/[cvs]/nfo/perl/libs/XML/XUpdate/XSLT.pm
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revision 1.1 by joko, Wed Apr 30 02:36:32 2003 UTC revision 1.3 by joko, Thu May 1 20:11:49 2003 UTC
# Line 7  Line 7 
7  #    $Id$  #    $Id$
8  #  #
9  #    $Log$  #    $Log$
10    #    Revision 1.3  2003/05/01 20:11:49  joko
11    #    * added pod from xupdate.pl
12    #    - extracted xml to external files
13    #
14  #    Revision 1.1  2003/04/30 02:36:32  joko  #    Revision 1.1  2003/04/30 02:36:32  joko
15  #    initial commit  #    initial commit
16  #  #
17  #  #
18  ###############################################################################  ###############################################################################
19    
20    =pod
21    
22    
23  =head1 NAME  =head1 NAME
24    
25  XML::XUpdate::XSLT - A perl module for updating xml documents using XUpdate via XSLT.  XML::XUpdate::XSLT - A perl module for updating xml documents using XUpdate via XSLT.
26    
27    
28    =head3 Overview
29    
30      This is not the same xupdate currently available from CPAN at
31      http://search.cpan.org/author/PAJAS/XML-XUpdate-LibXML-0.4.0/xupdate .
32      
33      Its intention - however - is identical:
34      xupdate - Process XUpdate commands against an XML document.
35    
36    
37    =head3 Their implementations differ:
38    
39        1. xupdate (by Petr Pajas) uses ...
40        XML::XUpdate::LibXML - Simple implementation of XUpdate format
41        
42        ... which is based on XML::LibXML which in turn is:
43        [...]
44        This module is an interface to the gnome libxml2 DOM parser (no SAX parser support yet),
45        and the DOM tree. It also provides an XML::XPath-like findnodes() interface, providing
46        access to the XPath API in libxml2.
47        [...]
48    
49        2. This xupdate attempts to implement the XUpdate specs using XSLT only.
50        
51    
52    =head3 Yet another xupdate - facts in short:
53    
54      S: It would be nice to have a pure perl thingy which does (almost) the same stuff....
55      
56      Q: Can we achieve compliance with its (XML::XUpdate::LibXML) API? (or just a subset ....)
57      
58      Q: Can we achieve the processing using CPAN's XML::XSLT?
59      S: Proposal: XML::XUpdate::XSLT!?
60      
61      Q: Can we mimic/use the interface of the - already established - 'xupdate' program???
62      
63      Q: Should we follow the CRUD path first? (CRUD means: Create, Retrieve, Update, Delete)
64      S?: Proposal: XML::XUpdate::XSLT::API uses XML::XUpdate::XSLT::CRUD
65    
66    
67    =head4 Todo
68    
69      o What about proper encoding? (ISO-8859-1 or UTF-8)
70      o Is it possible to create the required "xsl_template.xml" at runtime via XSL itself?
71      o Cache contents of external files (*.xml). Performance!
72      
73    
74  =cut  =cut
75    
76    
# Line 29  use warnings; Line 83  use warnings;
83    
84  use XML::XSLT 0.41;  use XML::XSLT 0.41;
85  use Carp;  use Carp;
86    use File::Basename;
87  use Data::Dumper;  use Data::Dumper;
88    
89  # Namespace constants  # Namespace constants
# Line 37  use constant NS_XUPDATE         => 'http Line 92  use constant NS_XUPDATE         => 'http
92    
93  use vars qw ( $VERSION );  use vars qw ( $VERSION );
94    
95  $VERSION = '0.02';  $VERSION = '0.01';
96    
97    
98  ######################################################################  ######################################################################
# Line 48  sub new { Line 103  sub new {
103    my $self = bless {}, $class;    my $self = bless {}, $class;
104    my $args = $self->__parse_args(@_);    my $args = $self->__parse_args(@_);
105        
106    $self->__init_default_macros();    $self->{DEBUG} = $args->{debug};
107      $self->{WARNINGS} = $args->{warnings};
108    
109  #=pod    $self->__init_default_stylesheets();
   $self->{XSLT_ENGINE} = XML::XSLT->new(  
     Source => $self->get_macro("xupdate2xsl"),  
     debug => $args->{debug},  
     warnings => $args->{warnings}  
   );  
 #=cut  
110    
   #print Dumper($self);  
111    return $self;    return $self;
112    
113  }  }
114    
115  sub get_macro {  sub get_stylesheet {
116      my $self = shift;
117      my $name = shift;
118      return $self->{XML}->{xsl}->{$name};
119    }
120    
121    sub set_stylesheet {
122    my $self = shift;    my $self = shift;
123    my $name = shift;    my $name = shift;
124    return $self->{MACROS}->{$name};    my $xml = shift;
125      my $options = shift;
126      if ($options->{encap}) {
127        my $template = $self->__slurp_file("xsl_template.xml");
128        # FIXME! What about the quirky? Is there a better one?
129        $template =~ s!<xsl:quirky_placeholder />!$xml!;
130        $xml = $template;
131      }
132      $self->{XML}->{xsl}->{$name} = $xml;
133  }  }
134    
135  sub open_document {  sub open_document {
# Line 85  sub open_xupdate { Line 148  sub open_xupdate {
148    
149  sub process {  sub process {
150    my $self = shift;    my $self = shift;
151    # first, translate xupdate to xsl    $self->_calculate();
152    $self->{XSLT_ENGINE}->open_xml( $self->{XML}->{xupdate} );    $self->_apply();
   $self->{XSLT_ENGINE}->process();  
   $self->{XML}->{XSL} = $self->{XSLT_ENGINE}->toString();  
153  }  }
154    
155    # First, translate the xupdate payload to xsl.
156    # FIXME: do DOM only!
157    sub _calculate {
158      my $self = shift;
159      $self->{XSLT_ENGINE_PREP} = XML::XSLT->new(
160        Source => $self->get_stylesheet("xupdate2xsl"),
161        debug => $self->{DEBUG},
162        warnings => $self->{WARNINGS}
163      );
164      $self->{XSLT_ENGINE_PREP}->open_xml( $self->{XML}->{xupdate} );
165      $self->{XSLT_ENGINE_PREP}->process();
166      $self->set_stylesheet( "_worker", $self->{XSLT_ENGINE_PREP}->toString(), { encap => 1 } );
167    }
168    
169    # After that, use this worker xsl to actually apply the changes to the original document.
170    # FIXME: do DOM only!
171    sub _apply {
172      my $self = shift;
173      #print $self->get_stylesheet("_worker"), "\n";
174      #return;
175      $self->{XSLT_ENGINE_LIVE} = XML::XSLT->new(
176        Source => $self->get_stylesheet("_worker"),
177        debug => $self->{DEBUG},
178        warnings => $self->{WARNINGS}
179      );
180      $self->{XSLT_ENGINE_LIVE}->open_xml( $self->{XML}->{document} );
181      $self->{XSLT_ENGINE_LIVE}->process();
182      $self->{XML}->{result} = $self->{XSLT_ENGINE_LIVE}->toString();
183    }  
184      
185  sub toString {  sub toString {
186    my $self = shift;    my $self = shift;
187    return $self->{XML}->{XSL};    return $self->{XML}->{result};
188  }  }
189    
190    
191  ######################################################################  ######################################################################
192  # AUXILIARY METHODS  # AUXILIARY METHODS
193    
194  # Argument parsing with backwards compatibility.  # Argument parsing (with backwards compatibility hook).
195  sub __parse_args {  sub __parse_args {
196    my $self = shift;    my $self = shift;
197    my %args;    my %args;
# Line 116  sub __parse_args { Line 207  sub __parse_args {
207  }  }
208    
209    
210  sub __init_default_macros {  sub __init_default_stylesheets {
211    my $self = shift;    my $self = shift;
212    $self->{MACROS}->{xupdate2xsl} = qq(<?xml version="1.0" encoding="ISO-8859-1"?>    if (my $payload = $self->__slurp_file("xupdate2xsl.xml")) {
213          $self->{XML}->{xsl}->{xupdate2xsl} = $payload;
214    <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">    }
215    }
216    
217    sub __slurp_file {
218      my $self = shift;
219      my $filename = shift;
220        
221        <!--    # does file exist?
222        Purpose of this XML Stylesheet is to implement a set of templates    if (! -e $filename) {
223        to translate XUpdate lingo into an intermediate xslt stylesheet      $filename = dirname(__FILE__) . "/$filename";
224        which actually performs the update to the original xml document.      if (! -e $filename) {
225        -->        croak("File $filename does not exist.");
226              }
227        <xsl:output method="xml" />    }
     
       <!-- 1. This is the passthru logic (copy all untouched nodes). -->  
       <xsl:template name="passthru"><xsl:copy><xsl:apply-templates /></xsl:copy></xsl:template>  
       <!-- activate this -->  
       <xsl:template match="*"><xsl:call-template name="passthru" /></xsl:template>  
       <!-- override some builtin rules: see http://www.w3.org/TR/xslt#built-in-rule -->  
       <xsl:template match="comment()"><xsl:call-template name="passthru" /></xsl:template>  
     
       <!-- 2. This is the translation part: XUpdate becomes XSLT -->  
         
       <!-- This node "encapsulates" common infrastructure. -->  
       <xsl:template match="xupdate:modifications">  
     
           <!-- 1. This is the passthru logic (copy all untouched nodes). -->  
           <!-- in fact this is the xsl from above translated to be able to be generated by xsl itself! -->  
               <xsl:comment> 1. passthru logic </xsl:comment>  
               <xsl:element name="xsl:template">  
                   <xsl:attribute name="name">passthru</xsl:attribute>  
                   <xsl:element name="xsl:copy"><xsl:element name="xsl:apply-templates" /></xsl:element>  
               </xsl:element>  
               <xsl:element name="xsl:template">  
                   <xsl:attribute name="match">*</xsl:attribute>  
                   <xsl:element name="xsl:call-template"><xsl:attribute name="name">passthru</xsl:attribute></xsl:element>  
               </xsl:element>  
               <xsl:element name="xsl:template">  
                   <xsl:attribute name="match">comment()</xsl:attribute>  
                   <xsl:element name="xsl:call-template"><xsl:attribute name="name">passthru</xsl:attribute></xsl:element>  
               </xsl:element>  
     
           <!-- continue with all inline nodes -->  
               <xsl:apply-templates />  
     
       </xsl:template>  
     
       <!-- This node "encapsulates" infrastructure for handling the directives. -->  
       <xsl:template match="xupdate:insert-after">  
           <xsl:comment> 2. context finder </xsl:comment>  
           <xsl:apply-templates />  
       </xsl:template>  
     
       <!-- This node passes through all attributes and childnodes rewriting the tagname only. -->  
       <xsl:template match="xupdate:element">  
           <xsl:comment> 3. rewrite / vivify elements/attributes </xsl:comment>  
           <xsl:element name="xsl:element">  
               <xsl:copy-of select="@*"/>  
               <xsl:apply-templates />  
           </xsl:element>  
       </xsl:template>  
     
       <!-- This node passes through all attributes and childnodes rewriting the tagname only. -->  
       <xsl:template match="xupdate:attribute">  
           <xsl:element name="xsl:attribute">  
               <xsl:copy-of select="@*"/>  
               <xsl:apply-templates />  
           </xsl:element>  
       </xsl:template>  
     
   </xsl:stylesheet>  
228        
229    );    open(FH, "<" . $filename);
230      my @lines = <FH>;
231      my $content = join("", @lines);
232      close(FH);
233      return $content;
234  }  }
235    
236  1;  1;
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