Add irspy_namespace()

[irspy-moved-to-github.git] / lib / ZOOM / IRSpy / Utils.pm

diff --git a/lib/ZOOM/IRSpy/Utils.pm b/lib/ZOOM/IRSpy/Utils.pm
index c139995..13ef7ae 100644 (file)
--- a/lib/ZOOM/IRSpy/Utils.pm
+++ b/lib/ZOOM/IRSpy/Utils.pm
@@ -1,4 +1,4 @@
-# $Id: Utils.pm,v 1.2 2006-10-30 16:13:49 mike Exp $
+# $Id: Utils.pm,v 1.9 2006-11-09 16:09:35 mike Exp $

 
 package ZOOM::IRSpy::Utils;
 
 
 package ZOOM::IRSpy::Utils;
 

@@ -7,7 +7,15 @@ use strict;
 use warnings;
 
 use Exporter 'import';
 use warnings;
 
 use Exporter 'import';

-our @EXPORT_OK = qw(xml_encode irspy_xpath_context);
+our @EXPORT_OK = qw(xml_encode 
+                   irspy_xpath_context
+                   modify_xml_document
+                   inheritance_tree);
+
+use XML::LibXML;
+use XML::LibXML::XPathContext;
+
+our $IRSPY_NS = 'http://indexdata.com/irspy/1.0';

 
 
 # Utility functions follow, exported for use of web UI
 
 
 # Utility functions follow, exported for use of web UI

@@ -28,18 +36,169 @@ sub xml_encode {
 }
 
 
 }
 
 

+# PRIVATE to irspy_namespace() and irspy_xpath_context()
+my %_namespaces = (
+                  e => 'http://explain.z3950.org/dtd/2.0/',
+                  i => $IRSPY_NS,
+                  );
+
+
+sub irspy_namespace {
+    my($prefix) = @_;
+
+    my $uri = $_namespaces{$prefix};
+    die "irspy_namespace(): no URI for namespace prefix '$prefix'"
+       if !defined $uri;
+
+    return $uri;
+}
+
+

 sub irspy_xpath_context {
 sub irspy_xpath_context {

-    my($zoom_record) = @_;
+    my($record) = @_;

 
 

-    my $xml = $zoom_record->render();
+    my $xml = ref $record ? $record->render() : $record;

     my $parser = new XML::LibXML();
     my $doc = $parser->parse_string($xml);
     my $root = $doc->getDocumentElement();
     my $xc = XML::LibXML::XPathContext->new($root);
     my $parser = new XML::LibXML();
     my $doc = $parser->parse_string($xml);
     my $root = $doc->getDocumentElement();
     my $xc = XML::LibXML::XPathContext->new($root);

-    $xc->registerNs(e => 'http://explain.z3950.org/dtd/2.0/');
-    $xc->registerNs(i => $ZOOM::IRSpy::irspy_ns);
+    foreach my $prefix (keys %_namespaces) {
+       $xc->registerNs($prefix, $_namespaces{$prefix});
+    }

     return $xc;
 }
 
 
     return $xc;
 }
 
 

+sub modify_xml_document {
+    my($xc, $fieldsByKey, $data) = @_;
+
+    my $nchanges = 0;
+    foreach my $key (keys %$data) {
+       my $value = $data->{$key};
+       my $ref = $fieldsByKey->{$key} or die "no field '$key'";
+       my($name, $nlines, $caption, $xpath, @addAfter) = @$ref;
+       #print "Considering $key='$value' ($xpath)<br/>\n";
+       my @nodes = $xc->findnodes($xpath);
+       if (@nodes) {
+           warn scalar(@nodes), " nodes match '$xpath'" if @nodes > 1;
+           my $node = $nodes[0];
+
+           if ($node->isa("XML::LibXML::Attr")) {
+               if ($value ne $node->getValue()) {
+                   $node->setValue($value);
+                   $nchanges++;
+                   #print "Attr $key: '", $node->getValue(), "' -> '$value' ($xpath)<br/>\n";
+               }
+           } elsif ($node->isa("XML::LibXML::Element")) {
+               # The contents could be any mixture of text and
+               # comments and maybe even other crud such as processing
+               # instructions.  The simplest thing is just to throw it all
+               # away and start again, making a single Text node the
+               # canonical representation.  But before we do that,
+               # we'll check whether the element is already
+               # canonical, to determine whether our change is a
+               # no-op.
+               my $old = "???";
+               my @children = $node->childNodes();
+               if (@children == 1) {
+                   my $child = $node->firstChild();
+                   if (ref $child && ref $child eq "XML::LibXML::Text") {
+                       $old = $child->getData();
+                       next if $value eq $old;
+                   }
+               }
+
+               $node->removeChildNodes();
+               my $child = new XML::LibXML::Text($value);
+               $node->appendChild($child);
+               $nchanges++;
+               #print "Elem $key: '$old' -> '$value' ($xpath)<br/>\n";
+           } else {
+               warn "unexpected node type $node";
+           }
+
+       } else {
+           next if !$value; # No need to create a new empty node
+           my($ppath, $element) = $xpath =~ /(.*)\/(.*)/;
+           dom_add_element($xc, $ppath, $element, $value, @addAfter);
+           #print "New $key ($xpath) = '$value'<br/>\n";
+           $nchanges++;
+       }
+    }
+
+    return $nchanges;
+}
+
+
+sub dom_add_element {
+    my($xc, $ppath, $element, $value, @addAfter) = @_;
+
+    #print "Adding $element='$value' at '$ppath' after (", join(", ", map { "'$_'" } @addAfter), ")<br/>\n";
+    my @nodes = $xc->findnodes($ppath);
+    if (@nodes == 0) {
+       # Oh dear, the parent node doesn't exist.  We could make it,
+       # but for now let's not and say we did.
+       warn "no parent node '$ppath': not adding '$element'='$value'";
+       return;
+    }
+    warn scalar(@nodes), " nodes match parent '$ppath'" if @nodes > 1;
+    my $node = $nodes[0];
+
+    my(undef, $prefix, $nsElem) = $element =~ /((.*?):)?(.*)/;
+    my $new = new XML::LibXML::Element($nsElem);
+    $new->setNamespace(irspy_namespace($prefix), $prefix)
+       if $prefix ne "";
+
+    $new->appendText($value);
+    foreach my $predecessor (reverse @addAfter) {
+       my($child) = $xc->findnodes($predecessor, $node);
+       if (defined $child) {
+           $node->insertAfter($new, $child);
+           #print "Added after '$predecessor'<br/>\n";
+           return;
+       }
+    }
+
+    # Didn't find any of the nodes that are supposed to precede the
+    # new one, so we need to insert the new node as the first of the
+    # parent's children.  However *sigh* there is no prependChild()
+    # analogous to appendChild(), so we have to go the long way round.
+    my @children = $node->childNodes();
+    if (@children) {
+       $node->insertBefore($new, $children[0]);
+       #print "Added new first child<br/>\n";
+    } else {
+       $node->appendChild($new);
+       #print "Added new only child<br/>\n";
+    }
+
+    if (0) {
+       my $text = xml_encode(inheritance_tree($xc));
+       $text =~ s/\n/<br\/>$&/sg;
+       print "<pre>$text</pre>\n";
+    }
+}
+
+
+sub inheritance_tree {
+    my($type, $level) = @_;
+    $level = 0 if !defined $level;
+    return "Woah!  Too deep, man!\n" if $level > 20;
+
+    $type = ref $type if ref $type;
+    my $text = "";
+    $text = "--> " if $level == 0;
+    $text .= ("\t" x $level) . "$type\n";
+    my @ISA = eval "\@${type}::ISA";
+    foreach my $superclass (@ISA) {
+       $text .= inheritance_tree($superclass, $level+1);
+    }
+
+    return $text;
+}
+
+
+#print "Loaded ZOOM::IRSpy::Utils.pm";
+
+

 1;
 1;