xml validation using perl

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

hi,

I am sending XML file as under: copyscript_28jan230pm dummy.xml and it is validated correcly and the output is as under: Enter username for Romulus: ddfd Enter password: Enter username for EMTT1: ...... Romulus, EMTT1 are parsed from XML, and before parsing it is being validated. Now i wanted to copy same XML file dummy.xml to |.xml. I have done it as cp dummy.xml \|.xml in a linux box. and the code for validation is

eval
 {
  $doc = $parser->parsefile ("$ARGV[0]");
 };
 if($@)
 {
      print "Invalid XML file,enter valid XML file \n";
      exit;
 }
[download]

Now as i supplied dummy.xml, there is no error and the xml file is parsed. when i supplied |.xml from the command line as <program_name> \|.xml, it is throwing an error as Invalid XML file,enter valid XML file, even though the xml file inside is wellformed and is same as dummy.xml . Can u please tell me how can we overcome this ?

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Re: xml validation using perl by dHarry (Abbot) on Feb 05, 2010 at 12:20 UTC
First of all it would help if you would say what parser you use... Secondly, as a general note to your (general) title: validating XML with Perl is a bit tricky. It depends for instance what level of validation you want to perform. Most of the Perl solutions support validation using DTD's. This gives you only (very) limited possibilities for validating your XML documents. DTD's were the first attempt for validating XML documents and IMHO not a very good one. There are certain disadvantages using DTD's no data types limited possibilites for expressing cardinality namespace support syntax is non-XML etc. Several schema languages were designed to counter these problems (Schematron, relaxng). The most popular and best supported is W3C XML Schema. It is safe to say this isn't exactly perfect either but many of the issues with DTD's were more or less solved. XML Schema gives you much more power to validate documents at the cost of added complexity, i.e. XML Schema is not simple, there is a learning curve. Furthermore I know of no Perl solution that fully supports XML Schema, as I recall it only subsets are supported. Depending on what you want to do this might work for you. I have my own set of tools to work with XML, if I would have to pick a Perl solution it would probably be XML::Xerces but I'm biased towards Xalan/Xerces. NB In the course of time some very clever/tricky solutions were devised to counter the problems with DTD's, e.g. adding datatypes but it never worked out that well. Cheers, Harry	[reply]
Re^2: xml validation using perl by ikegami (Patriarch) on Feb 08, 2010 at 05:52 UTC
Furthermore I know of no Perl solution that fully supports XML Schema, I haven't encountered any limitations with XML::LibXML. See XML::LibXML::Schema	[reply]
Re^3: xml validation using perl by dHarry (Abbot) on Feb 08, 2010 at 08:41 UTC
My libxml/XML Schema experience stems from some years ago. At that time it didn't really work. On the http://xmlsoft.org I read things like: A partial implementation of XML Schemas Part 1: Structure is being worked on but it would be far too early to make any conformance statement about it at the moment. And that it doesn't claim to completely implement: DOM and SAX?! This scares me away. I use Xalan/Xerces because I have good experience with it and they fully implement most of the W3C recommendations, see for example Xerces features. Of course there might be some exotic features I'll probably never use, still I'd like to make the choice myself. Cheers Harry	[reply]
Re: xml validation using perl by ikegami (Patriarch) on Feb 05, 2010 at 07:23 UTC
Your parser may require a 2-arg open expression rather than a file name. Try passing `"< $ARGV[0]"`	[reply] [d/l]