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

Hi everyone, I have a problem I just can't find a solution for. I really tried everything so i'm asking you. I have this login script which reads the user xml file looking for a match: 

my $digestuser ="dado";
my $digestpass ="cane";

my $file="user.xml";
my $parser=XML::LibXML->new();
my $doc=$parser->parse_file($file);
my $root = $doc->getDocumentElement;

for my $u ($doc->findnodes('userlist/user')) {
    print "inside-cycle";
    my $property=$u->findnodes('./username')->get_node(1); 
            if(($property->textContent()) eq $digestuser){
            
                
                print $userok;
                $property=$u->findnodes('./password')->get_node(1); 
                if(($property->textContent()) eq $digestpass){
                    $passok=1;
                    
                        print "i did it";
                    }
        last;    
    }
}

[download]

Now the problem is: it works until i link the xml file to it's schema. I need to link it but for some reason it stops working. the xml schema is this 

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
    xmlns="http://tecnologie-web.studenti.math.unipd.it/tecweb/~gpinat
+o"
    targetNamespace="http://tecnologie-web.studenti.math.unipd.it/tecw
+eb/~gpinato"
    elementFormDefault="qualified">

<xs:element name="userlist">
    <xs:complexType>
        <xs:sequence>
            <xs:element name="user" minOccurs="0" maxOccurs="unbounded
+">
                <xs:complexType>
                    <xs:sequence>
                        <xs:element name="username" type="xs:string" /
+>
                        <xs:element name="password" type="xs:string" /
+>
                        <xs:element name="email" type="xs:string" />
                    </xs:sequence>
                </xs:complexType>
            </xs:element>
        </xs:sequence>
    </xs:complexType>
</xs:element>

</xs:schema>

[download]

and my file is this

<?xml version="1.0" encoding="UTF-8"?>
<userlist xmlns="http://www.progetto.com" xmlns:xs="http://www.w3.org/
+2001/XMLSchema-instance" xs:schemaLocation="http://www.progetto.com u
+ser.xsd">
<user>
               <username>dado</username>
               <password>cane</password>
               <email>cane</email>
                </user></userlist>

[download]

with <userlist> it works, as soon as i add this thing here "xmlns="http://tecnologie-web.studenti.math.unipd.it/tecweb/~gpinato"" it stops. I really have lost days on this one but i cant find a solution. Can you PLEASE help me? i really don't know what to do anymore

Replies are listed 'Best First'.
Re: Can't read xml after linking schema
by choroba (Cardinal) on Jan 28, 2014 at 15:59 UTC
    The main problem is that you add not only the link to the schema, but also a namespace to your document. To handle documents containing namespaced elements, you have to use XML::LibXML::XPathContext: 
    #!/usr/bin/perl
use warnings;
use strict;

use XML::LibXML;

my ($userok, $passok) = (1, 0);

my $digestuser = 'dado';
my $digestpass = 'cane';

my $file   = 'user.xml';
my $parser = 'XML::LibXML'->new;
my $doc    = $parser->parse_file($file);
my $root   = $doc->getDocumentElement;

my $xpc = 'XML::LibXML::XPathContext'->new;
$xpc->registerNs('p', 'http://www.progetto.com');

for my $u ($xpc->findnodes('p:userlist/p:user', $doc)) {
    print "inside-cycle";
    my ($property) = $xpc->findnodes('p:username', $u);
    if ($property->textContent eq $digestuser) {
        print $userok;
        ($property) = $xpc->findnodes('p:password', $u);
        if ($property->textContent eq $digestpass) {
            $passok = 1;
            print "i did it";
        }
        last
    }
}

    [download]

    The wrapper XML::XSH2 simplifies the code to 

    open user.xml ;
my $digestuser = 'dado' ;
my $password   = 'cane' ;
my $passok ;
if p:userlist/p:user[p:username=$digestuser and p:password=$digestpass
+] $passok = 1 ;

    [download]
    لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
[reply]
[d/l]
[select]

      and what if I remove the line with the namespace? could it cause trouble?

[reply]
        It can cause serious trouble to any other code reading the file - if the code expected the namespace and it wasn't present, the code wouldn't find any nodes.
        لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
[reply]

      anyway it works and i f*****g love you, i'd buy you a lifetime supply of beer

[reply]
        No jokes. I am from the Czech Republic, we drink several litres a day!
        لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
[reply]

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