Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 2 | "http://www.w3.org/TR/REC-html40/loose.dtd"> |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 3 | <html> |
| 4 | <head> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 5 | <title>The XML library for Gnome</title> |
Daniel Veillard | 365e13b | 2000-07-02 07:56:37 +0000 | [diff] [blame^] | 6 | <meta name="GENERATOR" content="amaya V2.1"> |
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 | ec30341 | 2000-03-24 13:41:54 +0000 | [diff] [blame] | 11 | <p><a href="http://www.gnome.org/"><img src="smallfootonly.gif" alt="Gnome |
| 12 | Logo"></a><a href="http://www.w3.org/Status"><img src="w3c.png" alt="W3C |
| 13 | Logo"></a></p> |
| 14 | |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 15 | <h1 align="center">The XML library for Gnome</h1> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 16 | |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 17 | <h2 style="text-align: center">libxml, a.k.a. gnome-xml</h2> |
| 18 | |
| 19 | <p></p> |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 20 | <ul> |
| 21 | <li><a href="#Introducti">Introduction</a></li> |
| 22 | <li><a href="#Documentat">Documentation</a></li> |
Daniel Veillard | 10a2c65 | 1999-12-12 13:03:50 +0000 | [diff] [blame] | 23 | <li><a href="#Downloads">Downloads</a></li> |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 24 | <li><a href="#News">News</a></li> |
| 25 | <li><a href="#XML">XML</a></li> |
| 26 | <li><a href="#tree">The tree output</a></li> |
| 27 | <li><a href="#interface">The SAX interface</a></li> |
| 28 | <li><a href="#library">The XML library interfaces</a> |
| 29 | <ul> |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 30 | <li><a href="#Invoking">Invoking the parser: the pull way</a></li> |
| 31 | <li><a href="#Invoking">Invoking the parser: the push way</a></li> |
| 32 | <li><a href="#Invoking2">Invoking the parser: the SAX interface</a></li> |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 33 | <li><a href="#Building">Building a tree from scratch</a></li> |
| 34 | <li><a href="#Traversing">Traversing the tree</a></li> |
| 35 | <li><a href="#Modifying">Modifying the tree</a></li> |
| 36 | <li><a href="#Saving">Saving the tree</a></li> |
| 37 | <li><a href="#Compressio">Compression</a></li> |
| 38 | </ul> |
| 39 | </li> |
| 40 | <li><a href="#Entities">Entities or no entities</a></li> |
| 41 | <li><a href="#Namespaces">Namespaces</a></li> |
| 42 | <li><a href="#Validation">Validation</a></li> |
| 43 | <li><a href="#Principles">DOM principles</a></li> |
| 44 | <li><a href="#real">A real example</a></li> |
Daniel Veillard | c310d56 | 2000-06-23 18:32:15 +0000 | [diff] [blame] | 45 | <li><a href="#Contributi">Contribution</a></li> |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 46 | </ul> |
| 47 | |
| 48 | <h2><a name="Introducti">Introduction</a></h2> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 49 | |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 50 | <p>This document describes libxml, the <a |
| 51 | href="http://www.w3.org/XML/">XML</a> library provided in the <a |
| 52 | href="http://www.gnome.org/">Gnome</a> framework. XML is a standard for |
| 53 | building tag-based structured documents/data.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 54 | |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 55 | <p>Here are some key points about libxml:</p> |
| 56 | <ul> |
| 57 | <li>The internal document repesentation is as close as possible to the <a |
| 58 | href="http://www.w3.org/DOM/">DOM</a> interfaces.</li> |
| 59 | <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] | 60 | like interface</a>; the interface is designed to be compatible with <a |
| 61 | href="http://www.jclark.com/xml/expat.html">Expat</a>.</li> |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 62 | <li>Libxml now includes a nearly complete <a |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 63 | href="http://www.w3.org/TR/xpath">XPath</a> implementation.</li> |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 64 | <li>Libxml exports Push and Pull type parser interfaces for both XML and |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 65 | HTML.</li> |
Daniel Veillard | ec30341 | 2000-03-24 13:41:54 +0000 | [diff] [blame] | 66 | <li>This library is released both under the <a |
| 67 | href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C |
| 68 | IPR</a> and the GNU LGPL. Use either at your convenience, basically this |
| 69 | should make everybody happy, if not, drop me a mail.</li> |
Daniel Veillard | c310d56 | 2000-06-23 18:32:15 +0000 | [diff] [blame] | 70 | <li>There is <a href="upgrade.html">a first set of instructions</a> |
Daniel Veillard | edfb29b | 2000-03-14 19:59:05 +0000 | [diff] [blame] | 71 | concerning upgrade from libxml-1.x to libxml-2.x</li> |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 72 | </ul> |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 73 | |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 74 | <h2><a name="Documentat">Documentation</a></h2> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 75 | |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 76 | <p>There are some on-line resources about using libxml:</p> |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 77 | <ol> |
Daniel Veillard | 365e13b | 2000-07-02 07:56:37 +0000 | [diff] [blame^] | 78 | <li>Check the <a href="FAQ.html">FAQ</a></li> |
| 79 | <li>Check the <a href="http://xmlsoft.org/libxml.html">extensive |
| 80 | documentation</a> automatically extracted from code comments.</li> |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 81 | <li>This page provides a global overview and <a href="#real">some |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 82 | examples</a> on how to use libxml.</li> |
| 83 | <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a |
| 84 | href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice |
| 85 | documentation</a> explaining how to use the libxml SAX interface.</li> |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 86 | <li>George Lebl wrote <a |
| 87 | href="http://www-4.ibm.com/software/developer/library/gnome3/">an article |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 88 | for IBM developerWorks</a> about using libxml.</li> |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 89 | <li>It is also a good idea to check to <a href="mailto:raph@levien.com">Raph |
| 90 | Levien</a> <a href="http://levien.com/gnome/">web site</a> since he is |
| 91 | building the <a href="http://levien.com/gnome/gdome.html">DOM interface |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 92 | gdome</a> on top of libxml result tree and an implementation of <a |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 93 | href="http://www.w3.org/Graphics/SVG/">SVG</a> called <a |
| 94 | href="http://www.levien.com/svg/">gill</a>. Check his <a |
| 95 | href="http://www.levien.com/gnome/domination.html">DOMination |
| 96 | paper</a>.</li> |
Daniel Veillard | ec30341 | 2000-03-24 13:41:54 +0000 | [diff] [blame] | 97 | <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO |
| 98 | file</a></li> |
| 99 | <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are |
| 100 | starting a new project using libxml you should really use the 2.x |
| 101 | version.</li> |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 102 | <li>And don't forget to look at the <a href="/messages/">mailing-list |
Daniel Veillard | c310d56 | 2000-06-23 18:32:15 +0000 | [diff] [blame] | 103 | archive</a>.</li> |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 104 | </ol> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 105 | |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 106 | <h3>Reporting bugs and getting help</h3> |
Daniel Veillard | 4c3a203 | 1999-11-19 17:46:26 +0000 | [diff] [blame] | 107 | |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 108 | <p>Well, bugs or missing features are always possible, and I will make a point |
| 109 | of fixing them in a timely fashion. The best way to report a bug is to <a |
Daniel Veillard | 4c3a203 | 1999-11-19 17:46:26 +0000 | [diff] [blame] | 110 | href="http://bugs.gnome.org/db/pa/lgnome-xml.html">use the Gnome bug tracking |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 111 | database</a>. I look at reports there regularly and it's good to have a |
Daniel Veillard | 4c3a203 | 1999-11-19 17:46:26 +0000 | [diff] [blame] | 112 | reminder when a bug is still open. Check the <a |
| 113 | href="http://bugs.gnome.org/Reporting.html">instructions on reporting bugs</a> |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 114 | and be sure to specify that the bug is for the package gnome-xml.</p> |
Daniel Veillard | 4c3a203 | 1999-11-19 17:46:26 +0000 | [diff] [blame] | 115 | |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 116 | <p>There is also a mailing-list <a |
| 117 | href="mailto:xml@rufus.w3.org">xml@rufus.w3.org</a> for libxml, with an <a |
| 118 | href="http://xmlsoft.org/messages">on-line archive</a>. To subscribe to this |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 119 | majordomo based list, send a mail message to <a |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 120 | href="mailto:majordomo@rufus.w3.org">majordomo@rufus.w3.org</a> with |
| 121 | "subscribe xml" in the <strong>content</strong> of the message.</p> |
| 122 | |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 123 | <p>Alternatively, you can just send the bug to the <a |
Daniel Veillard | 10a2c65 | 1999-12-12 13:03:50 +0000 | [diff] [blame] | 124 | href="mailto:xml@rufus.w3.org">xml@rufus.w3.org</a> list.</p> |
Daniel Veillard | 4c3a203 | 1999-11-19 17:46:26 +0000 | [diff] [blame] | 125 | |
Daniel Veillard | ec30341 | 2000-03-24 13:41:54 +0000 | [diff] [blame] | 126 | <p>Of course, bugs reports with a suggested patch for fixing them will |
| 127 | probably be processed faster.</p> |
| 128 | |
| 129 | <p>If you're looking for help, a quick look at <a |
| 130 | href="http://xmlsoft.org/messages/#407">the list archive</a> may actually |
| 131 | provide the answer, I usually send source samples when answering libxml usage |
| 132 | questions. The <a href="http://xmlsoft.org/book1.html">auto-generated |
| 133 | documentantion</a> is not as polished as I would like (i need to learn more |
| 134 | about Docbook), but it's a good starting point.</p> |
| 135 | |
Daniel Veillard | 10a2c65 | 1999-12-12 13:03:50 +0000 | [diff] [blame] | 136 | <h2><a name="Downloads">Downloads</a></h2> |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 137 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 138 | <p>The latest versions of libxml can be found on <a |
Daniel Veillard | 6c8b117 | 2000-03-01 00:40:41 +0000 | [diff] [blame] | 139 | href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or on the <a |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 140 | href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either |
Daniel Veillard | 10a2c65 | 1999-12-12 13:03:50 +0000 | [diff] [blame] | 141 | as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source |
Daniel Veillard | c310d56 | 2000-06-23 18:32:15 +0000 | [diff] [blame] | 142 | archive</a> or <a href="ftp://ftp.gnome.org/pub/GNOME/contrib/rpms/">RPM |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 143 | packages</a>. (NOTE that you need both the <a |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 144 | href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a |
| 145 | href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a> |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 146 | packages installed to compile applications using libxml.)</p> |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 147 | |
Daniel Veillard | 6c8b117 | 2000-03-01 00:40:41 +0000 | [diff] [blame] | 148 | <p><a name="Snapshot">Snapshot:</a></p> |
| 149 | <ul> |
| 150 | <li>Code from the W3C cvs base libxml <a |
| 151 | href="ftp://rpmfind.net/pub/libxml/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li> |
| 152 | <li>Docs, content of the web site, the list archive included <a |
| 153 | href="ftp://rpmfind.net/pub/libxml/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li> |
| 154 | </ul> |
| 155 | |
| 156 | <p><a name="Contribs">Contribs:</a></p> |
| 157 | |
| 158 | <p>I do accept external contributions, especially if compiling on another |
| 159 | platform, get in touch with me to upload the package. I will keep them in the |
| 160 | <a href="ftp://rpmfind.net/pub/libxml/contribs/">contrib directory</a></p> |
| 161 | |
Daniel Veillard | c310d56 | 2000-06-23 18:32:15 +0000 | [diff] [blame] | 162 | <p>Libxml is also available from 2 CVS bases:</p> |
Daniel Veillard | 10a2c65 | 1999-12-12 13:03:50 +0000 | [diff] [blame] | 163 | <ul> |
| 164 | <li><p>The <a href="http://dev.w3.org/cvsweb/XML/">W3C CVS base</a>, |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 165 | available read-only using the CVS pserver authentification (I tend to use |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 166 | this base for my own development, so it's updated more regularly, but the |
| 167 | content may not be as stable):</p> |
Daniel Veillard | 10a2c65 | 1999-12-12 13:03:50 +0000 | [diff] [blame] | 168 | <pre>CVSROOT=:pserver:anonymous@dev.w3.org:/sources/public |
Daniel Veillard | 365e13b | 2000-07-02 07:56:37 +0000 | [diff] [blame^] | 169 | password: anonymous |
| 170 | module: XML</pre> |
Daniel Veillard | 10a2c65 | 1999-12-12 13:03:50 +0000 | [diff] [blame] | 171 | </li> |
| 172 | <li><p>The <a |
| 173 | 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] | 174 | CVS base</a>. Check the <a |
| 175 | href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a> page; |
| 176 | the CVS module is <b>gnome-xml</b>.</p> |
Daniel Veillard | 10a2c65 | 1999-12-12 13:03:50 +0000 | [diff] [blame] | 177 | </li> |
| 178 | </ul> |
| 179 | |
| 180 | <h2><a name="News">News</a></h2> |
| 181 | |
Daniel Veillard | 944b5ff | 1999-12-15 19:08:24 +0000 | [diff] [blame] | 182 | <h3>CVS only : check the <a |
| 183 | href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file |
| 184 | for really accurate description</h3> |
Daniel Veillard | 4c3a203 | 1999-11-19 17:46:26 +0000 | [diff] [blame] | 185 | <ul> |
Daniel Veillard | 10a2c65 | 1999-12-12 13:03:50 +0000 | [diff] [blame] | 186 | <li>working on HTML and XML links recognition layers, get in touch with me |
Daniel Veillard | 944b5ff | 1999-12-15 19:08:24 +0000 | [diff] [blame] | 187 | if you want to test those.</li> |
Daniel Veillard | 361d845 | 2000-04-03 19:48:13 +0000 | [diff] [blame] | 188 | </ul> |
| 189 | |
Daniel Veillard | 3f6f7f6 | 2000-06-30 17:58:25 +0000 | [diff] [blame] | 190 | <h3>2.1.0 and 1.8.8: June 29 2000</h3> |
| 191 | <ul> |
| 192 | <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to |
| 193 | <a href="upgrade.html">new instructions</a>. It fixes a nasty problem |
| 194 | about &#38; charref parsing</li> |
| 195 | <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it |
| 196 | also contains numerous fixes and enhancements: |
| 197 | <ul> |
| 198 | <li>added xmlStopParser() to stop parsing</li> |
| 199 | <li>improved a lot parsing speed when there is large CDATA blocs</li> |
| 200 | <li>includes XPath patches provided by Picdar Technology</li> |
| 201 | <li>tried to fix as much as possible DtD validation and namespace |
| 202 | related problems</li> |
| 203 | <li>output to a given encoding has been added/tested</li> |
| 204 | <li>lot of various fixes</li> |
| 205 | </ul> |
| 206 | </li> |
| 207 | </ul> |
| 208 | |
Daniel Veillard | e0aed30 | 2000-04-16 08:52:20 +0000 | [diff] [blame] | 209 | <h3>2.0.0: Apr 12 2000</h3> |
Daniel Veillard | 361d845 | 2000-04-03 19:48:13 +0000 | [diff] [blame] | 210 | <ul> |
| 211 | <li>First public release of libxml2. If you are using libxml, it's a good |
Daniel Veillard | e0aed30 | 2000-04-16 08:52:20 +0000 | [diff] [blame] | 212 | idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally |
| 213 | scheduled for Apr 3 the relase occured only on Apr 12 due to massive |
| 214 | workload.</li> |
Daniel Veillard | 361d845 | 2000-04-03 19:48:13 +0000 | [diff] [blame] | 215 | <li>The include are now located under $prefix/include/libxml (instead of |
Daniel Veillard | e0aed30 | 2000-04-16 08:52:20 +0000 | [diff] [blame] | 216 | $prefix/include/gnome-xml), they also are referenced by |
Daniel Veillard | 361d845 | 2000-04-03 19:48:13 +0000 | [diff] [blame] | 217 | <pre>#include <libxml/xxx.h></pre> |
Daniel Veillard | e0aed30 | 2000-04-16 08:52:20 +0000 | [diff] [blame] | 218 | <p>instead of</p> |
Daniel Veillard | 361d845 | 2000-04-03 19:48:13 +0000 | [diff] [blame] | 219 | <pre>#include "xxx.h"</pre> |
| 220 | </li> |
Daniel Veillard | 8f62198 | 2000-03-20 13:07:15 +0000 | [diff] [blame] | 221 | <li>a new URI module for parsing URIs and following strictly RFC 2396</li> |
| 222 | <li>the memory allocation routines used by libxml can now be overloaded |
| 223 | dynamically by using xmlMemSetup()</li> |
Daniel Veillard | 361d845 | 2000-04-03 19:48:13 +0000 | [diff] [blame] | 224 | <li>The previously CVS only tool tester has been renamed |
| 225 | <strong>xmllint</strong> and is now installed as part of the libxml2 |
| 226 | package</li> |
Daniel Veillard | e0aed30 | 2000-04-16 08:52:20 +0000 | [diff] [blame] | 227 | <li>The I/O interface has been revamped. There is now ways to plug in |
| 228 | specific I/O modules, either at the URI scheme detection level using |
| 229 | xmlRegisterInputCallbacks() or by passing I/O functions when creating a |
| 230 | parser context using xmlCreateIOParserCtxt()</li> |
| 231 | <li>there is a C preprocessor macro LIBXML_VERSION providing the version |
| 232 | number of the libxml module in use</li> |
| 233 | <li>a number of optional features of libxml can now be excluded at configure |
| 234 | time (FTP/HTTP/HTML/XPath/Debug)</li> |
Daniel Veillard | edfb29b | 2000-03-14 19:59:05 +0000 | [diff] [blame] | 235 | </ul> |
| 236 | |
| 237 | <h3>2.0.0beta: Mar 14 2000</h3> |
| 238 | <ul> |
| 239 | <li>This is a first Beta release of libxml version 2</li> |
| 240 | <li>It's available only from<a href="ftp://rpmfind.net/pub/libxml/"> |
| 241 | rpmfind.net FTP</a>, it's packaged as libxml2-2.0.0beta and available as |
| 242 | tar and RPMs</li> |
| 243 | <li>This version is now the head in the Gnome CVS base, the old one is |
| 244 | available under the tag LIB_XML_1_X</li> |
| 245 | <li>This includes a very large set of changes. Froma programmatic point of |
| 246 | view applications should not have to be modified too much, check the <a |
| 247 | href="upgrade.html">upgrade page</a></li> |
| 248 | <li>Some interfaces may changes (especially a bit about encoding).</li> |
| 249 | <li>the updates includes: |
Daniel Veillard | 6c8b117 | 2000-03-01 00:40:41 +0000 | [diff] [blame] | 250 | <ul> |
Daniel Veillard | edfb29b | 2000-03-14 19:59:05 +0000 | [diff] [blame] | 251 | <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly |
| 252 | handled now</li> |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 253 | <li>Better handling of entities, especially well formedness checking and |
| 254 | proper PEref extensions in external subsets</li> |
Daniel Veillard | 6c8b117 | 2000-03-01 00:40:41 +0000 | [diff] [blame] | 255 | <li>DTD conditional sections</li> |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 256 | <li>Validation now correcly handle entities content</li> |
Daniel Veillard | 6c8b117 | 2000-03-01 00:40:41 +0000 | [diff] [blame] | 257 | <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change |
| 258 | structures to accomodate DOM</a></li> |
Daniel Veillard | 6c8b117 | 2000-03-01 00:40:41 +0000 | [diff] [blame] | 259 | </ul> |
| 260 | </li> |
Daniel Veillard | edfb29b | 2000-03-14 19:59:05 +0000 | [diff] [blame] | 261 | <li>Serious progress were made toward compliance, <a |
| 262 | href="conf/result.html">here are the result of the test</a> against the |
| 263 | OASIS testsuite (except the japanese tests since I don't support that |
| 264 | encoding yet). This URL is rebuilt every couple of hours using the CVS |
| 265 | head version.</li> |
Daniel Veillard | e41f2b7 | 2000-01-30 20:00:07 +0000 | [diff] [blame] | 266 | </ul> |
| 267 | |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 268 | <h3>1.8.7: Mar 6 2000</h3> |
| 269 | <ul> |
| 270 | <li>This is a bug fix release:</li> |
| 271 | <li>It is possible to disable the ignorable blanks heuristic used by |
| 272 | libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note |
| 273 | that for adherence to XML spec, this behaviour will be disabled by default |
| 274 | in 2.x . The same function will allow to keep compatibility for old |
| 275 | code.</li> |
| 276 | <li>Blanks in <a> </a> constructs are not ignored anymore, avoiding |
| 277 | heuristic is really the Right Way :-\</li> |
| 278 | <li>The unchecked use of snprintf which was breaking libxml-1.8.6 |
| 279 | compilation on some platforms has been fixed</li> |
| 280 | <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing |
| 281 | URIs</li> |
| 282 | </ul> |
| 283 | |
Daniel Veillard | e41f2b7 | 2000-01-30 20:00:07 +0000 | [diff] [blame] | 284 | <h3>1.8.6: Jan 31 2000</h3> |
| 285 | <ul> |
| 286 | <li>added a nanoFTP transport module, debugged until the new version of <a |
| 287 | href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use |
| 288 | it without troubles</li> |
Daniel Veillard | da07c34 | 2000-01-25 18:31:22 +0000 | [diff] [blame] | 289 | </ul> |
| 290 | |
| 291 | <h3>1.8.5: Jan 21 2000</h3> |
| 292 | <ul> |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 293 | <li>adding APIs to parse a well balanced chunk of XML (production <a |
| 294 | href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the XML |
| 295 | spec)</li> |
Daniel Veillard | 461a66c | 2000-01-18 18:01:01 +0000 | [diff] [blame] | 296 | <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li> |
| 297 | <li>Jody Goldberg <jgoldberg@home.com> provided another patch trying to |
| 298 | solve the zlib checks problems</li> |
| 299 | <li>The current state in gnome CVS base is expected to ship as 1.8.5 with |
| 300 | gnumeric soon</li> |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 301 | </ul> |
| 302 | |
| 303 | <h3>1.8.4: Jan 13 2000</h3> |
| 304 | <ul> |
| 305 | <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li> |
| 306 | <li>all exit() call should have been removed from libxml</li> |
| 307 | <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li> |
| 308 | <li>added newDocFragment()</li> |
Daniel Veillard | f84f71f | 2000-01-05 19:54:23 +0000 | [diff] [blame] | 309 | </ul> |
| 310 | |
| 311 | <h3>1.8.3: Jan 5 2000</h3> |
| 312 | <ul> |
| 313 | <li>a Push interface for the XML and HTML parsers</li> |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 314 | <li>a shell-like interface to the document tree (try tester --shell :-)</li> |
Daniel Veillard | dbfd641 | 1999-12-28 16:35:14 +0000 | [diff] [blame] | 315 | <li>lots of bug fixes and improvement added over XMas hollidays</li> |
Daniel Veillard | 437b87b | 2000-01-03 17:30:46 +0000 | [diff] [blame] | 316 | <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] | 317 | <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li> |
| 318 | <li>Fixed bugs in xmlNewNs()</li> |
Daniel Veillard | 437b87b | 2000-01-03 17:30:46 +0000 | [diff] [blame] | 319 | <li>External entity loading code has been revamped, now it uses |
Daniel Veillard | f84f71f | 2000-01-05 19:54:23 +0000 | [diff] [blame] | 320 | xmlLoadExternalEntity(), some fix on entities processing were added</li> |
Daniel Veillard | 437b87b | 2000-01-03 17:30:46 +0000 | [diff] [blame] | 321 | <li>cleaned up WIN32 includes of socket stuff</li> |
Daniel Veillard | 5cb5ab8 | 1999-12-21 15:35:29 +0000 | [diff] [blame] | 322 | </ul> |
| 323 | |
| 324 | <h3>1.8.2: Dec 21 1999</h3> |
| 325 | <ul> |
Daniel Veillard | b24054a | 1999-12-18 15:32:46 +0000 | [diff] [blame] | 326 | <li>I got another problem with includes and C++, I hope this issue is fixed |
| 327 | for good this time</li> |
Daniel Veillard | 5cb5ab8 | 1999-12-21 15:35:29 +0000 | [diff] [blame] | 328 | <li>Added a few tree modification functions: xmlReplaceNode, |
| 329 | xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and |
| 330 | xmlDocSetRootElement</li> |
| 331 | <li>Tried to improve the HTML output with help from <a |
| 332 | href="mailto:clahey@umich.edu">Chris Lahey</a></li> |
Daniel Veillard | e4e5131 | 1999-12-18 15:32:46 +0000 | [diff] [blame] | 333 | </ul> |
Daniel Veillard | b24054a | 1999-12-18 15:32:46 +0000 | [diff] [blame] | 334 | |
Daniel Veillard | e4e5131 | 1999-12-18 15:32:46 +0000 | [diff] [blame] | 335 | <h3>1.8.1: Dec 18 1999</h3> |
| 336 | <ul> |
| 337 | <li>various patches to avoid troubles when using libxml with C++ compilers |
| 338 | the "namespace" keyword and C escaping in include files</li> |
| 339 | <li>a problem in one of the core macros IS_CHAR was corrected</li> |
| 340 | <li>fixed a bug introduced in 1.8.0 breaking default namespace processing, |
| 341 | and more specifically the Dia application</li> |
Daniel Veillard | 944b5ff | 1999-12-15 19:08:24 +0000 | [diff] [blame] | 342 | <li>fixed a posteriori validation (validation after parsing, or by using a |
| 343 | Dtd not specified in the original document)</li> |
Daniel Veillard | b24054a | 1999-12-18 15:32:46 +0000 | [diff] [blame] | 344 | <li>fixed a bug in</li> |
Daniel Veillard | 10a2c65 | 1999-12-12 13:03:50 +0000 | [diff] [blame] | 345 | </ul> |
| 346 | |
| 347 | <h3>1.8.0: Dec 12 1999</h3> |
| 348 | <ul> |
| 349 | <li>cleanup, especially memory wise</li> |
| 350 | <li>the parser should be more reliable, especially the HTML one, it should |
| 351 | not crash, whatever the input !</li> |
| 352 | <li>Integrated various patches, especially a speedup improvement for large |
| 353 | dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>, |
| 354 | configure with --with-buffers to enable them.</li> |
| 355 | <li>attribute normalization, oops should have been added long ago !</li> |
| 356 | <li>attributes defaulted from Dtds should be available, xmlSetProp() now |
| 357 | does entities escapting by default.</li> |
Daniel Veillard | 4c3a203 | 1999-11-19 17:46:26 +0000 | [diff] [blame] | 358 | </ul> |
Daniel Veillard | 3500838 | 1999-10-25 13:15:52 +0000 | [diff] [blame] | 359 | |
| 360 | <h3>1.7.4: Oct 25 1999</h3> |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 361 | <ul> |
Daniel Veillard | 3500838 | 1999-10-25 13:15:52 +0000 | [diff] [blame] | 362 | <li>Lots of HTML improvement</li> |
| 363 | <li>Fixed some errors when saving both XML and HTML</li> |
| 364 | <li>More examples, the regression tests should now look clean</li> |
| 365 | <li>Fixed a bug with contiguous charref</li> |
| 366 | </ul> |
| 367 | |
| 368 | <h3>1.7.3: Sep 29 1999</h3> |
| 369 | <ul> |
| 370 | <li>portability problems fixed</li> |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 371 | <li>snprintf was used unconditionnally, leading to link problems on system |
Daniel Veillard | 3500838 | 1999-10-25 13:15:52 +0000 | [diff] [blame] | 372 | were it's not available, fixed</li> |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 373 | </ul> |
| 374 | |
| 375 | <h3>1.7.1: Sep 24 1999</h3> |
| 376 | <ul> |
| 377 | <li>The basic type for strings manipulated by libxml has been renamed in |
| 378 | 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason |
| 379 | is that CHAR was conflicting with a predefined type on Windows. However on |
| 380 | non WIN32 environment, compatibility is provided by the way of a |
| 381 | <strong>#define </strong>.</li> |
| 382 | <li>Changed another error : the use of a structure field called errno, and |
| 383 | leading to troubles on platforms where it's a macro</li> |
| 384 | </ul> |
| 385 | |
| 386 | <h3>1.7.0: sep 23 1999</h3> |
| 387 | <ul> |
| 388 | <li>Added the ability to fetch remote DTD or parsed entities, see the <a |
| 389 | href="gnome-xml-nanohttp.html">nanohttp</a> module.</li> |
| 390 | <li>Added an errno to report errors by another mean than a simple printf |
| 391 | like callback</li> |
| 392 | <li>Finished ID/IDREF support and checking when validation</li> |
| 393 | <li>Serious memory leaks fixed (there is now a <a |
| 394 | href="gnome-xml-xmlmemory.html">memory wrapper</a> module)</li> |
| 395 | <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a> |
| 396 | implementation</li> |
| 397 | <li>Added an HTML parser front-end</li> |
| 398 | </ul> |
| 399 | |
| 400 | <h2><a name="XML">XML</a></h2> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 401 | |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 402 | <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] | 403 | markup-based structured documents. Here is <a name="example">an example XML |
| 404 | document</a>:</p> |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 405 | <pre><?xml version="1.0"?> |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 406 | <EXAMPLE prop1="gnome is great" prop2="&amp; linux too"> |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 407 | <head> |
| 408 | <title>Welcome to Gnome</title> |
| 409 | </head> |
| 410 | <chapter> |
| 411 | <title>The Linux adventure</title> |
| 412 | <p>bla bla bla ...</p> |
| 413 | <image href="linus.gif"/> |
| 414 | <p>...</p> |
| 415 | </chapter> |
| 416 | </EXAMPLE></pre> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 417 | |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 418 | <p>The first line specifies that it's an XML document and gives useful |
| 419 | information about its encoding. Then the document is a text format whose |
| 420 | structure is specified by tags between brackets. <strong>Each tag opened has |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 421 | to be closed</strong>. XML is pedantic about this. However, if a tag is empty |
| 422 | (no content), a single tag can serve as both the opening and closing tag if it |
| 423 | ends with <code>/></code> rather than with <code>></code>. Note that, for |
| 424 | example, the image tag has no content (just an attribute) and is closed by |
| 425 | ending the tag with <code>/></code>.</p> |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 426 | |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 427 | <p>XML can be applied sucessfully to a wide range of uses, from long term |
| 428 | structured document maintenance (where it follows the steps of SGML) to simple |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 429 | data encoding mechanisms like configuration file formatting (glade), |
| 430 | spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where |
| 431 | it is used to encode remote calls between a client and a server.</p> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 432 | |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 433 | <h2><a name="tree">The tree output</a></h2> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 434 | |
| 435 | <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] | 436 | returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 437 | <strong>xmlDoc</strong> structure). This structure contains information such |
| 438 | as the file name, the document type, and a <strong>root</strong> pointer which |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 439 | is the root of the document (or more exactly the first child under the root |
| 440 | which is the document). The tree is made of <strong>xmlNode</strong>s, chained |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 441 | in double-linked lists of siblings and with childs<->parent relationship. |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 442 | An xmlNode can also carry properties (a chain of xmlAttr structures). An |
| 443 | attribute may have a value which is a list of TEXT or ENTITY_REF nodes.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 444 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 445 | <p>Here is an example (erroneous with respect to the XML spec since there |
| 446 | should be only one ELEMENT under the root):</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 447 | |
| 448 | <p><img src="structure.gif" alt=" structure.gif "></p> |
| 449 | |
| 450 | <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] | 451 | called <strong>xmllint</strong> which parses XML files given as argument and |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 452 | prints them back as parsed. This is useful for detecting errors both in XML |
| 453 | code and in the XML parser itself. It has an option <strong>--debug</strong> |
| 454 | which prints the actual in-memory structure of the document, here is the |
| 455 | result with the <a href="#example">example</a> given before:</p> |
Daniel Veillard | 10c6a8f | 1998-10-28 01:00:12 +0000 | [diff] [blame] | 456 | <pre>DOCUMENT |
| 457 | version=1.0 |
| 458 | standalone=true |
| 459 | ELEMENT EXAMPLE |
| 460 | ATTRIBUTE prop1 |
| 461 | TEXT |
| 462 | content=gnome is great |
| 463 | ATTRIBUTE prop2 |
| 464 | ENTITY_REF |
| 465 | TEXT |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 466 | content= linux too |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 467 | ELEMENT head |
Daniel Veillard | 10c6a8f | 1998-10-28 01:00:12 +0000 | [diff] [blame] | 468 | ELEMENT title |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 469 | TEXT |
| 470 | content=Welcome to Gnome |
Daniel Veillard | 10c6a8f | 1998-10-28 01:00:12 +0000 | [diff] [blame] | 471 | ELEMENT chapter |
| 472 | ELEMENT title |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 473 | TEXT |
| 474 | content=The Linux adventure |
Daniel Veillard | 10c6a8f | 1998-10-28 01:00:12 +0000 | [diff] [blame] | 475 | ELEMENT p |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 476 | TEXT |
| 477 | content=bla bla bla ... |
Daniel Veillard | 10c6a8f | 1998-10-28 01:00:12 +0000 | [diff] [blame] | 478 | ELEMENT image |
| 479 | ATTRIBUTE href |
| 480 | TEXT |
| 481 | content=linus.gif |
| 482 | ELEMENT p |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 483 | TEXT |
| 484 | content=...</pre> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 485 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 486 | <p>This should be useful for learning the internal representation model.</p> |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 487 | |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 488 | <h2><a name="interface">The SAX interface</a></h2> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 489 | |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 490 | <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] | 491 | memory. In that case (and if you don't expect to save back the XML document |
| 492 | loaded using libxml), it's better to use the SAX interface of libxml. SAX is a |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 493 | <strong>callback-based interface</strong> to the parser. Before parsing, the |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 494 | application layer registers a customized set of callbacks which are called by |
| 495 | the library as it progresses through the XML input.</p> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 496 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 497 | <p>To get more detailed step-by-step guidance on using the SAX interface of |
| 498 | libxml, see the |
| 499 | href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 500 | documentation.written by <a href="mailto:james@daa.com.au">James |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 501 | Henstridge</a>.</p> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 502 | |
| 503 | <p>You can debug the SAX behaviour by using the <strong>testSAX</strong> |
| 504 | 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] | 505 | 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] | 506 | distribution). Here is the sequence of callbacks that would be reported by |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 507 | testSAX when parsing the example XML document shown earlier:</p> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 508 | <pre>SAX.setDocumentLocator() |
| 509 | SAX.startDocument() |
| 510 | SAX.getEntity(amp) |
| 511 | SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp; linux too') |
| 512 | SAX.characters( , 3) |
| 513 | SAX.startElement(head) |
| 514 | SAX.characters( , 4) |
| 515 | SAX.startElement(title) |
| 516 | SAX.characters(Welcome to Gnome, 16) |
| 517 | SAX.endElement(title) |
| 518 | SAX.characters( , 3) |
| 519 | SAX.endElement(head) |
| 520 | SAX.characters( , 3) |
| 521 | SAX.startElement(chapter) |
| 522 | SAX.characters( , 4) |
| 523 | SAX.startElement(title) |
| 524 | SAX.characters(The Linux adventure, 19) |
| 525 | SAX.endElement(title) |
| 526 | SAX.characters( , 4) |
| 527 | SAX.startElement(p) |
| 528 | SAX.characters(bla bla bla ..., 15) |
| 529 | SAX.endElement(p) |
| 530 | SAX.characters( , 4) |
| 531 | SAX.startElement(image, href='linus.gif') |
| 532 | SAX.endElement(image) |
| 533 | SAX.characters( , 4) |
| 534 | SAX.startElement(p) |
| 535 | SAX.characters(..., 3) |
| 536 | SAX.endElement(p) |
| 537 | SAX.characters( , 3) |
| 538 | SAX.endElement(chapter) |
| 539 | SAX.characters( , 1) |
| 540 | SAX.endElement(EXAMPLE) |
| 541 | SAX.endDocument()</pre> |
| 542 | |
Daniel Veillard | 402e8c8 | 2000-02-29 22:57:47 +0000 | [diff] [blame] | 543 | <p>Most of the other functionalities of libxml are based on the DOM |
| 544 | tree-building facility, so nearly everything up to the end of this document |
| 545 | presupposes the use of the standard DOM tree build. Note that the DOM tree |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 546 | itself is built by a set of registered default callbacks, without internal |
| 547 | specific interface.</p> |
| 548 | |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 549 | <h2><a name="library">The XML library interfaces</a></h2> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 550 | |
| 551 | <p>This section is directly intended to help programmers getting bootstrapped |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 552 | using the XML library from the C language. It is not intended to be extensive. |
| 553 | I hope the automatically generated documents will provide the completeness |
| 554 | required, but as a separate set of documents. The interfaces of the XML |
| 555 | library are by principle low level, there is nearly zero abstraction. Those |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 556 | interested in a higher level API should <a href="#DOM">look at DOM</a>.</p> |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 557 | |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 558 | <p>The <a href="gnome-xml-parser.html">parser interfaces for XML</a> are |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 559 | separated from the <a href="gnome-xml-htmlparser.html">HTML parser |
| 560 | 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] | 561 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 562 | <h3><a name="Invoking">Invoking the parser : the pull method</a></h3> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 563 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 564 | <p>Usually, the first thing to do is to read an XML input. The parser accepts |
| 565 | documents either from in-memory strings or from files. The functions are |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 566 | defined in "parser.h":</p> |
Daniel Veillard | 10c6a8f | 1998-10-28 01:00:12 +0000 | [diff] [blame] | 567 | <dl> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 568 | <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt> |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 569 | <dd><p>Parse a null-terminated string containing the document.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 570 | </dd> |
Daniel Veillard | 10c6a8f | 1998-10-28 01:00:12 +0000 | [diff] [blame] | 571 | </dl> |
| 572 | <dl> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 573 | <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt> |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 574 | <dd><p>Parse an XML document contained in a (possibly compressed) |
| 575 | file.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 576 | </dd> |
Daniel Veillard | 10c6a8f | 1998-10-28 01:00:12 +0000 | [diff] [blame] | 577 | </dl> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 578 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 579 | <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] | 580 | failure).</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 581 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 582 | <h3 id="Invoking1">Invoking the parser: the push method</h3> |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 583 | |
| 584 | <p>In order for the application to keep the control when the document is been |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 585 | fetched (which is common for GUI based programs) libxml provides a push |
| 586 | 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] | 587 | <pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax, |
| 588 | void *user_data, |
| 589 | const char *chunk, |
| 590 | int size, |
| 591 | const char *filename); |
| 592 | int xmlParseChunk (xmlParserCtxtPtr ctxt, |
| 593 | const char *chunk, |
| 594 | int size, |
| 595 | int terminate);</pre> |
| 596 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 597 | <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] | 598 | <pre> FILE *f; |
| 599 | |
| 600 | f = fopen(filename, "r"); |
| 601 | if (f != NULL) { |
| 602 | int res, size = 1024; |
| 603 | char chars[1024]; |
| 604 | xmlParserCtxtPtr ctxt; |
| 605 | |
| 606 | res = fread(chars, 1, 4, f); |
| 607 | if (res > 0) { |
| 608 | ctxt = xmlCreatePushParserCtxt(NULL, NULL, |
| 609 | chars, res, filename); |
| 610 | while ((res = fread(chars, 1, size, f)) > 0) { |
| 611 | xmlParseChunk(ctxt, chars, res, 0); |
| 612 | } |
| 613 | xmlParseChunk(ctxt, chars, 0, 1); |
| 614 | doc = ctxt->myDoc; |
| 615 | xmlFreeParserCtxt(ctxt); |
| 616 | } |
| 617 | }</pre> |
| 618 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 619 | <p>Also note that the HTML parser embedded into libxml also has a push |
| 620 | interface; the functions are just prefixed by "html" rather than "xml"</p> |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 621 | |
| 622 | <h3 id="Invoking2">Invoking the parser: the SAX interface</h3> |
| 623 | |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 624 | <p>A couple of comments can be made, first this mean that the parser is |
Daniel Veillard | 10c6a8f | 1998-10-28 01:00:12 +0000 | [diff] [blame] | 625 | memory-hungry, first to load the document in memory, second to build the tree. |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 626 | Reading a document without building the tree is possible using the SAX |
| 627 | interfaces (see SAX.h and <a |
| 628 | 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] | 629 | Henstridge's documentation</a>). Note also that the push interface can be |
| 630 | limited to SAX. Just use the two first arguments of |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 631 | <code>xmlCreatePushParserCtxt()</code>.</p> |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 632 | |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 633 | <h3><a name="Building">Building a tree from scratch</a></h3> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 634 | |
| 635 | <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] | 636 | there is a set of functions dedicated to building new elements. (These are |
Daniel Veillard | 361d845 | 2000-04-03 19:48:13 +0000 | [diff] [blame] | 637 | also described in <libxml/tree.h>.) For example, here is a piece of code |
| 638 | that produces the XML document used in the previous examples:</p> |
| 639 | <pre> #include <libxml/tree.h> |
| 640 | xmlDocPtr doc; |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 641 | xmlNodePtr tree, subtree; |
| 642 | |
| 643 | doc = xmlNewDoc("1.0"); |
| 644 | doc->root = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL); |
| 645 | xmlSetProp(doc->root, "prop1", "gnome is great"); |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 646 | xmlSetProp(doc->root, "prop2", "& linux too"); |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 647 | tree = xmlNewChild(doc->root, NULL, "head", NULL); |
| 648 | subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome"); |
| 649 | tree = xmlNewChild(doc->root, NULL, "chapter", NULL); |
| 650 | subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure"); |
| 651 | subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ..."); |
| 652 | subtree = xmlNewChild(tree, NULL, "image", NULL); |
| 653 | xmlSetProp(subtree, "href", "linus.gif");</pre> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 654 | |
| 655 | <p>Not really rocket science ...</p> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 656 | |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 657 | <h3><a name="Traversing">Traversing the tree</a></h3> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 658 | |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 659 | <p>Basically by <a href="gnome-xml-tree.html">including "tree.h"</a> your code |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 660 | has access to the internal structure of all the elements of the tree. The |
| 661 | names should be somewhat simple like <strong>parent</strong>, |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 662 | <strong>childs</strong>, <strong>next</strong>, <strong>prev</strong>, |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 663 | <strong>properties</strong>, etc... For example, still with the previous |
Daniel Veillard | 0142b84 | 2000-01-14 14:45:24 +0000 | [diff] [blame] | 664 | example:</p> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 665 | <pre><code>doc->root->childs->childs</code></pre> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 666 | |
| 667 | <p>points to the title element,</p> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 668 | <pre>doc->root->childs->next->child->child</pre> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 669 | |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 670 | <p>points to the text node containing the chapter title "The Linux |
| 671 | adventure".</p> |
Daniel Veillard | 10c6a8f | 1998-10-28 01:00:12 +0000 | [diff] [blame] | 672 | |
Daniel Veillard | b24054a | 1999-12-18 15:32:46 +0000 | [diff] [blame] | 673 | <p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em> to be |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 674 | present before the document root, so <code>doc->root</code> may point to an |
| 675 | element which is not the document Root Element, a function |
Daniel Veillard | 5cb5ab8 | 1999-12-21 15:35:29 +0000 | [diff] [blame] | 676 | <code>xmlDocGetRootElement()</code> was added for this purpose.</p> |
Daniel Veillard | b24054a | 1999-12-18 15:32:46 +0000 | [diff] [blame] | 677 | |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 678 | <h3><a name="Modifying">Modifying the tree</a></h3> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 679 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 680 | <p>Functions are provided for reading and writing the document content. Here |
| 681 | is an excerpt from the <a href="gnome-xml-tree.html">tree API</a>:</p> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 682 | <dl> |
Daniel Veillard | dd6b367 | 1999-09-23 22:19:22 +0000 | [diff] [blame] | 683 | <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const |
| 684 | xmlChar *value);</code></dt> |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 685 | <dd><p>This sets (or changes) an attribute carried by an ELEMENT node. The |
| 686 | value can be NULL.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 687 | </dd> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 688 | </dl> |
| 689 | <dl> |
Daniel Veillard | dd6b367 | 1999-09-23 22:19:22 +0000 | [diff] [blame] | 690 | <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 691 | *name);</code></dt> |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 692 | <dd><p>This function returns a pointer to the property content. Note that |
| 693 | no extra copy is made.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 694 | </dd> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 695 | </dl> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 696 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 697 | <p>Two functions are provided for reading and writing the text associated with |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 698 | elements:</p> |
| 699 | <dl> |
Daniel Veillard | dd6b367 | 1999-09-23 22:19:22 +0000 | [diff] [blame] | 700 | <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 701 | *value);</code></dt> |
| 702 | <dd><p>This function takes an "external" string and convert it to one text |
| 703 | node or possibly to a list of entity and text nodes. All non-predefined |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 704 | entity references like &Gnome; will be stored internally as entity |
| 705 | nodes, hence the result of the function may not be a single node.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 706 | </dd> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 707 | </dl> |
| 708 | <dl> |
Daniel Veillard | dd6b367 | 1999-09-23 22:19:22 +0000 | [diff] [blame] | 709 | <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 710 | inLine);</code></dt> |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 711 | <dd><p>This function is the inverse of |
| 712 | <code>xmlStringGetNodeList()</code>. It generates a new string |
| 713 | containing the content of the text and entity nodes. Note the extra |
| 714 | argument inLine. If this argument is set to 1, the function will expand |
| 715 | entity references. For example, instead of returning the &Gnome; |
| 716 | XML encoding in the string, it will substitute it with its value (say, |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 717 | "GNU Network Object Model Environment"). Set this argument if you want |
| 718 | to use the string for non-XML usage like User Interface.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 719 | </dd> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 720 | </dl> |
Daniel Veillard | 10c6a8f | 1998-10-28 01:00:12 +0000 | [diff] [blame] | 721 | |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 722 | <h3><a name="Saving">Saving a tree</a></h3> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 723 | |
| 724 | <p>Basically 3 options are possible:</p> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 725 | <dl> |
Daniel Veillard | dd6b367 | 1999-09-23 22:19:22 +0000 | [diff] [blame] | 726 | <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 727 | *size);</code></dt> |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 728 | <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] | 729 | </dd> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 730 | </dl> |
| 731 | <dl> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 732 | <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt> |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 733 | <dd><p>Dumps a document to an open file descriptor.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 734 | </dd> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 735 | </dl> |
| 736 | <dl> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 737 | <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt> |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 738 | <dd><p>Saves the document to a file. In this case, the compression |
| 739 | interface is triggered if it has been turned on.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 740 | </dd> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 741 | </dl> |
Daniel Veillard | 10c6a8f | 1998-10-28 01:00:12 +0000 | [diff] [blame] | 742 | |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 743 | <h3><a name="Compressio">Compression</a></h3> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 744 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 745 | <p>The library transparently handles compression when doing file-based |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 746 | accesses. The level of compression on saves can be turned on either globally |
| 747 | or individually for one file:</p> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 748 | <dl> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 749 | <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt> |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 750 | <dd><p>Gets the document compression ratio (0-9).</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 751 | </dd> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 752 | </dl> |
| 753 | <dl> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 754 | <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt> |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 755 | <dd><p>Sets the document compression ratio.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 756 | </dd> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 757 | </dl> |
| 758 | <dl> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 759 | <dt><code>int xmlGetCompressMode(void);</code></dt> |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 760 | <dd><p>Gets the default compression ratio.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 761 | </dd> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 762 | </dl> |
| 763 | <dl> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 764 | <dt><code>void xmlSetCompressMode(int mode);</code></dt> |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 765 | <dd><p>Sets the default compression ratio.</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 766 | </dd> |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 767 | </dl> |
| 768 | |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 769 | <h2><a name="Entities">Entities or no entities</a></h2> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 770 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 771 | <p>Entities in principle are similar to simple C macros. An entity defines an |
| 772 | abbreviation for a given string that you can reuse many times throughout the |
| 773 | content of your document. Entities are especially useful when a given string |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 774 | may occur frequently within a document, or to confine the change needed to a |
| 775 | document to a restricted area in the internal subset of the document (at the |
| 776 | beginning). Example:</p> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 777 | <pre>1 <?xml version="1.0"?> |
| 778 | 2 <!DOCTYPE EXAMPLE SYSTEM "example.dtd" [ |
| 779 | 3 <!ENTITY xml "Extensible Markup Language"> |
| 780 | 4 ]> |
| 781 | 5 <EXAMPLE> |
| 782 | 6 &xml; |
Daniel Veillard | 3500838 | 1999-10-25 13:15:52 +0000 | [diff] [blame] | 783 | 7 </EXAMPLE></pre> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 784 | |
| 785 | <p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 786 | it's name with '&' and following it by ';' without any spaces added. There |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 787 | are 5 predefined entities in libxml allowing you to escape charaters with |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 788 | predefined meaning in some parts of the xml document content: |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 789 | <strong>&lt;</strong> for the character '<', <strong>&gt;</strong> |
| 790 | for the character '>', <strong>&apos;</strong> for the character ''', |
| 791 | <strong>&quot;</strong> for the character '"', and |
| 792 | <strong>&amp;</strong> for the character '&'.</p> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 793 | |
| 794 | <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] | 795 | substitute an entity's content so that you can see the replacement text in |
| 796 | your application. Or you may prefer to keep entity references as such in the |
| 797 | content to be able to save the document back without losing this usually |
| 798 | precious information (if the user went through the pain of explicitly defining |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 799 | entities, he may have a a rather negative attitude if you blindly susbtitute |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 800 | them as saving time). The <a |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 801 | href="gnome-xml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a> |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 802 | function allows you to check and change the behaviour, which is to not |
| 803 | substitute entities by default.</p> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 804 | |
| 805 | <p>Here is the DOM tree built by libxml for the previous document in the |
| 806 | default case:</p> |
Daniel Veillard | 361d845 | 2000-04-03 19:48:13 +0000 | [diff] [blame] | 807 | <pre>/gnome/src/gnome-xml -> ./xmllint --debug test/ent1 |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 808 | DOCUMENT |
| 809 | version=1.0 |
| 810 | ELEMENT EXAMPLE |
| 811 | TEXT |
| 812 | content= |
| 813 | ENTITY_REF |
| 814 | INTERNAL_GENERAL_ENTITY xml |
| 815 | content=Extensible Markup Language |
| 816 | TEXT |
| 817 | content=</pre> |
| 818 | |
| 819 | <p>And here is the result when substituting entities:</p> |
| 820 | <pre>/gnome/src/gnome-xml -> ./tester --debug --noent test/ent1 |
| 821 | DOCUMENT |
| 822 | version=1.0 |
| 823 | ELEMENT EXAMPLE |
| 824 | TEXT |
| 825 | content= Extensible Markup Language</pre> |
| 826 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 827 | <p>So, entities or no entities? Basically, it depends on your use case. I |
| 828 | suggest that you keep the non-substituting default behaviour and avoid using |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 829 | entities in your XML document or data if you are not willing to handle the |
| 830 | entity references elements in the DOM tree.</p> |
| 831 | |
| 832 | <p>Note that at save time libxml enforce the conversion of the predefined |
| 833 | entities where necessary to prevent well-formedness problems, and will also |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 834 | transparently replace those with chars (i.e., it will not generate entity |
| 835 | 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] | 836 | finding them in the input).</p> |
| 837 | |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 838 | <h2><a name="Namespaces">Namespaces</a></h2> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 839 | |
Daniel Veillard | ec30341 | 2000-03-24 13:41:54 +0000 | [diff] [blame] | 840 | <p>The libxml library implements <a |
| 841 | href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by |
| 842 | recognizing namespace contructs in the input, and does namespace lookup |
| 843 | automatically when building the DOM tree. A namespace declaration is |
| 844 | associated with an in-memory structure and all elements or attributes within |
| 845 | that namespace point to it. Hence testing the namespace is a simple and fast |
| 846 | equality operation at the user level.</p> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 847 | |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 848 | <p>I suggest that people using libxml use a namespace, and declare it in the |
| 849 | root element of their document as the default namespace. Then they don't need |
| 850 | to use the prefix in the content but we will have a basis for future semantic |
| 851 | refinement and merging of data from different sources. This doesn't augment |
| 852 | significantly the size of the XML output, but significantly increase its value |
Daniel Veillard | ec30341 | 2000-03-24 13:41:54 +0000 | [diff] [blame] | 853 | in the long-term. Example:</p> |
| 854 | <pre><mydoc xmlns="http://mydoc.example.org/schemas/"> |
| 855 | <elem1>...</elem1> |
| 856 | <elem2>...</elem2> |
| 857 | </mydoc></pre> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 858 | |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 859 | <p>Concerning the namespace value, this has to be an URL, but the URL doesn't |
Daniel Veillard | ec30341 | 2000-03-24 13:41:54 +0000 | [diff] [blame] | 860 | have to point to any existing resource on the Web. It will bind all the |
| 861 | element and atributes with that URL. I suggest to use an URL within a domain |
| 862 | you control, and that the URL should contain some kind of version information |
| 863 | if possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is |
Daniel Veillard | 361d845 | 2000-04-03 19:48:13 +0000 | [diff] [blame] | 864 | a good namespace scheme.</p> |
Daniel Veillard | ec30341 | 2000-03-24 13:41:54 +0000 | [diff] [blame] | 865 | |
| 866 | <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] | 867 | version-independent prefix is installed on the root element of your document, |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 868 | and if the version information don't match something you know, warn the user |
| 869 | and be liberal in what you accept as the input. Also do *not* try to base |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 870 | namespace checking on the prefix value. <foo:text> may be exactly the same |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 871 | as <bar:text> in another document. What really matter is the URI associated |
| 872 | with the element or the attribute, not the prefix string (which is just a |
Daniel Veillard | ec30341 | 2000-03-24 13:41:54 +0000 | [diff] [blame] | 873 | shortcut for the full URI). In libxml element and attributes have a |
| 874 | <code>ns</code> field pointing to an xmlNs structure detailing the namespace |
| 875 | prefix and it's URI.</p> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 876 | |
| 877 | <p>@@Interfaces@@</p> |
| 878 | |
| 879 | <p>@@Examples@@</p> |
| 880 | |
| 881 | <p>Usually people object using namespace in the case of validation, I object |
| 882 | this and will make sure that using namespaces won't break validity checking, |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 883 | so even is you plan to use or currently are using validation I strongly |
| 884 | suggest adding namespaces to your document. A default namespace scheme |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 885 | <code>xmlns="http://...."</code> should not break validity even on less |
Daniel Veillard | 88f00ae | 2000-03-02 00:15:55 +0000 | [diff] [blame] | 886 | flexible parsers. Now using namespace to mix and differentiate content coming |
| 887 | from multiple DTDs will certainly break current validation schemes. I will try |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 888 | to provide ways to do this, but this may not be portable or standardized.</p> |
| 889 | |
Daniel Veillard | 2f4dfc4 | 1999-09-24 14:03:48 +0000 | [diff] [blame] | 890 | <h2><a name="Validation">Validation, or are you afraid of DTDs ?</a></h2> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 891 | |
| 892 | <p>Well what is validation and what is a DTD ?</p> |
| 893 | |
| 894 | <p>Validation is the process of checking a document against a set of |
| 895 | construction rules, a <strong>DTD</strong> (Document Type Definition) is such |
| 896 | a set of rules.</p> |
| 897 | |
| 898 | <p>The validation process and building DTDs are the two most difficult parts |
| 899 | of XML life cycle. Briefly a DTD defines all the possibles element to be |
| 900 | found within your document, what is the formal shape of your document tree (by |
| 901 | defining the allowed content of an element, either text, a regular expression |
| 902 | for the allowed list of children, or mixed content i.e. both text and childs). |
| 903 | The DTD also defines the allowed attributes for all elements and the types of |
| 904 | the attributes. For more detailed informations, I suggest to read the related |
| 905 | parts of the XML specification, the examples found under |
| 906 | gnome-xml/test/valid/dtd and the large amount of books available on XML. The |
| 907 | dia example in gnome-xml/test/valid should be both simple and complete enough |
| 908 | to allow you to build your own.</p> |
| 909 | |
| 910 | <p>A word of warning, building a good DTD which will fit your needs of your |
| 911 | application in the long-term is far from trivial, however the extra level of |
| 912 | quality it can insure is well worth the price for some sets of applications or |
| 913 | if you already have already a DTD defined for your application field.</p> |
| 914 | |
| 915 | <p>The validation is not completely finished but in a (very IMHO) usable |
| 916 | state. Until a real validation interface is defined the way to do it is to |
| 917 | define and set the <strong>xmlDoValidityCheckingDefaultValue</strong> external |
| 918 | variable to 1, this will of course be changed at some point:</p> |
| 919 | |
| 920 | <p>extern int xmlDoValidityCheckingDefaultValue;</p> |
| 921 | |
| 922 | <p>...</p> |
| 923 | |
| 924 | <p>xmlDoValidityCheckingDefaultValue = 1;</p> |
| 925 | |
| 926 | <p></p> |
| 927 | |
| 928 | <p>To handle external entities, use the function |
| 929 | <strong>xmlSetExternalEntityLoader</strong>(xmlExternalEntityLoader f); to |
| 930 | link in you HTTP/FTP/Entities database library to the standard libxml |
| 931 | core.</p> |
| 932 | |
| 933 | <p>@@interfaces@@</p> |
| 934 | |
Daniel Veillard | 3500838 | 1999-10-25 13:15:52 +0000 | [diff] [blame] | 935 | <h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 936 | |
| 937 | <p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document Object |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 938 | Model</em> this is an API for accessing XML or HTML structured documents. |
| 939 | Native support for DOM in Gnome is on the way (module gnome-dom), and it will |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 940 | be based on gnome-xml. This will be a far cleaner interface to manipulate XML |
Daniel Veillard | c08a2c6 | 1999-09-08 21:35:25 +0000 | [diff] [blame] | 941 | files within Gnome since it won't expose the internal structure. DOM defines a |
Daniel Veillard | 25940b7 | 1998-10-29 05:51:30 +0000 | [diff] [blame] | 942 | set of IDL (or Java) interfaces allowing to traverse and manipulate a |
| 943 | document. The DOM library will allow accessing and modifying "live" documents |
| 944 | presents on other programs like this:</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 945 | |
| 946 | <p><img src="DOM.gif" alt=" DOM.gif "></p> |
| 947 | |
| 948 | <p>This should help greatly doing things like modifying a gnumeric spreadsheet |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 949 | embedded in a GWP document for example.</p> |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 950 | |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 951 | <p>The current DOM implementation on top of libxml is the <a |
| 952 | href="http://cvs.gnome.org/lxr/source/gdome/">gdome Gnome module</a>, this is |
| 953 | a full DOM interface, thanks to <a href="mailto:raph@levien.com">Raph |
| 954 | Levien</a>.</p> |
| 955 | |
| 956 | <p>The gnome-dom module in the Gnome CVS base is obsolete</p> |
| 957 | |
Daniel Veillard | 3500838 | 1999-10-25 13:15:52 +0000 | [diff] [blame] | 958 | <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] | 959 | |
| 960 | <p>Here is a real size example, where the actual content of the application |
| 961 | 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] | 962 | 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] | 963 | storage structure. Here is an <a href="gjobs.xml">XML encoded jobs |
| 964 | base</a>:</p> |
| 965 | <pre><?xml version="1.0"?> |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 966 | <gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"> |
| 967 | <gjob:Jobs> |
| 968 | |
| 969 | <gjob:Job> |
| 970 | <gjob:Project ID="3"/> |
| 971 | <gjob:Application>GBackup</gjob:Application> |
| 972 | <gjob:Category>Development</gjob:Category> |
| 973 | |
| 974 | <gjob:Update> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 975 | <gjob:Status>Open</gjob:Status> |
| 976 | <gjob:Modified>Mon, 07 Jun 1999 20:27:45 -0400 MET DST</gjob:Modified> |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 977 | <gjob:Salary>USD 0.00</gjob:Salary> |
| 978 | </gjob:Update> |
| 979 | |
| 980 | <gjob:Developers> |
| 981 | <gjob:Developer> |
| 982 | </gjob:Developer> |
| 983 | </gjob:Developers> |
| 984 | |
| 985 | <gjob:Contact> |
| 986 | <gjob:Person>Nathan Clemons</gjob:Person> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 987 | <gjob:Email>nathan@windsofstorm.net</gjob:Email> |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 988 | <gjob:Company> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 989 | </gjob:Company> |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 990 | <gjob:Organisation> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 991 | </gjob:Organisation> |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 992 | <gjob:Webpage> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 993 | </gjob:Webpage> |
| 994 | <gjob:Snailmail> |
| 995 | </gjob:Snailmail> |
| 996 | <gjob:Phone> |
| 997 | </gjob:Phone> |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 998 | </gjob:Contact> |
| 999 | |
| 1000 | <gjob:Requirements> |
| 1001 | The program should be released as free software, under the GPL. |
| 1002 | </gjob:Requirements> |
| 1003 | |
| 1004 | <gjob:Skills> |
| 1005 | </gjob:Skills> |
| 1006 | |
| 1007 | <gjob:Details> |
| 1008 | A GNOME based system that will allow a superuser to configure |
| 1009 | compressed and uncompressed files and/or file systems to be backed |
| 1010 | up with a supported media in the system. This should be able to |
| 1011 | perform via find commands generating a list of files that are passed |
| 1012 | to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine |
| 1013 | or via operations performed on the filesystem itself. Email |
| 1014 | notification and GUI status display very important. |
| 1015 | </gjob:Details> |
| 1016 | |
| 1017 | </gjob:Job> |
| 1018 | |
| 1019 | </gjob:Jobs> |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 1020 | </gjob:Helping></pre> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1021 | |
| 1022 | <p>While loading the XML file into an internal DOM tree is a matter of calling |
| 1023 | only a couple of functions, browsing the tree to gather the informations and |
| 1024 | generate the internals structures is harder, and more error prone.</p> |
| 1025 | |
| 1026 | <p>The suggested principle is to be tolerant with respect to the input |
Daniel Veillard | f13e1ed | 2000-03-06 07:41:49 +0000 | [diff] [blame] | 1027 | structure. For example, the ordering of the attributes is not significant, |
| 1028 | Cthe XML specification is clear about it. It's also usually a good idea to not |
| 1029 | be dependent of the orders of the childs of a given node, unless it really |
| 1030 | makes things harder. Here is some code to parse the informations for a |
| 1031 | person:</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1032 | <pre>/* |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1033 | * A person record |
| 1034 | */ |
| 1035 | typedef struct person { |
| 1036 | char *name; |
| 1037 | char *email; |
| 1038 | char *company; |
| 1039 | char *organisation; |
| 1040 | char *smail; |
| 1041 | char *webPage; |
| 1042 | char *phone; |
| 1043 | } person, *personPtr; |
| 1044 | |
| 1045 | /* |
| 1046 | * And the code needed to parse it |
| 1047 | */ |
| 1048 | personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) { |
| 1049 | personPtr ret = NULL; |
| 1050 | |
| 1051 | DEBUG("parsePerson\n"); |
| 1052 | /* |
| 1053 | * allocate the struct |
| 1054 | */ |
| 1055 | ret = (personPtr) malloc(sizeof(person)); |
| 1056 | if (ret == NULL) { |
| 1057 | fprintf(stderr,"out of memory\n"); |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1058 | return(NULL); |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1059 | } |
| 1060 | memset(ret, 0, sizeof(person)); |
| 1061 | |
| 1062 | /* We don't care what the top level element name is */ |
| 1063 | cur = cur->childs; |
| 1064 | while (cur != NULL) { |
| 1065 | if ((!strcmp(cur->name, "Person")) && (cur->ns == ns)) |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1066 | ret->name = xmlNodeListGetString(doc, cur->childs, 1); |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1067 | if ((!strcmp(cur->name, "Email")) && (cur->ns == ns)) |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1068 | ret->email = xmlNodeListGetString(doc, cur->childs, 1); |
| 1069 | cur = cur->next; |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1070 | } |
| 1071 | |
| 1072 | return(ret); |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1073 | }</pre> |
| 1074 | |
| 1075 | <p>Here is a couple of things to notice:</p> |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1076 | <ul> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1077 | <li>Usually a recursive parsing style is the more convenient one, XML data |
| 1078 | being by nature subject to repetitive constructs and usualy exibit highly |
| 1079 | stuctured patterns.</li> |
| 1080 | <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>, i.e. |
| 1081 | the pointer to the global XML document and the namespace reserved to the |
| 1082 | application. Document wide information are needed for example to decode |
| 1083 | entities and it's a good coding practice to define a namespace for your |
| 1084 | application set of data and test that the element and attributes you're |
| 1085 | analyzing actually pertains to your application space. This is done by a |
| 1086 | simple equality test (cur->ns == ns).</li> |
| 1087 | <li>To retrieve text and attributes value, it is suggested to use the |
| 1088 | function <em>xmlNodeListGetString</em> to gather all the text and entity |
| 1089 | reference nodes generated by the DOM output and produce an single text |
| 1090 | string.</li> |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1091 | </ul> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1092 | |
| 1093 | <p>Here is another piece of code used to parse another level of the |
| 1094 | structure:</p> |
Daniel Veillard | 361d845 | 2000-04-03 19:48:13 +0000 | [diff] [blame] | 1095 | <pre>#include <libxml/tree.h> |
| 1096 | /* |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1097 | * a Description for a Job |
| 1098 | */ |
| 1099 | typedef struct job { |
| 1100 | char *projectID; |
| 1101 | char *application; |
| 1102 | char *category; |
| 1103 | personPtr contact; |
| 1104 | int nbDevelopers; |
| 1105 | personPtr developers[100]; /* using dynamic alloc is left as an exercise */ |
| 1106 | } job, *jobPtr; |
| 1107 | |
| 1108 | /* |
| 1109 | * And the code needed to parse it |
| 1110 | */ |
| 1111 | jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) { |
| 1112 | jobPtr ret = NULL; |
| 1113 | |
| 1114 | DEBUG("parseJob\n"); |
| 1115 | /* |
| 1116 | * allocate the struct |
| 1117 | */ |
| 1118 | ret = (jobPtr) malloc(sizeof(job)); |
| 1119 | if (ret == NULL) { |
| 1120 | fprintf(stderr,"out of memory\n"); |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1121 | return(NULL); |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1122 | } |
| 1123 | memset(ret, 0, sizeof(job)); |
| 1124 | |
| 1125 | /* We don't care what the top level element name is */ |
| 1126 | cur = cur->childs; |
| 1127 | while (cur != NULL) { |
| 1128 | |
| 1129 | if ((!strcmp(cur->name, "Project")) && (cur->ns == ns)) { |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1130 | ret->projectID = xmlGetProp(cur, "ID"); |
| 1131 | if (ret->projectID == NULL) { |
| 1132 | fprintf(stderr, "Project has no ID\n"); |
| 1133 | } |
| 1134 | } |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1135 | if ((!strcmp(cur->name, "Application")) && (cur->ns == ns)) |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1136 | ret->application = xmlNodeListGetString(doc, cur->childs, 1); |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1137 | if ((!strcmp(cur->name, "Category")) && (cur->ns == ns)) |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1138 | ret->category = xmlNodeListGetString(doc, cur->childs, 1); |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1139 | if ((!strcmp(cur->name, "Contact")) && (cur->ns == ns)) |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1140 | ret->contact = parsePerson(doc, ns, cur); |
| 1141 | cur = cur->next; |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1142 | } |
| 1143 | |
| 1144 | return(ret); |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1145 | }</pre> |
Daniel Veillard | 14fff06 | 1999-06-22 21:49:07 +0000 | [diff] [blame] | 1146 | |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1147 | <p>One can notice that once used to it, writing this kind of code is quite |
| 1148 | simple, but boring. Ultimately, it could be possble to write stubbers taking |
| 1149 | either C data structure definitions, a set of XML examples or an XML DTD and |
| 1150 | produce the code needed to import and export the content between C data and |
| 1151 | XML storage. This is left as an exercise to the reader :-)</p> |
| 1152 | |
| 1153 | <p>Feel free to use <a href="gjobread.c">the code for the full C parsing |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 1154 | example</a> as a template, it is also available with Makefile in the Gnome CVS |
| 1155 | base under gnome-xml/example</p> |
Daniel Veillard | b05deb7 | 1999-08-10 19:04:08 +0000 | [diff] [blame] | 1156 | |
Daniel Veillard | c310d56 | 2000-06-23 18:32:15 +0000 | [diff] [blame] | 1157 | <h2><a name="Contributi">Contributions</a></h2> |
| 1158 | <ul> |
| 1159 | <li><a href="mailto:ari@btigate.com">Ari Johnson</a> provides a C++ wrapper |
| 1160 | for libxml: |
| 1161 | <p>Website: <a |
| 1162 | href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p> |
| 1163 | <p>Download: <a |
| 1164 | href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p> |
| 1165 | </li> |
| 1166 | <li><a href="mailto:doolin@cs.utk.edu">David Doolin</a> provides a |
| 1167 | precompiled Windows version |
| 1168 | <p><a |
| 1169 | href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p> |
| 1170 | </li> |
Daniel Veillard | 3f6f7f6 | 2000-06-30 17:58:25 +0000 | [diff] [blame] | 1171 | <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> provided <a |
| 1172 | href="libxml-doc.el">an emacs module</a> to lookup libxml functions |
| 1173 | documentation</li> |
Daniel Veillard | c310d56 | 2000-06-23 18:32:15 +0000 | [diff] [blame] | 1174 | <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a |
| 1175 | href="http://xmlsoft.org/messages/0488.html">man pages</a> (not yet |
| 1176 | integrated in the distribution)</li> |
| 1177 | </ul> |
| 1178 | |
Daniel Veillard | c8eab3a | 1999-09-04 18:27:23 +0000 | [diff] [blame] | 1179 | <p></p> |
| 1180 | |
| 1181 | <p><a href="mailto:Daniel.Veillard@w3.org">Daniel Veillard</a></p> |
| 1182 | |
Daniel Veillard | 365e13b | 2000-07-02 07:56:37 +0000 | [diff] [blame^] | 1183 | <p>$Id: xml.html,v 1.35 2000/06/30 17:58:22 veillard Exp $</p> |
Daniel Veillard | ccb0963 | 1998-10-27 06:21:04 +0000 | [diff] [blame] | 1184 | </body> |
| 1185 | </html> |