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############################################################################## |
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# |
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# Perl module: XML::XUpdate::XSLT |
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# |
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# By Andreas Motl, andreas.motl@ilo.de |
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# |
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# $Id: XSLT.pm,v 1.1 2003/04/30 02:36:32 joko Exp $ |
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# |
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# $Log: XSLT.pm,v $ |
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# Revision 1.1 2003/04/30 02:36:32 joko |
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# initial commit |
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# |
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# |
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############################################################################### |
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|
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=pod |
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=head1 NAME |
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XML::XUpdate::XSLT - A perl module for updating xml documents using XUpdate via XSLT. |
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=head3 Overview |
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This is not the same xupdate currently available from CPAN at |
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http://search.cpan.org/author/PAJAS/XML-XUpdate-LibXML-0.4.0/xupdate . |
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Its intention - however - is identical: |
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xupdate - Process XUpdate commands against an XML document. |
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=head3 Their implementations differ: |
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1. xupdate (by Petr Pajas) uses ... |
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XML::XUpdate::LibXML - Simple implementation of XUpdate format |
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... which is based on XML::LibXML which in turn is: |
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[...] |
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This module is an interface to the gnome libxml2 DOM parser (no SAX parser support yet), |
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and the DOM tree. It also provides an XML::XPath-like findnodes() interface, providing |
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access to the XPath API in libxml2. |
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[...] |
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|
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2. This xupdate attempts to implement the XUpdate specs using XSLT only. |
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=head3 Yet another xupdate - facts in short: |
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S: It would be nice to have a pure perl thingy which does (almost) the same stuff.... |
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Q: Can we achieve compliance with its (XML::XUpdate::LibXML) API? (or just a subset ....) |
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|
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Q: Can we achieve the processing using CPAN's XML::XSLT? |
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S: Proposal: XML::XUpdate::XSLT!? |
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Q: Can we mimic/use the interface of the - already established - 'xupdate' program??? |
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Q: Should we follow the CRUD path first? (CRUD means: Create, Retrieve, Update, Delete) |
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S?: Proposal: XML::XUpdate::XSLT::API uses XML::XUpdate::XSLT::CRUD |
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=head4 Todo |
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o What about proper encoding? (ISO-8859-1 or UTF-8) |
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o Is it possible to create the required "xsl_template.xml" at runtime via XSL itself? |
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o Cache contents of external files (*.xml). Performance! |
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=cut |
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###################################################################### |
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package XML::XUpdate::XSLT; |
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###################################################################### |
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|
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use strict; |
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use warnings; |
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|
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use XML::XSLT 0.41; |
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use Carp; |
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use File::Basename; |
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use Data::Dumper; |
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# Namespace constants |
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use constant NS_XUPDATE => 'http://www.xmldb.org/xupdate'; |
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use vars qw ( $VERSION ); |
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$VERSION = '0.01'; |
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###################################################################### |
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# PUBLIC DEFINITIONS |
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|
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sub new { |
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my $class = shift; |
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my $self = bless {}, $class; |
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my $args = $self->__parse_args(@_); |
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$self->{DEBUG} = $args->{debug}; |
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$self->{WARNINGS} = $args->{warnings}; |
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$self->__init_default_stylesheets(); |
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return $self; |
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} |
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sub get_stylesheet { |
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my $self = shift; |
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my $name = shift; |
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return $self->{XML}->{xsl}->{$name}; |
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} |
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sub set_stylesheet { |
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my $self = shift; |
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my $name = shift; |
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my $xml = shift; |
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my $options = shift; |
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if ($options->{encap}) { |
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my $template = $self->__slurp_file("xsl_template.xml"); |
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# FIXME! What about the quirky? Is there a better one? |
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$template =~ s!<xsl:quirky_placeholder />!$xml!; |
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$xml = $template; |
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} |
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$self->{XML}->{xsl}->{$name} = $xml; |
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} |
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sub open_document { |
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my $self = shift; |
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my $xml = shift; |
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# FIXME: check for filename, filehandle and URL (etc.) |
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$self->{XML}->{document} = $xml; |
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} |
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sub open_xupdate { |
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my $self = shift; |
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my $xml = shift; |
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# FIXME: check for filename, filehandle and URL (etc.) |
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$self->{XML}->{xupdate} = $xml; |
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} |
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sub process { |
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my $self = shift; |
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$self->_calculate(); |
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$self->_apply(); |
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} |
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# First, translate the xupdate payload to xsl. |
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# FIXME: do DOM only! |
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sub _calculate { |
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my $self = shift; |
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$self->{XSLT_ENGINE_PREP} = XML::XSLT->new( |
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Source => $self->get_stylesheet("xupdate2xsl"), |
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debug => $self->{DEBUG}, |
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warnings => $self->{WARNINGS} |
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); |
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$self->{XSLT_ENGINE_PREP}->open_xml( $self->{XML}->{xupdate} ); |
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$self->{XSLT_ENGINE_PREP}->process(); |
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$self->set_stylesheet( "_worker", $self->{XSLT_ENGINE_PREP}->toString(), { encap => 1 } ); |
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} |
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# After that, use this worker xsl to actually apply the changes to the original document. |
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# FIXME: do DOM only! |
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sub _apply { |
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my $self = shift; |
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#print $self->get_stylesheet("_worker"), "\n"; |
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#return; |
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$self->{XSLT_ENGINE_LIVE} = XML::XSLT->new( |
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Source => $self->get_stylesheet("_worker"), |
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debug => $self->{DEBUG}, |
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warnings => $self->{WARNINGS} |
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); |
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$self->{XSLT_ENGINE_LIVE}->open_xml( $self->{XML}->{document} ); |
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$self->{XSLT_ENGINE_LIVE}->process(); |
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$self->{XML}->{result} = $self->{XSLT_ENGINE_LIVE}->toString(); |
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} |
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sub toString { |
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my $self = shift; |
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return $self->{XML}->{result}; |
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} |
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###################################################################### |
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# AUXILIARY METHODS |
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# Argument parsing (with backwards compatibility hook). |
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sub __parse_args { |
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my $self = shift; |
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my %args; |
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if(@_ % 2 ) { |
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$args{dummy} = shift; |
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%args = (%args, @_); |
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} else { |
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%args = @_; |
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} |
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return \%args; |
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} |
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sub __init_default_stylesheets { |
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my $self = shift; |
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if (my $payload = $self->__slurp_file("xupdate2xsl.xml")) { |
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$self->{XML}->{xsl}->{xupdate2xsl} = $payload; |
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} |
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} |
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sub __slurp_file { |
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my $self = shift; |
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my $filename = shift; |
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# does file exist? |
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if (! -e $filename) { |
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$filename = dirname(__FILE__) . "/$filename"; |
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if (! -e $filename) { |
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croak("File $filename does not exist."); |
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} |
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} |
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open(FH, "<" . $filename); |
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my @lines = <FH>; |
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my $content = join("", @lines); |
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close(FH); |
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return $content; |
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} |
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1; |
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__END__ |
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