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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> |
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22 | <h2>Python and bindings</h2> |
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23 | </td></tr></table></td></tr></table></td> |
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49 | <li> |
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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> |
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57 | <tr><td bgcolor="#fffacd"><ul> |
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58 | <li><a href="tutorial/libxslttutorial.html">Tutorial</a></li> |
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59 | <li><a href="xsltproc.html">Man page for xsltproc</a></li> |
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60 | <li><a href="http://mail.gnome.org/archives/xslt/">Mail archive</a></li> |
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61 | <li><a href="http://xmlsoft.org/">XML libxml</a></li> |
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62 | <li><a href="http://phd.cs.unibo.it/gdome2/">DOM gdome2</a></li> |
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63 | <li><a href="ftp://xmlsoft.org/">FTP</a></li> |
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64 | <li><a href="http://www.zlatkovic.com/projects/libxml/">Windows binaries</a></li> |
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65 | <li><a href="http://garypennington.net/libxml2/">Solaris binaries</a></li> |
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66 | <li><a href="http://www.zveno.com/open_source/libxml2xslt.html">MacOsX binaries</a></li> |
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67 | <li><a href="http://sourceforge.net/projects/libxml2-pas/">Pascal bindings</a></li> |
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68 | <li><a href="http://bugzilla.gnome.org/buglist.cgi?product=libxslt">Bug Tracker</a></li> |
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69 | <li><a href="http://xsldbg.sourceforge.net/">Xsldbg Debugger</a></li> |
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73 | <tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>API Indexes</b></center></td></tr> |
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74 | <tr><td bgcolor="#fffacd"><ul> |
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75 | <li><a href="APIchunk0.html">Alphabetic</a></li> |
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84 | <p>There is a number of language bindings and wrappers available for libxml2, |
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85 | the list below is not exhaustive. Please contact the <a href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a> |
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86 | (<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in |
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87 | order to get updates to this list or to discuss the specific topic of libxml2 |
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88 | or libxslt wrappers or bindings:</p> |
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89 | <ul> |
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90 | <li> |
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91 | <a href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt |
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92 | Sergeant</a> developped <a href="http://axkit.org/download/">XML::LibXML |
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93 | and XML::LibXSLT</a>, a perl wrapper for libxml2/libxslt as part of the |
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94 | <a href="http://axkit.com/">AxKit XML application server</a> |
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95 | </li> |
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96 | <li> |
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97 | <a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides and |
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98 | earlier version of the libxml/libxslt <a href="http://www.rexx.com/~dkuhlman">wrappers for Python</a> |
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99 | </li> |
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100 | <li>Petr Kozelka provides <a href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue |
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101 | libxml2</a> with Kylix, Delphi and other Pascal compilers</li> |
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102 | <li>Wai-Sun "Squidster" Chia provides <a href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and |
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103 | libxml2 bindings are also available in Ruby through the <a href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module |
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104 | maintained by Tobias Peters.</li> |
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105 | <li>Steve Ball and contributors maintains <a href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for |
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106 | Tcl</a> |
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107 | </li> |
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108 | </ul> |
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109 | <p>The libxslt Python module depends on the <a href="http://xmlsoft.org/python.html">libxml2 Python</a> module.</p> |
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110 | <p>The distribution includes a set of Python bindings, which are garanteed to |
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111 | be maintained as part of the library in the future, though the Python |
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112 | interface have not yet reached the maturity of the C API.</p> |
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113 | <p> |
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114 | <a href="mailto:stephane.bidoul@softwareag.com">Stéphane Bidoul</a> |
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115 | maintains <a href="http://users.skynet.be/sbi/libxml-python/">a Windows port |
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116 | of the Python bindings</a>.</p> |
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117 | <p>Note to people interested in building bindings, the API is formalized as |
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118 | <a href="libxslt-api.xml">an XML API description file</a> which allows to |
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119 | automate a large part of the Python bindings, this includes function |
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120 | descriptions, enums, structures, typedefs, etc... The Python script used to |
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121 | build the bindings is python/generator.py in the source distribution.</p> |
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122 | <p>To install the Python bindings there are 2 options:</p> |
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123 | <ul> |
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124 | <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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125 | RPM</a> and the <a href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python |
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126 | RPM</a>.</li> |
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127 | <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python |
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128 | module distribution</a> corresponding to your installed version of |
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129 | libxml2 and libxslt. Note that to install it you will need both libxml2 |
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130 | and libxslt installed and run "python setup.py build install" in the |
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131 | module tree.</li> |
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132 | </ul> |
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133 | <p>The distribution includes a set of examples and regression tests for the |
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134 | python bindings in the <code>python/tests</code> directory. Here are some |
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135 | excepts from those tests:</p> |
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136 | <h3>basic.py:</h3> |
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137 | <p>This is a basic test of XSLT interfaces: loading a stylesheet and a |
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138 | document, transforming the document and saving the result.</p> |
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139 | <pre>import libxml2 |
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140 | import libxslt |
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141 | |
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142 | styledoc = libxml2.parseFile("test.xsl") |
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143 | style = libxslt.parseStylesheetDoc(styledoc) |
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144 | doc = libxml2.parseFile("test.xml") |
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145 | result = style.applyStylesheet(doc, None) |
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146 | style.saveResultToFilename("foo", result, 0) |
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147 | style.freeStylesheet() |
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148 | doc.freeDoc() |
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149 | result.freeDoc()</pre> |
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150 | <p>The Python module is called libxslt, you will also need the libxml2 module |
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151 | for the operations on XML trees. Let's have a look at the objects manipulated |
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152 | in that example and how is the processing done:</p> |
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153 | <ul> |
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154 | <li> |
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155 | <code>styledoc</code> : is a libxml2 document tree. It is obtained by |
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156 | parsing the XML file "test.xsl" containing the stylesheet.</li> |
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157 | <li> |
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158 | <code>style</code> : this is a precompiled stylesheet ready to be used |
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159 | by the following transformations (note the plural form, multiple |
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160 | transformations can resuse the same stylesheet).</li> |
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161 | <li> |
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162 | <code>doc</code> : this is the document to apply the transformation to. |
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163 | In this case it is simply generated by parsing it from a file but any |
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164 | other processing is possible as long as one get a libxml2 Doc. Note that |
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165 | HTML tree are suitable for XSLT processing in libxslt. This is actually |
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166 | how this page is generated !</li> |
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167 | <li> |
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168 | <code>result</code> : this is a document generated by applying the |
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169 | stylesheet to the document. Note that some of the stylesheet informations |
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170 | may be related to the serialization of that document and as in this |
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171 | example a specific saveResultToFilename() method of the stylesheet should |
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172 | be used to save it to a file (in that case to "foo").</li> |
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173 | </ul> |
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174 | <p>Also note the need to explicitely deallocate documents with freeDoc() |
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175 | except for the stylesheet document which is freed when its compiled form is |
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176 | garbage collected.</p> |
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177 | <h3>extfunc.py:</h3> |
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178 | <p>This one is a far more complex test. It shows how to modify the behaviour |
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179 | of an XSLT transformation by passing parameters and how to extend the XSLT |
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180 | engine with functions defined in python:</p> |
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181 | <pre>import libxml2 |
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182 | import libxslt |
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183 | import string |
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184 | |
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185 | nodeName = None |
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186 | def f(ctx, str): |
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187 | global nodeName |
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188 | |
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189 | # |
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190 | # Small check to verify the context is correcly accessed |
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191 | # |
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192 | try: |
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193 | pctxt = libxslt.xpathParserContext(_obj=ctx) |
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194 | ctxt = pctxt.context() |
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195 | tctxt = ctxt.transformContext() |
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196 | nodeName = tctxt.insertNode().name |
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197 | except: |
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198 | pass |
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199 | |
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200 | return string.upper(str) |
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201 | |
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202 | libxslt.registerExtModuleFunction("foo", "http://example.com/foo", f)</pre> |
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203 | <p>This code defines and register an extension function. Note that the |
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204 | function can be bound to any name (foo) and how the binding is also |
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205 | associated to a namespace name "http://example.com/foo". From an XSLT point |
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206 | of view the function just returns an upper case version of the string passed |
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207 | as a parameter. But the first part of the function also read some contextual |
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208 | information from the current XSLT processing environement, in that case it |
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209 | looks for the current insertion node in the resulting output (either the |
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210 | resulting document or the Result Value Tree being generated), and saves it to |
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211 | a global variable for checking that the access actually worked.</p> |
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212 | <p>For more informations on the xpathParserContext and transformContext |
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213 | objects check the <a href="internals.html">libray internals description</a>. |
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214 | The pctxt is actually an object from a class derived from the |
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215 | libxml2.xpathParserContext() with just a couple more properties including the |
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216 | possibility to look up the XSLT transformation context from the XPath |
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217 | context.</p> |
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218 | <pre>styledoc = libxml2.parseDoc(""" |
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219 | <xsl:stylesheet version='1.0' |
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220 | xmlns:xsl='http://www.w3.org/1999/XSL/Transform' |
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221 | xmlns:foo='http://example.com/foo' |
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222 | xsl:exclude-result-prefixes='foo'> |
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223 | |
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224 | <xsl:param name='bar'>failure</xsl:param> |
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225 | <xsl:template match='/'> |
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226 | <article><xsl:value-of select='foo:foo($bar)'/></article> |
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227 | </xsl:template> |
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228 | </xsl:stylesheet> |
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229 | """)</pre> |
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230 | <p>Here is a simple example of how to read an XML document from a python |
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231 | string with libxml2. Note how this stylesheet:</p> |
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232 | <ul> |
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233 | <li>Uses a global parameter <code>bar</code> |
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234 | </li> |
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235 | <li>Reference the extension function f</li> |
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236 | <li>how the Namespace name "http://example.com/foo" has to be bound to a |
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237 | prefix</li> |
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238 | <li>how that prefix is excluded from the output</li> |
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239 | <li>how the function is called from the select</li> |
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240 | </ul> |
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241 | <pre>style = libxslt.parseStylesheetDoc(styledoc) |
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242 | doc = libxml2.parseDoc("<doc/>") |
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243 | result = style.applyStylesheet(doc, { "bar": "'success'" }) |
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244 | style.freeStylesheet() |
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245 | doc.freeDoc()</pre> |
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246 | <p>that part is identical, to the basic example except that the |
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247 | transformation is passed a dictionnary of parameters. Note that the string |
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248 | passed "success" had to be quoted, otherwise it is interpreted as an XPath |
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249 | query for the childs of root named "success".</p> |
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250 | <pre>root = result.children |
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251 | if root.name != "article": |
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252 | print "Unexpected root node name" |
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253 | sys.exit(1) |
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254 | if root.content != "SUCCESS": |
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255 | print "Unexpected root node content, extension function failed" |
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256 | sys.exit(1) |
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257 | if nodeName != 'article': |
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258 | print "The function callback failed to access its context" |
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259 | sys.exit(1) |
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260 | |
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261 | result.freeDoc()</pre> |
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262 | <p>That part just verifies that the transformation worked, that the parameter |
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263 | got properly passed to the engine, that the function f() got called and that |
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264 | it properly accessed the context to find the name of the insertion node.</p> |
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265 | <h3>pyxsltproc.py:</h3> |
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266 | <p>this module is a bit too long to be described there but it is basically a |
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267 | rewrite of the xsltproc command line interface of libxslt in Python. It |
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268 | provides nearly all the functionalities of xsltproc and can be used as a base |
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269 | module to write Python customized XSLT processors. One of the thing to notice |
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270 | are:</p> |
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271 | <pre>libxml2.lineNumbersDefault(1) |
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272 | libxml2.substituteEntitiesDefault(1)</pre> |
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273 | <p>those two calls in the main() function are needed to force the libxml2 |
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274 | processor to generate DOM trees compliant with the XPath data model.</p> |
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275 | <p><a href="bugs.html">Daniel Veillard</a></p> |
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276 | </td></tr></table></td></tr></table></td></tr></table></td> |
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277 | </tr></table></td></tr></table> |
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279 | </html> |
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