3>2.4.23: July 6 2002</h3>
				661	<ul>
				662	<li>performances patches: Peter Jacobi</li>
				663	<li>c14n fixes, testsuite and performances: Aleksey Sanin</li>
				664	<li>added xmlDocFormatDump: Chema Celorio</li>
				665	<li>new tutorial: John Fleck</li>
				666	<li>new hash functions and performances: Sander Vesik, portability fix from
				667	Peter Jacobi</li>
				668	<li>a number of bug fixes: XPath (William Brack, Richard Jinks), XML and
				669	HTML parsers, ID lookup function</li>
				670	<li>removal of all remaining sprintf: Aleksey Sanin</li>
				671	</ul>
				672
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	673	<h3>2.4.22: May 27 2002</h3>
				674	<ul>
				675	<li>a number of bug fixes: configure scripts, base handling, parser, memory
				676	usage, HTML parser, XPath, documentation (Christian Cornelssen),
Daniel Veillard	2147367	2002-06-17 07:29:22 +0000	[diff] [blame]	677	indentation, URI parsing</li>
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	678	<li>Optimizations for XMLSec, fixing and making public some of the network
				679	protocol handlers (Aleksey)</li>
				680	<li>performance patch from Gary Pennington</li>
				681	<li>Charles Bozeman provided date and time support for XML Schemas
				682	datatypes</li>
				683	</ul>
				684
Daniel Veillard	cf27f7c	2002-04-30 07:12:39 +0000	[diff] [blame]	685	<h3>2.4.21: Apr 29 2002</h3>
				686
				687	<p>This release is both a bug fix release and also contains the early XML
				688	Schemas <a href="http://www.w3.org/TR/xmlschema-1/">structures</a> and <a
				689	href="http://www.w3.org/TR/xmlschema-2/">datatypes</a> code, beware, all
				690	interfaces are likely to change, there is huge holes, it is clearly a work in
				691	progress and don't even think of putting this code in a production system,
Daniel Veillard	e6d8e20	2002-05-02 06:11:10 +0000	[diff] [blame]	692	it's actually not compiled in by default. The real fixes are:</p>
Daniel Veillard	cf27f7c	2002-04-30 07:12:39 +0000	[diff] [blame]	693	<ul>
				694	<li>a couple of bugs or limitations introduced in 2.4.20</li>
				695	<li>patches for Borland C++ and MSC by Igor</li>
				696	<li>some fixes on XPath strings and conformance patches by Richard
				697	Jinks</li>
				698	<li>patch from Aleksey for the ExcC14N specification</li>
				699	<li>OSF/1 bug fix by Bjorn</li>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	700	</ul>
				701
Daniel Veillard	a7084cd	2002-04-15 17:12:47 +0000	[diff] [blame]	702	<h3>2.4.20: Apr 15 2002</h3>
				703	<ul>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	704	<li>bug fixes: file descriptor leak, XPath, HTML output, DTD validation</li>
Daniel Veillard	a7084cd	2002-04-15 17:12:47 +0000	[diff] [blame]	705	<li>XPath conformance testing by Richard Jinks</li>
				706	<li>Portability fixes: Solaris, MPE/iX, Windows, OSF/1, python bindings,
				707	libxml.m4</li>
				708	</ul>
				709
Daniel Veillard	1927409	2002-03-25 16:48:03 +0000	[diff] [blame]	710	<h3>2.4.19: Mar 25 2002</h3>
				711	<ul>
				712	<li>bug fixes: half a dozen XPath bugs, Validation, ISO-Latin to UTF8
				713	encoder</li>
				714	<li>portability fixes in the HTTP code</li>
Daniel Veillard	b2fb8ed	2002-04-01 09:33:12 +0000	[diff] [blame]	715	<li>memory allocation checks using valgrind, and profiling tests</li>
Daniel Veillard	1927409	2002-03-25 16:48:03 +0000	[diff] [blame]	716	<li>revamp of the Windows build and Makefiles</li>
				717	</ul>
				718
Daniel Veillard	34ce8be	2002-03-18 19:37:11 +0000	[diff] [blame]	719	<h3>2.4.18: Mar 18 2002</h3>
				720	<ul>
				721	<li>bug fixes: tree, SAX, canonicalization, validation, portability,
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	722	XPath</li>
Daniel Veillard	34ce8be	2002-03-18 19:37:11 +0000	[diff] [blame]	723	<li>removed the --with-buffer option it was becoming unmaintainable</li>
				724	<li>serious cleanup of the Python makefiles</li>
				725	<li>speedup patch to XPath very effective for DocBook stylesheets</li>
				726	<li>Fixes for Windows build, cleanup of the documentation</li>
				727	</ul>
				728
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	729	<h3>2.4.17: Mar 8 2002</h3>
				730	<ul>
				731	<li>a lot of bug fixes, including "namespace nodes have no parents in
				732	XPath"</li>
				733	<li>fixed/improved the Python wrappers, added more examples and more
				734	regression tests, XPath extension functions can now return node-sets</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	735	<li>added the XML Canonicalization support from Aleksey Sanin</li>
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	736	</ul>
				737
Daniel Veillard	5f4b599	2002-02-20 10:22:49 +0000	[diff] [blame]	738	<h3>2.4.16: Feb 20 2002</h3>
				739	<ul>
				740	<li>a lot of bug fixes, most of them were triggered by the XML Testsuite
				741	from OASIS and W3C. Compliance has been significantly improved.</li>
				742	<li>a couple of portability fixes too.</li>
				743	</ul>
				744
Daniel Veillard	397ff11	2002-02-11 18:27:20 +0000	[diff] [blame]	745	<h3>2.4.15: Feb 11 2002</h3>
				746	<ul>
				747	<li>Fixed the Makefiles, especially the python module ones</li>
				748	<li>A few bug fixes and cleanup</li>
				749	<li>Includes cleanup</li>
				750	</ul>
				751
Daniel Veillard	b6c1e2f	2002-02-08 14:52:52 +0000	[diff] [blame]	752	<h3>2.4.14: Feb 8 2002</h3>
				753	<ul>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	754	<li>Change of License to the <a
Daniel Veillard	b6c1e2f	2002-02-08 14:52:52 +0000	[diff] [blame]	755	href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	756	License</a> basically for integration in XFree86 codebase, and removing
				757	confusion around the previous dual-licensing</li>
Daniel Veillard	b6c1e2f	2002-02-08 14:52:52 +0000	[diff] [blame]	758	<li>added Python bindings, beta software but should already be quite
				759	complete</li>
				760	<li>a large number of fixes and cleanups, especially for all tree
				761	manipulations</li>
				762	<li>cleanup of the headers, generation of a reference API definition in
				763	XML</li>
				764	</ul>
				765
				766	<h3>2.4.13: Jan 14 2002</h3>
Daniel Veillard	744683d	2002-01-14 17:30:20 +0000	[diff] [blame]	767	<ul>
				768	<li>update of the documentation: John Fleck and Charlie Bozeman</li>
				769	<li>cleanup of timing code from Justin Fletcher</li>
				770	<li>fixes for Windows and initial thread support on Win32: Igor and Serguei
				771	Narojnyi</li>
				772	<li>Cygwin patch from Robert Collins</li>
				773	<li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li>
				774	</ul>
				775
Daniel Veillard	ef90ba7	2001-12-07 14:24:22 +0000	[diff] [blame]	776	<h3>2.4.12: Dec 7 2001</h3>
				777	<ul>
				778	<li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman),
				779	XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups
				780	(robert)</li>
				781	<li>Eric Lavigne contributed project files for MacOS</li>
				782	<li>some makefiles cleanups</li>
				783	</ul>
				784
Daniel Veillard	a487105	2001-11-26 13:19:48 +0000	[diff] [blame]	785	<h3>2.4.11: Nov 26 2001</h3>
				786	<ul>
				787	<li>fixed a couple of errors in the includes, fixed a few bugs, some code
				788	cleanups</li>
				789	<li>xmllint man pages improvement by Heiko Rupp</li>
				790	<li>updated VMS build instructions from John A Fotheringham</li>
				791	<li>Windows Makefiles updates from Igor</li>
				792	</ul>
				793
Daniel Veillard	43d3f61	2001-11-10 11:57:23 +0000	[diff] [blame]	794	<h3>2.4.10: Nov 10 2001</h3>
				795	<ul>
				796	<li>URI escaping fix (Joel Young)</li>
				797	<li>added xmlGetNodePath() (for paths or XPointers generation)</li>
				798	<li>Fixes namespace handling problems when using DTD and validation</li>
				799	<li>improvements on xmllint: Morus Walter patches for --format and
				800	--encode, Stefan Kost and Heiko Rupp improvements on the --shell</li>
				801	<li>fixes for xmlcatalog linking pointed by Weiqi Gao</li>
				802	<li>fixes to the HTML parser</li>
				803	</ul>
				804
				805	<h3>2.4.9: Nov 6 2001</h3>
				806	<ul>
				807	<li>fixes more catalog bugs</li>
				808	<li>avoid a compilation problem, improve xmlGetLineNo()</li>
				809	</ul>
				810
Daniel Veillard	ed421aa	2001-11-04 21:22:45 +0000	[diff] [blame]	811	<h3>2.4.8: Nov 4 2001</h3>
				812	<ul>
				813	<li>fixed SGML catalogs broken in previous release, updated xmlcatalog
				814	tool</li>
				815	<li>fixed a compile errors and some includes troubles.</li>
				816	</ul>
				817
Daniel Veillard	52dcab3	2001-10-30 12:51:17 +0000	[diff] [blame]	818	<h3>2.4.7: Oct 30 2001</h3>
				819	<ul>
				820	<li>exported some debugging interfaces</li>
				821	<li>serious rewrite of the catalog code</li>
				822	<li>integrated Gary Pennington thread safety patch, added configure option
				823	and regression tests</li>
				824	<li>removed an HTML parser bug</li>
				825	<li>fixed a couple of potentially serious validation bugs</li>
				826	<li>integrated the SGML DocBook support in xmllint</li>
				827	<li>changed the nanoftp anonymous login passwd</li>
				828	<li>some I/O cleanup and a couple of interfaces for Perl wrapper</li>
				829	<li>general bug fixes</li>
				830	<li>updated xmllint man page by John Fleck</li>
				831	<li>some VMS and Windows updates</li>
				832	</ul>
				833
Daniel Veillard	60087f3	2001-10-10 09:45:09 +0000	[diff] [blame]	834	<h3>2.4.6: Oct 10 2001</h3>
				835	<ul>
Daniel Veillard	52dcab3	2001-10-30 12:51:17 +0000	[diff] [blame]	836	<li>added an updated man pages by John Fleck</li>
Daniel Veillard	60087f3	2001-10-10 09:45:09 +0000	[diff] [blame]	837	<li>portability and configure fixes</li>
				838	<li>an infinite loop on the HTML parser was removed (William)</li>
				839	<li>Windows makefile patches from Igor</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	840	<li>fixed half a dozen bugs reported for libxml or libxslt</li>
Daniel Veillard	60087f3	2001-10-10 09:45:09 +0000	[diff] [blame]	841	<li>updated xmlcatalog to be able to modify SGML super catalogs</li>
				842	</ul>
				843
Daniel Veillard	dadd087	2001-09-15 09:21:44 +0000	[diff] [blame]	844	<h3>2.4.5: Sep 14 2001</h3>
				845	<ul>
				846	<li>Remove a few annoying bugs in 2.4.4</li>
				847	<li>forces the HTML serializer to output decimal charrefs since some
				848	version of Netscape can't handle hexadecimal ones</li>
				849	</ul>
				850
				851	<h3>1.8.16: Sep 14 2001</h3>
				852	<ul>
				853	<li>maintenance release of the old libxml1 branch, couple of bug and
				854	portability fixes</li>
				855	</ul>
				856
Daniel Veillard	04382ae	2001-09-12 18:51:30 +0000	[diff] [blame]	857	<h3>2.4.4: Sep 12 2001</h3>
				858	<ul>
				859	<li>added --convert to xmlcatalog, bug fixes and cleanups of XML
				860	Catalog</li>
				861	<li>a few bug fixes and some portability changes</li>
				862	<li>some documentation cleanups</li>
				863	</ul>
				864
Daniel Veillard	3993690	2001-08-24 00:49:01 +0000	[diff] [blame]	865	<h3>2.4.3: Aug 23 2001</h3>
				866	<ul>
				867	<li>XML Catalog support see the doc</li>
				868	<li>New NaN/Infinity floating point code</li>
				869	<li>A few bug fixes</li>
				870	</ul>
				871
				872	<h3>2.4.2: Aug 15 2001</h3>
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	873	<ul>
				874	<li>adds xmlLineNumbersDefault() to control line number generation</li>
				875	<li>lot of bug fixes</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	876	<li>the Microsoft MSC projects files should now be up to date</li>
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	877	<li>inheritance of namespaces from DTD defaulted attributes</li>
				878	<li>fixes a serious potential security bug</li>
				879	<li>added a --format option to xmllint</li>
				880	</ul>
				881
				882	<h3>2.4.1: July 24 2001</h3>
				883	<ul>
				884	<li>possibility to keep line numbers in the tree</li>
				885	<li>some computation NaN fixes</li>
				886	<li>extension of the XPath API</li>
				887	<li>cleanup for alpha and ia64 targets</li>
				888	<li>patch to allow saving through HTTP PUT or POST</li>
Daniel Veillard	09ab7e1	2001-07-10 15:49:44 +0000	[diff] [blame]	889	</ul>
				890
				891	<h3>2.4.0: July 10 2001</h3>
				892	<ul>
				893	<li>Fixed a few bugs in XPath, validation, and tree handling.</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	894	<li>Fixed XML Base implementation, added a couple of examples to the
Daniel Veillard	09ab7e1	2001-07-10 15:49:44 +0000	[diff] [blame]	895	regression tests</li>
				896	<li>A bit of cleanup</li>
Daniel Veillard	ab8500d	2000-10-15 21:06:19 +0000	[diff] [blame]	897	</ul>
				898
Daniel Veillard	5b43fde	2001-07-05 23:31:40 +0000	[diff] [blame]	899	<h3>2.3.14: July 5 2001</h3>
				900	<ul>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	901	<li>fixed some entities problems and reduce memory requirement when
				902	substituting them</li>
Daniel Veillard	5b43fde	2001-07-05 23:31:40 +0000	[diff] [blame]	903	<li>lots of improvements in the XPath queries interpreter can be
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	904	substantially faster</li>
Daniel Veillard	5b43fde	2001-07-05 23:31:40 +0000	[diff] [blame]	905	<li>Makefiles and configure cleanups</li>
				906	<li>Fixes to XPath variable eval, and compare on empty node set</li>
				907	<li>HTML tag closing bug fixed</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	908	<li>Fixed an URI reference computation problem when validating</li>
Daniel Veillard	5b43fde	2001-07-05 23:31:40 +0000	[diff] [blame]	909	</ul>
				910
Daniel Veillard	2adbb51	2001-06-28 16:20:36 +0000	[diff] [blame]	911	<h3>2.3.13: June 28 2001</h3>
				912	<ul>
				913	<li>2.3.12 configure.in was broken as well as the push mode XML parser</li>
				914	<li>a few more fixes for compilation on Windows MSC by Yon Derek</li>
				915	</ul>
				916
				917	<h3>1.8.14: June 28 2001</h3>
				918	<ul>
				919	<li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li>
				920	<li>Small Makefile fix</li>
				921	</ul>
				922
Daniel Veillard	1164810	2001-06-26 16:08:24 +0000	[diff] [blame]	923	<h3>2.3.12: June 26 2001</h3>
				924	<ul>
				925	<li>lots of cleanup</li>
				926	<li>a couple of validation fix</li>
				927	<li>fixed line number counting</li>
				928	<li>fixed serious problems in the XInclude processing</li>
				929	<li>added support for UTF8 BOM at beginning of entities</li>
				930	<li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0
				931	miscompile uri.c (William), Thomas Leitner provided a fix for the
				932	optimizer on Tru64</li>
				933	<li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for
				934	compilation on Windows MSC</li>
				935	<li>update of libxml-doc.el (Felix Natter)</li>
				936	<li>fixed 2 bugs in URI normalization code</li>
				937	</ul>
				938
Daniel Veillard	e3c81b5	2001-06-17 14:50:34 +0000	[diff] [blame]	939	<h3>2.3.11: June 17 2001</h3>
				940	<ul>
				941	<li>updates to trio, Makefiles and configure should fix some portability
				942	problems (alpha)</li>
				943	<li>fixed some HTML serialization problems (pre, script, and block/inline
				944	handling), added encoding aware APIs, cleanup of this code</li>
				945	<li>added xmlHasNsProp()</li>
				946	<li>implemented a specific PI for encoding support in the DocBook SGML
				947	parser</li>
				948	<li>some XPath fixes (-Infinity, / as a function parameter and namespaces
				949	node selection)</li>
				950	<li>fixed a performance problem and an error in the validation code</li>
				951	<li>fixed XInclude routine to implement the recursive behaviour</li>
				952	<li>fixed xmlFreeNode problem when libxml is included statically twice</li>
				953	<li>added --version to xmllint for bug reports</li>
				954	</ul>
				955
Daniel Veillard	2e4f188	2001-06-01 10:11:57 +0000	[diff] [blame]	956	<h3>2.3.10: June 1 2001</h3>
				957	<ul>
				958	<li>fixed the SGML catalog support</li>
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	959	<li>a number of reported bugs got fixed, in XPath, iconv detection,
				960	XInclude processing</li>
Daniel Veillard	2e4f188	2001-06-01 10:11:57 +0000	[diff] [blame]	961	<li>XPath string function should now handle unicode correctly</li>
				962	</ul>
				963
Daniel Veillard	4623acd	2001-05-19 15:13:15 +0000	[diff] [blame]	964	<h3>2.3.9: May 19 2001</h3>
				965
				966	<p>Lots of bugfixes, and added a basic SGML catalog support:</p>
				967	<ul>
				968	<li>HTML push bugfix #54891 and another patch from Jonas Borgström</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	969	<li>some serious speed optimization again</li>
Daniel Veillard	4623acd	2001-05-19 15:13:15 +0000	[diff] [blame]	970	<li>some documentation cleanups</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	971	<li>trying to get better linking on Solaris (-R)</li>
Daniel Veillard	4623acd	2001-05-19 15:13:15 +0000	[diff] [blame]	972	<li>XPath API cleanup from Thomas Broyer</li>
				973	<li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed
				974	xmlValidGetValidElements()</li>
				975	<li>Added an INSTALL file</li>
				976	<li>Attribute removal added to API: #54433</li>
				977	<li>added a basic support for SGML catalogs</li>
				978	<li>fixed xmlKeepBlanksDefault(0) API</li>
				979	<li>bugfix in xmlNodeGetLang()</li>
				980	<li>fixed a small configure portability problem</li>
				981	<li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li>
				982	</ul>
				983
Daniel Veillard	a265af7	2001-05-14 11:13:58 +0000	[diff] [blame]	984	<h3>1.8.13: May 14 2001</h3>
				985	<ul>
				986	<li>bugfixes release of the old libxml1 branch used by Gnome</li>
				987	</ul>
				988
Daniel Veillard	3bbbe6f	2001-05-03 11:15:37 +0000	[diff] [blame]	989	<h3>2.3.8: May 3 2001</h3>
				990	<ul>
				991	<li>Integrated an SGML DocBook parser for the Gnome project</li>
				992	<li>Fixed a few things in the HTML parser</li>
				993	<li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating
				994	point portability issue</li>
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	995	<li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for
				996	DOM+validation using the XML REC as input and a 700MHz celeron).</li>
Daniel Veillard	3bbbe6f	2001-05-03 11:15:37 +0000	[diff] [blame]	997	<li>incorporated more Windows cleanup</li>
				998	<li>added xmlSaveFormatFile()</li>
				999	<li>fixed problems in copying nodes with entities references (gdome)</li>
				1000	<li>removed some troubles surrounding the new validation module</li>
				1001	</ul>
				1002
Daniel Veillard	a41123c	2001-04-22 19:31:20 +0000	[diff] [blame]	1003	<h3>2.3.7: April 22 2001</h3>
				1004	<ul>
				1005	<li>lots of small bug fixes, corrected XPointer</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1006	<li>Non deterministic content model validation support</li>
Daniel Veillard	a41123c	2001-04-22 19:31:20 +0000	[diff] [blame]	1007	<li>added xmlDocCopyNode for gdome2</li>
				1008	<li>revamped the way the HTML parser handles end of tags</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1009	<li>XPath: corrections of namespaces support and number formatting</li>
Daniel Veillard	a41123c	2001-04-22 19:31:20 +0000	[diff] [blame]	1010	<li>Windows: Igor Zlatkovic patches for MSC compilation</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1011	<li>HTML output fixes from P C Chow and William M. Brack</li>
Daniel Veillard	a41123c	2001-04-22 19:31:20 +0000	[diff] [blame]	1012	<li>Improved validation speed sensible for DocBook</li>
				1013	<li>fixed a big bug with ID declared in external parsed entities</li>
				1014	<li>portability fixes, update of Trio from Bjorn Reese</li>
				1015	</ul>
				1016
Daniel Veillard	afc7311	2001-04-11 11:51:41 +0000	[diff] [blame]	1017	<h3>2.3.6: April 8 2001</h3>
				1018	<ul>
				1019	<li>Code cleanup using extreme gcc compiler warning options, found and
				1020	cleared half a dozen potential problem</li>
				1021	<li>the Eazel team found an XML parser bug</li>
				1022	<li>cleaned up the user of some of the string formatting function. used the
				1023	trio library code to provide the one needed when the platform is missing
				1024	them</li>
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	1025	<li>xpath: removed a memory leak and fixed the predicate evaluation
				1026	problem, extended the testsuite and cleaned up the result. XPointer seems
				1027	broken ...</li>
Daniel Veillard	afc7311	2001-04-11 11:51:41 +0000	[diff] [blame]	1028	</ul>
				1029
Daniel Veillard	56a4cb8	2001-03-24 17:00:36 +0000	[diff] [blame]	1030	<h3>2.3.5: Mar 23 2001</h3>
				1031	<ul>
				1032	<li>Biggest change is separate parsing and evaluation of XPath expressions,
				1033	there is some new APIs for this too</li>
				1034	<li>included a number of bug fixes(XML push parser, 51876, notations,
				1035	52299)</li>
				1036	<li>Fixed some portability issues</li>
				1037	</ul>
				1038
Daniel Veillard	e356c28	2001-03-10 12:32:04 +0000	[diff] [blame]	1039	<h3>2.3.4: Mar 10 2001</h3>
				1040	<ul>
				1041	<li>Fixed bugs #51860 and #51861</li>
				1042	<li>Added a global variable xmlDefaultBufferSize to allow default buffer
				1043	size to be application tunable.</li>
				1044	<li>Some cleanup in the validation code, still a bug left and this part
				1045	should probably be rewritten to support ambiguous content model :-\</li>
				1046	<li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3
				1047	parser</li>
				1048	<li>Fixed another bug in xmlNodeGetContent()</li>
				1049	<li>Bjorn fixed XPath node collection and Number formatting</li>
				1050	<li>Fixed a loop reported in the HTML parsing</li>
				1051	<li>blank space are reported even if the Dtd content model proves that they
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1052	are formatting spaces, this is for XML conformance</li>
Daniel Veillard	e356c28	2001-03-10 12:32:04 +0000	[diff] [blame]	1053	</ul>
				1054
Daniel Veillard	b402c07	2001-03-01 17:28:58 +0000	[diff] [blame]	1055	<h3>2.3.3: Mar 1 2001</h3>
				1056	<ul>
				1057	<li>small change in XPath for XSLT</li>
				1058	<li>documentation cleanups</li>
				1059	<li>fix in validation by Gary Pennington</li>
				1060	<li>serious parsing performances improvements</li>
				1061	</ul>
				1062
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	1063	<h3>2.3.2: Feb 24 2001</h3>
Daniel Veillard	7168110	2001-02-24 17:48:53 +0000	[diff] [blame]	1064	<ul>
				1065	<li>chasing XPath bugs, found a bunch, completed some TODO</li>
				1066	<li>fixed a Dtd parsing bug</li>
				1067	<li>fixed a bug in xmlNodeGetContent</li>
				1068	<li>ID/IDREF support partly rewritten by Gary Pennington</li>
				1069	</ul>
				1070
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	1071	<h3>2.3.1: Feb 15 2001</h3>
Daniel Veillard	6e6a6cc	2001-02-15 15:55:44 +0000	[diff] [blame]	1072	<ul>
				1073	<li>some XPath and HTML bug fixes for XSLT</li>
				1074	<li>small extension of the hash table interfaces for DOM gdome2
				1075	implementation</li>
				1076	<li>A few bug fixes</li>
				1077	</ul>
				1078
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	1079	<h3>2.3.0: Feb 8 2001 (2.2.12 was on 25 Jan but I didn't kept track)</h3>
Daniel Veillard	6e6a6cc	2001-02-15 15:55:44 +0000	[diff] [blame]	1080	<ul>
				1081	<li>Lots of XPath bug fixes</li>
				1082	<li>Add a mode with Dtd lookup but without validation error reporting for
				1083	XSLT</li>
				1084	<li>Add support for text node without escaping (XSLT)</li>
				1085	<li>bug fixes for xmlCheckFilename</li>
				1086	<li>validation code bug fixes from Gary Pennington</li>
				1087	<li>Patch from Paul D. Smith correcting URI path normalization</li>
				1088	<li>Patch to allow simultaneous install of libxml-devel and
				1089	libxml2-devel</li>
				1090	<li>the example Makefile is now fixed</li>
				1091	<li>added HTML to the RPM packages</li>
				1092	<li>tree copying bugfixes</li>
				1093	<li>updates to Windows makefiles</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1094	<li>optimization patch from Bjorn Reese</li>
Daniel Veillard	6e6a6cc	2001-02-15 15:55:44 +0000	[diff] [blame]	1095	</ul>
				1096
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	1097	<h3>2.2.11: Jan 4 2001</h3>
Daniel Veillard	503b893	2001-01-05 06:36:31 +0000	[diff] [blame]	1098	<ul>
				1099	<li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
				1100	<li>added htmlHandleOmittedElem()</li>
				1101	<li>Applied Bjorn Reese's IPV6 first patch</li>
				1102	<li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard	8268716	2001-01-22 15:32:01 +0000	[diff] [blame]	1103	<li>added XPointer xmlns() new scheme support</li>
Daniel Veillard	503b893	2001-01-05 06:36:31 +0000	[diff] [blame]	1104	</ul>
				1105
Daniel Veillard	2ddd23d	2000-11-25 10:42:19 +0000	[diff] [blame]	1106	<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard	9d343c4	2000-11-25 10:12:43 +0000	[diff] [blame]	1107	<ul>
				1108	<li>Fix the Windows problems of 2.2.8</li>
				1109	<li>integrate OpenVMS patches</li>
				1110	<li>better handling of some nasty HTML input</li>
				1111	<li>Improved the XPointer implementation</li>
				1112	<li>integrate a number of provided patches</li>
				1113	</ul>
				1114
Daniel Veillard	2ddd23d	2000-11-25 10:42:19 +0000	[diff] [blame]	1115	<h3>2.2.9: Nov 25 2000</h3>
				1116	<ul>
				1117	<li>erroneous release :-(</li>
				1118	</ul>
				1119
Daniel Veillard	28929b2	2000-11-13 18:22:49 +0000	[diff] [blame]	1120	<h3>2.2.8: Nov 13 2000</h3>
				1121	<ul>
				1122	<li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
				1123	support</li>
				1124	<li>Patch in conditional section handling</li>
				1125	<li>updated MS compiler project</li>
				1126	<li>fixed some XPath problems</li>
				1127	<li>added an URI escaping function</li>
				1128	<li>some other bug fixes</li>
				1129	</ul>
				1130
				1131	<h3>2.2.7: Oct 31 2000</h3>
				1132	<ul>
				1133	<li>added message redirection</li>
				1134	<li>XPath improvements (thanks TOM !)</li>
				1135	<li>xmlIOParseDTD() added</li>
				1136	<li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
				1137	<li>some cleanup of the Makefile, autoconf and the distribution content</li>
				1138	</ul>
				1139
Daniel Veillard	29a11cc	2000-10-25 13:32:39 +0000	[diff] [blame]	1140	<h3>2.2.6: Oct 25 2000:</h3>
				1141	<ul>
				1142	<li>Added an hash table module, migrated a number of internal structure to
				1143	those</li>
				1144	<li>Fixed a posteriori validation problems</li>
				1145	<li>HTTP module cleanups</li>
				1146	<li>HTML parser improvements (tag errors, script/style handling, attribute
				1147	normalization)</li>
				1148	<li>coalescing of adjacent text nodes</li>
				1149	<li>couple of XPath bug fixes, exported the internal API</li>
				1150	</ul>
				1151
Daniel Veillard	ab8500d	2000-10-15 21:06:19 +0000	[diff] [blame]	1152	<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard	4c3a203	1999-11-19 17:46:26 +0000	[diff] [blame]	1153	<ul>
Daniel Veillard	189446d	2000-10-13 10:23:06 +0000	[diff] [blame]	1154	<li>XPointer implementation and testsuite</li>
				1155	<li>Lot of XPath fixes, added variable and functions registration, more
				1156	tests</li>
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	1157	<li>Portability fixes, lots of enhancements toward an easy Windows build
				1158	and release</li>
Daniel Veillard	189446d	2000-10-13 10:23:06 +0000	[diff] [blame]	1159	<li>Late validation fixes</li>
				1160	<li>Integrated a lot of contributed patches</li>
				1161	<li>added memory management docs</li>
Daniel Veillard	ab8500d	2000-10-15 21:06:19 +0000	[diff] [blame]	1162	<li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard	189446d	2000-10-13 10:23:06 +0000	[diff] [blame]	1163	</ul>
				1164
				1165	<h3>2.2.4: Oct 1 2000:</h3>
				1166	<ul>
				1167	<li>main XPath problem fixed</li>
				1168	<li>Integrated portability patches for Windows</li>
				1169	<li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard	361d845	2000-04-03 19:48:13 +0000	[diff] [blame]	1170	</ul>
				1171
Daniel Veillard	d5f97f8	2000-09-17 16:38:14 +0000	[diff] [blame]	1172	<h3>2.2.3: Sep 17 2000</h3>
				1173	<ul>
				1174	<li>bug fixes</li>
				1175	<li>cleanup of entity handling code</li>
				1176	<li>overall review of all loops in the parsers, all sprintf usage has been
				1177	checked too</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1178	<li>Far better handling of larges Dtd. Validating against DocBook XML Dtd
Daniel Veillard	d5f97f8	2000-09-17 16:38:14 +0000	[diff] [blame]	1179	works smoothly now.</li>
				1180	</ul>
				1181
				1182	<h3>1.8.10: Sep 6 2000</h3>
				1183	<ul>
				1184	<li>bug fix release for some Gnome projects</li>
				1185	</ul>
				1186
				1187	<h3>2.2.2: August 12 2000</h3>
Daniel Veillard	786d7c8	2000-08-12 23:38:57 +0000	[diff] [blame]	1188	<ul>
				1189	<li>mostly bug fixes</li>
Daniel Veillard	ec78c0f	2000-08-25 10:25:23 +0000	[diff] [blame]	1190	<li>started adding routines to access xml parser context options</li>
Daniel Veillard	786d7c8	2000-08-12 23:38:57 +0000	[diff] [blame]	1191	</ul>
				1192
Daniel Veillard	d5f97f8	2000-09-17 16:38:14 +0000	[diff] [blame]	1193	<h3>2.2.1: July 21 2000</h3>
Daniel Veillard	a2679fa	2000-07-22 02:38:15 +0000	[diff] [blame]	1194	<ul>
				1195	<li>a purely bug fixes release</li>
				1196	<li>fixed an encoding support problem when parsing from a memory block</li>
				1197	<li>fixed a DOCTYPE parsing problem</li>
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	1198	<li>removed a bug in the function allowing to override the memory
				1199	allocation routines</li>
Daniel Veillard	a2679fa	2000-07-22 02:38:15 +0000	[diff] [blame]	1200	</ul>
				1201
Daniel Veillard	d5f97f8	2000-09-17 16:38:14 +0000	[diff] [blame]	1202	<h3>2.2.0: July 14 2000</h3>
Daniel Veillard	94e9060	2000-07-17 14:38:19 +0000	[diff] [blame]	1203	<ul>
				1204	<li>applied a lot of portability fixes</li>
				1205	<li>better encoding support/cleanup and saving (content is now always
				1206	encoded in UTF-8)</li>
				1207	<li>the HTML parser now correctly handles encodings</li>
				1208	<li>added xmlHasProp()</li>
				1209	<li>fixed a serious problem with &#38;</li>
				1210	<li>propagated the fix to FTP client</li>
				1211	<li>cleanup, bugfixes, etc ...</li>
				1212	<li>Added a page about <a href="encoding.html">libxml Internationalization
				1213	support</a></li>
				1214	</ul>
				1215
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	1216	<h3>1.8.9: July 9 2000</h3>
				1217	<ul>
				1218	<li>fixed the spec the RPMs should be better</li>
				1219	<li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
				1220	rpmfind users problem</li>
				1221	</ul>
				1222
Daniel Veillard	6388e17	2000-07-03 16:07:19 +0000	[diff] [blame]	1223	<h3>2.1.1: July 1 2000</h3>
				1224	<ul>
				1225	<li>fixes a couple of bugs in the 2.1.0 packaging</li>
				1226	<li>improvements on the HTML parser</li>
				1227	</ul>
				1228
Daniel Veillard	3f6f7f6	2000-06-30 17:58:25 +0000	[diff] [blame]	1229	<h3>2.1.0 and 1.8.8: June 29 2000</h3>
				1230	<ul>
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	1231	<li>1.8.8 is mostly a commodity package for upgrading to libxml2 according
				1232	to <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
Daniel Veillard	3f6f7f6	2000-06-30 17:58:25 +0000	[diff] [blame]	1233	about &#38; charref parsing</li>
				1234	<li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
				1235	also contains numerous fixes and enhancements:
				1236	<ul>
				1237	<li>added xmlStopParser() to stop parsing</li>
				1238	<li>improved a lot parsing speed when there is large CDATA blocs</li>
				1239	<li>includes XPath patches provided by Picdar Technology</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1240	<li>tried to fix as much as possible DTD validation and namespace
Daniel Veillard	3f6f7f6	2000-06-30 17:58:25 +0000	[diff] [blame]	1241	related problems</li>
				1242	<li>output to a given encoding has been added/tested</li>
				1243	<li>lot of various fixes</li>
				1244	</ul>
				1245	</li>
				1246	</ul>
				1247
Daniel Veillard	e0aed30	2000-04-16 08:52:20 +0000	[diff] [blame]	1248	<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard	361d845	2000-04-03 19:48:13 +0000	[diff] [blame]	1249	<ul>
				1250	<li>First public release of libxml2. If you are using libxml, it's a good
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1251	idea to check the 1.x to 2.x upgrade instructions. NOTE: while initially
				1252	scheduled for Apr 3 the release occurred only on Apr 12 due to massive
Daniel Veillard	e0aed30	2000-04-16 08:52:20 +0000	[diff] [blame]	1253	workload.</li>
Daniel Veillard	361d845	2000-04-03 19:48:13 +0000	[diff] [blame]	1254	<li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillard	e0aed30	2000-04-16 08:52:20 +0000	[diff] [blame]	1255	$prefix/include/gnome-xml), they also are referenced by
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	1256	<pre>#include <libxml/xxx.h></pre>
Daniel Veillard	e0aed30	2000-04-16 08:52:20 +0000	[diff] [blame]	1257	<p>instead of</p>
Daniel Veillard	361d845	2000-04-03 19:48:13 +0000	[diff] [blame]	1258	<pre>#include "xxx.h"</pre>
				1259	</li>
Daniel Veillard	8f62198	2000-03-20 13:07:15 +0000	[diff] [blame]	1260	<li>a new URI module for parsing URIs and following strictly RFC 2396</li>
				1261	<li>the memory allocation routines used by libxml can now be overloaded
				1262	dynamically by using xmlMemSetup()</li>
Daniel Veillard	361d845	2000-04-03 19:48:13 +0000	[diff] [blame]	1263	<li>The previously CVS only tool tester has been renamed
				1264	<strong>xmllint</strong> and is now installed as part of the libxml2
				1265	package</li>
Daniel Veillard	e0aed30	2000-04-16 08:52:20 +0000	[diff] [blame]	1266	<li>The I/O interface has been revamped. There is now ways to plug in
				1267	specific I/O modules, either at the URI scheme detection level using
				1268	xmlRegisterInputCallbacks() or by passing I/O functions when creating a
				1269	parser context using xmlCreateIOParserCtxt()</li>
				1270	<li>there is a C preprocessor macro LIBXML_VERSION providing the version
				1271	number of the libxml module in use</li>
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	1272	<li>a number of optional features of libxml can now be excluded at
				1273	configure time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillard	edfb29b	2000-03-14 19:59:05 +0000	[diff] [blame]	1274	</ul>
				1275
				1276	<h3>2.0.0beta: Mar 14 2000</h3>
				1277	<ul>
				1278	<li>This is a first Beta release of libxml version 2</li>
Daniel Veillard	e356c28	2001-03-10 12:32:04 +0000	[diff] [blame]	1279	<li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org
				1280	FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and
				1281	RPMs</li>
Daniel Veillard	edfb29b	2000-03-14 19:59:05 +0000	[diff] [blame]	1282	<li>This version is now the head in the Gnome CVS base, the old one is
				1283	available under the tag LIB_XML_1_X</li>
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	1284	<li>This includes a very large set of changes. From a programmatic point
				1285	of view applications should not have to be modified too much, check the
				1286	<a href="upgrade.html">upgrade page</a></li>
Daniel Veillard	edfb29b	2000-03-14 19:59:05 +0000	[diff] [blame]	1287	<li>Some interfaces may changes (especially a bit about encoding).</li>
				1288	<li>the updates includes:
Daniel Veillard	6c8b117	2000-03-01 00:40:41 +0000	[diff] [blame]	1289	<ul>
Daniel Veillard	edfb29b	2000-03-14 19:59:05 +0000	[diff] [blame]	1290	<li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
				1291	handled now</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1292	<li>Better handling of entities, especially well-formedness checking
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	1293	and proper PEref extensions in external subsets</li>
Daniel Veillard	6c8b117	2000-03-01 00:40:41 +0000	[diff] [blame]	1294	<li>DTD conditional sections</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1295	<li>Validation now correctly handle entities content</li>
Daniel Veillard	6c8b117	2000-03-01 00:40:41 +0000	[diff] [blame]	1296	<li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1297	structures to accommodate DOM</a></li>
Daniel Veillard	6c8b117	2000-03-01 00:40:41 +0000	[diff] [blame]	1298	</ul>
				1299	</li>
Daniel Veillard	edfb29b	2000-03-14 19:59:05 +0000	[diff] [blame]	1300	<li>Serious progress were made toward compliance, <a
				1301	href="conf/result.html">here are the result of the test</a> against the
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1302	OASIS testsuite (except the Japanese tests since I don't support that
Daniel Veillard	edfb29b	2000-03-14 19:59:05 +0000	[diff] [blame]	1303	encoding yet). This URL is rebuilt every couple of hours using the CVS
				1304	head version.</li>
Daniel Veillard	e41f2b7	2000-01-30 20:00:07 +0000	[diff] [blame]	1305	</ul>
				1306
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	1307	<h3>1.8.7: Mar 6 2000</h3>
				1308	<ul>
				1309	<li>This is a bug fix release:</li>
				1310	<li>It is possible to disable the ignorable blanks heuristic used by
				1311	libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	1312	that for adherence to XML spec, this behaviour will be disabled by
				1313	default in 2.x . The same function will allow to keep compatibility for
				1314	old code.</li>
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	1315	<li>Blanks in <a> </a> constructs are not ignored anymore,
				1316	avoiding heuristic is really the Right Way :-\</li>
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	1317	<li>The unchecked use of snprintf which was breaking libxml-1.8.6
				1318	compilation on some platforms has been fixed</li>
				1319	<li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
				1320	URIs</li>
				1321	</ul>
				1322
Daniel Veillard	e41f2b7	2000-01-30 20:00:07 +0000	[diff] [blame]	1323	<h3>1.8.6: Jan 31 2000</h3>
				1324	<ul>
				1325	<li>added a nanoFTP transport module, debugged until the new version of <a
				1326	href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
				1327	it without troubles</li>
Daniel Veillard	da07c34	2000-01-25 18:31:22 +0000	[diff] [blame]	1328	</ul>
				1329
				1330	<h3>1.8.5: Jan 21 2000</h3>
				1331	<ul>
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	1332	<li>adding APIs to parse a well balanced chunk of XML (production <a
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	1333	href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the
				1334	XML spec)</li>
Daniel Veillard	461a66c	2000-01-18 18:01:01 +0000	[diff] [blame]	1335	<li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	1336	<li>Jody Goldberg <jgoldberg@home.com> provided another patch trying
				1337	to solve the zlib checks problems</li>
Daniel Veillard	461a66c	2000-01-18 18:01:01 +0000	[diff] [blame]	1338	<li>The current state in gnome CVS base is expected to ship as 1.8.5 with
				1339	gnumeric soon</li>
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	1340	</ul>
				1341
				1342	<h3>1.8.4: Jan 13 2000</h3>
				1343	<ul>
				1344	<li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
				1345	<li>all exit() call should have been removed from libxml</li>
				1346	<li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
				1347	<li>added newDocFragment()</li>
Daniel Veillard	f84f71f	2000-01-05 19:54:23 +0000	[diff] [blame]	1348	</ul>
				1349
				1350	<h3>1.8.3: Jan 5 2000</h3>
				1351	<ul>
				1352	<li>a Push interface for the XML and HTML parsers</li>
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	1353	<li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1354	<li>lots of bug fixes and improvement added over XMas holidays</li>
Daniel Veillard	437b87b	2000-01-03 17:30:46 +0000	[diff] [blame]	1355	<li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillard	f84f71f	2000-01-05 19:54:23 +0000	[diff] [blame]	1356	<li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
				1357	<li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard	437b87b	2000-01-03 17:30:46 +0000	[diff] [blame]	1358	<li>External entity loading code has been revamped, now it uses
Daniel Veillard	f84f71f	2000-01-05 19:54:23 +0000	[diff] [blame]	1359	xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard	437b87b	2000-01-03 17:30:46 +0000	[diff] [blame]	1360	<li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard	5cb5ab8	1999-12-21 15:35:29 +0000	[diff] [blame]	1361	</ul>
				1362
				1363	<h3>1.8.2: Dec 21 1999</h3>
				1364	<ul>
Daniel Veillard	b24054a	1999-12-18 15:32:46 +0000	[diff] [blame]	1365	<li>I got another problem with includes and C++, I hope this issue is fixed
				1366	for good this time</li>
Daniel Veillard	5cb5ab8	1999-12-21 15:35:29 +0000	[diff] [blame]	1367	<li>Added a few tree modification functions: xmlReplaceNode,
				1368	xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
				1369	xmlDocSetRootElement</li>
				1370	<li>Tried to improve the HTML output with help from <a
				1371	href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillard	e4e5131	1999-12-18 15:32:46 +0000	[diff] [blame]	1372	</ul>
Daniel Veillard	b24054a	1999-12-18 15:32:46 +0000	[diff] [blame]	1373
Daniel Veillard	e4e5131	1999-12-18 15:32:46 +0000	[diff] [blame]	1374	<h3>1.8.1: Dec 18 1999</h3>
				1375	<ul>
				1376	<li>various patches to avoid troubles when using libxml with C++ compilers
				1377	the "namespace" keyword and C escaping in include files</li>
				1378	<li>a problem in one of the core macros IS_CHAR was corrected</li>
				1379	<li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
				1380	and more specifically the Dia application</li>
Daniel Veillard	944b5ff	1999-12-15 19:08:24 +0000	[diff] [blame]	1381	<li>fixed a posteriori validation (validation after parsing, or by using a
				1382	Dtd not specified in the original document)</li>
Daniel Veillard	b24054a	1999-12-18 15:32:46 +0000	[diff] [blame]	1383	<li>fixed a bug in</li>
Daniel Veillard	10a2c65	1999-12-12 13:03:50 +0000	[diff] [blame]	1384	</ul>
				1385
				1386	<h3>1.8.0: Dec 12 1999</h3>
				1387	<ul>
				1388	<li>cleanup, especially memory wise</li>
				1389	<li>the parser should be more reliable, especially the HTML one, it should
				1390	not crash, whatever the input !</li>
				1391	<li>Integrated various patches, especially a speedup improvement for large
				1392	dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
				1393	configure with --with-buffers to enable them.</li>
				1394	<li>attribute normalization, oops should have been added long ago !</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1395	<li>attributes defaulted from DTDs should be available, xmlSetProp() now
				1396	does entities escaping by default.</li>
Daniel Veillard	4c3a203	1999-11-19 17:46:26 +0000	[diff] [blame]	1397	</ul>
Daniel Veillard	3500838	1999-10-25 13:15:52 +0000	[diff] [blame]	1398
				1399	<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	1400	<ul>
Daniel Veillard	3500838	1999-10-25 13:15:52 +0000	[diff] [blame]	1401	<li>Lots of HTML improvement</li>
				1402	<li>Fixed some errors when saving both XML and HTML</li>
				1403	<li>More examples, the regression tests should now look clean</li>
				1404	<li>Fixed a bug with contiguous charref</li>
				1405	</ul>
				1406
				1407	<h3>1.7.3: Sep 29 1999</h3>
				1408	<ul>
				1409	<li>portability problems fixed</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1410	<li>snprintf was used unconditionally, leading to link problems on system
Daniel Veillard	3500838	1999-10-25 13:15:52 +0000	[diff] [blame]	1411	were it's not available, fixed</li>
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	1412	</ul>
				1413
				1414	<h3>1.7.1: Sep 24 1999</h3>
				1415	<ul>
				1416	<li>The basic type for strings manipulated by libxml has been renamed in
				1417	1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	1418	is that CHAR was conflicting with a predefined type on Windows. However
				1419	on non WIN32 environment, compatibility is provided by the way of a
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	1420	<strong>#define </strong>.</li>
				1421	<li>Changed another error : the use of a structure field called errno, and
				1422	leading to troubles on platforms where it's a macro</li>
				1423	</ul>
				1424
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1425	<h3>1.7.0: Sep 23 1999</h3>
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	1426	<ul>
				1427	<li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard	9cb5ff4	2001-01-29 08:22:21 +0000	[diff] [blame]	1428	href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	1429	<li>Added an errno to report errors by another mean than a simple printf
				1430	like callback</li>
				1431	<li>Finished ID/IDREF support and checking when validation</li>
				1432	<li>Serious memory leaks fixed (there is now a <a
Daniel Veillard	9cb5ff4	2001-01-29 08:22:21 +0000	[diff] [blame]	1433	href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	1434	<li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
				1435	implementation</li>
				1436	<li>Added an HTML parser front-end</li>
				1437	</ul>
				1438
				1439	<h2><a name="XML">XML</a></h2>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	1440
Daniel Veillard	402e8c8	2000-02-29 22:57:47 +0000	[diff] [blame]	1441	<p><a href="http://www.w3.org/TR/REC-xml">XML is a standard</a> for
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	1442	markup-based structured documents. Here is <a name="example">an example XML
				1443	document</a>:</p>
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	1444	<pre><?xml version="1.0"?>
				1445	<EXAMPLE prop1="gnome is great" prop2="&amp; linux too">
				1446	<head>
				1447	<title>Welcome to Gnome</title>
				1448	</head>
				1449	<chapter>
				1450	<title>The Linux adventure</title>
				1451	<p>bla bla bla ...</p>
				1452	<image href="linus.gif"/>
				1453	<p>...</p>
				1454	</chapter>
				1455	</EXAMPLE></pre>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	1456
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1457	<p>The first line specifies that it is an XML document and gives useful
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	1458	information about its encoding. Then the rest of the document is a text
				1459	format whose structure is specified by tags between brackets. <strong>Each
				1460	tag opened has to be closed</strong>. XML is pedantic about this. However, if
				1461	a tag is empty (no content), a single tag can serve as both the opening and
				1462	closing tag if it ends with <code>/></code> rather than with
				1463	<code>></code>. Note that, for example, the image tag has no content (just
				1464	an attribute) and is closed by ending the tag with <code>/></code>.</p>
Daniel Veillard	ccb0963	1998-10-27 06:21:04 +0000	[diff] [blame]	1465
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	1466	<p>XML can be applied successfully to a wide range of tasks, ranging from
				1467	long term structured document maintenance (where it follows the steps of
				1468	SGML) to simple data encoding mechanisms like configuration file formatting
				1469	(glade), spreadsheets (gnumeric), or even shorter lived documents such as
				1470	WebDAV where it is used to encode remote calls between a client and a
				1471	server.</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	1472
Daniel Veillard	8268716	2001-01-22 15:32:01 +0000	[diff] [blame]	1473	<h2><a name="XSLT">XSLT</a></h2>
				1474
Daniel Veillard	6e6a6cc	2001-02-15 15:55:44 +0000	[diff] [blame]	1475	<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
				1476
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	1477	<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a
				1478	language for transforming XML documents into other XML documents (or
				1479	HTML/textual output).</p>
Daniel Veillard	8268716	2001-01-22 15:32:01 +0000	[diff] [blame]	1480
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	1481	<p>A separate library called libxslt is being developed on top of libxml2.
				1482	This module "libxslt" too can be found in the Gnome CVS base.</p>
Daniel Veillard	8268716	2001-01-22 15:32:01 +0000	[diff] [blame]	1483
Daniel Veillard	383b147	2001-01-23 11:39:52 +0000	[diff] [blame]	1484	<p>You can check the <a
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	1485	href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a>
				1486	supported and the progresses on the <a
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1487	href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog"
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1488	name="Changelog">Changelog</a>.</p>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1489
				1490	<h2><a name="Python">Python and bindings</a></h2>
				1491
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	1492	<p>There are a number of language bindings and wrappers available for
				1493	libxml2, the list below is not exhaustive. Please contact the <a
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1494	href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a>
				1495	(<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in
				1496	order to get updates to this list or to discuss the specific topic of libxml2
				1497	or libxslt wrappers or bindings:</p>
				1498	<ul>
Daniel Veillard	c14401e	2002-11-20 14:28:17 +0000	[diff] [blame]	1499	<li><a href="http://libxmlplusplus.sourceforge.net/">Libxml++</a> seems the
				1500	most up-to-date C++ bindings for libxml2, check the <a
				1501	href="http://libxmlplusplus.sourceforge.net/reference/html/hierarchy.html">documentation</a>
				1502	and the <a
				1503	href="http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/libxmlplusplus/libxml%2b%2b/examples/">examples</a>.</li>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1504	<li>There is another <a href="http://libgdome-cpp.berlios.de/">C++ wrapper
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1505	based on the gdome2 bindings</a> maintained by Tobias Peters.</li>
Daniel Veillard	9b6fd30	2002-05-13 12:06:47 +0000	[diff] [blame]	1506	<li>and a third C++ wrapper by Peter Jones <pjones@pmade.org>
				1507	<p>Website: <a
				1508	href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
				1509	</li>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1510	<li><a
				1511	href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1512	Sergeant</a> developed <a
				1513	href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	1514	libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1515	application server</a>.</li>
Daniel Veillard	2147367	2002-06-17 07:29:22 +0000	[diff] [blame]	1516	<li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides an
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	1517	earlier version of the libxml/libxslt <a
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1518	href="http://www.rexx.com/~dkuhlman">wrappers for Python</a>.</li>
Daniel Veillard	2147367	2002-06-17 07:29:22 +0000	[diff] [blame]	1519	<li>Gopal.V and Peter Minten develop <a
				1520	href="http://savannah.gnu.org/projects/libxmlsharp">libxml#</a>, a set of
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1521	C# libxml2 bindings.</li>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1522	<li>Petr Kozelka provides <a
				1523	href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1524	libxml2</a> with Kylix, Delphi and other Pascal compilers.</li>
Daniel Veillard	b2fb8ed	2002-04-01 09:33:12 +0000	[diff] [blame]	1525	<li>Uwe Fechner also provides <a
				1526	href="http://sourceforge.net/projects/idom2-pas/">idom2</a>, a DOM2
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1527	implementation for Kylix2/D5/D6 from Borland.</li>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1528	<li>Wai-Sun "Squidster" Chia provides <a
				1529	href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
				1530	libxml2 bindings are also available in Ruby through the <a
				1531	href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
				1532	maintained by Tobias Peters.</li>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	1533	<li>Steve Ball and contributors maintains <a
				1534	href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1535	Tcl</a>.</li>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	1536	<li>There is support for libxml2 in the DOM module of PHP.</li>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1537	</ul>
				1538
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	1539	<p>The distribution includes a set of Python bindings, which are guaranteed
				1540	to be maintained as part of the library in the future, though the Python
Daniel Veillard	0b79dfe	2002-02-23 13:02:31 +0000	[diff] [blame]	1541	interface have not yet reached the maturity of the C API.</p>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	1542
				1543	<p>To install the Python bindings there are 2 options:</p>
Daniel Veillard	0b79dfe	2002-02-23 13:02:31 +0000	[diff] [blame]	1544	<ul>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	1545	<li>If you use an RPM based distribution, simply install the <a
				1546	href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python
				1547	RPM</a> (and if needed the <a
				1548	href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
				1549	RPM</a>).</li>
				1550	<li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python
				1551	module distribution</a> corresponding to your installed version of
				1552	libxml2 and libxslt. Note that to install it you will need both libxml2
				1553	and libxslt installed and run "python setup.py build install" in the
				1554	module tree.</li>
Daniel Veillard	0b79dfe	2002-02-23 13:02:31 +0000	[diff] [blame]	1555	</ul>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	1556
				1557	<p>The distribution includes a set of examples and regression tests for the
				1558	python bindings in the <code>python/tests</code> directory. Here are some
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1559	excerpts from those tests:</p>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1560
				1561	<h3>tst.py:</h3>
				1562
				1563	<p>This is a basic test of the file interface and DOM navigation:</p>
				1564	<pre>import libxml2
				1565
				1566	doc = libxml2.parseFile("tst.xml")
				1567	if doc.name != "tst.xml":
				1568	print "doc.name failed"
				1569	sys.exit(1)
				1570	root = doc.children
				1571	if root.name != "doc":
				1572	print "root.name failed"
				1573	sys.exit(1)
				1574	child = root.children
				1575	if child.name != "foo":
				1576	print "child.name failed"
				1577	sys.exit(1)
				1578	doc.freeDoc()</pre>
				1579
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1580	<p>The Python module is called libxml2; parseFile is the equivalent of
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1581	xmlParseFile (most of the bindings are automatically generated, and the xml
				1582	prefix is removed and the casing convention are kept). All node seen at the
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1583	binding level share the same subset of accessors:</p>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1584	<ul>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	1585	<li><code>name</code> : returns the node name</li>
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	1586	<li><code>type</code> : returns a string indicating the node type</li>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	1587	<li><code>content</code> : returns the content of the node, it is based on
				1588	xmlNodeGetContent() and hence is recursive.</li>
				1589	<li><code>parent</code> , <code>children</code>, <code>last</code>,
				1590	<code>next</code>, <code>prev</code>, <code>doc</code>,
				1591	<code>properties</code>: pointing to the associated element in the tree,
				1592	those may return None in case no such link exists.</li>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1593	</ul>
				1594
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1595	<p>Also note the need to explicitly deallocate documents with freeDoc() .
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1596	Reference counting for libxml2 trees would need quite a lot of work to
				1597	function properly, and rather than risk memory leaks if not implemented
				1598	correctly it sounds safer to have an explicit function to free a tree. The
				1599	wrapper python objects like doc, root or child are them automatically garbage
				1600	collected.</p>
				1601
				1602	<h3>validate.py:</h3>
				1603
				1604	<p>This test check the validation interfaces and redirection of error
				1605	messages:</p>
				1606	<pre>import libxml2
				1607
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1608	#deactivate error messages from the validation
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1609	def noerr(ctx, str):
				1610	pass
				1611
				1612	libxml2.registerErrorHandler(noerr, None)
				1613
				1614	ctxt = libxml2.createFileParserCtxt("invalid.xml")
				1615	ctxt.validate(1)
				1616	ctxt.parseDocument()
				1617	doc = ctxt.doc()
				1618	valid = ctxt.isValid()
				1619	doc.freeDoc()
				1620	if valid != 0:
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1621	print "validity check failed"</pre>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1622
				1623	<p>The first thing to notice is the call to registerErrorHandler(), it
				1624	defines a new error handler global to the library. It is used to avoid seeing
				1625	the error messages when trying to validate the invalid document.</p>
				1626
				1627	<p>The main interest of that test is the creation of a parser context with
				1628	createFileParserCtxt() and how the behaviour can be changed before calling
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1629	parseDocument() . Similarly the informations resulting from the parsing phase
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1630	are also available using context methods.</p>
				1631
				1632	<p>Contexts like nodes are defined as class and the libxml2 wrappers maps the
				1633	C function interfaces in terms of objects method as much as possible. The
				1634	best to get a complete view of what methods are supported is to look at the
				1635	libxml2.py module containing all the wrappers.</p>
				1636
				1637	<h3>push.py:</h3>
				1638
				1639	<p>This test show how to activate the push parser interface:</p>
				1640	<pre>import libxml2
				1641
				1642	ctxt = libxml2.createPushParser(None, "<foo", 4, "test.xml")
				1643	ctxt.parseChunk("/>", 2, 1)
				1644	doc = ctxt.doc()
				1645
				1646	doc.freeDoc()</pre>
				1647
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1648	<p>The context is created with a special call based on the
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1649	xmlCreatePushParser() from the C library. The first argument is an optional
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1650	SAX callback object, then the initial set of data, the length and the name of
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1651	the resource in case URI-References need to be computed by the parser.</p>
				1652
				1653	<p>Then the data are pushed using the parseChunk() method, the last call
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1654	setting the third argument terminate to 1.</p>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1655
				1656	<h3>pushSAX.py:</h3>
				1657
				1658	<p>this test show the use of the event based parsing interfaces. In this case
				1659	the parser does not build a document, but provides callback information as
				1660	the parser makes progresses analyzing the data being provided:</p>
				1661	<pre>import libxml2
				1662	log = ""
				1663
				1664	class callback:
				1665	def startDocument(self):
				1666	global log
				1667	log = log + "startDocument:"
				1668
				1669	def endDocument(self):
				1670	global log
				1671	log = log + "endDocument:"
				1672
				1673	def startElement(self, tag, attrs):
				1674	global log
				1675	log = log + "startElement %s %s:" % (tag, attrs)
				1676
				1677	def endElement(self, tag):
				1678	global log
				1679	log = log + "endElement %s:" % (tag)
				1680
				1681	def characters(self, data):
				1682	global log
				1683	log = log + "characters: %s:" % (data)
				1684
				1685	def warning(self, msg):
				1686	global log
				1687	log = log + "warning: %s:" % (msg)
				1688
				1689	def error(self, msg):
				1690	global log
				1691	log = log + "error: %s:" % (msg)
				1692
				1693	def fatalError(self, msg):
				1694	global log
				1695	log = log + "fatalError: %s:" % (msg)
				1696
				1697	handler = callback()
				1698
				1699	ctxt = libxml2.createPushParser(handler, "<foo", 4, "test.xml")
				1700	chunk = " url='tst'>b"
				1701	ctxt.parseChunk(chunk, len(chunk), 0)
				1702	chunk = "ar</foo>"
				1703	ctxt.parseChunk(chunk, len(chunk), 1)
				1704
Daniel Veillard	fcbfa2d	2002-02-21 17:54:27 +0000	[diff] [blame]	1705	reference = "startDocument:startElement foo {'url': 'tst'}:" + \
				1706	"characters: bar:endElement foo:endDocument:"
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1707	if log != reference:
				1708	print "Error got: %s" % log
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1709	print "Expected: %s" % reference</pre>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1710
				1711	<p>The key object in that test is the handler, it provides a number of entry
				1712	points which can be called by the parser as it makes progresses to indicate
				1713	the information set obtained. The full set of callback is larger than what
				1714	the callback class in that specific example implements (see the SAX
				1715	definition for a complete list). The wrapper will only call those supplied by
				1716	the object when activated. The startElement receives the names of the element
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1717	and a dictionary containing the attributes carried by this element.</p>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1718
				1719	<p>Also note that the reference string generated from the callback shows a
				1720	single character call even though the string "bar" is passed to the parser
				1721	from 2 different call to parseChunk()</p>
				1722
				1723	<h3>xpath.py:</h3>
				1724
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1725	<p>This is a basic test of XPath wrappers support</p>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1726	<pre>import libxml2
				1727
				1728	doc = libxml2.parseFile("tst.xml")
				1729	ctxt = doc.xpathNewContext()
				1730	res = ctxt.xpathEval("//*")
				1731	if len(res) != 2:
				1732	print "xpath query: wrong node set size"
				1733	sys.exit(1)
				1734	if res[0].name != "doc" or res[1].name != "foo":
				1735	print "xpath query: wrong node set value"
				1736	sys.exit(1)
				1737	doc.freeDoc()
				1738	ctxt.xpathFreeContext()</pre>
				1739
				1740	<p>This test parses a file, then create an XPath context to evaluate XPath
				1741	expression on it. The xpathEval() method execute an XPath query and returns
				1742	the result mapped in a Python way. String and numbers are natively converted,
				1743	and node sets are returned as a tuple of libxml2 Python nodes wrappers. Like
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1744	the document, the XPath context need to be freed explicitly, also not that
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1745	the result of the XPath query may point back to the document tree and hence
				1746	the document must be freed after the result of the query is used.</p>
				1747
				1748	<h3>xpathext.py:</h3>
				1749
				1750	<p>This test shows how to extend the XPath engine with functions written in
				1751	python:</p>
				1752	<pre>import libxml2
				1753
				1754	def foo(ctx, x):
				1755	return x + 1
				1756
				1757	doc = libxml2.parseFile("tst.xml")
				1758	ctxt = doc.xpathNewContext()
				1759	libxml2.registerXPathFunction(ctxt._o, "foo", None, foo)
				1760	res = ctxt.xpathEval("foo(1)")
				1761	if res != 2:
				1762	print "xpath extension failure"
				1763	doc.freeDoc()
				1764	ctxt.xpathFreeContext()</pre>
				1765
				1766	<p>Note how the extension function is registered with the context (but that
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1767	part is not yet finalized, this may change slightly in the future).</p>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1768
				1769	<h3>tstxpath.py:</h3>
				1770
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1771	<p>This test is similar to the previous one but shows how the extension
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1772	function can access the XPath evaluation context:</p>
				1773	<pre>def foo(ctx, x):
				1774	global called
				1775
				1776	#
				1777	# test that access to the XPath evaluation contexts
				1778	#
				1779	pctxt = libxml2.xpathParserContext(_obj=ctx)
				1780	ctxt = pctxt.context()
				1781	called = ctxt.function()
				1782	return x + 1</pre>
				1783
				1784	<p>All the interfaces around the XPath parser(or rather evaluation) context
				1785	are not finalized, but it should be sufficient to do contextual work at the
				1786	evaluation point.</p>
				1787
				1788	<h3>Memory debugging:</h3>
				1789
				1790	<p>last but not least, all tests starts with the following prologue:</p>
				1791	<pre>#memory debug specific
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	1792	libxml2.debugMemory(1)</pre>
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1793
				1794	<p>and ends with the following epilogue:</p>
				1795	<pre>#memory debug specific
				1796	libxml2.cleanupParser()
				1797	if libxml2.debugMemory(1) == 0:
				1798	print "OK"
				1799	else:
				1800	print "Memory leak %d bytes" % (libxml2.debugMemory(1))
				1801	libxml2.dumpMemory()</pre>
				1802
				1803	<p>Those activate the memory debugging interface of libxml2 where all
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1804	allocated block in the library are tracked. The prologue then cleans up the
Daniel Veillard	6dbcaf8	2002-02-20 14:37:47 +0000	[diff] [blame]	1805	library state and checks that all allocated memory has been freed. If not it
				1806	calls dumpMemory() which saves that list in a <code>.memdump</code> file.</p>
Daniel Veillard	8268716	2001-01-22 15:32:01 +0000	[diff] [blame]	1807
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	1808	<h2><a name="architecture">libxml architecture</a></h2>
Daniel Veillard	4540be4	2000-08-19 16:40:28 +0000	[diff] [blame]	1809
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	1810	<p>Libxml is made of multiple components; some of them are optional, and most
				1811	of the block interfaces are public. The main components are:</p>
Daniel Veillard	4540be4	2000-08-19 16:40:28 +0000	[diff] [blame]	1812	<ul>
				1813	<li>an Input/Output layer</li>
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	1814	<li>FTP and HTTP client layers (optional)</li>
Daniel Veillard	4540be4	2000-08-19 16:40:28 +0000	[diff] [blame]	1815	<li>an Internationalization layer managing the encodings support</li>
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	1816	<li>a URI module</li>
Daniel Veillard	4540be4	2000-08-19 16:40:28 +0000	[diff] [blame]	1817	<li>the XML parser and its basic SAX interface</li>
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	1818	<li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard	4540be4	2000-08-19 16:40:28 +0000	[diff] [blame]	1819	<li>a SAX tree module to build an in-memory DOM representation</li>
				1820	<li>a tree module to manipulate the DOM representation</li>
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	1821	<li>a validation module using the DOM representation (optional)</li>
Daniel Veillard	4540be4	2000-08-19 16:40:28 +0000	[diff] [blame]	1822	<li>an XPath module for global lookup in a DOM representation
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	1823	(optional)</li>
				1824	<li>a debug module (optional)</li>
Daniel Veillard	4540be4	2000-08-19 16:40:28 +0000	[diff] [blame]	1825	</ul>
				1826
				1827	<p>Graphically this gives the following:</p>
				1828
				1829	<p><img src="libxml.gif" alt="a graphical view of the various"></p>
				1830
				1831	<p></p>
				1832
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	1833	<h2><a name="tree">The tree output</a></h2>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	1834
				1835	<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard	402e8c8	2000-02-29 22:57:47 +0000	[diff] [blame]	1836	returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	1837	<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard	306be99	2000-07-03 12:38:45 +0000	[diff] [blame]	1838	as the file name, the document type, and a <strong>children</strong> pointer
				1839	which is the root of the document (or more exactly the first child under the
				1840	root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	1841	chained in double-linked lists of siblings and with a children<->parent
Daniel Veillard	306be99	2000-07-03 12:38:45 +0000	[diff] [blame]	1842	relationship. An xmlNode can also carry properties (a chain of xmlAttr
				1843	structures). An attribute may have a value which is a list of TEXT or
				1844	ENTITY_REF nodes.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	1845
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	1846	<p>Here is an example (erroneous with respect to the XML spec since there
				1847	should be only one ELEMENT under the root):</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	1848
				1849	<p><img src="structure.gif" alt=" structure.gif "></p>
				1850
				1851	<p>In the source package there is a small program (not installed by default)
Daniel Veillard	361d845	2000-04-03 19:48:13 +0000	[diff] [blame]	1852	called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	1853	prints them back as parsed. This is useful for detecting errors both in XML
				1854	code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	1855	which prints the actual in-memory structure of the document; here is the
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	1856	result with the <a href="#example">example</a> given before:</p>
Daniel Veillard	10c6a8f	1998-10-28 01:00:12 +0000	[diff] [blame]	1857	<pre>DOCUMENT
				1858	version=1.0
				1859	standalone=true
				1860	ELEMENT EXAMPLE
				1861	ATTRIBUTE prop1
				1862	TEXT
				1863	content=gnome is great
				1864	ATTRIBUTE prop2
				1865	ENTITY_REF
				1866	TEXT
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	1867	content= linux too
Daniel Veillard	402e8c8	2000-02-29 22:57:47 +0000	[diff] [blame]	1868	ELEMENT head
Daniel Veillard	10c6a8f	1998-10-28 01:00:12 +0000	[diff] [blame]	1869	ELEMENT title
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	1870	TEXT
				1871	content=Welcome to Gnome
Daniel Veillard	10c6a8f	1998-10-28 01:00:12 +0000	[diff] [blame]	1872	ELEMENT chapter
				1873	ELEMENT title
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	1874	TEXT
				1875	content=The Linux adventure
Daniel Veillard	10c6a8f	1998-10-28 01:00:12 +0000	[diff] [blame]	1876	ELEMENT p
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	1877	TEXT
				1878	content=bla bla bla ...
Daniel Veillard	10c6a8f	1998-10-28 01:00:12 +0000	[diff] [blame]	1879	ELEMENT image
				1880	ATTRIBUTE href
				1881	TEXT
				1882	content=linus.gif
				1883	ELEMENT p
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	1884	TEXT
				1885	content=...</pre>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	1886
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	1887	<p>This should be useful for learning the internal representation model.</p>
Daniel Veillard	ccb0963	1998-10-27 06:21:04 +0000	[diff] [blame]	1888
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	1889	<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	1890
Daniel Veillard	402e8c8	2000-02-29 22:57:47 +0000	[diff] [blame]	1891	<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	1892	memory. In that case (and if you don't expect to save back the XML document
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	1893	loaded using libxml), it's better to use the SAX interface of libxml. SAX is
				1894	a <strong>callback-based interface</strong> to the parser. Before parsing,
				1895	the application layer registers a customized set of callbacks which are
				1896	called by the library as it progresses through the XML input.</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	1897
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	1898	<p>To get more detailed step-by-step guidance on using the SAX interface of
Daniel Veillard	4540be4	2000-08-19 16:40:28 +0000	[diff] [blame]	1899	libxml, see the <a
				1900	href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
				1901	documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	1902	Henstridge</a>.</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	1903
				1904	<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
				1905	program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	1906	binary packages of libxml, but you can find it in the tar source
Daniel Veillard	402e8c8	2000-02-29 22:57:47 +0000	[diff] [blame]	1907	distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	1908	testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	1909	<pre>SAX.setDocumentLocator()
				1910	SAX.startDocument()
				1911	SAX.getEntity(amp)
				1912	SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp; linux too')
				1913	SAX.characters( , 3)
				1914	SAX.startElement(head)
				1915	SAX.characters( , 4)
				1916	SAX.startElement(title)
				1917	SAX.characters(Welcome to Gnome, 16)
				1918	SAX.endElement(title)
				1919	SAX.characters( , 3)
				1920	SAX.endElement(head)
				1921	SAX.characters( , 3)
				1922	SAX.startElement(chapter)
				1923	SAX.characters( , 4)
				1924	SAX.startElement(title)
				1925	SAX.characters(The Linux adventure, 19)
				1926	SAX.endElement(title)
				1927	SAX.characters( , 4)
				1928	SAX.startElement(p)
				1929	SAX.characters(bla bla bla ..., 15)
				1930	SAX.endElement(p)
				1931	SAX.characters( , 4)
				1932	SAX.startElement(image, href='linus.gif')
				1933	SAX.endElement(image)
				1934	SAX.characters( , 4)
				1935	SAX.startElement(p)
				1936	SAX.characters(..., 3)
				1937	SAX.endElement(p)
				1938	SAX.characters( , 3)
				1939	SAX.endElement(chapter)
				1940	SAX.characters( , 1)
				1941	SAX.endElement(EXAMPLE)
				1942	SAX.endDocument()</pre>
				1943
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	1944	<p>Most of the other interfaces of libxml are based on the DOM tree-building
				1945	facility, so nearly everything up to the end of this document presupposes the
				1946	use of the standard DOM tree build. Note that the DOM tree itself is built by
				1947	a set of registered default callbacks, without internal specific
				1948	interface.</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	1949
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	1950	<h2><a name="Validation">Validation & DTDs</a></h2>
				1951
				1952	<p>Table of Content:</p>
				1953	<ol>
				1954	<li><a href="#General5">General overview</a></li>
				1955	<li><a href="#definition">The definition</a></li>
				1956	<li><a href="#Simple">Simple rules</a>
				1957	<ol>
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	1958	<li><a href="#reference">How to reference a DTD from a document</a></li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	1959	<li><a href="#Declaring">Declaring elements</a></li>
				1960	<li><a href="#Declaring1">Declaring attributes</a></li>
				1961	</ol>
				1962	</li>
				1963	<li><a href="#Some">Some examples</a></li>
				1964	<li><a href="#validate">How to validate</a></li>
				1965	<li><a href="#Other">Other resources</a></li>
				1966	</ol>
				1967
				1968	<h3><a name="General5">General overview</a></h3>
				1969
				1970	<p>Well what is validation and what is a DTD ?</p>
				1971
				1972	<p>DTD is the acronym for Document Type Definition. This is a description of
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	1973	the content for a family of XML files. This is part of the XML 1.0
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1974	specification, and allows one to describe and verify that a given document
				1975	instance conforms to the set of rules detailing its structure and content.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	1976
				1977	<p>Validation is the process of checking a document against a DTD (more
				1978	generally against a set of construction rules).</p>
				1979
				1980	<p>The validation process and building DTDs are the two most difficult parts
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1981	of the XML life cycle. Briefly a DTD defines all the possible elements to be
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	1982	found within your document, what is the formal shape of your document tree
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	1983	(by defining the allowed content of an element; either text, a regular
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	1984	expression for the allowed list of children, or mixed content i.e. both text
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	1985	and children). The DTD also defines the valid attributes for all elements and
				1986	the types of those attributes.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	1987
				1988	<h3><a name="definition1">The definition</a></h3>
				1989
				1990	<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a
				1991	href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of
				1992	Rev1</a>):</p>
				1993	<ul>
				1994	<li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring
				1995	elements</a></li>
				1996	<li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring
				1997	attributes</a></li>
				1998	</ul>
				1999
				2000	<p>(unfortunately) all this is inherited from the SGML world, the syntax is
				2001	ancient...</p>
				2002
				2003	<h3><a name="Simple1">Simple rules</a></h3>
				2004
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	2005	<p>Writing DTDs can be done in many ways. The rules to build them if you need
				2006	something permanent or something which can evolve over time can be radically
				2007	different. Really complex DTDs like DocBook ones are flexible but quite
				2008	harder to design. I will just focus on DTDs for a formats with a fixed simple
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2009	structure. It is just a set of basic rules, and definitely not exhaustive nor
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2010	usable for complex DTD design.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2011
				2012	<h4><a name="reference1">How to reference a DTD from a document</a>:</h4>
				2013
				2014	<p>Assuming the top element of the document is <code>spec</code> and the dtd
				2015	is placed in the file <code>mydtd</code> in the subdirectory
				2016	<code>dtds</code> of the directory from where the document were loaded:</p>
				2017
				2018	<p><code><!DOCTYPE spec SYSTEM "dtds/mydtd"></code></p>
				2019
				2020	<p>Notes:</p>
				2021	<ul>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	2022	<li>The system string is actually an URI-Reference (as defined in <a
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2023	href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	2024	full URL string indicating the location of your DTD on the Web. This is a
				2025	really good thing to do if you want others to validate your document.</li>
				2026	<li>It is also possible to associate a <code>PUBLIC</code> identifier (a
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2027	magic string) so that the DTD is looked up in catalogs on the client side
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	2028	without having to locate it on the web.</li>
				2029	<li>A DTD contains a set of element and attribute declarations, but they
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2030	don't define what the root of the document should be. This is explicitly
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2031	told to the parser/validator as the first element of the
				2032	<code>DOCTYPE</code> declaration.</li>
				2033	</ul>
				2034
				2035	<h4><a name="Declaring2">Declaring elements</a>:</h4>
				2036
				2037	<p>The following declares an element <code>spec</code>:</p>
				2038
				2039	<p><code><!ELEMENT spec (front, body, back?)></code></p>
				2040
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	2041	<p>It also expresses that the spec element contains one <code>front</code>,
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	2042	one <code>body</code> and one optional <code>back</code> children elements in
				2043	this order. The declaration of one element of the structure and its content
				2044	are done in a single declaration. Similarly the following declares
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2045	<code>div1</code> elements:</p>
				2046
Daniel Veillard	5173727	2002-01-23 23:10:38 +0000	[diff] [blame]	2047	<p><code><!ELEMENT div1 (head, (p \| list \| note)*, div2?)></code></p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2048
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	2049	<p>which means div1 contains one <code>head</code> then a series of optional
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2050	<code>p</code>, <code>list</code>s and <code>note</code>s and then an
				2051	optional <code>div2</code>. And last but not least an element can contain
				2052	text:</p>
				2053
				2054	<p><code><!ELEMENT b (#PCDATA)></code></p>
				2055
				2056	<p><code>b</code> contains text or being of mixed content (text and elements
				2057	in no particular order):</p>
				2058
				2059	<p><code><!ELEMENT p (#PCDATA\|a\|ul\|b\|i\|em)*></code></p>
				2060
				2061	<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>,
				2062	<code>b</code>, <code>i </code>or <code>em</code> elements in no particular
				2063	order.</p>
				2064
				2065	<h4><a name="Declaring1">Declaring attributes</a>:</h4>
				2066
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	2067	<p>Again the attributes declaration includes their content definition:</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2068
				2069	<p><code><!ATTLIST termdef name CDATA #IMPLIED></code></p>
				2070
				2071	<p>means that the element <code>termdef</code> can have a <code>name</code>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2072	attribute containing text (<code>CDATA</code>) and which is optional
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2073	(<code>#IMPLIED</code>). The attribute value can also be defined within a
				2074	set:</p>
				2075
				2076	<p><code><!ATTLIST list type (bullets\|ordered\|glossary)
				2077	"ordered"></code></p>
				2078
				2079	<p>means <code>list</code> element have a <code>type</code> attribute with 3
				2080	allowed values "bullets", "ordered" or "glossary" and which default to
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2081	"ordered" if the attribute is not explicitly specified.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2082
				2083	<p>The content type of an attribute can be text (<code>CDATA</code>),
				2084	anchor/reference/references
				2085	(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies)
				2086	(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s)
				2087	(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a
				2088	<code>chapter</code> element can have an optional <code>id</code> attribute
				2089	of type <code>ID</code>, usable for reference from attribute of type
				2090	IDREF:</p>
				2091
				2092	<p><code><!ATTLIST chapter id ID #IMPLIED></code></p>
				2093
				2094	<p>The last value of an attribute definition can be <code>#REQUIRED
				2095	</code>meaning that the attribute has to be given, <code>#IMPLIED</code>
				2096	meaning that it is optional, or the default value (possibly prefixed by
				2097	<code>#FIXED</code> if it is the only allowed).</p>
				2098
				2099	<p>Notes:</p>
				2100	<ul>
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	2101	<li>Usually the attributes pertaining to a given element are declared in a
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2102	single expression, but it is just a convention adopted by a lot of DTD
				2103	writers:
				2104	<pre><!ATTLIST termdef
				2105	id ID #REQUIRED
				2106	name CDATA #IMPLIED></pre>
				2107	<p>The previous construct defines both <code>id</code> and
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	2108	<code>name</code> attributes for the element <code>termdef</code>.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2109	</li>
				2110	</ul>
				2111
				2112	<h3><a name="Some1">Some examples</a></h3>
				2113
				2114	<p>The directory <code>test/valid/dtds/</code> in the libxml distribution
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	2115	contains some complex DTD examples. The example in the file
				2116	<code>test/valid/dia.xml</code> shows an XML file where the simple DTD is
				2117	directly included within the document.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2118
				2119	<h3><a name="validate1">How to validate</a></h3>
				2120
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	2121	<p>The simplest way is to use the xmllint program included with libxml. The
				2122	<code>--valid</code> option turns-on validation of the files given as input.
				2123	For example the following validates a copy of the first revision of the XML
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2124	1.0 specification:</p>
				2125
				2126	<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p>
				2127
Daniel Veillard	0b28e88	2002-07-24 23:47:05 +0000	[diff] [blame]	2128	<p>the -- noout is used to disable output of the resulting tree.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2129
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	2130	<p>The <code>--dtdvalid dtd</code> allows validation of the document(s)
				2131	against a given DTD.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2132
				2133	<p>Libxml exports an API to handle DTDs and validation, check the <a
				2134	href="http://xmlsoft.org/html/libxml-valid.html">associated
				2135	description</a>.</p>
				2136
				2137	<h3><a name="Other1">Other resources</a></h3>
				2138
				2139	<p>DTDs are as old as SGML. So there may be a number of examples on-line, I
				2140	will just list one for now, others pointers welcome:</p>
				2141	<ul>
				2142	<li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li>
				2143	</ul>
				2144
				2145	<p>I suggest looking at the examples found under test/valid/dtd and any of
				2146	the large number of books available on XML. The dia example in test/valid
				2147	should be both simple and complete enough to allow you to build your own.</p>
				2148
				2149	<p></p>
				2150
				2151	<h2><a name="Memory">Memory Management</a></h2>
				2152
				2153	<p>Table of Content:</p>
				2154	<ol>
				2155	<li><a href="#General3">General overview</a></li>
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	2156	<li><a href="#setting">Setting libxml set of memory routines</a></li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2157	<li><a href="#cleanup">Cleaning up after parsing</a></li>
				2158	<li><a href="#Debugging">Debugging routines</a></li>
				2159	<li><a href="#General4">General memory requirements</a></li>
				2160	</ol>
				2161
				2162	<h3><a name="General3">General overview</a></h3>
				2163
				2164	<p>The module <code><a
				2165	href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
				2166	provides the interfaces to the libxml memory system:</p>
				2167	<ul>
				2168	<li>libxml does not use the libc memory allocator directly but xmlFree(),
				2169	xmlMalloc() and xmlRealloc()</li>
				2170	<li>those routines can be reallocated to a specific set of routine, by
				2171	default the libc ones i.e. free(), malloc() and realloc()</li>
				2172	<li>the xmlmemory.c module includes a set of debugging routine</li>
				2173	</ul>
				2174
				2175	<h3><a name="setting">Setting libxml set of memory routines</a></h3>
				2176
				2177	<p>It is sometimes useful to not use the default memory allocator, either for
				2178	debugging, analysis or to implement a specific behaviour on memory management
				2179	(like on embedded systems). Two function calls are available to do so:</p>
				2180	<ul>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	2181	<li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet
				2182	()</a> which return the current set of functions in use by the parser</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2183	<li><a
				2184	href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	2185	which allow to set up a new set of memory allocation functions</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2186	</ul>
				2187
				2188	<p>Of course a call to xmlMemSetup() should probably be done before calling
				2189	any other libxml routines (unless you are sure your allocations routines are
				2190	compatibles).</p>
				2191
				2192	<h3><a name="cleanup">Cleaning up after parsing</a></h3>
				2193
				2194	<p>Libxml is not stateless, there is a few set of memory structures needing
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2195	allocation before the parser is fully functional (some encoding structures
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2196	for example). This also mean that once parsing is finished there is a tiny
				2197	amount of memory (a few hundred bytes) which can be recollected if you don't
				2198	reuse the parser immediately:</p>
				2199	<ul>
				2200	<li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	2201	()</a> is a centralized routine to free the parsing states. Note that it
				2202	won't deallocate any produced tree if any (use the xmlFreeDoc() and
				2203	related routines for this).</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2204	<li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	2205	()</a> is the dual routine allowing to preallocate the parsing state
				2206	which can be useful for example to avoid initialization reentrancy
				2207	problems when using libxml in multithreaded applications</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2208	</ul>
				2209
				2210	<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild
				2211	at the next invocation of parser routines, but be careful of the consequences
				2212	in multithreaded applications.</p>
				2213
				2214	<h3><a name="Debugging">Debugging routines</a></h3>
				2215
				2216	<p>When configured using --with-mem-debug flag (off by default), libxml uses
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2217	a set of memory allocation debugging routines keeping track of all allocated
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2218	blocks and the location in the code where the routine was called. A couple of
				2219	other debugging routines allow to dump the memory allocated infos to a file
				2220	or call a specific routine when a given block number is allocated:</p>
				2221	<ul>
				2222	<li><a
				2223	href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	2224	<a
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2225	href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>
				2226	and <a
				2227	href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>
				2228	are the memory debugging replacement allocation routines</li>
				2229	<li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	2230	()</a> dumps all the informations about the allocated memory block lefts
				2231	in the <code>.memdump</code> file</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2232	</ul>
				2233
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2234	<p>When developing libxml memory debug is enabled, the tests programs call
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2235	xmlMemoryDump () and the "make test" regression tests will check for any
				2236	memory leak during the full regression test sequence, this helps a lot
				2237	ensuring that libxml does not leak memory and bullet proof memory
				2238	allocations use (some libc implementations are known to be far too permissive
				2239	resulting in major portability problems!).</p>
				2240
				2241	<p>If the .memdump reports a leak, it displays the allocation function and
				2242	also tries to give some informations about the content and structure of the
				2243	allocated blocks left. This is sufficient in most cases to find the culprit,
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2244	but not always. Assuming the allocation problem is reproducible, it is
				2245	possible to find more easily:</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2246	<ol>
				2247	<li>write down the block number xxxx not allocated</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2248	<li>export the environment variable XML_MEM_BREAKPOINT=xxxx , the easiest
Daniel Veillard	7579482	2002-04-11 16:24:32 +0000	[diff] [blame]	2249	when using GDB is to simply give the command
				2250	<p><code>set environment XML_MEM_BREAKPOINT xxxx</code></p>
				2251	<p>before running the program.</p>
				2252	</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2253	<li>run the program under a debugger and set a breakpoint on
				2254	xmlMallocBreakpoint() a specific function called when this precise block
				2255	is allocated</li>
				2256	<li>when the breakpoint is reached you can then do a fine analysis of the
				2257	allocation an step to see the condition resulting in the missing
				2258	deallocation.</li>
				2259	</ol>
				2260
				2261	<p>I used to use a commercial tool to debug libxml memory problems but after
				2262	noticing that it was not detecting memory leaks that simple mechanism was
Daniel Veillard	7579482	2002-04-11 16:24:32 +0000	[diff] [blame]	2263	used and proved extremely efficient until now. Lately I have also used <a
				2264	href="http://developer.kde.org/~sewardj/">valgrind</a> with quite some
				2265	success, it is tied to the i386 architecture since it works by emulating the
				2266	processor and instruction set, it is slow but extremely efficient, i.e. it
				2267	spot memory usage errors in a very precise way.</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2268
				2269	<h3><a name="General4">General memory requirements</a></h3>
				2270
				2271	<p>How much libxml memory require ? It's hard to tell in average it depends
				2272	of a number of things:</p>
				2273	<ul>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2274	<li>the parser itself should work in a fixed amount of memory, except for
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2275	information maintained about the stacks of names and entities locations.
				2276	The I/O and encoding handlers will probably account for a few KBytes.
				2277	This is true for both the XML and HTML parser (though the HTML parser
				2278	need more state).</li>
				2279	<li>If you are generating the DOM tree then memory requirements will grow
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2280	nearly linear with the size of the data. In general for a balanced
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2281	textual document the internal memory requirement is about 4 times the
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2282	size of the UTF8 serialization of this document (example the XML-1.0
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2283	recommendation is a bit more of 150KBytes and takes 650KBytes of main
				2284	memory when parsed). Validation will add a amount of memory required for
				2285	maintaining the external Dtd state which should be linear with the
				2286	complexity of the content model defined by the Dtd</li>
				2287	<li>If you don't care about the advanced features of libxml like
				2288	validation, DOM, XPath or XPointer, but really need to work fixed memory
				2289	requirements, then the SAX interface should be used.</li>
				2290	</ul>
				2291
				2292	<p></p>
				2293
				2294	<h2><a name="Encodings">Encodings support</a></h2>
				2295
				2296	<p>Table of Content:</p>
				2297	<ol>
				2298	<li><a href="encoding.html#What">What does internationalization support
				2299	mean ?</a></li>
				2300	<li><a href="encoding.html#internal">The internal encoding, how and
				2301	why</a></li>
				2302	<li><a href="encoding.html#implemente">How is it implemented ?</a></li>
				2303	<li><a href="encoding.html#Default">Default supported encodings</a></li>
				2304	<li><a href="encoding.html#extend">How to extend the existing
				2305	support</a></li>
				2306	</ol>
				2307
				2308	<h3><a name="What">What does internationalization support mean ?</a></h3>
				2309
				2310	<p>XML was designed from the start to allow the support of any character set
				2311	by using Unicode. Any conformant XML parser has to support the UTF-8 and
				2312	UTF-16 default encodings which can both express the full unicode ranges. UTF8
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2313	is a variable length encoding whose greatest points are to reuse the same
				2314	encoding for ASCII and to save space for Western encodings, but it is a bit
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2315	more complex to handle in practice. UTF-16 use 2 bytes per characters (and
				2316	sometimes combines two pairs), it makes implementation easier, but looks a
				2317	bit overkill for Western languages encoding. Moreover the XML specification
				2318	allows document to be encoded in other encodings at the condition that they
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2319	are clearly labeled as such. For example the following is a wellformed XML
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2320	document encoded in ISO-8859 1 and using accentuated letter that we French
				2321	likes for both markup and content:</p>
				2322	<pre><?xml version="1.0" encoding="ISO-8859-1"?>
				2323	<très>là</très></pre>
				2324
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2325	<p>Having internationalization support in libxml means the following:</p>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2326	<ul>
				2327	<li>the document is properly parsed</li>
				2328	<li>informations about it's encoding are saved</li>
				2329	<li>it can be modified</li>
				2330	<li>it can be saved in its original encoding</li>
				2331	<li>it can also be saved in another encoding supported by libxml (for
				2332	example straight UTF8 or even an ASCII form)</li>
				2333	</ul>
				2334
				2335	<p>Another very important point is that the whole libxml API, with the
				2336	exception of a few routines to read with a specific encoding or save to a
				2337	specific encoding, is completely agnostic about the original encoding of the
				2338	document.</p>
				2339
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2340	<p>It should be noted too that the HTML parser embedded in libxml now obey
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2341	the same rules too, the following document will be (as of 2.2.2) handled in
				2342	an internationalized fashion by libxml too:</p>
				2343	<pre><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
				2344	"http://www.w3.org/TR/REC-html40/loose.dtd">
				2345	<html lang="fr">
				2346	<head>
				2347	<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1">
				2348	</head>
				2349	<body>
				2350	<p>W3C crée des standards pour le Web.</body>
				2351	</html></pre>
				2352
				2353	<h3><a name="internal">The internal encoding, how and why</a></h3>
				2354
				2355	<p>One of the core decision was to force all documents to be converted to a
				2356	default internal encoding, and that encoding to be UTF-8, here are the
				2357	rationale for those choices:</p>
				2358	<ul>
				2359	<li>keeping the native encoding in the internal form would force the libxml
				2360	users (or the code associated) to be fully aware of the encoding of the
				2361	original document, for examples when adding a text node to a document,
				2362	the content would have to be provided in the document encoding, i.e. the
				2363	client code would have to check it before hand, make sure it's conformant
				2364	to the encoding, etc ... Very hard in practice, though in some specific
				2365	cases this may make sense.</li>
				2366	<li>the second decision was which encoding. From the XML spec only UTF8 and
				2367	UTF16 really makes sense as being the two only encodings for which there
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2368	is mandatory support. UCS-4 (32 bits fixed size encoding) could be
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2369	considered an intelligent choice too since it's a direct Unicode mapping
				2370	support. I selected UTF-8 on the basis of efficiency and compatibility
				2371	with surrounding software:
				2372	<ul>
				2373	<li>UTF-8 while a bit more complex to convert from/to (i.e. slightly
				2374	more costly to import and export CPU wise) is also far more compact
				2375	than UTF-16 (and UCS-4) for a majority of the documents I see it used
				2376	for right now (RPM RDF catalogs, advogato data, various configuration
				2377	file formats, etc.) and the key point for today's computer
				2378	architecture is efficient uses of caches. If one nearly double the
				2379	memory requirement to store the same amount of data, this will trash
				2380	caches (main memory/external caches/internal caches) and my take is
				2381	that this harms the system far more than the CPU requirements needed
				2382	for the conversion to UTF-8</li>
				2383	<li>Most of libxml version 1 users were using it with straight ASCII
				2384	most of the time, doing the conversion with an internal encoding
				2385	requiring all their code to be rewritten was a serious show-stopper
				2386	for using UTF-16 or UCS-4.</li>
				2387	<li>UTF-8 is being used as the de-facto internal encoding standard for
				2388	related code like the <a href="http://www.pango.org/">pango</a>
				2389	upcoming Gnome text widget, and a lot of Unix code (yep another place
				2390	where Unix programmer base takes a different approach from Microsoft
				2391	- they are using UTF-16)</li>
				2392	</ul>
				2393	</li>
				2394	</ul>
				2395
				2396	<p>What does this mean in practice for the libxml user:</p>
				2397	<ul>
				2398	<li>xmlChar, the libxml data type is a byte, those bytes must be assembled
				2399	as UTF-8 valid strings. The proper way to terminate an xmlChar * string
				2400	is simply to append 0 byte, as usual.</li>
				2401	<li>One just need to make sure that when using chars outside the ASCII set,
				2402	the values has been properly converted to UTF-8</li>
				2403	</ul>
				2404
				2405	<h3><a name="implemente">How is it implemented ?</a></h3>
				2406
				2407	<p>Let's describe how all this works within libxml, basically the I18N
				2408	(internationalization) support get triggered only during I/O operation, i.e.
				2409	when reading a document or saving one. Let's look first at the reading
				2410	sequence:</p>
				2411	<ol>
				2412	<li>when a document is processed, we usually don't know the encoding, a
				2413	simple heuristic allows to detect UTF-18 and UCS-4 from whose where the
				2414	ASCII range (0-0x7F) maps with ASCII</li>
				2415	<li>the xml declaration if available is parsed, including the encoding
				2416	declaration. At that point, if the autodetected encoding is different
				2417	from the one declared a call to xmlSwitchEncoding() is issued.</li>
				2418	<li>If there is no encoding declaration, then the input has to be in either
				2419	UTF-8 or UTF-16, if it is not then at some point when processing the
				2420	input, the converter/checker of UTF-8 form will raise an encoding error.
				2421	You may end-up with a garbled document, or no document at all ! Example:
				2422	<pre>~/XML -> ./xmllint err.xml
				2423	err.xml:1: error: Input is not proper UTF-8, indicate encoding !
				2424	<très>là</très>
				2425	^
				2426	err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C
				2427	<très>là</très>
				2428	^</pre>
				2429	</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2430	<li>xmlSwitchEncoding() does an encoding name lookup, canonicalize it, and
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2431	then search the default registered encoding converters for that encoding.
				2432	If it's not within the default set and iconv() support has been compiled
				2433	it, it will ask iconv for such an encoder. If this fails then the parser
				2434	will report an error and stops processing:
				2435	<pre>~/XML -> ./xmllint err2.xml
				2436	err2.xml:1: error: Unsupported encoding UnsupportedEnc
				2437	<?xml version="1.0" encoding="UnsupportedEnc"?>
				2438	^</pre>
				2439	</li>
Daniel Veillard	46c5c1d	2002-05-20 07:15:54 +0000	[diff] [blame]	2440	<li>From that point the encoder processes progressively the input (it is
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2441	plugged as a front-end to the I/O module) for that entity. It captures
				2442	and convert on-the-fly the document to be parsed to UTF-8. The parser
				2443	itself just does UTF-8 checking of this input and process it
				2444	transparently. The only difference is that the encoding information has
				2445	been added to the parsing context (more precisely to the input
				2446	corresponding to this entity).</li>
				2447	<li>The result (when using DOM) is an internal form completely in UTF-8
				2448	with just an encoding information on the document node.</li>
				2449	</ol>
				2450
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2451	<p>Ok then what happens when saving the document (assuming you
				2452	collected/built an xmlDoc DOM like structure) ? It depends on the function
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2453	called, xmlSaveFile() will just try to save in the original encoding, while
				2454	xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given
				2455	encoding:</p>
				2456	<ol>
				2457	<li>if no encoding is given, libxml will look for an encoding value
				2458	associated to the document and if it exists will try to save to that
				2459	encoding,
				2460	<p>otherwise everything is written in the internal form, i.e. UTF-8</p>
				2461	</li>
				2462	<li>so if an encoding was specified, either at the API level or on the
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2463	document, libxml will again canonicalize the encoding name, lookup for a
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2464	converter in the registered set or through iconv. If not found the
				2465	function will return an error code</li>
				2466	<li>the converter is placed before the I/O buffer layer, as another kind of
				2467	buffer, then libxml will simply push the UTF-8 serialization to through
				2468	that buffer, which will then progressively be converted and pushed onto
				2469	the I/O layer.</li>
				2470	<li>It is possible that the converter code fails on some input, for example
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2471	trying to push an UTF-8 encoded Chinese character through the UTF-8 to
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2472	ISO-8859-1 converter won't work. Since the encoders are progressive they
				2473	will just report the error and the number of bytes converted, at that
				2474	point libxml will decode the offending character, remove it from the
				2475	buffer and replace it with the associated charRef encoding &#123; and
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2476	resume the conversion. This guarantees that any document will be saved
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2477	without losses (except for markup names where this is not legal, this is
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2478	a problem in the current version, in practice avoid using non-ascii
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2479	characters for tags or attributes names @@). A special "ascii" encoding
				2480	name is used to save documents to a pure ascii form can be used when
				2481	portability is really crucial</li>
				2482	</ol>
				2483
				2484	<p>Here is a few examples based on the same test document:</p>
				2485	<pre>~/XML -> ./xmllint isolat1
				2486	<?xml version="1.0" encoding="ISO-8859-1"?>
				2487	<très>là</très>
				2488	~/XML -> ./xmllint --encode UTF-8 isolat1
				2489	<?xml version="1.0" encoding="UTF-8"?>
				2490	<trÃ¨s>lÃ </trÃ¨s>
				2491	~/XML -> </pre>
				2492
				2493	<p>The same processing is applied (and reuse most of the code) for HTML I18N
				2494	processing. Looking up and modifying the content encoding is a bit more
				2495	difficult since it is located in a <meta> tag under the <head>,
				2496	so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have
				2497	been provided. The parser also attempts to switch encoding on the fly when
				2498	detecting such a tag on input. Except for that the processing is the same
				2499	(and again reuses the same code).</p>
				2500
				2501	<h3><a name="Default">Default supported encodings</a></h3>
				2502
				2503	<p>libxml has a set of default converters for the following encodings
				2504	(located in encoding.c):</p>
				2505	<ol>
				2506	<li>UTF-8 is supported by default (null handlers)</li>
				2507	<li>UTF-16, both little and big endian</li>
				2508	<li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li>
				2509	<li>ASCII, useful mostly for saving</li>
				2510	<li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML
				2511	predefined entities like &copy; for the Copyright sign.</li>
				2512	</ol>
				2513
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	2514	<p>More over when compiled on an Unix platform with iconv support the full
				2515	set of encodings supported by iconv can be instantly be used by libxml. On a
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2516	linux machine with glibc-2.1 the list of supported encodings and aliases fill
				2517	3 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the
				2518	various Japanese ones.</p>
				2519
				2520	<h4>Encoding aliases</h4>
				2521
				2522	<p>From 2.2.3, libxml has support to register encoding names aliases. The
				2523	goal is to be able to parse document whose encoding is supported but where
				2524	the name differs (for example from the default set of names accepted by
				2525	iconv). The following functions allow to register and handle new aliases for
				2526	existing encodings. Once registered libxml will automatically lookup the
				2527	aliases when handling a document:</p>
				2528	<ul>
				2529	<li>int xmlAddEncodingAlias(const char name, const char alias);</li>
				2530	<li>int xmlDelEncodingAlias(const char *alias);</li>
				2531	<li>const char * xmlGetEncodingAlias(const char *alias);</li>
				2532	<li>void xmlCleanupEncodingAliases(void);</li>
				2533	</ul>
				2534
				2535	<h3><a name="extend">How to extend the existing support</a></h3>
				2536
				2537	<p>Well adding support for new encoding, or overriding one of the encoders
				2538	(assuming it is buggy) should not be hard, just write an input and output
				2539	conversion routines to/from UTF-8, and register them using
				2540	xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be
				2541	called automatically if the parser(s) encounter such an encoding name
				2542	(register it uppercase, this will help). The description of the encoders,
				2543	their arguments and expected return values are described in the encoding.h
				2544	header.</p>
				2545
				2546	<p>A quick note on the topic of subverting the parser to use a different
				2547	internal encoding than UTF-8, in some case people will absolutely want to
				2548	keep the internal encoding different, I think it's still possible (but the
				2549	encoding must be compliant with ASCII on the same subrange) though I didn't
				2550	tried it. The key is to override the default conversion routines (by
				2551	registering null encoders/decoders for your charsets), and bypass the UTF-8
				2552	checking of the parser by setting the parser context charset
				2553	(ctxt->charset) to something different than XML_CHAR_ENCODING_UTF8, but
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2554	there is no guarantee that this will work. You may also have some troubles
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2555	saving back.</p>
				2556
				2557	<p>Basically proper I18N support is important, this requires at least
				2558	libxml-2.0.0, but a lot of features and corrections are really available only
				2559	starting 2.2.</p>
				2560
				2561	<h2><a name="IO">I/O Interfaces</a></h2>
				2562
				2563	<p>Table of Content:</p>
				2564	<ol>
				2565	<li><a href="#General1">General overview</a></li>
				2566	<li><a href="#basic">The basic buffer type</a></li>
				2567	<li><a href="#Input">Input I/O handlers</a></li>
				2568	<li><a href="#Output">Output I/O handlers</a></li>
				2569	<li><a href="#entities">The entities loader</a></li>
				2570	<li><a href="#Example2">Example of customized I/O</a></li>
				2571	</ol>
				2572
				2573	<h3><a name="General1">General overview</a></h3>
				2574
				2575	<p>The module <code><a
				2576	href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides
				2577	the interfaces to the libxml I/O system. This consists of 4 main parts:</p>
				2578	<ul>
				2579	<li>Entities loader, this is a routine which tries to fetch the entities
				2580	(files) based on their PUBLIC and SYSTEM identifiers. The default loader
				2581	don't look at the public identifier since libxml do not maintain a
				2582	catalog. You can redefine you own entity loader by using
				2583	<code>xmlGetExternalEntityLoader()</code> and
Daniel Veillard	9c46682	2001-10-25 12:03:39 +0000	[diff] [blame]	2584	<code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the
				2585	example</a>.</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2586	<li>Input I/O buffers which are a commodity structure used by the parser(s)
				2587	input layer to handle fetching the informations to feed the parser. This
				2588	provides buffering and is also a placeholder where the encoding
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2589	converters to UTF8 are piggy-backed.</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2590	<li>Output I/O buffers are similar to the Input ones and fulfill similar
				2591	task but when generating a serialization from a tree.</li>
				2592	<li>A mechanism to register sets of I/O callbacks and associate them with
				2593	specific naming schemes like the protocol part of the URIs.
				2594	<p>This affect the default I/O operations and allows to use specific I/O
				2595	handlers for certain names.</p>
				2596	</li>
				2597	</ul>
				2598
				2599	<p>The general mechanism used when loading http://rpmfind.net/xml.html for
				2600	example in the HTML parser is the following:</p>
				2601	<ol>
				2602	<li>The default entity loader calls <code>xmlNewInputFromFile()</code> with
				2603	the parsing context and the URI string.</li>
				2604	<li>the URI string is checked against the existing registered handlers
				2605	using their match() callback function, if the HTTP module was compiled
				2606	in, it is registered and its match() function will succeeds</li>
				2607	<li>the open() function of the handler is called and if successful will
				2608	return an I/O Input buffer</li>
				2609	<li>the parser will the start reading from this buffer and progressively
				2610	fetch information from the resource, calling the read() function of the
				2611	handler until the resource is exhausted</li>
				2612	<li>if an encoding change is detected it will be installed on the input
				2613	buffer, providing buffering and efficient use of the conversion
				2614	routines</li>
				2615	<li>once the parser has finished, the close() function of the handler is
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2616	called once and the Input buffer and associated resources are
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2617	deallocated.</li>
				2618	</ol>
				2619
				2620	<p>The user defined callbacks are checked first to allow overriding of the
				2621	default libxml I/O routines.</p>
				2622
				2623	<h3><a name="basic">The basic buffer type</a></h3>
				2624
				2625	<p>All the buffer manipulation handling is done using the
				2626	<code>xmlBuffer</code> type define in <code><a
				2627	href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a
				2628	resizable memory buffer. The buffer allocation strategy can be selected to be
				2629	either best-fit or use an exponential doubling one (CPU vs. memory use
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	2630	trade-off). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2631	<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a
				2632	system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number
				2633	of functions allows to manipulate buffers with names starting with the
				2634	<code>xmlBuffer...</code> prefix.</p>
				2635
				2636	<h3><a name="Input">Input I/O handlers</a></h3>
				2637
				2638	<p>An Input I/O handler is a simple structure
				2639	<code>xmlParserInputBuffer</code> containing a context associated to the
				2640	resource (file descriptor, or pointer to a protocol handler), the read() and
				2641	close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset
				2642	encoding handler are also present to support charset conversion when
				2643	needed.</p>
				2644
				2645	<h3><a name="Output">Output I/O handlers</a></h3>
				2646
				2647	<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an
				2648	Input one except the callbacks are write() and close().</p>
				2649
				2650	<h3><a name="entities">The entities loader</a></h3>
				2651
				2652	<p>The entity loader resolves requests for new entities and create inputs for
				2653	the parser. Creating an input from a filename or an URI string is done
				2654	through the xmlNewInputFromFile() routine. The default entity loader do not
				2655	handle the PUBLIC identifier associated with an entity (if any). So it just
				2656	calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in
				2657	XML).</p>
				2658
				2659	<p>If you want to hook up a catalog mechanism then you simply need to
				2660	override the default entity loader, here is an example:</p>
				2661	<pre>#include <libxml/xmlIO.h>
				2662
				2663	xmlExternalEntityLoader defaultLoader = NULL;
				2664
				2665	xmlParserInputPtr
				2666	xmlMyExternalEntityLoader(const char URL, const char ID,
				2667	xmlParserCtxtPtr ctxt) {
				2668	xmlParserInputPtr ret;
				2669	const char *fileID = NULL;
				2670	/* lookup for the fileID depending on ID */
				2671
				2672	ret = xmlNewInputFromFile(ctxt, fileID);
				2673	if (ret != NULL)
				2674	return(ret);
				2675	if (defaultLoader != NULL)
				2676	ret = defaultLoader(URL, ID, ctxt);
				2677	return(ret);
				2678	}
				2679
				2680	int main(..) {
				2681	...
				2682
				2683	/*
				2684	* Install our own entity loader
				2685	*/
				2686	defaultLoader = xmlGetExternalEntityLoader();
				2687	xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
				2688
				2689	...
				2690	}</pre>
				2691
				2692	<h3><a name="Example2">Example of customized I/O</a></h3>
				2693
				2694	<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a
				2695	real use case</a>, xmlDocDump() closes the FILE * passed by the application
				2696	and this was a problem. The <a
				2697	href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a
				2698	new output handler with the closing call deactivated:</p>
				2699	<ol>
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	2700	<li>First define a new I/O output allocator where the output don't close
				2701	the file:
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2702	<pre>xmlOutputBufferPtr
				2703	xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) {
				2704	xmlOutputBufferPtr ret;
				2705
				2706	if (xmlOutputCallbackInitialized == 0)
				2707	xmlRegisterDefaultOutputCallbacks();
				2708
				2709	if (file == NULL) return(NULL);
				2710	ret = xmlAllocOutputBuffer(encoder);
				2711	if (ret != NULL) {
				2712	ret->context = file;
				2713	ret->writecallback = xmlFileWrite;
				2714	ret->closecallback = NULL; /* No close callback */
				2715	}
				2716	return(ret); <br>
Daniel Veillard	1eb2424	2002-03-18 11:33:03 +0000	[diff] [blame]	2717
Daniel Veillard	34ce8be	2002-03-18 19:37:11 +0000	[diff] [blame]	2718
				2719
Daniel Veillard	1927409	2002-03-25 16:48:03 +0000	[diff] [blame]	2720
Daniel Veillard	b2fb8ed	2002-04-01 09:33:12 +0000	[diff] [blame]	2721
Daniel Veillard	7579482	2002-04-11 16:24:32 +0000	[diff] [blame]	2722
Daniel Veillard	a7084cd	2002-04-15 17:12:47 +0000	[diff] [blame]	2723
Daniel Veillard	0bfbb42	2002-04-26 09:21:45 +0000	[diff] [blame]	2724
Daniel Veillard	93d3a47	2002-04-26 14:04:55 +0000	[diff] [blame]	2725
Daniel Veillard	cf27f7c	2002-04-30 07:12:39 +0000	[diff] [blame]	2726
Daniel Veillard	e6d8e20	2002-05-02 06:11:10 +0000	[diff] [blame]	2727
Daniel Veillard	9b6fd30	2002-05-13 12:06:47 +0000	[diff] [blame]	2728
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	2729
Daniel Veillard	2147367	2002-06-17 07:29:22 +0000	[diff] [blame]	2730
Daniel Veillard	782afda	2002-07-08 15:12:49 +0000	[diff] [blame]	2731
Daniel Veillard	42766c0	2002-08-22 20:52:17 +0000	[diff] [blame]	2732
Daniel Veillard	e166254	2002-08-28 11:50:59 +0000	[diff] [blame]	2733
Daniel Veillard	e16b574	2002-09-26 17:50:03 +0000	[diff] [blame]	2734
Daniel Veillard	321be0c	2002-10-08 21:26:42 +0000	[diff] [blame]	2735
Daniel Veillard	4826743	2002-10-18 11:21:38 +0000	[diff] [blame]	2736
Daniel Veillard	dad3f68	2002-11-17 16:47:27 +0000	[diff] [blame]	2737
Daniel Veillard	c14401e	2002-11-20 14:28:17 +0000	[diff] [blame]	2738
Daniel Veillard	f9c4cad	2002-11-22 15:57:07 +0000	[diff] [blame^]	2739
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2740	} </pre>
				2741	</li>
				2742	<li>And then use it to save the document:
				2743	<pre>FILE *f;
				2744	xmlOutputBufferPtr output;
				2745	xmlDocPtr doc;
				2746	int res;
				2747
				2748	f = ...
				2749	doc = ....
				2750
				2751	output = xmlOutputBufferCreateOwn(f, NULL);
				2752	res = xmlSaveFileTo(output, doc, NULL);
				2753	</pre>
				2754	</li>
				2755	</ol>
				2756
				2757	<h2><a name="Catalog">Catalog support</a></h2>
				2758
				2759	<p>Table of Content:</p>
				2760	<ol>
				2761	<li><a href="General2">General overview</a></li>
				2762	<li><a href="#definition">The definition</a></li>
				2763	<li><a href="#Simple">Using catalogs</a></li>
				2764	<li><a href="#Some">Some examples</a></li>
				2765	<li><a href="#reference">How to tune catalog usage</a></li>
				2766	<li><a href="#validate">How to debug catalog processing</a></li>
				2767	<li><a href="#Declaring">How to create and maintain catalogs</a></li>
				2768	<li><a href="#implemento">The implementor corner quick review of the
				2769	API</a></li>
				2770	<li><a href="#Other">Other resources</a></li>
				2771	</ol>
				2772
				2773	<h3><a name="General2">General overview</a></h3>
				2774
				2775	<p>What is a catalog? Basically it's a lookup mechanism used when an entity
				2776	(a file or a remote resource) references another entity. The catalog lookup
				2777	is inserted between the moment the reference is recognized by the software
				2778	(XML parser, stylesheet processing, or even images referenced for inclusion
				2779	in a rendering) and the time where loading that resource is actually
				2780	started.</p>
				2781
				2782	<p>It is basically used for 3 things:</p>
				2783	<ul>
				2784	<li>mapping from "logical" names, the public identifiers and a more
				2785	concrete name usable for download (and URI). For example it can associate
				2786	the logical name
				2787	<p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
				2788	<p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be
				2789	downloaded</p>
				2790	<p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
				2791	</li>
				2792	<li>remapping from a given URL to another one, like an HTTP indirection
				2793	saying that
				2794	<p>"http://www.oasis-open.org/committes/tr.xsl"</p>
				2795	<p>should really be looked at</p>
				2796	<p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
				2797	</li>
				2798	<li>providing a local cache mechanism allowing to load the entities
				2799	associated to public identifiers or remote resources, this is a really
				2800	important feature for any significant deployment of XML or SGML since it
				2801	allows to avoid the aleas and delays associated to fetching remote
				2802	resources.</li>
				2803	</ul>
				2804
				2805	<h3><a name="definition">The definitions</a></h3>
				2806
				2807	<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p>
				2808	<ul>
				2809	<li>the older SGML catalogs, the official spec is SGML Open Technical
				2810	Resolution TR9401:1997, but is better understood by reading <a
				2811	href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from
				2812	James Clark. This is relatively old and not the preferred mode of
				2813	operation of libxml.</li>
				2814	<li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	2815	Catalogs</a> is far more flexible, more recent, uses an XML syntax and
				2816	should scale quite better. This is the default option of libxml.</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	2817	</ul>
				2818
				2819	<p></p>
				2820
				2821	<h3><a name="Simple">Using catalog</a></h3>
				2822
				2823	<p>In a normal environment libxml will by default check the presence of a
				2824	catalog in /etc/xml/catalog, and assuming it has been correctly populated,
				2825	the processing is completely transparent to the document user. To take a
				2826	concrete example, suppose you are authoring a DocBook document, this one
				2827	starts with the following DOCTYPE definition:</p>
				2828	<pre><?xml version='1.0'?>
				2829	<!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
				2830	"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"></pre>
				2831
				2832	<p>When validating the document with libxml, the catalog will be
				2833	automatically consulted to lookup the public identifier "-//Norman Walsh//DTD
				2834	DocBk XML V3.1.4//EN" and the system identifier
				2835	"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have
				2836	been installed on your system and the catalogs actually point to them, libxml
				2837	will fetch them from the local disk.</p>
				2838
				2839	<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this
				2840	DOCTYPE example it's a really old version, but is fine as an example.</p>
				2841
				2842	<p>Libxml will check the catalog each time that it is requested to load an
				2843	entity, this includes DTD, external parsed entities, stylesheets, etc ... If
				2844	your system is correctly configured all the authoring phase and processing
				2845	should use only local files, even if your document stays portable because it
				2846	uses the canonical public and system ID, referencing the remote document.</p>
				2847
				2848	<h3><a name="Some">Some examples:</a></h3>
				2849
				2850	<p>Here is a couple of fragments from XML Catalogs used in libxml early
				2851	regression tests in <code>test/catalogs</code> :</p>
				2852	<pre><?xml version="1.0"?>
				2853	<!DOCTYPE catalog PUBLIC
				2854	"-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
				2855	"http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd">
				2856	<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog">
				2857	<public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
				2858	uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/>
				2859	...</pre>
				2860
				2861	<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are
				2862	written in XML, there is a specific namespace for catalog elements
				2863	"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this
				2864	catalog is a <code>public</code> mapping it allows to associate a Public
				2865	Identifier with an URI.</p>
				2866	<pre>...
				2867	<rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
				2868	rewritePrefix="file:///usr/share/xml/docbook/"/>
				2869	...</pre>
				2870
				2871	<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that
				2872	any URI starting with a given prefix should be looked at another URI
				2873	constructed by replacing the prefix with an new one. In effect this acts like
				2874	a cache system for a full area of the Web. In practice it is extremely useful
				2875	with a file prefix if you have installed a copy of those resources on your
				2876	local system.</p>
				2877	<pre>...
				2878	<delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
				2879	catalog="file:///usr/share/xml/docbook.xml"/>
				2880	<delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
				2881	catalog="file:///usr/share/xml/docbook.xml"/>
				2882	<delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
				2883	catalog="file:///usr/share/xml/docbook.xml"/>
				2884	<delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
				2885	catalog="file:///usr/share/xml/docbook.xml"/>
				2886	<delegateURI uriStartString="http://www.oasis-open.org/docbook/"
				2887	catalog="file:///usr/share/xml/docbook.xml"/>
				2888	...</pre>
				2889
				2890	<p>Delegation is the core features which allows to build a tree of catalogs,
				2891	easier to maintain than a single catalog, based on Public Identifier, System
				2892	Identifier or URI prefixes it instructs the catalog software to look up
				2893	entries in another resource. This feature allow to build hierarchies of
				2894	catalogs, the set of entries presented should be sufficient to redirect the
				2895	resolution of all DocBook references to the specific catalog in
				2896	<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all
				2897	references for DocBook 4.2.1 to a specific catalog installed at the same time
				2898	as the DocBook resources on the local machine.</p>
				2899
				2900	<h3><a name="reference">How to tune catalog usage:</a></h3>
				2901
				2902	<p>The user can change the default catalog behaviour by redirecting queries
				2903	to its own set of catalogs, this can be done by setting the
				2904	<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an
				2905	empty one should deactivate loading the default <code>/etc/xml/catalog</code>
				2906	default catalog</p>
				2907
				2908	<h3><a name="validate">How to debug catalog processing:</a></h3>
				2909
				2910	<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will
				2911	make libxml output debugging informations for each catalog operations, for
				2912	example:</p>
				2913	<pre>orchis:~/XML -> xmllint --memory --noout test/ent2
				2914	warning: failed to load external entity "title.xml"
				2915	orchis:~/XML -> export XML_DEBUG_CATALOG=
				2916	orchis:~/XML -> xmllint --memory --noout test/ent2
				2917	Failed to parse catalog /etc/xml/catalog
				2918	Failed to parse catalog /etc/xml/catalog
				2919	warning: failed to load external entity "title.xml"
				2920	Catalogs cleanup
				2921	orchis:~/XML -> </pre>
				2922
				2923	<p>The test/ent2 references an entity, running the parser from memory makes
				2924	the base URI unavailable and the the "title.xml" entity cannot be loaded.
				2925	Setting up the debug environment variable allows to detect that an attempt is
				2926	made to load the <code>/etc/xml/catalog</code> but since it's not present the
				2927	resolution fails.</p>
				2928
				2929	<p>But the most advanced way to debug XML catalog processing is to use the
				2930	<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load
				2931	catalogs and make resolution queries to see what is going on. This is also
				2932	used for the regression tests:</p>
				2933	<pre>orchis:~/XML -> ./xmlcatalog test/catalogs/docbook.xml \
				2934	"-//OASIS//DTD DocBook XML V4.1.2//EN"
				2935	http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
				2936	orchis:~/XML -> </pre>
				2937
				2938	<p>For debugging what is going on, adding one -v flags increase the verbosity
				2939	level to indicate the processing done (adding a second flag also indicate
				2940	what elements are recognized at parsing):</p>
				2941	<pre>orchis:~/XML -> ./xmlcatalog -v test/catalogs/docbook.xml \
				2942	"-//OASIS//DTD DocBook XML V4.1.2//EN"
				2943	Parsing catalog test/catalogs/docbook.xml's content
				2944	Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
				2945	http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
				2946	Catalogs cleanup
				2947	orchis:~/XML -> </pre>
				2948
				2949	<p>A shell interface is also available to debug and process multiple queries
				2950	(and for regression tests):</p>
				2951	<pre>orchis:~/XML -> ./xmlcatalog -shell test/catalogs/docbook.xml \
				2952	"-//OASIS//DTD DocBook XML V4.1.2//EN"
				2953	> help
				2954	Commands available:
				2955	public PublicID: make a PUBLIC identifier lookup
				2956	system SystemID: make a SYSTEM identifier lookup
				2957	resolve PublicID SystemID: do a full resolver lookup
				2958	add 'type' 'orig' 'replace' : add an entry
				2959	del 'values' : remove values
				2960	dump: print the current catalog state
				2961	debug: increase the verbosity level
				2962	quiet: decrease the verbosity level
				2963	exit: quit the shell
				2964	> public "-//OASIS//DTD DocBook XML V4.1.2//EN"
				2965	http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
				2966	> quit
				2967	orchis:~/XML -> </pre>
				2968
				2969	<p>This should be sufficient for most debugging purpose, this was actually
				2970	used heavily to debug the XML Catalog implementation itself.</p>
				2971
				2972	<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3>
				2973
				2974	<p>Basically XML Catalogs are XML files, you can either use XML tools to
				2975	manage them or use <strong>xmlcatalog</strong> for this. The basic step is
				2976	to create a catalog the -create option provide this facility:</p>
				2977	<pre>orchis:~/XML -> ./xmlcatalog --create tst.xml
				2978	<?xml version="1.0"?>
				2979	<!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
				2980	"http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd">
				2981	<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/>
				2982	orchis:~/XML -> </pre>
				2983
				2984	<p>By default xmlcatalog does not overwrite the original catalog and save the
				2985	result on the standard output, this can be overridden using the -noout
				2986	option. The <code>-add</code> command allows to add entries in the
				2987	catalog:</p>
				2988	<pre>orchis:~/XML -> ./xmlcatalog --noout --create --add "public" \
				2989	"-//OASIS//DTD DocBook XML V4.1.2//EN" \
				2990	http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
				2991	orchis:~/XML -> cat tst.xml
				2992	<?xml version="1.0"?>
				2993	<!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
				2994	"http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd">
				2995	<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog">
				2996	<public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
				2997	uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/>
				2998	</catalog>
				2999	orchis:~/XML -> </pre>
				3000
				3001	<p>The <code>-add</code> option will always take 3 parameters even if some of
				3002	the XML Catalog constructs (like nextCatalog) will have only a single
				3003	argument, just pass a third empty string, it will be ignored.</p>
				3004
				3005	<p>Similarly the <code>-del</code> option remove matching entries from the
				3006	catalog:</p>
				3007	<pre>orchis:~/XML -> ./xmlcatalog --del \
				3008	"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
				3009	<?xml version="1.0"?>
				3010	<!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
				3011	"http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd">
				3012	<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/>
				3013	orchis:~/XML -> </pre>
				3014
				3015	<p>The catalog is now empty. Note that the matching of <code>-del</code> is
				3016	exact and would have worked in a similar fashion with the Public ID
				3017	string.</p>
				3018
				3019	<p>This is rudimentary but should be sufficient to manage a not too complex
				3020	catalog tree of resources.</p>
				3021
				3022	<h3><a name="implemento">The implementor corner quick review of the
				3023	API:</a></h3>
				3024
				3025	<p>First, and like for every other module of libxml, there is an
				3026	automatically generated <a href="html/libxml-catalog.html">API page for
				3027	catalog support</a>.</p>
				3028
				3029	<p>The header for the catalog interfaces should be included as:</p>
				3030	<pre>#include <libxml/catalog.h></pre>
				3031
				3032	<p>The API is voluntarily kept very simple. First it is not obvious that
				3033	applications really need access to it since it is the default behaviour of
				3034	libxml (Note: it is possible to completely override libxml default catalog by
				3035	using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to
				3036	plug an application specific resolver).</p>
				3037
				3038	<p>Basically libxml support 2 catalog lists:</p>
				3039	<ul>
				3040	<li>the default one, global shared by all the application</li>
				3041	<li>a per-document catalog, this one is built if the document uses the
				3042	<code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is
				3043	associated to the parser context and destroyed when the parsing context
				3044	is destroyed.</li>
				3045	</ul>
				3046
				3047	<p>the document one will be used first if it exists.</p>
				3048
				3049	<h4>Initialization routines:</h4>
				3050
				3051	<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be
				3052	used at startup to initialize the catalog, if the catalog should be
				3053	initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs()
				3054	should be called before xmlInitializeCatalog() which would otherwise do a
				3055	default initialization first.</p>
				3056
				3057	<p>The xmlCatalogAddLocal() call is used by the parser to grow the document
				3058	own catalog list if needed.</p>
				3059
				3060	<h4>Preferences setup:</h4>
				3061
				3062	<p>The XML Catalog spec requires the possibility to select default
				3063	preferences between public and system delegation,
				3064	xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and
				3065	xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should
				3066	be forbidden, allowed for global catalog, for document catalog or both, the
				3067	default is to allow both.</p>
				3068
				3069	<p>And of course xmlCatalogSetDebug() allows to generate debug messages
				3070	(through the xmlGenericError() mechanism).</p>
				3071
				3072	<h4>Querying routines:</h4>
				3073
				3074	<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic()
				3075	and xmlCatalogResolveURI() are relatively explicit if you read the XML
				3076	Catalog specification they correspond to section 7 algorithms, they should
				3077	also work if you have loaded an SGML catalog with a simplified semantic.</p>
				3078
				3079	<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but
				3080	operate on the document catalog list</p>
				3081
				3082	<h4>Cleanup and Miscellaneous:</h4>
				3083
				3084	<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is
				3085	the per-document equivalent.</p>
				3086
				3087	<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the
				3088	first catalog in the global list, and xmlCatalogDump() allows to dump a
				3089	catalog state, those routines are primarily designed for xmlcatalog, I'm not
				3090	sure that exposing more complex interfaces (like navigation ones) would be
				3091	really useful.</p>
				3092
				3093	<p>The xmlParseCatalogFile() is a function used to load XML Catalog files,
				3094	it's similar as xmlParseFile() except it bypass all catalog lookups, it's
				3095	provided because this functionality may be useful for client tools.</p>
				3096
				3097	<h4>threaded environments:</h4>
				3098
				3099	<p>Since the catalog tree is built progressively, some care has been taken to
				3100	try to avoid troubles in multithreaded environments. The code is now thread
				3101	safe assuming that the libxml library has been compiled with threads
				3102	support.</p>
				3103
				3104	<p></p>
				3105
				3106	<h3><a name="Other">Other resources</a></h3>
				3107
				3108	<p>The XML Catalog specification is relatively recent so there isn't much
				3109	literature to point at:</p>
				3110	<ul>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3111	<li>You can find a good rant from Norm Walsh about <a
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3112	href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the
				3113	need for catalogs</a>, it provides a lot of context informations even if
Daniel Veillard	93d3a47	2002-04-26 14:04:55 +0000	[diff] [blame]	3114	I don't agree with everything presented. Norm also wrote a more recent
				3115	article <a
				3116	href="http://wwws.sun.com/software/xml/developers/resolver/article/">XML
				3117	entities and URI resolvers</a> describing them.</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3118	<li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML
				3119	catalog proposal</a> from John Cowan</li>
				3120	<li>The <a href="http://www.rddl.org/">Resource Directory Description
				3121	Language</a> (RDDL) another catalog system but more oriented toward
				3122	providing metadata for XML namespaces.</li>
				3123	<li>the page from the OASIS Technical <a
				3124	href="http://www.oasis-open.org/committees/entity/">Committee on Entity
				3125	Resolution</a> who maintains XML Catalog, you will find pointers to the
				3126	specification update, some background and pointers to others tools
				3127	providing XML Catalog support</li>
Daniel Veillard	35e937a	2002-01-19 22:21:54 +0000	[diff] [blame]	3128	<li>Here is a <a href="buildDocBookCatalog">shell script</a> to generate
				3129	XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/
				3130	directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on
				3131	the resources found on the system. Otherwise it will just create
				3132	~/xmlcatalog and ~/dbkxmlcatalog and doing:
Daniel Veillard	c575b99	2002-02-08 13:28:40 +0000	[diff] [blame]	3133	<p><code>export XMLCATALOG=$HOME/xmlcatalog</code></p>
Daniel Veillard	35e937a	2002-01-19 22:21:54 +0000	[diff] [blame]	3134	<p>should allow to process DocBook documentations without requiring
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3135	network accesses for the DTD or stylesheets</p>
Daniel Veillard	35e937a	2002-01-19 22:21:54 +0000	[diff] [blame]	3136	</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3137	<li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a
Daniel Veillard	35e937a	2002-01-19 22:21:54 +0000	[diff] [blame]	3138	small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems
				3139	to work fine for me too</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3140	<li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog
				3141	manual page</a></li>
				3142	</ul>
				3143
				3144	<p>If you have suggestions for corrections or additions, simply contact
				3145	me:</p>
				3146
				3147	<h2><a name="library">The parser interfaces</a></h2>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3148
				3149	<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3150	using the XML library from the C language. It is not intended to be
				3151	extensive. I hope the automatically generated documents will provide the
				3152	completeness required, but as a separate set of documents. The interfaces of
				3153	the XML library are by principle low level, there is nearly zero abstraction.
				3154	Those interested in a higher level API should <a href="#DOM">look at
				3155	DOM</a>.</p>
Daniel Veillard	ccb0963	1998-10-27 06:21:04 +0000	[diff] [blame]	3156
Daniel Veillard	9cb5ff4	2001-01-29 08:22:21 +0000	[diff] [blame]	3157	<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
				3158	separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3159	interfaces</a>. Let's have a look at how the XML parser can be called:</p>
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	3160
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3161	<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3162
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3163	<p>Usually, the first thing to do is to read an XML input. The parser accepts
				3164	documents either from in-memory strings or from files. The functions are
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3165	defined in "parser.h":</p>
Daniel Veillard	10c6a8f	1998-10-28 01:00:12 +0000	[diff] [blame]	3166	<dl>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3167	<dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3168	<dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3169	</dd>
Daniel Veillard	10c6a8f	1998-10-28 01:00:12 +0000	[diff] [blame]	3170	</dl>
				3171	<dl>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3172	<dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	3173	<dd><p>Parse an XML document contained in a (possibly compressed)
				3174	file.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3175	</dd>
Daniel Veillard	10c6a8f	1998-10-28 01:00:12 +0000	[diff] [blame]	3176	</dl>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3177
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3178	<p>The parser returns a pointer to the document structure (or NULL in case of
Daniel Veillard	10c6a8f	1998-10-28 01:00:12 +0000	[diff] [blame]	3179	failure).</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3180
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3181	<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	3182
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3183	<p>In order for the application to keep the control when the document is
				3184	being fetched (which is common for GUI based programs) libxml provides a push
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3185	interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	3186	<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
				3187	void *user_data,
				3188	const char *chunk,
				3189	int size,
				3190	const char *filename);
				3191	int xmlParseChunk (xmlParserCtxtPtr ctxt,
				3192	const char *chunk,
				3193	int size,
				3194	int terminate);</pre>
				3195
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3196	<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	3197	<pre> FILE *f;
				3198
				3199	f = fopen(filename, "r");
				3200	if (f != NULL) {
				3201	int res, size = 1024;
				3202	char chars[1024];
				3203	xmlParserCtxtPtr ctxt;
				3204
				3205	res = fread(chars, 1, 4, f);
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3206	if (res > 0) {
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	3207	ctxt = xmlCreatePushParserCtxt(NULL, NULL,
				3208	chars, res, filename);
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3209	while ((res = fread(chars, 1, size, f)) > 0) {
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	3210	xmlParseChunk(ctxt, chars, res, 0);
				3211	}
				3212	xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3213	doc = ctxt->myDoc;
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	3214	xmlFreeParserCtxt(ctxt);
				3215	}
				3216	}</pre>
				3217
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	3218	<p>The HTML parser embedded into libxml also has a push interface; the
				3219	functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	3220
				3221	<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
				3222
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	3223	<p>The tree-building interface makes the parser memory-hungry, first loading
				3224	the document in memory and then building the tree itself. Reading a document
				3225	without building the tree is possible using the SAX interfaces (see SAX.h and
				3226	<a href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3227	Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3228	limited to SAX: just use the two first arguments of
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	3229	<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillard	ccb0963	1998-10-27 06:21:04 +0000	[diff] [blame]	3230
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	3231	<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3232
				3233	<p>The other way to get an XML tree in memory is by building it. Basically
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	3234	there is a set of functions dedicated to building new elements. (These are
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3235	also described in <libxml/tree.h>.) For example, here is a piece of
				3236	code that produces the XML document used in the previous examples:</p>
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3237	<pre> #include <libxml/tree.h>
Daniel Veillard	361d845	2000-04-03 19:48:13 +0000	[diff] [blame]	3238	xmlDocPtr doc;
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3239	xmlNodePtr tree, subtree;
				3240
				3241	doc = xmlNewDoc("1.0");
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3242	doc->children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
				3243	xmlSetProp(doc->children, "prop1", "gnome is great");
				3244	xmlSetProp(doc->children, "prop2", "& linux too");
				3245	tree = xmlNewChild(doc->children, NULL, "head", NULL);
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3246	subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3247	tree = xmlNewChild(doc->children, NULL, "chapter", NULL);
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3248	subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
				3249	subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
				3250	subtree = xmlNewChild(tree, NULL, "image", NULL);
				3251	xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3252
				3253	<p>Not really rocket science ...</p>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3254
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	3255	<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3256
Daniel Veillard	9cb5ff4	2001-01-29 08:22:21 +0000	[diff] [blame]	3257	<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3258	code has access to the internal structure of all the elements of the tree.
				3259	The names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard	306be99	2000-07-03 12:38:45 +0000	[diff] [blame]	3260	<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3261	<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard	0142b84	2000-01-14 14:45:24 +0000	[diff] [blame]	3262	example:</p>
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3263	<pre><code>doc->children->children->children</code></pre>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3264
				3265	<p>points to the title element,</p>
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3266	<pre>doc->children->children->next->children->children</pre>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3267
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	3268	<p>points to the text node containing the chapter title "The Linux
				3269	adventure".</p>
Daniel Veillard	10c6a8f	1998-10-28 01:00:12 +0000	[diff] [blame]	3270
Daniel Veillard	b24054a	1999-12-18 15:32:46 +0000	[diff] [blame]	3271	<p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em> to be
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3272	present before the document root, so <code>doc->children</code> may point
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3273	to an element which is not the document Root Element; a function
Daniel Veillard	5cb5ab8	1999-12-21 15:35:29 +0000	[diff] [blame]	3274	<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillard	b24054a	1999-12-18 15:32:46 +0000	[diff] [blame]	3275
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	3276	<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3277
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3278	<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard	9cb5ff4	2001-01-29 08:22:21 +0000	[diff] [blame]	3279	is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3280	<dl>
Daniel Veillard	dd6b367	1999-09-23 22:19:22 +0000	[diff] [blame]	3281	<dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
				3282	xmlChar *value);</code></dt>
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3283	<dd><p>This sets (or changes) an attribute carried by an ELEMENT node.
				3284	The value can be NULL.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3285	</dd>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3286	</dl>
				3287	<dl>
Daniel Veillard	dd6b367	1999-09-23 22:19:22 +0000	[diff] [blame]	3288	<dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3289	*name);</code></dt>
Daniel Veillard	c92c304	2000-09-29 02:42:04 +0000	[diff] [blame]	3290	<dd><p>This function returns a pointer to new copy of the property
				3291	content. Note that the user must deallocate the result.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3292	</dd>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3293	</dl>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3294
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3295	<p>Two functions are provided for reading and writing the text associated
				3296	with elements:</p>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3297	<dl>
Daniel Veillard	dd6b367	1999-09-23 22:19:22 +0000	[diff] [blame]	3298	<dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3299	*value);</code></dt>
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	3300	<dd><p>This function takes an "external" string and converts it to one
				3301	text node or possibly to a list of entity and text nodes. All
				3302	non-predefined entity references like &Gnome; will be stored
				3303	internally as entity nodes, hence the result of the function may not be
				3304	a single node.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3305	</dd>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3306	</dl>
				3307	<dl>
Daniel Veillard	dd6b367	1999-09-23 22:19:22 +0000	[diff] [blame]	3308	<dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3309	inLine);</code></dt>
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	3310	<dd><p>This function is the inverse of
				3311	<code>xmlStringGetNodeList()</code>. It generates a new string
				3312	containing the content of the text and entity nodes. Note the extra
				3313	argument inLine. If this argument is set to 1, the function will expand
				3314	entity references. For example, instead of returning the &Gnome;
				3315	XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3316	"GNU Network Object Model Environment").</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3317	</dd>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3318	</dl>
Daniel Veillard	10c6a8f	1998-10-28 01:00:12 +0000	[diff] [blame]	3319
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	3320	<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3321
				3322	<p>Basically 3 options are possible:</p>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3323	<dl>
Daniel Veillard	dd6b367	1999-09-23 22:19:22 +0000	[diff] [blame]	3324	<dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3325	*size);</code></dt>
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3326	<dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3327	</dd>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3328	</dl>
				3329	<dl>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3330	<dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3331	<dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3332	</dd>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3333	</dl>
				3334	<dl>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3335	<dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	3336	<dd><p>Saves the document to a file. In this case, the compression
				3337	interface is triggered if it has been turned on.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3338	</dd>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3339	</dl>
Daniel Veillard	10c6a8f	1998-10-28 01:00:12 +0000	[diff] [blame]	3340
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	3341	<h3><a name="Compressio">Compression</a></h3>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3342
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3343	<p>The library transparently handles compression when doing file-based
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	3344	accesses. The level of compression on saves can be turned on either globally
				3345	or individually for one file:</p>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3346	<dl>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3347	<dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3348	<dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3349	</dd>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3350	</dl>
				3351	<dl>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3352	<dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3353	<dd><p>Sets the document compression ratio.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3354	</dd>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3355	</dl>
				3356	<dl>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3357	<dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3358	<dd><p>Gets the default compression ratio.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3359	</dd>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3360	</dl>
				3361	<dl>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3362	<dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3363	<dd><p>Sets the default compression ratio.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3364	</dd>
Daniel Veillard	25940b7	1998-10-29 05:51:30 +0000	[diff] [blame]	3365	</dl>
				3366
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	3367	<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3368
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3369	<p>Entities in principle are similar to simple C macros. An entity defines an
				3370	abbreviation for a given string that you can reuse many times throughout the
				3371	content of your document. Entities are especially useful when a given string
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	3372	may occur frequently within a document, or to confine the change needed to a
				3373	document to a restricted area in the internal subset of the document (at the
				3374	beginning). Example:</p>
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3375	<pre>1 <?xml version="1.0"?>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3376	2 <!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3377	3 <!ENTITY xml "Extensible Markup Language">
				3378	4 ]>
				3379	5 <EXAMPLE>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3380	6 &xml;
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3381	7 </EXAMPLE></pre>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3382
				3383	<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3384	its name with '&' and following it by ';' without any spaces added. There
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3385	are 5 predefined entities in libxml allowing you to escape characters with
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3386	predefined meaning in some parts of the xml document content:
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3387	<strong>&lt;</strong> for the character '<', <strong>&gt;</strong>
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3388	for the character '>', <strong>&apos;</strong> for the character ''',
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3389	<strong>&quot;</strong> for the character '"', and
				3390	<strong>&amp;</strong> for the character '&'.</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3391
				3392	<p>One of the problems related to entities is that you may want the parser to
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	3393	substitute an entity's content so that you can see the replacement text in
				3394	your application. Or you may prefer to keep entity references as such in the
				3395	content to be able to save the document back without losing this usually
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3396	precious information (if the user went through the pain of explicitly
				3397	defining entities, he may have a a rather negative attitude if you blindly
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3398	substitute them as saving time). The <a
Daniel Veillard	9cb5ff4	2001-01-29 08:22:21 +0000	[diff] [blame]	3399	href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3400	function allows you to check and change the behaviour, which is to not
				3401	substitute entities by default.</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3402
				3403	<p>Here is the DOM tree built by libxml for the previous document in the
				3404	default case:</p>
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3405	<pre>/gnome/src/gnome-xml -> ./xmllint --debug test/ent1
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3406	DOCUMENT
				3407	version=1.0
				3408	ELEMENT EXAMPLE
				3409	TEXT
				3410	content=
				3411	ENTITY_REF
				3412	INTERNAL_GENERAL_ENTITY xml
				3413	content=Extensible Markup Language
				3414	TEXT
				3415	content=</pre>
				3416
				3417	<p>And here is the result when substituting entities:</p>
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3418	<pre>/gnome/src/gnome-xml -> ./tester --debug --noent test/ent1
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3419	DOCUMENT
				3420	version=1.0
				3421	ELEMENT EXAMPLE
				3422	TEXT
				3423	content= Extensible Markup Language</pre>
				3424
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3425	<p>So, entities or no entities? Basically, it depends on your use case. I
				3426	suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3427	entities in your XML document or data if you are not willing to handle the
				3428	entity references elements in the DOM tree.</p>
				3429
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3430	<p>Note that at save time libxml enforces the conversion of the predefined
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3431	entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3432	transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3433	reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3434	finding them in the input).</p>
				3435
Daniel Veillard	7b9c4b7	2000-08-25 16:26:50 +0000	[diff] [blame]	3436	<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3437	on top of the libxml SAX interface is difficult!!! If you plan to use
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3438	non-predefined entities in your documents, then the learning curve to handle
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3439	then using the SAX API may be long. If you plan to use complex documents, I
Daniel Veillard	7b9c4b7	2000-08-25 16:26:50 +0000	[diff] [blame]	3440	strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard	8c6d6af	2000-08-25 17:14:13 +0000	[diff] [blame]	3441	deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard	7b9c4b7	2000-08-25 16:26:50 +0000	[diff] [blame]	3442
Daniel Veillard	2f4dfc4	1999-09-24 14:03:48 +0000	[diff] [blame]	3443	<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3444
Daniel Veillard	ec30341	2000-03-24 13:41:54 +0000	[diff] [blame]	3445	<p>The libxml library implements <a
				3446	href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3447	recognizing namespace constructs in the input, and does namespace lookup
Daniel Veillard	ec30341	2000-03-24 13:41:54 +0000	[diff] [blame]	3448	automatically when building the DOM tree. A namespace declaration is
				3449	associated with an in-memory structure and all elements or attributes within
				3450	that namespace point to it. Hence testing the namespace is a simple and fast
				3451	equality operation at the user level.</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3452
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	3453	<p>I suggest that people using libxml use a namespace, and declare it in the
				3454	root element of their document as the default namespace. Then they don't need
				3455	to use the prefix in the content but we will have a basis for future semantic
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3456	refinement and merging of data from different sources. This doesn't increase
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	3457	the size of the XML output significantly, but significantly increases its
				3458	value in the long-term. Example:</p>
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3459	<pre><mydoc xmlns="http://mydoc.example.org/schemas/">
				3460	<elem1>...</elem1>
				3461	<elem2>...</elem2>
				3462	</mydoc></pre>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3463
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	3464	<p>The namespace value has to be an absolute URL, but the URL doesn't have to
				3465	point to any existing resource on the Web. It will bind all the element and
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	3466	attributes with that URL. I suggest to use an URL within a domain you
				3467	control, and that the URL should contain some kind of version information if
				3468	possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a
				3469	good namespace scheme.</p>
Daniel Veillard	ec30341	2000-03-24 13:41:54 +0000	[diff] [blame]	3470
				3471	<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard	88f00ae	2000-03-02 00:15:55 +0000	[diff] [blame]	3472	version-independent prefix is installed on the root element of your document,
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3473	and if the version information don't match something you know, warn the user
				3474	and be liberal in what you accept as the input. Also do not try to base
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3475	namespace checking on the prefix value. <foo:text> may be exactly the
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3476	same as <bar:text> in another document. What really matters is the URI
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3477	associated with the element or the attribute, not the prefix string (which is
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3478	just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillard	ec30341	2000-03-24 13:41:54 +0000	[diff] [blame]	3479	<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3480	prefix and its URI.</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3481
				3482	<p>@@Interfaces@@</p>
				3483
				3484	<p>@@Examples@@</p>
				3485
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3486	<p>Usually people object to using namespaces together with validity checking.
				3487	I will try to make sure that using namespaces won't break validity checking,
				3488	so even if you plan to use or currently are using validation I strongly
Daniel Veillard	f13e1ed	2000-03-06 07:41:49 +0000	[diff] [blame]	3489	suggest adding namespaces to your document. A default namespace scheme
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3490	<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3491	flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3492	from multiple DTDs will certainly break current validation schemes. I will
				3493	try to provide ways to do this, but this may not be portable or
				3494	standardized.</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3495
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3496	<h2><a name="Upgrading">Upgrading 1.x code</a></h2>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3497
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3498	<p>Incompatible changes:</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3499
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3500	<p>Version 2 of libxml is the first version introducing serious backward
				3501	incompatible changes. The main goals were:</p>
				3502	<ul>
				3503	<li>a general cleanup. A number of mistakes inherited from the very early
				3504	versions couldn't be changed due to compatibility constraints. Example
				3505	the "childs" element in the nodes.</li>
				3506	<li>Uniformization of the various nodes, at least for their header and link
				3507	parts (doc, parent, children, prev, next), the goal is a simpler
				3508	programming model and simplifying the task of the DOM implementors.</li>
				3509	<li>better conformances to the XML specification, for example version 1.x
				3510	had an heuristic to try to detect ignorable white spaces. As a result the
				3511	SAX event generated were ignorableWhitespace() while the spec requires
				3512	character() in that case. This also mean that a number of DOM node
				3513	containing blank text may populate the DOM tree which were not present
				3514	before.</li>
				3515	</ul>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3516
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3517	<h3>How to fix libxml-1.x code:</h3>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3518
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3519	<p>So client code of libxml designed to run with version 1.x may have to be
				3520	changed to compile against version 2.x of libxml. Here is a list of changes
				3521	that I have collected, they may not be sufficient, so in case you find other
				3522	change which are required, <a href="mailto:Daniel.Ïeillardw3.org">drop me a
				3523	mail</a>:</p>
				3524	<ol>
				3525	<li>The package name have changed from libxml to libxml2, the library name
				3526	is now -lxml2 . There is a new xml2-config script which should be used to
				3527	select the right parameters libxml2</li>
				3528	<li>Node <strong>childs</strong> field has been renamed
				3529	<strong>children</strong> so s/childs/children/g should be applied
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3530	(probability of having "childs" anywhere else is close to 0+</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3531	<li>The document don't have anymore a <strong>root</strong> element it has
				3532	been replaced by <strong>children</strong> and usually you will get a
				3533	list of element here. For example a Dtd element for the internal subset
				3534	and it's declaration may be found in that list, as well as processing
				3535	instructions or comments found before or after the document root element.
				3536	Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3537	a document. Alternatively if you are sure to not reference DTDs nor have
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3538	PIs or comments before or after the root element
				3539	s/->root/->children/g will probably do it.</li>
				3540	<li>The white space issue, this one is more complex, unless special case of
				3541	validating parsing, the line breaks and spaces usually used for indenting
				3542	and formatting the document content becomes significant. So they are
				3543	reported by SAX and if your using the DOM tree, corresponding nodes are
				3544	generated. Too approach can be taken:
				3545	<ol>
				3546	<li>lazy one, use the compatibility call
				3547	<strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are
				3548	relying on a special (and possibly broken) set of heuristics of
				3549	libxml to detect ignorable blanks. Don't complain if it breaks or
				3550	make your application not 100% clean w.r.t. to it's input.</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3551	<li>the Right Way: change you code to accept possibly insignificant
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3552	blanks characters, or have your tree populated with weird blank text
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3553	nodes. You can spot them using the commodity function
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3554	<strong>xmlIsBlankNode(node)</strong> returning 1 for such blank
				3555	nodes.</li>
				3556	</ol>
				3557	<p>Note also that with the new default the output functions don't add any
				3558	extra indentation when saving a tree in order to be able to round trip
				3559	(read and save) without inflating the document with extra formatting
				3560	chars.</p>
				3561	</li>
				3562	<li>The include path has changed to $prefix/libxml/ and the includes
				3563	themselves uses this new prefix in includes instructions... If you are
				3564	using (as expected) the
				3565	<pre>xml2-config --cflags</pre>
				3566	<p>output to generate you compile commands this will probably work out of
				3567	the box</p>
				3568	</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3569	<li>xmlDetectCharEncoding takes an extra argument indicating the length in
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3570	byte of the head of the document available for character detection.</li>
				3571	</ol>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3572
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3573	<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3574
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3575	<p>Two new version of libxml (1.8.11) and libxml2 (2.3.4) have been released
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3576	to allow smooth upgrade of existing libxml v1code while retaining
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3577	compatibility. They offers the following:</p>
				3578	<ol>
				3579	<li>similar include naming, one should use
				3580	<strong>#include<libxml/...></strong> in both cases.</li>
				3581	<li>similar identifiers defined via macros for the child and root fields:
				3582	respectively <strong>xmlChildrenNode</strong> and
				3583	<strong>xmlRootNode</strong></li>
				3584	<li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be
				3585	inserted once in the client code</li>
				3586	</ol>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3587
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3588	<p>So the roadmap to upgrade your existing libxml applications is the
				3589	following:</p>
				3590	<ol>
				3591	<li>install the libxml-1.8.8 (and libxml-devel-1.8.8) packages</li>
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3592	<li>find all occurrences where the xmlDoc <strong>root</strong> field is
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3593	used and change it to <strong>xmlRootNode</strong></li>
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	3594	<li>similarly find all occurrences where the xmlNode
				3595	<strong>childs</strong> field is used and change it to
				3596	<strong>xmlChildrenNode</strong></li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3597	<li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your
				3598	<strong>main()</strong> or in the library init entry point</li>
				3599	<li>Recompile, check compatibility, it should still work</li>
Daniel Veillard	c0801af	2002-05-28 16:28:42 +0000	[diff] [blame]	3600	<li>Change your configure script to look first for xml2-config and fall
				3601	back using xml-config . Use the --cflags and --libs output of the command
				3602	as the Include and Linking parameters needed to use libxml.</li>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3603	<li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and
				3604	libxml-devel-1.8.y can be kept simultaneously)</li>
				3605	<li>remove your config.cache, relaunch your configuration mechanism, and
				3606	recompile, if steps 2 and 3 were done right it should compile as-is</li>
				3607	<li>Test that your application is still running correctly, if not this may
				3608	be due to extra empty nodes due to formating spaces being kept in libxml2
				3609	contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your
				3610	code before calling the parser (next to
				3611	<strong>LIBXML_TEST_VERSION</strong> is a fine place).</li>
				3612	</ol>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3613
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3614	<p>Following those steps should work. It worked for some of my own code.</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3615
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3616	<p>Let me put some emphasis on the fact that there is far more changes from
				3617	libxml 1.x to 2.x than the ones you may have to patch for. The overall code
				3618	has been considerably cleaned up and the conformance to the XML specification
				3619	has been drastically improved too. Don't take those changes as an excuse to
				3620	not upgrade, it may cost a lot on the long term ...</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3621
Daniel Veillard	52dcab3	2001-10-30 12:51:17 +0000	[diff] [blame]	3622	<h2><a name="Thread">Thread safety</a></h2>
				3623
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3624	<p>Starting with 2.4.7, libxml makes provisions to ensure that concurrent
Daniel Veillard	52dcab3	2001-10-30 12:51:17 +0000	[diff] [blame]	3625	threads can safely work in parallel parsing different documents. There is
				3626	however a couple of things to do to ensure it:</p>
				3627	<ul>
				3628	<li>configure the library accordingly using the --with-threads options</li>
				3629	<li>call xmlInitParser() in the "main" thread before using any of the
				3630	libxml API (except possibly selecting a different memory allocator)</li>
				3631	</ul>
				3632
				3633	<p>Note that the thread safety cannot be ensured for multiple threads sharing
				3634	the same document, the locking must be done at the application level, libxml
				3635	exports a basic mutex and reentrant mutexes API in <libxml/threads.h>.
				3636	The parts of the library checked for thread safety are:</p>
				3637	<ul>
				3638	<li>concurrent loading</li>
				3639	<li>file access resolution</li>
				3640	<li>catalog access</li>
				3641	<li>catalog building</li>
				3642	<li>entities lookup/accesses</li>
				3643	<li>validation</li>
				3644	<li>global variables per-thread override</li>
				3645	<li>memory handling</li>
				3646	</ul>
				3647
				3648	<p>XPath is supposed to be thread safe now, but this wasn't tested
				3649	seriously.</p>
				3650
Daniel Veillard	3500838	1999-10-25 13:15:52 +0000	[diff] [blame]	3651	<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3652
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3653	<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document
				3654	Object Model</em>; this is an API for accessing XML or HTML structured
				3655	documents. Native support for DOM in Gnome is on the way (module gnome-dom),
				3656	and will be based on gnome-xml. This will be a far cleaner interface to
				3657	manipulate XML files within Gnome since it won't expose the internal
				3658	structure.</p>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3659
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3660	<p>The current DOM implementation on top of libxml is the <a
Daniel Veillard	a47fb3d	2001-03-25 17:23:49 +0000	[diff] [blame]	3661	href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this
				3662	is a full DOM interface, thanks to Paolo Casarini, check the <a
				3663	href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more
				3664	informations.</p>
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3665
Daniel Veillard	3500838	1999-10-25 13:15:52 +0000	[diff] [blame]	3666	<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3667
				3668	<p>Here is a real size example, where the actual content of the application
				3669	data is not kept in the DOM tree but uses internal structures. It is based on
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3670	a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3671	storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
				3672	base</a>:</p>
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3673	<pre><?xml version="1.0"?>
				3674	<gjob:Helping xmlns:gjob="http://www.gnome.org/some-location">
				3675	<gjob:Jobs>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3676
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3677	<gjob:Job>
				3678	<gjob:Project ID="3"/>
				3679	<gjob:Application>GBackup</gjob:Application>
				3680	<gjob:Category>Development</gjob:Category>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3681
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3682	<gjob:Update>
				3683	<gjob:Status>Open</gjob:Status>
				3684	<gjob:Modified>Mon, 07 Jun 1999 20:27:45 -0400 MET DST</gjob:Modified>
				3685	<gjob:Salary>USD 0.00</gjob:Salary>
				3686	</gjob:Update>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3687
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3688	<gjob:Developers>
				3689	<gjob:Developer>
				3690	</gjob:Developer>
				3691	</gjob:Developers>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3692
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3693	<gjob:Contact>
				3694	<gjob:Person>Nathan Clemons</gjob:Person>
				3695	<gjob:Email>nathan@windsofstorm.net</gjob:Email>
				3696	<gjob:Company>
				3697	</gjob:Company>
				3698	<gjob:Organisation>
				3699	</gjob:Organisation>
				3700	<gjob:Webpage>
				3701	</gjob:Webpage>
				3702	<gjob:Snailmail>
				3703	</gjob:Snailmail>
				3704	<gjob:Phone>
				3705	</gjob:Phone>
				3706	</gjob:Contact>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3707
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3708	<gjob:Requirements>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3709	The program should be released as free software, under the GPL.
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3710	</gjob:Requirements>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3711
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3712	<gjob:Skills>
				3713	</gjob:Skills>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3714
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3715	<gjob:Details>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3716	A GNOME based system that will allow a superuser to configure
				3717	compressed and uncompressed files and/or file systems to be backed
				3718	up with a supported media in the system. This should be able to
				3719	perform via find commands generating a list of files that are passed
				3720	to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
				3721	or via operations performed on the filesystem itself. Email
				3722	notification and GUI status display very important.
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3723	</gjob:Details>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3724
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3725	</gjob:Job>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3726
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3727	</gjob:Jobs>
				3728	</gjob:Helping></pre>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3729
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3730	<p>While loading the XML file into an internal DOM tree is a matter of
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3731	calling only a couple of functions, browsing the tree to gather the data and
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3732	generate the internal structures is harder, and more error prone.</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3733
				3734	<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3735	structure. For example, the ordering of the attributes is not significant,
				3736	the XML specification is clear about it. It's also usually a good idea not to
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	3737	depend on the order of the children of a given node, unless it really makes
				3738	things harder. Here is some code to parse the information for a person:</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3739	<pre>/*
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3740	* A person record
				3741	*/
				3742	typedef struct person {
				3743	char *name;
				3744	char *email;
				3745	char *company;
				3746	char *organisation;
				3747	char *smail;
				3748	char *webPage;
				3749	char *phone;
				3750	} person, *personPtr;
				3751
				3752	/*
				3753	* And the code needed to parse it
				3754	*/
				3755	personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
				3756	personPtr ret = NULL;
				3757
				3758	DEBUG("parsePerson\n");
				3759	/*
				3760	* allocate the struct
				3761	*/
				3762	ret = (personPtr) malloc(sizeof(person));
				3763	if (ret == NULL) {
				3764	fprintf(stderr,"out of memory\n");
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3765	return(NULL);
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3766	}
				3767	memset(ret, 0, sizeof(person));
				3768
				3769	/* We don't care what the top level element name is */
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3770	cur = cur->xmlChildrenNode;
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3771	while (cur != NULL) {
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3772	if ((!strcmp(cur->name, "Person")) && (cur->ns == ns))
				3773	ret->name = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1);
				3774	if ((!strcmp(cur->name, "Email")) && (cur->ns == ns))
				3775	ret->email = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1);
				3776	cur = cur->next;
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3777	}
				3778
				3779	return(ret);
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3780	}</pre>
				3781
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3782	<p>Here are a couple of things to notice:</p>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3783	<ul>
Daniel Veillard	91e9d58	2001-02-26 07:31:12 +0000	[diff] [blame]	3784	<li>Usually a recursive parsing style is the more convenient one: XML data
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3785	is by nature subject to repetitive constructs and usually exhibits highly
				3786	structured patterns.</li>
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3787	<li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>,
				3788	i.e. the pointer to the global XML document and the namespace reserved to
				3789	the application. Document wide information are needed for example to
				3790	decode entities and it's a good coding practice to define a namespace for
				3791	your application set of data and test that the element and attributes
				3792	you're analyzing actually pertains to your application space. This is
				3793	done by a simple equality test (cur->ns == ns).</li>
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	3794	<li>To retrieve text and attributes value, you can use the function
				3795	<em>xmlNodeListGetString</em> to gather all the text and entity reference
				3796	nodes generated by the DOM output and produce an single text string.</li>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3797	</ul>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3798
				3799	<p>Here is another piece of code used to parse another level of the
				3800	structure:</p>
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3801	<pre>#include <libxml/tree.h>
Daniel Veillard	361d845	2000-04-03 19:48:13 +0000	[diff] [blame]	3802	/*
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3803	* a Description for a Job
				3804	*/
				3805	typedef struct job {
				3806	char *projectID;
				3807	char *application;
				3808	char *category;
				3809	personPtr contact;
				3810	int nbDevelopers;
				3811	personPtr developers[100]; /* using dynamic alloc is left as an exercise */
				3812	} job, *jobPtr;
				3813
				3814	/*
				3815	* And the code needed to parse it
				3816	*/
				3817	jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
				3818	jobPtr ret = NULL;
				3819
				3820	DEBUG("parseJob\n");
				3821	/*
				3822	* allocate the struct
				3823	*/
				3824	ret = (jobPtr) malloc(sizeof(job));
				3825	if (ret == NULL) {
				3826	fprintf(stderr,"out of memory\n");
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3827	return(NULL);
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3828	}
				3829	memset(ret, 0, sizeof(job));
				3830
				3831	/* We don't care what the top level element name is */
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3832	cur = cur->xmlChildrenNode;
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3833	while (cur != NULL) {
				3834
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3835	if ((!strcmp(cur->name, "Project")) && (cur->ns == ns)) {
				3836	ret->projectID = xmlGetProp(cur, "ID");
				3837	if (ret->projectID == NULL) {
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3838	fprintf(stderr, "Project has no ID\n");
				3839	}
				3840	}
Daniel Veillard	60979bd	2000-07-10 12:17:33 +0000	[diff] [blame]	3841	if ((!strcmp(cur->name, "Application")) && (cur->ns == ns))
				3842	ret->application = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1);
				3843	if ((!strcmp(cur->name, "Category")) && (cur->ns == ns))
				3844	ret->category = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1);
				3845	if ((!strcmp(cur->name, "Contact")) && (cur->ns == ns))
				3846	ret->contact = parsePerson(doc, ns, cur);
				3847	cur = cur->next;
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3848	}
				3849
				3850	return(ret);
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3851	}</pre>
Daniel Veillard	14fff06	1999-06-22 21:49:07 +0000	[diff] [blame]	3852
Daniel Veillard	ec70e91	2001-02-26 20:10:45 +0000	[diff] [blame]	3853	<p>Once you are used to it, writing this kind of code is quite simple, but
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3854	boring. Ultimately, it could be possible to write stubbers taking either C
Daniel Veillard	3d6ae1c	2001-08-15 13:12:39 +0000	[diff] [blame]	3855	data structure definitions, a set of XML examples or an XML DTD and produce
				3856	the code needed to import and export the content between C data and XML
				3857	storage. This is left as an exercise to the reader :-)</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3858
Daniel Veillard	6f0adb5	2000-07-03 11:41:26 +0000	[diff] [blame]	3859	<p>Feel free to use <a href="example/gjobread.c">the code for the full C
				3860	parsing example</a> as a template, it is also available with Makefile in the
				3861	Gnome CVS base under gnome-xml/example</p>
Daniel Veillard	b05deb7	1999-08-10 19:04:08 +0000	[diff] [blame]	3862
Daniel Veillard	c310d56	2000-06-23 18:32:15 +0000	[diff] [blame]	3863	<h2><a name="Contributi">Contributions</a></h2>
				3864	<ul>
Daniel Veillard	b8cfbd1	2001-10-25 10:53:28 +0000	[diff] [blame]	3865	<li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of
				3866	patches, Gary Pennington worked on the validation API, threading support
				3867	and Solaris port.</li>
				3868	<li>John Fleck helps maintaining the documentation and man pages.</li>
Daniel Veillard	b2fb8ed	2002-04-01 09:33:12 +0000	[diff] [blame]	3869	<li><a href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now
				3870	the maintainer of the Windows port, <a
Daniel Veillard	9518953	2001-07-26 18:30:26 +0000	[diff] [blame]	3871	href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
				3872	provides binaries</a></li>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	3873	<li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides
				3874	<a href="http://garypennington.net/libxml2/">Solaris binaries</a></li>
Daniel Veillard	e356c28	2001-03-10 12:32:04 +0000	[diff] [blame]	3875	<li><a
				3876	href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard	63d8314	2002-05-20 06:51:05 +0000	[diff] [blame]	3877	Sergeant</a> developed <a
				3878	href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	3879	libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
				3880	application server</a></li>
				3881	<li><a href="mailto:fnatter@gmx.net">Felix Natter</a> and <a
				3882	href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a
Daniel Veillard	ca98976	2001-06-23 17:39:29 +0000	[diff] [blame]	3883	href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions
Daniel Veillard	3f6f7f6	2000-06-30 17:58:25 +0000	[diff] [blame]	3884	documentation</li>
Daniel Veillard	af43f63	2002-03-08 15:05:20 +0000	[diff] [blame]	3885	<li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
				3886	href="http://xmlsoft.org/messages/0488.html">man pages</a></li>
Daniel Veillard	5168dbf	2001-07-07 00:18:23 +0000	[diff] [blame]	3887	<li>there is a module for <a
				3888	href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support
				3889	in OpenNSD/AOLServer</a></li>
Daniel Veillard	2d347fa	2002-03-17 10:34:11 +0000	[diff] [blame]	3890	<li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provided the
				3891	first version of libxml/libxslt <a
				3892	href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
Daniel Veillard	1aadc44	2001-11-28 13:10:32 +0000	[diff] [blame]	3893	<li>Petr Kozelka provides <a
				3894	href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
				3895	libxml2</a> with Kylix and Delphi and other Pascal compilers</li>
Daniel Veillard	2d347fa	2002-03-17 10:34:11 +0000	[diff] [blame]	3896	<li><a href="mailto:aleksey@aleksey.com">Aleksey Sanin</a> implemented the
				3897	<a href="http://www.w3.org/Signature/">XML Canonicalization and XML
				3898	Digital Signature</a> <a
				3899	href="http://www.aleksey.com/xmlsec/">implementations for libxml2</a></li>
Daniel Veillard	c310d56	2000-06-23 18:32:15 +0000	[diff] [blame]	3900	</ul>
				3901
Daniel Veillard	c8eab3a	1999-09-04 18:27:23 +0000	[diff] [blame]	3902	<p></p>
Daniel Veillard	ccb0963	1998-10-27 06:21:04 +0000	[diff] [blame]	3903	</body>
				3904	</html>