-# $Id: Record.pm,v 1.5 2006-07-21 11:30:51 mike Exp $
+# $Id: Record.pm,v 1.13 2006-09-26 09:08:09 mike Exp $
package ZOOM::IRSpy::Record;
use strict;
use warnings;
+use Exporter 'import';
+our @EXPORT_OK = qw(xml_encode);
+
use XML::LibXML;
+use XML::LibXML::XPathContext;
=head1 NAME
sub new {
my $class = shift();
- my($target, $zeerex) = @_;
+ my($irspy, $target, $zeerex) = @_;
if (!defined $zeerex) {
$zeerex = _empty_zeerex_record($target);
my $parser = new XML::LibXML();
return bless {
+ irspy => $irspy,
target => $target,
- zeerex => $parser->parse_string($zeerex),
+ parser => $parser,
+ zeerex => $parser->parse_string($zeerex)->documentElement(),
}, $class;
}
### Doesn't recognise SRU/SRW URLs
my($host, $port, $db) = ZOOM::IRSpy::_parse_target_string($target);
+ my $xhost = xml_encode($host);
+ my $xport = xml_encode($port);
+ my $xdb = xml_encode($db);
return <<__EOT__;
<explain xmlns="http://explain.z3950.org/dtd/2.0/">
<serverInfo protocol="Z39.50" version="1995">
- <host>$host</host>
- <port>$port</port>
- <database>$db</database>
+ <host>$xhost</host>
+ <port>$xport</port>
+ <database>$xdb</database>
</serverInfo>
</explain>
__EOT__
}
+# I can't -- just can't, can't, can't -- believe that this function
+# isn't provided by one of the core XML modules. But the evidence all
+# says that it's not: among other things, XML::Generator and
+# Template::Plugin both roll their own. So I will do likewise. D'oh!
+#
+sub xml_encode {
+ my ($text) = @_;
+ $text =~ s/&/&/g;
+ $text =~ s/</</g;
+ $text =~ s/>/>/g;
+ $text =~ s/['']/'/g;
+ $text =~ s/[""]/"/g;
+ return $text;
+}
+
+
+sub append_entry {
+ my $this = shift();
+ my($xpath, $frag) = @_;
+
+ #print STDERR "this=$this, xpath='$xpath', frag='$frag'\n";
+ my $root = $this->{zeerex}; # XML::LibXML::Element ISA XML::LibXML::Node
+ my $xc = XML::LibXML::XPathContext->new($root);
+ $xc->registerNs(zeerex => "http://explain.z3950.org/dtd/2.0/");
+ $xc->registerNs(irspy => "http://indexdata.com/irspy/1.0");
+
+ my @nodes = $xc->findnodes($xpath);
+ if (@nodes == 0) {
+ # Make the node that we're inserting into, if possible. A
+ # fully general version would work its way through each
+ # component of the XPath, but for now we just treat it as a
+ # single chunk to go inside the top-level node.
+ $this->_half_decent_appendWellBalancedChunk($root,
+ "<$xpath></$xpath>");
+ @nodes = $xc->findnodes($xpath);
+ die("still no matches for '$xpath' after creating: can't append")
+ if @nodes == 0;
+ }
+
+ $this->{irspy}->log("irspy",
+ scalar(@nodes), " matches for '$xpath': using first")
+ if @nodes > 1;
+
+ $this->_half_decent_appendWellBalancedChunk($nodes[0], $frag);
+}
+
+
+# *sigh*
+#
+# _Clearly_ the right way to append a well-balanced chunk of XML to
+# a node's children is to call appendWellBalancedChunk() from the
+# XML::LibXML::Element class. However, this fails in the common case
+# where the ZeeRex record we're working with doesn't declare the
+# "irspy" namespace that the inserted fragments use.
+#
+# To my utter astonishment it seems that XML::LibXML (as of version
+# 1.58, 31st March 2004) doesn't provide ANY way to register a
+# namespace for parsing, which makes the parse_balanced_chunk()
+# function that appendWellBalancedChunk() uses effectively useless.
+# It _is_ possible to use setNamespace() on a node, to register a new
+# namespace mapping for that node -- but that only affects pre-parsed
+# trees, and is no use for parsing. Hence the following pair of lines
+# DOES NOT WORK:
+# $node->setNamespace("http://indexdata.com/irspy/1.0", "irspy", 0);
+# $node->appendWellBalancedChunk($frag);
+#
+# Instead I have to go the long way round, hence this method. I have
+# two candidate re-implementations, of which the former is marginally
+# less loathsome, but does require that the excess namespace
+# declarations be factored out later -- as least, if you want neat
+# output.
+#
+sub _half_decent_appendWellBalancedChunk {
+ my $this = shift();
+ my($node, $frag) = @_;
+
+ if (1) {
+ $frag =~ s,>, xmlns:irspy="http://indexdata.com/irspy/1.0">,;
+ $node->appendWellBalancedChunk($frag);
+ return;
+ }
+
+ # Instead -- and to call this brain-damaged would be an insult
+ # to all those fine people out there with actual brain damage
+ # -- I have to "parse" the XML fragment myself and insert the
+ # resulting hand-build DOM tree. Someone shoot me now.
+ my($open, $content, $close) = $frag =~ /^<(.*?)>(.*)<\/(.*?)>$/;
+ die "can't 'parse' XML fragment '$frag'"
+ if !defined $open;
+ my($tag, $attrs) = $open =~ /(.*?)\s(.*)/;
+ $tag = $open if !defined $tag;
+ die "mismatched XML start/end <$open>...<$close>"
+ if $close ne $tag;
+ print STDERR "tag='$tag', attrs=[$attrs], content='$content'\n";
+ die "## no code yet to make DOM node";
+}
+
+
=head1 SEE ALSO
ZOOM::IRSpy