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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>, a perl wrapper for libxml2/libxslt as part of the
95 <a href="http://axkit.com/">AxKit XML application server</a>
98 <a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides and
99 earlier version of the libxml/libxslt <a href="http://www.rexx.com/~dkuhlman">wrappers for Python</a>
101 <li>Petr Kozelka provides <a href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
102 libxml2</a> with Kylix, Delphi and other Pascal compilers</li>
103 <li>Wai-Sun "Squidster" Chia provides <a href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
104 libxml2 bindings are also available in Ruby through the <a href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
105 maintained by Tobias Peters.</li>
106 <li>Steve Ball and contributors maintains <a href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
110 <a href="mailto:xmlwrapp@pmade.org">Peter Jones</a> maintains C++
111 bindings for libxslt within <a href="http://pmade.org/pjones/software/xmlwrapp/">xmlwrapp</a>
114 <a href="phillim2@comcast.net">Mike Phillips</a> provides a module
115 using <a href="http://siasl.dyndns.org/projects/projects.html">libxslt
118 <p>The libxslt Python module depends on the <a href="http://xmlsoft.org/python.html">libxml2 Python</a> module.</p>
119 <p>The distribution includes a set of Python bindings, which are garanteed to
120 be maintained as part of the library in the future, though the Python
121 interface have not yet reached the maturity of the C API.</p>
123 <a href="mailto:stephane.bidoul@softwareag.com">Stéphane Bidoul</a>
124 maintains <a href="http://users.skynet.be/sbi/libxml-python/">a Windows port
125 of the Python bindings</a>.</p>
126 <p>Note to people interested in building bindings, the API is formalized as
127 <a href="libxslt-api.xml">an XML API description file</a> which allows to
128 automate a large part of the Python bindings, this includes function
129 descriptions, enums, structures, typedefs, etc... The Python script used to
130 build the bindings is python/generator.py in the source distribution.</p>
131 <p>To install the Python bindings there are 2 options:</p>
133 <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
134 RPM</a> and the <a href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
136 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python
137 module distribution</a> corresponding to your installed version of
138 libxml2 and libxslt. Note that to install it you will need both libxml2
139 and libxslt installed and run "python setup.py build install" in the
142 <p>The distribution includes a set of examples and regression tests for the
143 python bindings in the <code>python/tests</code> directory. Here are some
144 excepts from those tests:</p>
146 <p>This is a basic test of XSLT interfaces: loading a stylesheet and a
147 document, transforming the document and saving the result.</p>
151 styledoc = libxml2.parseFile("test.xsl")
152 style = libxslt.parseStylesheetDoc(styledoc)
153 doc = libxml2.parseFile("test.xml")
154 result = style.applyStylesheet(doc, None)
155 style.saveResultToFilename("foo", result, 0)
156 style.freeStylesheet()
158 result.freeDoc()</pre>
159 <p>The Python module is called libxslt, you will also need the libxml2 module
160 for the operations on XML trees. Let's have a look at the objects manipulated
161 in that example and how is the processing done:</p>
164 <code>styledoc</code> : is a libxml2 document tree. It is obtained by
165 parsing the XML file "test.xsl" containing the stylesheet.</li>
167 <code>style</code> : this is a precompiled stylesheet ready to be used
168 by the following transformations (note the plural form, multiple
169 transformations can resuse the same stylesheet).</li>
171 <code>doc</code> : this is the document to apply the transformation to.
172 In this case it is simply generated by parsing it from a file but any
173 other processing is possible as long as one get a libxml2 Doc. Note that
174 HTML tree are suitable for XSLT processing in libxslt. This is actually
175 how this page is generated !</li>
177 <code>result</code> : this is a document generated by applying the
178 stylesheet to the document. Note that some of the stylesheet informations
179 may be related to the serialization of that document and as in this
180 example a specific saveResultToFilename() method of the stylesheet should
181 be used to save it to a file (in that case to "foo").</li>
183 <p>Also note the need to explicitely deallocate documents with freeDoc()
184 except for the stylesheet document which is freed when its compiled form is
185 garbage collected.</p>
187 <p>This one is a far more complex test. It shows how to modify the behaviour
188 of an XSLT transformation by passing parameters and how to extend the XSLT
189 engine with functions defined in python:</p>
199 # Small check to verify the context is correcly accessed
202 pctxt = libxslt.xpathParserContext(_obj=ctx)
203 ctxt = pctxt.context()
204 tctxt = ctxt.transformContext()
205 nodeName = tctxt.insertNode().name
209 return string.upper(str)
211 libxslt.registerExtModuleFunction("foo", "http://example.com/foo", f)</pre>
212 <p>This code defines and register an extension function. Note that the
213 function can be bound to any name (foo) and how the binding is also
214 associated to a namespace name "http://example.com/foo". From an XSLT point
215 of view the function just returns an upper case version of the string passed
216 as a parameter. But the first part of the function also read some contextual
217 information from the current XSLT processing environement, in that case it
218 looks for the current insertion node in the resulting output (either the
219 resulting document or the Result Value Tree being generated), and saves it to
220 a global variable for checking that the access actually worked.</p>
221 <p>For more informations on the xpathParserContext and transformContext
222 objects check the <a href="internals.html">libray internals description</a>.
223 The pctxt is actually an object from a class derived from the
224 libxml2.xpathParserContext() with just a couple more properties including the
225 possibility to look up the XSLT transformation context from the XPath
227 <pre>styledoc = libxml2.parseDoc("""
228 <xsl:stylesheet version='1.0'
229 xmlns:xsl='http://www.w3.org/1999/XSL/Transform'
230 xmlns:foo='http://example.com/foo'
231 xsl:exclude-result-prefixes='foo'>
233 <xsl:param name='bar'>failure</xsl:param>
234 <xsl:template match='/'>
235 <article><xsl:value-of select='foo:foo($bar)'/></article>
236 </xsl:template>
237 </xsl:stylesheet>
238 """)</pre>
239 <p>Here is a simple example of how to read an XML document from a python
240 string with libxml2. Note how this stylesheet:</p>
242 <li>Uses a global parameter <code>bar</code>
244 <li>Reference the extension function f</li>
245 <li>how the Namespace name "http://example.com/foo" has to be bound to a
247 <li>how that prefix is excluded from the output</li>
248 <li>how the function is called from the select</li>
250 <pre>style = libxslt.parseStylesheetDoc(styledoc)
251 doc = libxml2.parseDoc("<doc/>")
252 result = style.applyStylesheet(doc, { "bar": "'success'" })
253 style.freeStylesheet()
255 <p>that part is identical, to the basic example except that the
256 transformation is passed a dictionnary of parameters. Note that the string
257 passed "success" had to be quoted, otherwise it is interpreted as an XPath
258 query for the childs of root named "success".</p>
259 <pre>root = result.children
260 if root.name != "article":
261 print "Unexpected root node name"
263 if root.content != "SUCCESS":
264 print "Unexpected root node content, extension function failed"
266 if nodeName != 'article':
267 print "The function callback failed to access its context"
270 result.freeDoc()</pre>
271 <p>That part just verifies that the transformation worked, that the parameter
272 got properly passed to the engine, that the function f() got called and that
273 it properly accessed the context to find the name of the insertion node.</p>
274 <h3>pyxsltproc.py:</h3>
275 <p>this module is a bit too long to be described there but it is basically a
276 rewrite of the xsltproc command line interface of libxslt in Python. It
277 provides nearly all the functionalities of xsltproc and can be used as a base
278 module to write Python customized XSLT processors. One of the thing to notice
280 <pre>libxml2.lineNumbersDefault(1)
281 libxml2.substituteEntitiesDefault(1)</pre>
282 <p>those two calls in the main() function are needed to force the libxml2
283 processor to generate DOM trees compliant with the XPath data model.</p>
284 <p><a href="bugs.html">Daniel Veillard</a></p>
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