CODEWITHSUNDEEP
xmlperl
Aaron Xavier
Aaron Xavier

Reputation: 73

PERL XML::LibXML changes tag structure when outputting XML

THE SITUATION

After I have edited an XML and changed the values successfully, I need to write the changes back to the file. However, when I do this, the first tag of the XML, which has two attributes (a) date_time and (b) xmlns:xsi gets switched around after the uodate.

The following is the sample of the XML:

XML Document sample

THE ORIGINAL XML 

<?xml version="1.0" encoding="UTF-8"?>
<basenet date_time="201202131140" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"     >
<msg_ver>01</msg_ver>
<sender_id>1234</sender_id>
<recipient_id>Bob</recipient_id> 
</basenet>

The Output

<?xml version="1.0" encoding="UTF-8"?>
<tradenet xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"     date_time="201202131140">
<msg_ver>01</msg_ver>
<sender_id>1234</sender_id>
<recipient_id>Bob</recipient_id> 
</tradenet>

The Code

 sub CHANGE_DATE_SEQ_NUM()
  {

# load
open my $fh, '<', $newfile;
binmode $fh; # drop all PerlIO layers possibly created by a use open pragma
my $doc = XML::LibXML->load_xml(IO => $fh);

    my $query  = "/tradenet/message/header/unique_ref_no/date/text( )";
    my $query2  = "/tradenet/message/header/unique_ref_no/seq_no/text( )";
    my $query3  = "/tradenet/message/transport/out_tpt/dept_date/text( )";
    #print $query3;

    my($node)   = $doc->findnodes($query);
    my($node2)  = $doc->findnodes($query2);
    my($node3)  = $doc->findnodes($query3);


        $node->setData("$date");
        $node2->setData("$file_seq_number");
        $node3->setData("$date");


             # save
         open my $out, '>', $newfile;
         binmode $out; # as above
         $doc->toFH($out);
   }

My Question Why does the date_time and xmlns:xsi in the tag get switched? The switch is causing my XML to fail the validation at my server side.

Thank you for you time.

Upvotes: 0

Views: 223

Answers (1)

ikegami
ikegami

Reputation: 385764

Attribute order is meaningless in XML, so the bug is in your validation code.

It probably would have been less efficient for XML::LibXML or underlying libxml2 to preserve the order, so they didn't, seeing as there's no reason to do so. The attributes are probably stored in a hash table.

Upvotes: 1

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