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LibXSLT(3)                           User Contributed Perl Documentation                          LibXSLT(3)



NAME
       XML::LibXSLT - Interface to the gnome libxslt library

SYNOPSIS
         use XML::LibXSLT;
         use XML::LibXML;

         my $xslt = XML::LibXSLT->new();

         my $source = XML::LibXML->load_xml(location => 'foo.xml');
         my $style_doc = XML::LibXML->load_xml(location=>'bar.xsl', no_cdata=>1);

         my $stylesheet = $xslt->parse_stylesheet($style_doc);

         my $results = $stylesheet->transform($source);

         print $stylesheet->output_as_bytes($results);

DESCRIPTION
       This module is an interface to the gnome project's libxslt. This is an extremely good XSLT engine,
       highly compliant and also very fast. I have tests showing this to be more than twice as fast as
       Sablotron.

OPTIONS
       XML::LibXSLT has some global options. Note that these are probably not thread or even fork safe - so
       only set them once per process. Each one of these options can be called either as class methods, or
       as instance methods. However either way you call them, it still sets global options.

       Each of the option methods returns its previous value, and can be called without a parameter to
       retrieve the current value.

       max_depth
             XML::LibXSLT->max_depth(1000);

           This option sets the maximum recursion depth for a stylesheet. See the very end of section 5.4 of
           the XSLT specification for more details on recursion and detecting it. If your stylesheet or XML
           file requires seriously deep recursion, this is the way to set it. Default value is 250.

       debug_callback
             XML::LibXSLT->debug_callback($subref);

           Sets a callback to be used for debug messages. If you don't set this, debug messages will be
           ignored.

       register_function
             XML::LibXSLT->register_function($uri, $name, $subref);
             $stylesheet->register_function($uri, $name, $subref);

           Registers an XSLT extension function mapped to the given URI. For example:

             XML::LibXSLT->register_function("urn:foo", "bar",
               sub { scalar localtime });

           Will register a "bar" function in the "urn:foo" namespace (which you have to define in your XSLT
           using "xmlns:...") that will return the current date and time as a string:

             <xsl:stylesheet version="1.0"
               xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
               xmlns:foo="urn:foo">
             <xsl:template match="/">
               The time is: <xsl:value-of select="foo:bar()"/>
             </xsl:template>
             </xsl:stylesheet>

           Parameters can be in whatever format you like. If you pass in a nodelist it will be a
           XML::LibXML::NodeList object in your perl code, but ordinary values (strings, numbers and
           booleans) will be ordinary perl scalars. If you wish them to be "XML::LibXML::Literal",
           "XML::LibXML::Number" and "XML::LibXML::Number" values respectively then set the variable
           $XML::LibXSLT::USE_LIBXML_DATA_TYPES to a true value. Return values can be a nodelist or a plain
           value - the code will just do the right thing.  But only a single return value is supported (a
           list is not converted to a nodelist).

       register_element
                   $stylesheet->register_element($uri, $name, $subref)

           Registers an XSLT extension element $name mapped to the given URI. For example:

             $stylesheet->register_element("urn:foo", "hello", sub {
                     my $name = $_[2]->getAttribute( "name" );
                     return XML::LibXML::Text->new( "Hello, $name!" );
             });

           Will register a "hello" element in the "urn:foo" namespace that returns a "Hello, X!" text node.
           You must define this namespace in your XSLT and include its prefix in the
           "extension-element-prefixes" list:

             <xsl:stylesheet version="1.0"
               xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
               xmlns:foo="urn:foo"
                   extension-element-prefixes="foo">
             <xsl:template match="/">
               <foo:hello name="bob"/>
             </xsl:template>
             </xsl:stylesheet>

           The callback is passed the input document node as $_[1] and the stylesheet node as $_[2]. $_[0]
           is reserved for future use.

API
       The following methods are available on the new XML::LibXSLT object:

       parse_stylesheet($stylesheet_doc)
           $stylesheet_doc here is an XML::LibXML::Document object (see XML::LibXML) representing an XSLT
           file. This method will return a XML::LibXSLT::Stylesheet object, or undef on failure. If the XSLT
           is invalid, an exception will be thrown, so wrap the call to parse_stylesheet in an eval{} block
           to trap this.

           IMPORTANT: $stylesheet_doc should not contain CDATA sections, otherwise libxslt may misbehave.
           The best way to assure this is to load the stylesheet with no_cdata flag, e.g.

             my $stylesheet_doc = XML::LibXML->load_xml(location=>"some.xsl", no_cdata=>1);

       parse_stylesheet_file($filename)
           Exactly the same as the above, but parses the given filename directly.

Input Callbacks
       To define XML::LibXSLT or XML::LibXSLT::Stylesheet specific input callbacks, reuse the XML::LibXML
       input callback API as described in XML::LibXML::InputCallback(3).

Security Callbacks
       To create security preferences for the transformation see XML::LibXSLT::Security. Once the security
       preferences have been defined you can apply them to an XML::LibXSLT or XML::LibXSLT::Stylesheet
       instance using the "security_callbacks()" method.

XML::LibXSLT::Stylesheet
       The main API is on the stylesheet, though it is fairly minimal.

       One of the main advantages of XML::LibXSLT is that you have a generic stylesheet object which you
       call the transform() method passing in a document to transform. This allows you to have multiple
       transformations happen with one stylesheet without requiring a reparse.

       transform(doc, %params)
             my $results = $stylesheet->transform($doc, foo => "value);
             print $stylesheet->output_as_bytes($results);

           Transforms the passed in XML::LibXML::Document object, and returns a new XML::LibXML::Document.
           Extra hash entries are used as parameters.  See output_string

       transform_file(filename, %params)
             my $results = $stylesheet->transform_file($filename, bar => "value");

       output_as_bytes(result)
           Returns a scalar that is the XSLT rendering of the XML::LibXML::Document object using the desired
           output format (specified in the xsl:output tag in the stylesheet). Note that you can also call
           $result->toString, but that will *always* output the document in XML format which may not be what
           you asked for in the xsl:output tag. The scalar is a byte string encoded in the output encoding
           specified in the stylesheet.

       output_as_chars(result)
           Like "output_as_bytes(result)", but always return the output as (UTF-8 encoded) string of
           characters.

       output_string(result)
           DEPRECATED: This method is something between "output_as_bytes(result)" and
           "output_as_bytes(result)": The scalar returned by this function appears to Perl as characters
           (UTF8 flag is on) if the output encoding specified in the XSLT stylesheet was UTF-8 and as bytes
           if no output encoding was specified or if the output encoding was other than UTF-8. Since the
           behavior of this function depends on the particular stylesheet, it is deprecated in favor of
           "output_as_bytes(result)" and "output_as_chars(result)".

       output_fh(result, fh)
           Outputs the result to the filehandle given in $fh.

       output_file(result, filename)
           Outputs the result to the file named in $filename.

       output_encoding()
           Returns the output encoding of the results. Defaults to "UTF-8".

       media_type()
           Returns the output media_type of the results. Defaults to "text/html".

Parameters
       LibXSLT expects parameters in XPath format. That is, if you wish to pass a string to the XSLT engine,
       you actually have to pass it as a quoted string:

         $stylesheet->transform($doc, param => "'string'");

       Note the quotes within quotes there!

       Obviously this isn't much fun, so you can make it easy on yourself:

         $stylesheet->transform($doc, XML::LibXSLT::xpath_to_string(
               param => "string"
               ));

       The utility function does the right thing with respect to strings in XPath, including when you have
       quotes already embedded within your string.

XML::LibXSLT::Security
       Provides an interface to the libxslt security framework by allowing callbacks to be defined that can
       restrict access to various resources (files or URLs) during a transformation.

       The libxslt security framework allows callbacks to be defined for certain actions that a stylesheet
       may attempt during a transformation. It may be desirable to restrict some of these actions (for
       example, writing a new file using exsl:document). The actions that may be restricted are:

       read_file
           Called when the stylesheet attempts to open a local file (ie: when using the document()
           function).

       write_file
           Called when an attempt is made to write a local file (ie: when using the exsl:document element).

       create_dir
           Called when a directory needs to be created in order to write a file.

           NOTE: By default, create_dir is not allowed. To enable it a callback must be registered.

       read_net
           Called when the stylesheet attempts to read from the network.

       write_net
           Called when the stylesheet attempts to write to the network.

   Using XML::LibXSLT::Security
       The interface for this module is similar to XML::LibXML::InputCallback. After creating a new instance
       you may register callbacks for each of the security options listed above. Then you apply the security
       preferences to the XML::LibXSLT or XML::LibXSLT::Stylesheet object using "security_callbacks()".

         my $security = XML::LibXSLT::Security->new();
         $security->register_callback( read_file  => $read_cb );
         $security->register_callback( write_file => $write_cb );
         $security->register_callback( create_dir => $create_cb );
         $security->register_callback( read_net   => $read_net_cb );
         $security->register_callback( write_net  => $write_net_cb );

         $xslt->security_callbacks( $security );
          -OR-$stylesheet->security_callbacks( -OR$stylesheet->security_callbacks(
         $stylesheet->security_callbacks( $security );

       The registered callback functions are called when access to a resource is requested. If the access
       should be allowed the callback should return 1, if not it should return 0. The callback functions
       should accept the following arguments:

       $tctxt
           This is the transform context (XML::LibXSLT::TransformContext). You can use this to get the
           current XML::LibXSLT::Stylesheet object by calling "stylesheet()".

             my $stylesheet = $tctxt->stylesheet();

           The stylesheet object can then be used to share contextual information between different calls to
           the security callbacks.

       $value
           This is the name of the resource (file or URI) that has been requested.

       If a particular option (except for "create_dir") doesn't have a registered callback, then the
       stylesheet will have full access for that action.

   Interface
       new()
           Creates a new XML::LibXSLT::Security object.

       register_callback( $option, $callback )
           Registers a callback function for the given security option (listed above).

       unregister_callback( $option )
           Removes the callback for the given option. This has the effect of allowing all access for the
           given option (except for "create_dir").

BENCHMARK
       Included in the distribution is a simple benchmark script, which has two drivers - one for LibXSLT
       and one for Sablotron. The benchmark requires the testcases files from the XSLTMark distribution
       which you can find at http://www.datapower.com/XSLTMark/

       Put the testcases directory in the directory created by this distribution, and then run:

         perl benchmark.pl -h

       to get a list of options.

       The benchmark requires XML::XPath at the moment, but I hope to factor that out of the equation fairly
       soon. It also requires Time::HiRes, which I could be persuaded to factor out, replacing it with
       Benchmark.pm, but I haven't done so yet.

       I would love to get drivers for XML::XSLT and XML::Transformiix, if you would like to contribute
       them. Also if you get this running on Win32, I'd love to get a driver for MSXSLT via OLE, to see what
       we can do against those Redmond boys!

LIBRARY VERSIONS
       For debugging purposes, XML::LibXSLT provides version information about the libxslt C library (but do
       not confuse it with the version number of XML::LibXSLT module itself, i.e. with
       $XML::LibXSLT::VERSION). XML::LibXSLT issues a warning if the runtime version of the library is less
       then the compile-time version.

       XML::LibXSLT::LIBXSLT_VERSION()
           Returns version number of libxslt library which was used to compile XML::LibXSLT as an integer.
           For example, for libxslt-1.1.18, it will return 10118.

       XML::LibXSLT::LIBXSLT_DOTTED_VERSION()
           Returns version number of libxslt library which was used to compile XML::LibXSLT as a string,
           e.g. "1.1.18".

       XML::LibXSLT::LIBXSLT_RUNTIME_VERSION()
           Returns version number of libxslt library to which XML::LibXSLT is linked at runtime (either
           dynamically or statically). For example, for example, for libxslt.so.1.1.18, it will return
           10118.

       XML::LibXSLT::HAVE_EXLT()
           Returns 1 if the module was compiled with libexslt, 0 otherwised.

LICENSE
       This is free software, you may use it and distribute it under the same terms as Perl itself.

       Copyright 2001-2009, AxKit.com Ltd.

AUTHOR
       Matt Sergeant, matt@sergeant.org

       Security callbacks implementation contributed by Shane Corgatelli.

MAINTAINER
       Petr Pajas , pajas@matfyz.org

BUGS
       Please report bugs via

         http://rt.cpan.org/NoAuth/Bugs.html?Dist=XML-LibXSLT

SEE ALSO
       XML::LibXML



perl v5.12.5                                     2011-10-28                                       LibXSLT(3)