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| 10 | </style><title>Python and bindings</title></head><body bgcolor="#8b7765" text="#000000" link="#a06060" vlink="#000000"><table border="0" width="100%" cellpadding="5" cellspacing="0" align="center"><tr><td width="120"><a href="http://swpat.ffii.org/"><img src="epatents.png" alt="Action against software patents" /></a></td><td width="180"><a href="http://www.gnome.org/"><img src="gnome2.png" alt="GNOME2 Logo" /></a><a href="http://www.w3.org/Status"><img src="w3c.png" alt="W3C logo" /></a><a href="http://www.redhat.com"><img src="redhat.gif" alt="Red Hat Logo" /></a><div align="left"><a href="http://xmlsoft.org/XSLT/"><img src="Libxslt-Logo-180x168.gif" alt="Made with Libxslt Logo" /></a></div></td><td><table border="0" width="90%" cellpadding="2" cellspacing="0" align="center" bgcolor="#000000"><tr><td><table width="100%" border="0" cellspacing="1" cellpadding="3" bgcolor="#fffacd"><tr><td align="center"><h1>The XSLT C library for GNOME</h1><h2>Python and bindings</h2></td></tr></table></td></tr></table></td></tr></table><table border="0" cellpadding="4" cellspacing="0" width="100%" align="center"><tr><td bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td valign="top" width="200" bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="1" width="100%" bgcolor="#000000"><tr><td><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Main Menu</b></center></td></tr><tr><td bgcolor="#fffacd"><form action="search.php" enctype="application/x-www-form-urlencoded" method="get"><input name="query" type="text" size="20" value="" /><input name="submit" type="submit" value="Search ..." /></form><ul><li><a href="index.html">Home</a></li><li><a href="intro.html">Introduction</a></li><li><a href="docs.html">Documentation</a></li><li><a href="bugs.html">Reporting bugs and getting help</a></li><li><a href="help.html">How to help</a></li><li><a href="downloads.html">Downloads</a></li><li><a href="FAQ.html">FAQ</a></li><li><a href="news.html">News</a></li><li><a href="xsltproc2.html">The xsltproc tool</a></li><li><a href="docbook.html">DocBook</a></li><li><a href="API.html">The programming API</a></li><li><a href="python.html">Python and bindings</a></li><li><a href="internals.html">Library internals</a></li><li><a href="extensions.html">Writing extensions</a></li><li><a href="contribs.html">Contributions</a></li><li><a href="EXSLT/index.html" style="font-weight:bold">libexslt</a></li><li><a href="xslt.html">flat page</a>, <a href="site.xsl">stylesheet</a></li><li><a href="html/index.html" style="font-weight:bold">API Menu</a></li><li><a href="ChangeLog.html">ChangeLog</a></li></ul></td></tr></table><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Related links</b></center></td></tr><tr><td bgcolor="#fffacd"><ul><li><a href="tutorial/libxslttutorial.html">Tutorial</a>,
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| 11 | <a href="tutorial2/libxslt_pipes.html">Tutorial2</a></li><li><a href="xsltproc.html">Man page for xsltproc</a></li><li><a href="http://mail.gnome.org/archives/xslt/">Mail archive</a></li><li><a href="http://xmlsoft.org/">XML libxml2</a></li><li><a href="ftp://xmlsoft.org/">FTP</a></li><li><a href="http://www.zlatkovic.com/projects/libxml/">Windows binaries</a></li><li><a href="http://garypennington.net/libxml2/">Solaris binaries</a></li><li><a href="http://www.explain.com.au/oss/libxml2xslt.html">MacOsX binaries</a></li><li><a href="http://bugzilla.gnome.org/buglist.cgi?product=libxslt">Bug Tracker</a></li><li><a href="http://codespeak.net/lxml/">lxml Python bindings</a></li><li><a href="http://cpan.uwinnipeg.ca/dist/XML-LibXSLT">Perl XSLT bindings</a></li><li><a href="http://www.zend.com/php5/articles/php5-xmlphp.php#Heading17">XSLT with PHP</a></li><li><a href="http://www.mod-xslt2.com/">Apache module</a></li><li><a href="http://sourceforge.net/projects/libxml2-pas/">Pascal bindings</a></li><li><a href="http://xsldbg.sourceforge.net/">Xsldbg Debugger</a></li></ul></td></tr></table><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>API Indexes</b></center></td></tr><tr><td bgcolor="#fffacd"><ul><li><a href="APIchunk0.html">Alphabetic</a></li><li><a href="APIconstructors.html">Constructors</a></li><li><a href="APIfunctions.html">Functions/Types</a></li><li><a href="APIfiles.html">Modules</a></li><li><a href="APIsymbols.html">Symbols</a></li></ul></td></tr></table></td></tr></table></td><td valign="top" bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="1" width="100%"><tr><td><table border="0" cellspacing="0" cellpadding="1" width="100%" bgcolor="#000000"><tr><td><table border="0" cellpadding="3" cellspacing="1" width="100%"><tr><td bgcolor="#fffacd"><p>There is a number of language bindings and wrappers available for libxml2,
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| 12 | the list below is not exhaustive. Please contact the <a href="http://mail.gnome.org/mailman/listinfo/xml-bindings">[email protected]</a>
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| 13 | (<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in
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| 14 | order to get updates to this list or to discuss the specific topic of libxml2
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| 15 | or libxslt wrappers or bindings:</p><ul><li><a href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
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| 16 | Sergeant</a> developped <a href="http://axkit.org/download/">XML::LibXML
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| 17 | and XML::LibXSLT</a>, Perl wrappers for libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML application server</a></li>
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| 18 | <li><a href="mailto:[email protected]">Dave Kuhlman</a> provides and
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| 19 | earlier version of the libxml/libxslt <a href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
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| 20 | <li>Petr Kozelka provides <a href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
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| 21 | libxml2</a> with Kylix, Delphi and other Pascal compilers</li>
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| 22 | <li>Wai-Sun "Squidster" Chia provides <a href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
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| 23 | libxml2 bindings are also available in Ruby through the <a href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
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| 24 | maintained by Tobias Peters.</li>
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| 25 | <li>Steve Ball and contributors maintains <a href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
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| 26 | Tcl</a></li>
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| 27 | <li><a href="mailto:[email protected]">Peter Jones</a> maintains C++
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| 28 | bindings for libxslt within <a href="http://pmade.org/pjones/software/xmlwrapp/">xmlwrapp</a></li>
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| 29 | <li><a href="[email protected]">Mike Phillips</a> provides a module
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| 30 | using <a href="http://siasl.dyndns.org/projects/projects.html">libxslt
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| 31 | for PHP</a>.</li>
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| 32 | <li><a href="http://savannah.gnu.org/projects/classpathx/">LibxmlJ</a> is
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| 33 | an effort to create a 100% JAXP-compatible Java wrapper for libxml2 and
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| 34 | libxslt as part of GNU ClasspathX project.</li>
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| 35 | <li>Patrick McPhee provides Rexx bindings fof libxml2 and libxslt, look for
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| 36 | <a href="http://www.interlog.com/~ptjm/software.html">RexxXML</a>.</li>
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| 37 | <li><a href="http://www.satimage.fr/software/en/xml_suite.html">Satimage</a>
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| 38 | provides <a href="http://www.satimage.fr/software/en/downloads_osaxen.html">XMLLib
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| 39 | osax</a>. This is an osax for Mac OS X with a set of commands to
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| 40 | implement in AppleScript the XML DOM, XPATH and XSLT.</li>
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| 41 | </ul><p>The libxslt Python module depends on the <a href="http://xmlsoft.org/python.html">libxml2 Python</a> module.</p><p>The distribution includes a set of Python bindings, which are guaranteed to
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| 42 | be maintained as part of the library in the future, though the Python
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| 43 | interface have not yet reached the completeness of the C API.</p><p><a href="mailto:[email protected]">Stéphane Bidoul</a>
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| 44 | maintains <a href="http://users.skynet.be/sbi/libxml-python/">a Windows port
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| 45 | of the Python bindings</a>.</p><p>Note to people interested in building bindings, the API is formalized as
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| 46 | <a href="libxslt-api.xml">an XML API description file</a> which allows to
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| 47 | automate a large part of the Python bindings, this includes function
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| 48 | descriptions, enums, structures, typedefs, etc... The Python script used to
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| 49 | build the bindings is python/generator.py in the source distribution.</p><p>To install the Python bindings there are 2 options:</p><ul><li>If you use an RPM based distribution, simply install the <a href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python
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| 50 | RPM</a> and the <a href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
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| 51 | RPM</a>.</li>
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| 52 | <li>Otherwise use the <a href="ftp://xmlsoft.org/libxml2/python/">libxml2-python
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| 53 | module distribution</a> corresponding to your installed version of
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| 54 | libxml2 and libxslt. Note that to install it you will need both libxml2
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| 55 | and libxslt installed and run "python setup.py build install" in the
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| 56 | module tree.</li>
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| 57 | </ul><p>The distribution includes a set of examples and regression tests for the
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| 58 | python bindings in the <code>python/tests</code> directory. Here are some
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| 59 | excepts from those tests:</p><h3>basic.py:</h3><p>This is a basic test of XSLT interfaces: loading a stylesheet and a
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| 60 | document, transforming the document and saving the result.</p><pre>import libxml2
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| 61 | import libxslt
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| 62 |
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| 63 | styledoc = libxml2.parseFile("test.xsl")
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| 64 | style = libxslt.parseStylesheetDoc(styledoc)
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| 65 | doc = libxml2.parseFile("test.xml")
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| 66 | result = style.applyStylesheet(doc, None)
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| 67 | style.saveResultToFilename("foo", result, 0)
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| 68 | style.freeStylesheet()
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| 69 | doc.freeDoc()
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| 70 | result.freeDoc()</pre><p>The Python module is called libxslt, you will also need the libxml2 module
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| 71 | for the operations on XML trees. Let's have a look at the objects manipulated
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| 72 | in that example and how is the processing done:</p><ul><li><code>styledoc</code> : is a libxml2 document tree. It is obtained by
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| 73 | parsing the XML file "test.xsl" containing the stylesheet.</li>
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| 74 | <li><code>style</code> : this is a precompiled stylesheet ready to be used
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| 75 | by the following transformations (note the plural form, multiple
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| 76 | transformations can resuse the same stylesheet).</li>
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| 77 | <li><code>doc</code> : this is the document to apply the transformation to.
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| 78 | In this case it is simply generated by parsing it from a file but any
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| 79 | other processing is possible as long as one get a libxml2 Doc. Note that
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| 80 | HTML tree are suitable for XSLT processing in libxslt. This is actually
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| 81 | how this page is generated !</li>
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| 82 | <li><code>result</code> : this is a document generated by applying the
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| 83 | stylesheet to the document. Note that some of the stylesheet information
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| 84 | may be related to the serialization of that document and as in this
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| 85 | example a specific saveResultToFilename() method of the stylesheet should
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| 86 | be used to save it to a file (in that case to "foo").</li>
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| 87 | </ul><p>Also note the need to explicitely deallocate documents with freeDoc()
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| 88 | except for the stylesheet document which is freed when its compiled form is
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| 89 | garbage collected.</p><h3>extfunc.py:</h3><p>This one is a far more complex test. It shows how to modify the behaviour
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| 90 | of an XSLT transformation by passing parameters and how to extend the XSLT
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| 91 | engine with functions defined in python:</p><pre>import libxml2
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| 92 | import libxslt
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| 93 | import string
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| 94 |
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| 95 | nodeName = None
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| 96 | def f(ctx, str):
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| 97 | global nodeName
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| 98 |
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| 99 | #
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| 100 | # Small check to verify the context is correcly accessed
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| 101 | #
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| 102 | try:
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| 103 | pctxt = libxslt.xpathParserContext(_obj=ctx)
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| 104 | ctxt = pctxt.context()
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| 105 | tctxt = ctxt.transformContext()
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| 106 | nodeName = tctxt.insertNode().name
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| 107 | except:
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| 108 | pass
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| 109 |
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| 110 | return string.upper(str)
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| 111 |
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| 112 | libxslt.registerExtModuleFunction("foo", "http://example.com/foo", f)</pre><p>This code defines and register an extension function. Note that the
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| 113 | function can be bound to any name (foo) and how the binding is also
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| 114 | associated to a namespace name "http://example.com/foo". From an XSLT point
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| 115 | of view the function just returns an upper case version of the string passed
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| 116 | as a parameter. But the first part of the function also read some contextual
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| 117 | information from the current XSLT processing environement, in that case it
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| 118 | looks for the current insertion node in the resulting output (either the
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| 119 | resulting document or the Result Value Tree being generated), and saves it to
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| 120 | a global variable for checking that the access actually worked.</p><p>For more information on the xpathParserContext and transformContext
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| 121 | objects check the <a href="internals.html">libray internals description</a>.
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| 122 | The pctxt is actually an object from a class derived from the
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| 123 | libxml2.xpathParserContext() with just a couple more properties including the
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| 124 | possibility to look up the XSLT transformation context from the XPath
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| 125 | context.</p><pre>styledoc = libxml2.parseDoc("""
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| 126 | <xsl:stylesheet version='1.0'
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| 127 | xmlns:xsl='http://www.w3.org/1999/XSL/Transform'
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| 128 | xmlns:foo='http://example.com/foo'
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| 129 | xsl:exclude-result-prefixes='foo'>
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| 130 |
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| 131 | <xsl:param name='bar'>failure</xsl:param>
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| 132 | <xsl:template match='/'>
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| 133 | <article><xsl:value-of select='foo:foo($bar)'/></article>
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| 134 | </xsl:template>
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| 135 | </xsl:stylesheet>
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| 136 | """)</pre><p>Here is a simple example of how to read an XML document from a python
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| 137 | string with libxml2. Note how this stylesheet:</p><ul><li>Uses a global parameter <code>bar</code></li>
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| 138 | <li>Reference the extension function f</li>
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| 139 | <li>how the Namespace name "http://example.com/foo" has to be bound to a
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| 140 | prefix</li>
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| 141 | <li>how that prefix is excluded from the output</li>
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| 142 | <li>how the function is called from the select</li>
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| 143 | </ul><pre>style = libxslt.parseStylesheetDoc(styledoc)
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| 144 | doc = libxml2.parseDoc("<doc/>")
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| 145 | result = style.applyStylesheet(doc, { "bar": "'success'" })
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| 146 | style.freeStylesheet()
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| 147 | doc.freeDoc()</pre><p>that part is identical, to the basic example except that the
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| 148 | transformation is passed a dictionary of parameters. Note that the string
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| 149 | passed "success" had to be quoted, otherwise it is interpreted as an XPath
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| 150 | query for the childs of root named "success".</p><pre>root = result.children
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| 151 | if root.name != "article":
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| 152 | print "Unexpected root node name"
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| 153 | sys.exit(1)
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| 154 | if root.content != "SUCCESS":
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| 155 | print "Unexpected root node content, extension function failed"
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| 156 | sys.exit(1)
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| 157 | if nodeName != 'article':
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| 158 | print "The function callback failed to access its context"
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| 159 | sys.exit(1)
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| 160 |
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| 161 | result.freeDoc()</pre><p>That part just verifies that the transformation worked, that the parameter
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| 162 | got properly passed to the engine, that the function f() got called and that
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| 163 | it properly accessed the context to find the name of the insertion node.</p><h3>pyxsltproc.py:</h3><p>this module is a bit too long to be described there but it is basically a
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| 164 | rewrite of the xsltproc command line interface of libxslt in Python. It
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| 165 | provides nearly all the functionalities of xsltproc and can be used as a base
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| 166 | module to write Python customized XSLT processors. One of the thing to notice
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| 167 | are:</p><pre>libxml2.lineNumbersDefault(1)
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| 168 | libxml2.substituteEntitiesDefault(1)</pre><p>those two calls in the main() function are needed to force the libxml2
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| 169 | processor to generate DOM trees compliant with the XPath data model.</p><p><a href="bugs.html">Daniel Veillard</a></p></td></tr></table></td></tr></table></td></tr></table></td></tr></table></td></tr></table></body></html>
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