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package Koha::XSLT_Handler; |
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# Copyright 2014 Rijksmuseum |
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# |
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# This file is part of Koha. |
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# |
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# Koha is free software; you can redistribute it and/or modify it under the |
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# terms of the GNU General Public License as published by the Free Software |
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# Foundation; either version 3 of the License, or (at your option) any later |
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# version. |
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# |
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# Koha is distributed in the hope that it will be useful, but WITHOUT ANY |
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# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR |
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# A PARTICULAR PURPOSE. See the GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License along |
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# with Koha; if not, write to the Free Software Foundation, Inc., |
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
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=head1 NAME |
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Koha::XSLT_Handler - Facilitate use of XSLT transformations |
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=head1 SYNOPSIS |
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use Koha::XSLT_Handler; |
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my $xslt_engine = Koha::XSLT_Handler->new; |
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my $output = $xslt_engine->transform($xml, $xsltfilename); |
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my $err= $xslt_engine->err; # error number |
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my $errstr= $xslt_engine->errstr; # error message |
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$xslt_engine->refresh($xsltfilename); |
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=head1 DESCRIPTION |
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A XSLT handler object on top of LibXML and LibXSLT, allowing you to |
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run XSLT stylesheets repeatedly without loading them again. |
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Errors occurring during loading, parsing or transforming are reported |
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via the err and errstr attributes. |
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Reloading XSLT files can be done with the refresh method. |
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=head1 METHODS |
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=head2 new |
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Create handler object (via Class::Accessor) |
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=head2 transform |
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Run transformation for specific string and stylesheet |
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=head2 refresh |
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Allow to reload stylesheets when transforming again |
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=head1 PROPERTIES |
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=head2 err |
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Error number (see list of ERROR CODES) |
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=head2 errstr |
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Error message |
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=head2 do_not_return_source |
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If true, transform returns undef on failure. By default, it returns the |
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original string passed. Errors are reported as described. |
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=head1 ERROR CODES |
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=head2 Error 1 |
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No XSLT file passed |
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=head2 Error 2 |
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XSLT file not found |
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=head2 Error 3 |
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Error while loading stylesheet xml: [furter information] |
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=head2 Error 4 |
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Error while parsing stylesheet: [furter information] |
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=head2 Error 5 |
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Error while parsing input: [furter information] |
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=head2 Error 6 |
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Error while transforming input: [furter information] |
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=head2 Error 7 |
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No string to transform |
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=head1 INTERNALS |
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For documentation purposes. You are not encouraged to access them. |
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=head2 last_xsltfile |
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Contains the last successfully executed XSLT filename |
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=head2 xslt_hash |
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Hash reference to loaded stylesheets |
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=head1 ADDITIONAL COMMENTS |
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=cut |
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use Modern::Perl; |
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use XML::LibXML; |
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use XML::LibXSLT; |
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use base qw(Class::Accessor); |
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__PACKAGE__->mk_ro_accessors(qw( err errstr )); |
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__PACKAGE__->mk_accessors(qw( do_not_return_source )); |
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=head2 transform |
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my $output= $xslt_engine->transform( $xml, $xsltfilename ); |
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if( $xslt_engine->err ) { |
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#decide what to do on failure.. |
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} |
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my $output2= $xslt_engine->transform( $xml2 ); |
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Pass a xml string and a fully qualified path of a XSLT file. |
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If you do not pass a filename, the last file used is assumed. |
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Returns the transformed string. |
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Check the error number in err to know if something went wrong. |
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In that case do_not_return_source did determine the return value. |
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=cut |
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sub transform { |
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my ( $self, $orgxml, $file ) = @_; |
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#Initialized yet? |
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if( !$self->{xslt_hash} ) { |
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$self->_init; |
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} |
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else { |
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$self->_set_error; #clear error |
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} |
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my $retval= $self->{do_not_return_source}? undef: $orgxml; |
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#check if no string passed |
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if( !defined $orgxml ) { |
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$self->_set_error(7); |
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return; #always undef |
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} |
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#If no file passed, use the last file again |
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if( !$file ) { |
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if( !$self->{last_xsltfile} ) { |
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$self->_set_error(1); |
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return $retval; |
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} |
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$file= $self->{last_xsltfile}; |
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} |
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#load stylesheet |
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my $stsh= $self->{xslt_hash}->{$file} // $self->_load($file); |
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return $retval if $self->{err}; |
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#parse input and transform |
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my $parser = XML::LibXML->new(); |
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my $source= eval { $parser->parse_string($orgxml) }; |
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if( $@ ) { |
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$self->_set_error(5, $@); |
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return $retval; |
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} |
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my $str= eval { |
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my $result= $stsh->transform($source); |
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$stsh->output_as_chars($result); |
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}; |
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if( $@ ) { |
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$self->_set_error(6, $@); |
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return $retval; |
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} |
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$self->{last_xsltfile}= $file; |
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return $str; |
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} |
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=head2 refresh |
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$xslt_engine->refresh; |
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$xslt_engine->refresh( $xsltfilename ); |
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Pass a file for an individual refresh or no file to refresh all. |
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Refresh returns the number of items affected. |
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What we actually do, is just clear the internal cache for reloading next |
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time when transform is called. |
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The return value is mainly theoretical. Since this is supposed to work |
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always(...), there is no actual need to test it. |
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Note that refresh does also clear the error information. |
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=cut |
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sub refresh { |
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my ( $self, $file )= @_; |
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$self->_set_error; |
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return if !$self->{xslt_hash}; |
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my $rv; |
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if( $file ) { |
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$rv= delete $self->{xslt_hash}->{$file}? 1: 0; |
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} |
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else { |
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$rv= scalar keys %{ $self->{xslt_hash} }; |
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$self->{xslt_hash}= {}; |
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} |
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return $rv; |
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} |
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# ************** INTERNAL ROUTINES ******************************************** |
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# _init |
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# Internal routine for initialization. |
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sub _init { |
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my $self= shift; |
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$self->_set_error; |
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$self->{xslt_hash}={}; |
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$self->{do_not_return_source}=0 unless exists $self->{do_not_return_source}; |
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#by default we return source on a failing transformation |
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#but it could be passed at construction time already |
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return; |
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} |
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# _load |
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# Internal routine for loading a new stylesheet. |
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sub _load { |
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my ($self, $file)= @_; |
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if( !$file || !-e $file ) { |
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$self->_set_error(2); |
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return; |
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} |
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#load sheet |
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my $parser = XML::LibXML->new; |
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my $style_doc = eval { $parser->load_xml( location => $file ) }; |
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if( $@ ) { |
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$self->_set_error(3, $@); |
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return; |
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} |
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#parse sheet |
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my $xslt = XML::LibXSLT->new; |
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$self->{xslt_hash}->{$file} = eval { $xslt->parse_stylesheet($style_doc) }; |
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if( $@ ) { |
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$self->_set_error(4, $@); |
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delete $self->{xslt_hash}->{$file}; |
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return; |
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} |
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return $self->{xslt_hash}->{$file}; |
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} |
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# _set_error |
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# Internal routine for handling error information. |
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sub _set_error { |
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my ($self, $errno, $addmsg)= @_; |
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if(!$errno) { #clear the error |
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$self->{err}= undef; |
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$self->{errstr}= undef; |
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return; |
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} |
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$self->{err}= $errno; |
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if($errno==1) { |
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$self->{errstr}= "No XSLT file passed."; |
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} |
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elsif($errno==2) { |
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$self->{errstr}= "XSLT file not found."; |
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} |
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elsif($errno==3) { |
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$self->{errstr}= "Error while loading stylesheet xml:"; |
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} |
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elsif($errno==4) { |
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$self->{errstr}= "Error while parsing stylesheet:"; |
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} |
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elsif($errno==5) { |
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$self->{errstr}= "Error while parsing input:"; |
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} |
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elsif($errno==6) { |
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$self->{errstr}= "Error while transforming input:"; |
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} |
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elsif($errno==7) { |
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$self->{errstr}= "No string to transform."; |
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} |
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if( $addmsg ) { |
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$self->{errstr}.= " $addmsg"; |
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} |
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return; |
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} |
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=head1 AUTHOR |
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Marcel de Rooy, Rijksmuseum Netherlands |
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=cut |
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1; |