Parse handler for Attributes in XML

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

Hi, Finally after having some tough time with XML parsing i am relatively comfortable now , but stuck with a small problem in parsing the below XML

<DCA>
    <testcase type = "Interactive">
    <step command ="LaunchApp " param1 = "executablepath" param2 = "di
+rpath"/>
    <step command = "Gohere"/>
    <step command = "Changemode" param1 = "100"/>
    <step command = "CaptureRectanlge" param1 = "3" param2 = "96" para
+m3 = "726" param4 = "580"/>
    <step command = "CompareImage" param1 = "D:\\img1.jpg" param2 = "D
+:\\img2.jpg "/>
    </testcase>
    
    <testcase type = "broswer">
    <step command ="Launchapp " param1 = "executablepath" param2 = "di
+rpath"/>
    <step command = "Gohere"/>
    <step command = "Channgemode" param1 = "100"/>
    <step command = "CaptureRectanlge" param1 = "3" param2 = "96" para
+m3 = "726" param4 = "580"/>
    <step command = "CompareImage" image1 = "D:\\img1.jpg" image2 = "D
+:\\img2.jpg "/>
    </testcase>
</DCA>
[download]

I am using XML::Parser module to traverse through the elements but i am not able to define handlers for the attributes for this xml. How can i access the attributes in each step, here is my below code. I want to access each and every attribute like 'command' , 'param1'. etc. Any help is highly appreciated.

use warnings;
use 5.010;
use XML::Simple;
use XML::MyXML;
use XML::Twig;
use XML::Parser;

my $parser = new XML::Parser;
$parser->setHandlers(Start => \&startElement,
                           End => \&endElement,);                     
+      

$parser->parsefile('D:\\ABC\\Perl Projects\\DCA.xml');

sub startElement {
       my( $parseinst, $element, %attrs ) = @_;
       SWITCH: {
              if ($element eq "testcase") {
                     $count++;
                     $tag = "testcase";
                     print "Testcase $count:\n";
                     last SWITCH;
              }
              if ($element eq "step") {
                     print "Step: ";
                     $tag = "step";
                     last SWITCH;
              }
              if (%attrs eq "command") {
                     print "Command: ";
                     $tag = "Command";
                     last SWITCH;
              }
       }
}

sub endElement {
       my( $parseinst, $element ) = @_;
       if ($element eq "testcase") {
              print "\n\n";
       } elsif ($element eq "title") {
              print "\n";
       }
}
[download]

Comment on Parse handler for Attributes in XML Select or Download Code

Replies are listed 'Best First'.
Re: Parse handler for Attributes in XML by tangent (Parson) on Apr 10, 2012 at 10:13 UTC
All the attributes are in the hash %attrs: `for my $attr (keys %attrs) { if ($attr eq 'command') { print "Command: $attrs{$attr}\n"; } }` [download] To access a specific attribute (e.g. command) just say: `my $command = $attrs{command};` [download]	[reply] [d/l] [select]
Re^2: Parse handler for Attributes in XML by balajinagaraju (Sexton) on Apr 10, 2012 at 10:24 UTC
Thanks a lot Tangent, your piece of advice worked well. I still have some specifics to handle will come back incase i am not able to get it myself:-). Thanks for your time.	[reply]
Re: Parse handler for Attributes in XML by kcott (Archbishop) on Apr 10, 2012 at 10:09 UTC
I'm not particularly familiar with `XML::Parser` but this line in particular leapt out at me: `if (%attrs eq "command") {` [download] I suspect you want something like: `if (exists $attrs{command}) {` [download] I also noticed your XML has no closing tag (i.e. `</DCA>`) - possibly a cut-n-paste error. -- Ken	[reply] [d/l] [select]
Re^2: Parse handler for Attributes in XML by balajinagaraju (Sexton) on Apr 10, 2012 at 10:13 UTC
Thanks Ken, But i want to access specific attributes rather than checking for the presence of the attributes.	[reply]
Re^3: Parse handler for Attributes in XML by kcott (Archbishop) on Apr 10, 2012 at 10:53 UTC
`$attrs{command}` is a specific attribute. Checking for existence before attempting to access a value (e.g. `... $attrs{command} eq 'some_value' ...`) avoids autovivification; depending on what other code you write, this may or may not be important. However, the main point I was trying to get across was that `%attrs eq "command"` was not doing what you wanted/intended/expected. The following short piece of code may help to further explain this: `$ perl -Mstrict -Mwarnings -E ' > my %x = (a => 1); > say +(%x eq q{a}) ? 1 : 0; > say %x; > say qq{@{[%x]}}; > ' 0 a1 a 1` [download] -- Ken	[reply] [d/l] [select]