How to access an xml array from Perl?

Question

I have a perl script that connects to my Icecast2 server and monitors the list of users. I'm trying to access the list of listeners as an array so that I can perform an action for each listener

Relevant Subroutine:

sub process_list_clients()
{
        my ($mount) = @_;
        my $icecast_mount = Net::Icecast2::Mount->new(
            host => $ic_host,
            port => $ic_port,
            protocol => $ic_protocol,
            login    => $ic_login,
            password => $ic_password,
            mount    => $mount
        );

        my $xml = $icecast_mount->list_clients;

        print STDERR Dumper($xml);
        print STDERR "Listeners: " . $xml->{source}->{Listeners} . "\n";
        print STDERR "Mount: " . $xml->{source}->{mount} . "\n";
        my @listeners = $xml->{source}->{listener};
        foreach my $listener (@listeners)
        {
                print STDERR Dumper($listener);
        }
}

Output from the subroutine:

Listeners: 6
Mount: /masked
$VAR1 = [
          {
            'ID' => '233307',
            'Connected' => '705',
            'IP' => 'masked',
            'UserAgent' => 'FreeSWITCH(mod_shout)/1.0'
          },
          {
            'ID' => '233336',
            'Connected' => '622',
            'IP' => 'masked',
            'UserAgent' => 'FreeSWITCH(mod_shout)/1.0'
          },
          {
            'ID' => '233370',
            'Connected' => '503',
            'IP' => 'masked',
            'UserAgent' => 'FreeSWITCH(mod_shout)/1.0'
          },
          {
            'ID' => '233392',
            'Connected' => '433',
            'IP' => 'masked',
            'UserAgent' => 'FreeSWITCH(mod_shout)/1.0'
          },
          {
            'ID' => '233419',
            'Connected' => '347',
            'IP' => 'masked',
            'UserAgent' => 'FreeSWITCH(mod_shout)/1.0'
          },
          {
            'ID' => '233445',
            'Connected' => '275',
            'IP' => 'masked',
            'UserAgent' => 'FreeSWITCH(mod_shout)/1.0'
          }
        ];

Here is the xml output from Icecast2:

<icestats>
<source mount="/masked">
<Listeners>7</Listeners>
<listener>
<IP>masked</IP>
<UserAgent>FreeSWITCH(mod_shout)/1.0</UserAgent>
<Connected>798</Connected>
<ID>233307</ID>
</listener>
<listener>
<IP>masked</IP>
<UserAgent>FreeSWITCH(mod_shout)/1.0</UserAgent>
<Connected>715</Connected>
<ID>233336</ID>
</listener>
<listener>
<IP>masked</IP>
<UserAgent>FreeSWITCH(mod_shout)/1.0</UserAgent>
<Connected>596</Connected>
<ID>233370</ID>
</listener>
<listener>
<IP>masked</IP>
<UserAgent>FreeSWITCH(mod_shout)/1.0</UserAgent>
<Connected>526</Connected>
<ID>233392</ID>
</listener>
<listener>
<IP>masked</IP>
<UserAgent>FreeSWITCH(mod_shout)/1.0</UserAgent>
<Connected>440</Connected>
<ID>233419</ID>
</listener>
<listener>
<IP>masked</IP>
<UserAgent>FreeSWITCH(mod_shout)/1.0</UserAgent>
<Connected>368</Connected>
<ID>233445</ID>
</listener>
<listener>
<IP>masked</IP>
<UserAgent>FreeSWITCH(mod_shout)/1.0</UserAgent>
<Connected>91</Connected>
<ID>233511</ID>
</listener>
</source>
</icestats>

simbabque · Accepted Answer · 2018-04-26 09:53:48Z

3

Try doing this (example is for IP value) :

my @listeners = @{ $xml->{source}->{listener} };
foreach my $listener (@listeners) {
    print "$listener->{IP}\n";
}

The $VAR1 from Data::Dumper show that you have a reference to an ARRAY. So you have to de-reference it when you want an @array with the @{ } syntax.

The basic and the thing that every Perl coder should know :

my $array_ref = []; # a reference to a void ARRAY
my $hash_ref = {};  # a reference to a void HASH

Check
http://perldoc.perl.org/perlref.html
http://perldoc.perl.org/perlreftut.html

edited Apr 26, 2018 at 9:53

simbabque

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answered Dec 14, 2014 at 23:00

Gilles Quénot

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4 Comments

dkwiebe Over a year ago

That prints the IP address off of the first listener only.

Gilles Quénot Over a year ago

And now ? Is it what you expected ?

dkwiebe Over a year ago

Thanks, that's exactly what I was looking for. It now prints off a list of IP addresses.

dkwiebe Over a year ago

This answer works perfectly. My question might deserve a downvote but not this answer.

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