XML Validation

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

I have looked high and low for a simple way to validate (not merely to check for well-formedness) an XML v 1.0 document against its dtd. I have looked through this site and am aware of merlyn's previous advice to use XML::Checker.

The problem is that the XML::Checker module is not well documented and the sample code throws the following exception:Can't call method "Start" on an undefined value at /usr/lib/perl5/site_perl/5.6.0/XML/Checker/Parser.pm line 194. Here's the code:

#!/usr/bin/perl -w

use XML::Checker::Parser;

my $parser = new XML::Checker::Parser ();

die "Can't create object" unless (ref $parser);

eval {
    local $XML::Checker::FAIL = \&my_fail;
    $parser->parsefile ("/usr/local/pd/ADS/index.xml");
};
if ($@) {
    # Either XML::Parser (expat) threw an exception or my_fail() died.
    #... your error handling code here ...
        print "you suck!\ngo eat a bone!\n";
}


# Throws an exception (with die) when an error is encountered, this
# will stop the parsing process.
# Don't die if a warning or info message is encountered, just print a 
+message.
sub my_fail {
    my $code = shift;
    die XML::Checker::error_string ($code, @_) if $code < 200;
    XML::Checker::print_error ($code, @_);
}
[download]

and here's the DTD I am trying to validate against:

<?xml version="1.0" encoding="UTF-8"?>
<!ELEMENT PDList (PD*)>
<!ATTLIST PDList RunDateTime CDATA #REQUIRED>
<!ELEMENT PD (  PayPlan,
                Grade,
                OccupationalSeries,
                NASAPositionTitle,
                OPMPositionTitle,
                FileName,
                NASALocation,
                DutyLocation,
                OrganizationalCode,
                NASAClassCode,
                SourceSystem)>

<!ATTLIST PD PDNumber CDATA #REQUIRED>

<!ELEMENT PayPlan (#PCDATA)>
<!ELEMENT Grade (#PCDATA)>
<!ELEMENT OccupationalSeries (#PCDATA)>
<!ELEMENT NASAPositionTitle (#PCDATA)>
<!ELEMENT OPMPositionTitle (#PCDATA)>
<!ELEMENT FileName (#PCDATA)>
<!ELEMENT NASALocation (#PCDATA)>
<!ELEMENT DutyLocation (#PCDATA)>
<!ELEMENT OrganizationalCode (#PCDATA)>
<!ELEMENT NASAClassCode (#PCDATA)>
<!ELEMENT SourceSystem (#PCDATA)>
[download]

and here's the xml that I want to validate:

<!DOCTYPE PDList SYSTEM "http://ifmp.nasa.gov/PDList.dtd">
<PDList RunDateTime="200203211000">
        <PD PDNumber="10449">
                <PayPlan>Text</PayPlan>
                <Grade>Text</Grade>
                <OccupationalSeries>Text</OccupationalSeries>
                <NASAPositionTitle>Text</NASAPositionTitle>
                <OPMPositionTitle>Text</OPMPositionTitle>
                <FileName>Text</FileName>
                <NASALocation>Text</NASALocation>
                <DutyLocation>Text</DutyLocation>
                <OrganizationalCode>Text</OrganizationalCode>
                <NASAClassCode>Text</NASAClassCode>
                <SourceSystem>Avue version whatever</SourceSystem>
        </PD>
        <PD PDNumber="1306x">
                <PayPlan>Text</PayPlan>
                <Grade>Text</Grade>
                <OccupationalSeries>Text</OccupationalSeries>
                <NASAPositionTitle>Text</NASAPositionTitle>
                <OPMPositionTitle>Text</OPMPositionTitle>
                <FileName>Text</FileName>
                <NASALocation>Text</NASALocation>
                <DutyLocation>Text</DutyLocation>
                <OrganizationalCode>Text</OrganizationalCode>
                <NASAClassCode>Text</NASAClassCode>
                <SourceSystem>Avue version whatever</SourceSystem>
        </PD>
        <PD PDNumber="1307x">
                <PayPlan>Text</PayPlan>
                <Grade>Text</Grade>
                <OccupationalSeries>Text</OccupationalSeries>
                <NASAPositionTitle>Text</NASAPositionTitle>
                <OPMPositionTitle>Text</OPMPositionTitle>
                <FileName>Text</FileName>
                <NASALocation>Text</NASALocation>
                <DutyLocation>Text</DutyLocation>
                <OrganizationalCode>Text</OrganizationalCode>
                <NASAClassCode>Text</NASAClassCode>
                <SourceSystem>Avue version whatever</SourceSystem>
        </PD>
</PDList>
[download]

Any help or a really easy example script would be a big help. Thanks friends! I like chicken.

Comment on XML Validation Select or Download Code

Replies are listed 'Best First'.
Re: XML Validation by vek (Prior) on Apr 02, 2002 at 20:57 UTC
Personally I wouldn't use XML::Checker. Why not try XML::LibXML instead: `my $validator = XML::LibXML->new(); $validator->validation(1); #test if the XML is well formed: my $doc; eval { $doc = $validator->parse_string($theXML); }; if ($@) { # it's not well formed, your error handling code here... } #test if the XML conforms to the DTD: eval { $doc->validate(); }; if ($@) { # it doesn't conform, your error code handling here... }` [download]	[reply] [d/l]
Re: Re: XML Validation by Stegalex (Chaplain) on Apr 03, 2002 at 17:49 UTC
Thanks vek, works like a charm! I like chicken.	[reply]
Re: XML Validation by Matts (Deacon) on Apr 02, 2002 at 20:42 UTC
libxml2 has much better validation than XML::Checker offers. Either use XML::LibXML or xmllint via a system call to do the validation.	[reply]
Re^2: XML Validation by songahji (Friar) on Feb 02, 2006 at 21:45 UTC
thanks for xmllint idea .. ++	[reply]


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