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18 <a href="http://www.gnome.org/"><img src="gnome2.png" alt="Gnome2 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>
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21 <h1>The XSLT C library for Gnome</h1>
22 <h2>Python and bindings</h2>
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50 <a href="xslt.html">flat page</a>, <a href="site.xsl">stylesheet</a>
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56 <tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Related links</b></center></td></tr>
57 <tr><td bgcolor="#fffacd"><ul>
58 <li><a href="tutorial/libxslttutorial.html">Tutorial</a></li>
59 <li><a href="xsltproc.html">Man page for xsltproc</a></li>
60 <li><a href="http://mail.gnome.org/archives/xslt/">Mail archive</a></li>
61 <li><a href="http://xmlsoft.org/">XML libxml</a></li>
62 <li><a href="http://phd.cs.unibo.it/gdome2/">DOM gdome2</a></li>
63 <li><a href="ftp://xmlsoft.org/">FTP</a></li>
64 <li><a href="http://www.zlatkovic.com/projects/libxml/">Windows binaries</a></li>
65 <li><a href="http://garypennington.net/libxml2/">Solaris binaries</a></li>
66 <li><a href="http://www.zveno.com/open_source/libxml2xslt.html">MacOsX binaries</a></li>
67 <li><a href="http://sourceforge.net/projects/libxml2-pas/">Pascal bindings</a></li>
68 <li><a href="http://bugzilla.gnome.org/buglist.cgi?product=libxslt">Bug Tracker</a></li>
69 <li><a href="http://xsldbg.sourceforge.net/">Xsldbg Debugger</a></li>
70 <li><a href="http://www.mod-xslt.com/mod-xslt/">Apache module</a></li>
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85 <p>There is a number of language bindings and wrappers available for libxml2,
86 the list below is not exhaustive. Please contact the <a href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a>
87 (<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in
88 order to get updates to this list or to discuss the specific topic of libxml2
89 or libxslt wrappers or bindings:</p>
92 <a href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
93 Sergeant</a> developped <a href="http://axkit.org/download/">XML::LibXML
94 and XML::LibXSLT</a>, Perl wrappers for libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML application server</a>
97 <a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides and
98 earlier version of the libxml/libxslt <a href="http://www.rexx.com/~dkuhlman">wrappers for Python</a>
100 <li>Petr Kozelka provides <a href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
101 libxml2</a> with Kylix, Delphi and other Pascal compilers</li>
102 <li>Wai-Sun "Squidster" Chia provides <a href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
103 libxml2 bindings are also available in Ruby through the <a href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
104 maintained by Tobias Peters.</li>
105 <li>Steve Ball and contributors maintains <a href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
109 <a href="mailto:xmlwrapp@pmade.org">Peter Jones</a> maintains C++
110 bindings for libxslt within <a href="http://pmade.org/pjones/software/xmlwrapp/">xmlwrapp</a>
113 <a href="phillim2@comcast.net">Mike Phillips</a> provides a module
114 using <a href="http://siasl.dyndns.org/projects/projects.html">libxslt
117 <a href="http://savannah.gnu.org/projects/classpathx/">LibxmlJ</a> is
118 an effort to create a 100% JAXP-compatible Java wrapper for libxml2 and
119 libxslt as part of GNU ClasspathX project.</li>
121 <p>The libxslt Python module depends on the <a href="http://xmlsoft.org/python.html">libxml2 Python</a> module.</p>
122 <p>The distribution includes a set of Python bindings, which are garanteed to
123 be maintained as part of the library in the future, though the Python
124 interface have not yet reached the completeness of the C API.</p>
126 <a href="mailto:stephane.bidoul@softwareag.com">Stéphane Bidoul</a>
127 maintains <a href="http://users.skynet.be/sbi/libxml-python/">a Windows port
128 of the Python bindings</a>.</p>
129 <p>Note to people interested in building bindings, the API is formalized as
130 <a href="libxslt-api.xml">an XML API description file</a> which allows to
131 automate a large part of the Python bindings, this includes function
132 descriptions, enums, structures, typedefs, etc... The Python script used to
133 build the bindings is python/generator.py in the source distribution.</p>
134 <p>To install the Python bindings there are 2 options:</p>
136 <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
137 RPM</a> and the <a href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
139 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python
140 module distribution</a> corresponding to your installed version of
141 libxml2 and libxslt. Note that to install it you will need both libxml2
142 and libxslt installed and run "python setup.py build install" in the
145 <p>The distribution includes a set of examples and regression tests for the
146 python bindings in the <code>python/tests</code> directory. Here are some
147 excepts from those tests:</p>
149 <p>This is a basic test of XSLT interfaces: loading a stylesheet and a
150 document, transforming the document and saving the result.</p>
154 styledoc = libxml2.parseFile("test.xsl")
155 style = libxslt.parseStylesheetDoc(styledoc)
156 doc = libxml2.parseFile("test.xml")
157 result = style.applyStylesheet(doc, None)
158 style.saveResultToFilename("foo", result, 0)
159 style.freeStylesheet()
161 result.freeDoc()</pre>
162 <p>The Python module is called libxslt, you will also need the libxml2 module
163 for the operations on XML trees. Let's have a look at the objects manipulated
164 in that example and how is the processing done:</p>
167 <code>styledoc</code> : is a libxml2 document tree. It is obtained by
168 parsing the XML file "test.xsl" containing the stylesheet.</li>
170 <code>style</code> : this is a precompiled stylesheet ready to be used
171 by the following transformations (note the plural form, multiple
172 transformations can resuse the same stylesheet).</li>
174 <code>doc</code> : this is the document to apply the transformation to.
175 In this case it is simply generated by parsing it from a file but any
176 other processing is possible as long as one get a libxml2 Doc. Note that
177 HTML tree are suitable for XSLT processing in libxslt. This is actually
178 how this page is generated !</li>
180 <code>result</code> : this is a document generated by applying the
181 stylesheet to the document. Note that some of the stylesheet informations
182 may be related to the serialization of that document and as in this
183 example a specific saveResultToFilename() method of the stylesheet should
184 be used to save it to a file (in that case to "foo").</li>
186 <p>Also note the need to explicitely deallocate documents with freeDoc()
187 except for the stylesheet document which is freed when its compiled form is
188 garbage collected.</p>
190 <p>This one is a far more complex test. It shows how to modify the behaviour
191 of an XSLT transformation by passing parameters and how to extend the XSLT
192 engine with functions defined in python:</p>
202 # Small check to verify the context is correcly accessed
205 pctxt = libxslt.xpathParserContext(_obj=ctx)
206 ctxt = pctxt.context()
207 tctxt = ctxt.transformContext()
208 nodeName = tctxt.insertNode().name
212 return string.upper(str)
214 libxslt.registerExtModuleFunction("foo", "http://example.com/foo", f)</pre>
215 <p>This code defines and register an extension function. Note that the
216 function can be bound to any name (foo) and how the binding is also
217 associated to a namespace name "http://example.com/foo". From an XSLT point
218 of view the function just returns an upper case version of the string passed
219 as a parameter. But the first part of the function also read some contextual
220 information from the current XSLT processing environement, in that case it
221 looks for the current insertion node in the resulting output (either the
222 resulting document or the Result Value Tree being generated), and saves it to
223 a global variable for checking that the access actually worked.</p>
224 <p>For more informations on the xpathParserContext and transformContext
225 objects check the <a href="internals.html">libray internals description</a>.
226 The pctxt is actually an object from a class derived from the
227 libxml2.xpathParserContext() with just a couple more properties including the
228 possibility to look up the XSLT transformation context from the XPath
230 <pre>styledoc = libxml2.parseDoc("""
231 <xsl:stylesheet version='1.0'
232 xmlns:xsl='http://www.w3.org/1999/XSL/Transform'
233 xmlns:foo='http://example.com/foo'
234 xsl:exclude-result-prefixes='foo'>
236 <xsl:param name='bar'>failure</xsl:param>
237 <xsl:template match='/'>
238 <article><xsl:value-of select='foo:foo($bar)'/></article>
239 </xsl:template>
240 </xsl:stylesheet>
241 """)</pre>
242 <p>Here is a simple example of how to read an XML document from a python
243 string with libxml2. Note how this stylesheet:</p>
245 <li>Uses a global parameter <code>bar</code>
247 <li>Reference the extension function f</li>
248 <li>how the Namespace name "http://example.com/foo" has to be bound to a
250 <li>how that prefix is excluded from the output</li>
251 <li>how the function is called from the select</li>
253 <pre>style = libxslt.parseStylesheetDoc(styledoc)
254 doc = libxml2.parseDoc("<doc/>")
255 result = style.applyStylesheet(doc, { "bar": "'success'" })
256 style.freeStylesheet()
258 <p>that part is identical, to the basic example except that the
259 transformation is passed a dictionnary of parameters. Note that the string
260 passed "success" had to be quoted, otherwise it is interpreted as an XPath
261 query for the childs of root named "success".</p>
262 <pre>root = result.children
263 if root.name != "article":
264 print "Unexpected root node name"
266 if root.content != "SUCCESS":
267 print "Unexpected root node content, extension function failed"
269 if nodeName != 'article':
270 print "The function callback failed to access its context"
273 result.freeDoc()</pre>
274 <p>That part just verifies that the transformation worked, that the parameter
275 got properly passed to the engine, that the function f() got called and that
276 it properly accessed the context to find the name of the insertion node.</p>
277 <h3>pyxsltproc.py:</h3>
278 <p>this module is a bit too long to be described there but it is basically a
279 rewrite of the xsltproc command line interface of libxslt in Python. It
280 provides nearly all the functionalities of xsltproc and can be used as a base
281 module to write Python customized XSLT processors. One of the thing to notice
283 <pre>libxml2.lineNumbersDefault(1)
284 libxml2.substituteEntitiesDefault(1)</pre>
285 <p>those two calls in the main() function are needed to force the libxml2
286 processor to generate DOM trees compliant with the XPath data model.</p>
287 <p><a href="bugs.html">Daniel Veillard</a></p>
288 </td></tr></table></td></tr></table></td></tr></table></td>
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