shamu has asked for the wisdom of the Perl Monks concerning the following question:

I'm using XML::LibXML 1.66 and libxml2 2.6.26, to parse some XML that I would like to print the XML as it is read, without modification. When I run the following, all the entities are expanded...not what I want. Anyone know how to correct this? 
#!/usr/bin/perl

use strict;
use XML::LibXML;

my $fh = *DATA;
my $parser      = XML::LibXML->new();
$parser->expand_entities(0);
my $doc         = $parser->parse_fh( $fh );
my $root        = $doc->getDocumentElement;
my $format      = 1;
my $docencoding = 1;

foreach my $xform_node ($root->findnodes('jobs/job')) {
    next if($xform_node->nodeType != &XML_ELEMENT_NODE);

    my $path        = $xform_node->findvalue('info/directory');
    my $xmlstring   = $xform_node->toString($format,$docencoding);

    print "$path\n";
    print "$xmlstring\n";
}

__DATA__
<?xml version="1.0" encoding="UTF-8"?>
<repository>
<jobs>
<job>
  <name>Screening</name>
  <directory>&#47;Biometrics&#47;TestCase</directory>
  <created_user>admin</created_user>
  <created_date>2007&#47;11&#47;29 15:29:07.000</created_date>
  <modified_user>admin</modified_user>
  <modified_date>2008&#47;02&#47;11 15:58:28.000</modified_date>
</job>
</jobs>
</repository>

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Replies are listed 'Best First'.
Re: XML::LibXML expand_entities always expands entities
by pc88mxer (Vicar) on May 14, 2008 at 16:26 UTC
    The entities that this option refers to are not character entities (like &#47;) but ones defined by <!ENTITY ...> declarations. See this page for more info.

    Here's an example of how it works: 

    #!/usr/bin/perl

use strict;
use XML::LibXML;

my $fh = *DATA;
my $parser      = XML::LibXML->new();
$parser->expand_entities($ARGV[0]);
my $doc         = $parser->parse_fh( $fh );
my $root        = $doc->getDocumentElement;

print $root->toString(1, 1), "\n";

__END__
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE author [
  <!ELEMENT author (#PCDATA)>
  <!ENTITY js "Jo Smith">
]>
<author>&js;</author>

    [download]
    If called with a true argument, the output will be: 
    <author>Jo Smith</author>

    [download]
    and if called with a false argument, the output is: 
    <author>&js;</author>

    [download]
[reply]
[d/l]
[select]
      How can I prevent standard entities (e.g. &#47;) from being decoded?
[reply]
    		[reply]
    Re: XML::LibXML expand_entities always expands entities
    by ikegami (Patriarch) on May 14, 2008 at 17:15 UTC
      May I ask why? "&#47;" and the character it decodes to are completely equivalent in XML. There might not even be a way since the parser may not distinguish between the two.
    		[reply]
    [d/l]
        I'm reading a file and I want the contents to match exactly, the contents should be unmodified. I'd like to perform a diff on the source and destination, they don't match if one is '&#47;' and the other is '/'.
    		[reply]

          This may or may not be any help but I do something somewhat related. I decode all the safe entities in HTML before parsing it with XML::LibXML. Along these lines- 

          use HTML::Entities;
our %Charmap = %HTML::Entities::entity2char;
delete @Charmap{qw( amp lt gt quot apos )};
HTML::Entities::_decode_entities($html, \%Charmap);

          [download]

          You would then have something closer up front for comparing. Maybe. They're both processed data but at least you'd know they processed the same.

    		[reply]
    [d/l]

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