strange bug accessing a variable in template toolkit - perl

I'm struggling with a bug, that I can't nail down.
I have a function that takes a postcode, does a lookup, and returns a latitude, longitude and area name.
for example, pass it AD300 it returns (something like) 42.6, 1.55, ordino - it works very well.
The function is called like this:
my ($lat, $lng, $area) = $object->release();
The return values are fine, and I can print them in perl with a warn
warn "Area $area, $rellat, $rellng";
This works fine. "Area Ordino, 42.6, 1.55"
I then take one of these values, say $area, add it to a hash of data, and pass it to a web page where it is preprocessed via TT (as I do successfully with a load of other variables).
I'm assigning the value to the hash in the normal way. e.g.
$hash->{'area'} = $area;
Here is where the fun begins. When I try to reference the value in TT e.g. [% hash.area %]
I don't get "Ordino" printed on the web page, I'm told I've passed an Array reference to TT.
After a little debugging, I've found that my hash variable hash.area, is somehow referencing an array (according to TT) holding the three values that I've returned from the subroutine "release". I.e.
hash.area = [42.6, 1.55, ordino] according to TT.
That is, to get the value "Ordino" within the web page, I have to access [% hash.area.2 %].
Further, I can set $hash->{'area'} to equal any of the variables, $lat, $lng, or $area and get the same behavior. TT believes all three variables reference the same array. that is
$lat = $lng = $area = [42.6, 1.55, ordino] according to TT
This is bizare, I can happily print the variables in perl and they appears as normal - not an array. I've tried dumping the hash with dumper, no array, everything is fine. Yet somehow, TT is finding an array. It's doing my head in.
The site is quite large, with a lot of pages and I happily pass variables and hashes via TT to web pages all the time, and have been for 4 years now. I've never seen this. On other pages, I even pass exactly the same output from the "release" method and it is processed correctly.
I don't think my TT processing code is the problem, however the following is relevant.
my $tt = Template->new({
INCLUDE_PATH => [ #$template_directories ],
COMPILE_EXT => '.ttc',
COMPILE_DIR => '/tmp/ttc',
FILTERS => YMGN::View->filters,
PLUGIN_BASE => [ 'YMGN::V::TT::Plugins' ],
EVAL_PERL => 1
});
$self->{tt} = $tt;
$self->{template_directories} = $template_directories;
$self->{output} = $params->{output} || undef;
$self->{data} = $params->{data} || [];
The above creates a new tt object and is part of the "new" function (refed below).
"data" contains the hash. "output" holds the processed template ready to send to users browser. We call new (above), process the data and create the output with the code below.
sub process {
my $self = shift;
my $params = shift;
if (!ref $self || !exists $self->{tt}) {
my $class = $self;
$self = $class->new($params);
}
if (!$self->{output}) {
die "You need to specify output";
}
delete $self->{error};
$self->y->utils->untaint(\$self->{template});
my $rv = $self->{tt}->process(
$self->{template},
$self->{data},
$self->{output},
binmode => ':utf8',
);
if (!$rv) {
warn $self->{tt}->error();
return {
error => $self->{tt}->error(),
};
}
return 0;
}
All of the above is sanitised because there is a lot of other stuff going on.
I believe what's important is that the data going in looks correct, here is a full dump of the complete data that is being processed by tt (at the point of processing). The thing that is causing the problem is bubbles->[*]->{'release'} (note, that release == area in the data. The name was changed for unrelated reasons). As you can see, dumper thinks it's a string. TT deals with everything else fine.
data $VAR1 = {
'system' => {
system stuff
},
'features' => {
site feature config
},
'message_count' => '0',
'bubbles' => [
bless( {
'history' => [
{
'creator' => '73',
'points' => '10',
'screenname' => 'sarah10',
'classname' => 'Flootit::M::Bubbles',
'id' => '1378',
'updated' => '1352050471',
'type' => 'teleport',
'label' => 'teleport',
'class' => 'Flootit::M::Bubbles'
}
],
'creator' => '6',
'release' => 'Escaldes-Engordany',
'image' => 'http://six.flooting.com/files/833/7888.png',
'pop_time' => '1352050644',
'y' => $VAR1->{'y'},
'taken_by' => '0',
'city' => '3',
'title' => 'hey a new bubble',
'id' => '566',
'class' => 'Flootit::M::Bubbles',
'prize' => 'go for it kids'
}, 'Flootit::M::Bubbles' ),
bless( {
'history' => [
{
'creator' => '6',
'points' => '10',
'screenname' => 'sarah20',
'classname' => 'Flootit::M::Bubbles',
'id' => '1723',
'updated' => '1349548017',
'type' => 'teleport',
'label' => 'teleport',
'class' => 'Flootit::M::Bubbles'
},
{
'creator' => '6',
'points' => '5',
'screenname' => 'sarah20',
'classname' => 'Flootit::M::Bubbles',
'id' => '1732',
'updated' => '1349547952',
'type' => 'blow',
'label' => 'blow',
'class' => 'Flootit::M::Bubbles'
}
],
'creator' => '89',
'release' => 'Ordino',
'image' => 'http://six.flooting.com/files/1651/8035.png',
'pop_time' => '1351203843',
'y' => $VAR1->{'y'},
'taken_by' => '0',
'city' => '3',
'title' => 'test4',
'id' => '1780',
'class' => 'Flootit::M::Bubbles',
'prize' => 'asdfasdf dsadsasdfasdfasdf'
}, 'Flootit::M::Bubbles' ),
bless( {
'history' => [],
'creator' => '6',
'release' => 'Andorra la Vella',
'image' => 'http://six.flooting.com/files/1671/8042.png',
'pop_time' => '0',
'y' => $VAR1->{'y'},
'taken_by' => '0',
'city' => '3',
'title' => 'Pretty flowers, tres joli',
'id' => '1797',
'class' => 'Flootit::M::Bubbles',
'prize' => 'With lots of pretty pictures'
}, 'Flootit::M::Bubbles' ),
bless( {
'history' => [],
'creator' => '6',
'release' => 'Hillrise Ward',
'image' => 'http://six.flooting.com/files/1509/8003.png',
'pop_time' => '0',
'y' => $VAR1->{'y'},
'taken_by' => '0',
'city' => '3',
'title' => 'Test beats',
'id' => '1546',
'class' => 'Flootit::M::Bubbles',
'prize' => 'Sound great'
}, 'Flootit::M::Bubbles' )
]
};
What comes out after processing is this (in $output)
There is a
[% FOREACH floot IN bubbles %]
Floating around ARRAY(0xfaf5d448). from [% floot.release %]
if we make this [% floot.release.2 %] it gives the correct value.
All the other fields can be referenced correctly - go figure.
The code that puts "bubbles" together is;
my $bubbles = $y->model('Bubbles')->search(['type' => 'golden', 'image' => '!NULL',
'bubble_prizes' => ['p', { 'p.bubble' => 'self.id'}], ], {
order_by => '(created>CURRENT_DATE() AND thumbsup+thumbsdown<10) DESC, COALESCE(thumbsup,0)-COALESCE(thumbsdown,0) DESC, pop_time DESC',
count => 10,
fields => ['p.title as title', 'p.prize as prize', 'city', 'taken_by', 'pop_time', 'id', 'creator'],
});
for (my $i=0; $i<#$bubbles; $i++) {
# Find specified bubbles (see below for when not found here)
my ($rellat, $rellng, $area) = $bubbles->[$i]->release() ;
$bubbles->[$i]->{'release'} = $area;
}
}
The controller then takes $bubble, bundles it up with session / site data, puts it inside an anonymous hash (as you can see in the data above) and passes it to view for processing.
The code for release is :
sub release {
my $self = shift;
my $postcode = $self->y->model('Prizes')->find({bubble => $self->id})->postcode;
my ( $user_lat, $user_long, $region_name );
if($postcode)
{
( $user_lat, $user_long, $region_name ) = $self->y->api('Location')->from_postcode($postcode);
return ( $user_lat, $user_long, $region_name );
}
}
API::Location is quite large, however the relevant lines are;
$postcode_record = $self->y->model('GeoData')->find( {
source => "ALL_COUNTRIES_POSTCODES",
country => $country_code,
sourceid => $postcode, } );
return ( $postcode_record->latitude, $postcode_record->longitude, $postcode_record->town );
The data dumps I've shown you are taken from inside TT.pm (part of view).
So, any ideas what might be going on or where to start? What can I do to try and debug this further? I'm out of ideas.

Maybe it's because $area is a blessed object; Try this to convert to a scalar string :
$string = ''.$area;
# e.g.
$hash->{'area'} = ''.$area;
Following #Moritz comment, to check that $area is blessed:
print ref($area);
use Data::Dumper; warn Dumper($area);
And q{""} overloaded:
print defined ${ref($area).'::'}{'(""'};
EDIT
sub release can return
- undef if $postcode evaluate to false
- a list but as it is used in as scalar context returns the last argument $region_name like parenthesized list (comma expression)
sub release {
my $self = shift;
my $postcode = $self->y->model('Prizes')->find({bubble => $self->id})->postcode;
my ( $user_lat, $user_long, $region_name );
if($postcode)
{
( $user_lat, $user_long, $region_name ) = $self->y->api('Location')->from_postcode($postcode);
return ( $user_lat, $user_long, $region_name );
}
}
It will be relevant to Dump $region_name or $area, or to look at from_postcode.

I found that the problem went away on other development servers and the production server.
I therefore tried uninstalling and reinstalling TT, however that didn't help.
As it appears it's an environment issue on my dev server, so I am retiring the box and starting a new one.

Related

Perl printing of a hash gives ARRAY(xxxxxxx)

I know there are many questions already with this kind of subject, but as far as I know (perl beginner so I could be wrong), I'm not using an array so I don't understand where this output comes from
$VAR1 = {
'BridgeMode' => {
'Ten-GigabitEthernet1/0/5' => {
'Description' => 'poort1',
'Duplex' => 'F(a)',
'Interface' => 'Ten-GigabitEthernet1/0/5',
'Link' => 'UP',
'PVID' => '100',
'Speed' => '10G(a)',
'Type' => 'A',
'Vlan100' => {
'UntaggedPorts' => [
'Ten-GigabitEthernet1/0/5'
]
},
'vlanID' => [
'Vlan100'
]
},
Above is the content of my dumper and this is my print statement:
my $untaggedInterface = $data{BridgeMode}{"Ten-GigabitEthernet1/0/5"}{Vlan100}{UntaggedPorts} ;
print "Untagged: $untaggedInterface \n" ;
I would expect that the print statement would print "Ten-GigabitEthernet1/0/5" but instead it shows this:
Untagged: ARRAY(0x24a8ec0)
edit - it is possible that there exists an tagged and an untagged:
$VAR1 = {
'BridgeMode' => {
'Ten-GigabitEthernet1/0/12' => {
'Description' => 'poort5',
'Duplex' => 'F(a)',
'Interface' => 'Ten-GigabitEthernet1/0/12',
'Link' => 'UP',
'PVID' => '100',
'Speed' => '10G(a)',
'Type' => 'H',
'Vlan100' => {
'UntaggedPorts' => [
'Ten-GigabitEthernet1/0/12'
]
},
'Vlan107' => {
'TaggedPorts' => [
'Ten-GigabitEthernet1/0/12'
]
},
edit: printing the content of the array
my #untaggedInterface = $data{BridgeMode}{"Ten-GigabitEthernet1/0/5"}{Vlan100}{UntaggedPorts} ;
print join(", ", #untaggedInterface) ;
stil gives
ARRAY(0x1c03a68)
You would get the expected result if you had the following, i.e. a string instead of a string array:
'UntaggedPorts' => 'Ten-GigabitEthernet1/0/12'
Otherwise, you must specify the index of the array element:
my $untaggedInterface = $data{BridgeMode}{"Ten-GigabitEthernet1/0/5"}{Vlan100}{UntaggedPorts}[0];

Accessing a nested data structure

I have an array of hashes nested to multiple levels. I need to extract a value from all deeply-nested hashes that have a given value for a different key in the same hash
This is a collection of entities from our database, and the data represents contacts within each entity and all of their contact values.
There is a hash key contact_method_type_id which refers to an integer defining the type of contact method. The contact_method_type_id that I care about is 1, which is email.
The first contact has three different contact_methods. The first is 4 which is an office phone, the second is a 2 which is a home phone, and the third is a 1 which is email.
Within the same hash is there is a 'contact_method_value', which is the string representation of their email address.
I need a way to extract just these values into a new array
Here are the contents of the first element of the array
$VAR1 = [
{ 'total' => '2',
'results' => [
{ 'contact_type_name' => 'Primary Technical Contact',
'street' => undef,
'state_id' => undef,
'state_name' => undef,
'last_name' => 'Barb',
'entities' => [
{ 'entity_name' => 'XXXXX',
'entity_id' => 'XXXXX'
}
],
'state_abbr_name' => undef,
'city' => undef,
'country_id' => undef,
'latitude' => undef,
'contact_id' => 'XXXXXX',
'contact_type_id' => '1',
'roles' => [],
'contact_methods' => [
{ 'entity_name' => undef,
'contact_method_value' => 'XXXXXXX',
'contact_method_type_id' => '4',
'contact_method_id' => '24041',
'entity_id' => undef,
'contact_method_type_name' => 'Cell Phone'
},
{ 'entity_name' => undef,
'contact_method_value' => 'XXXXXX',
'contact_method_type_id' => '2',
'contact_method_id' => '24051',
'entity_id' => undef,
'contact_method_type_name' => 'Office Phone'
},
{ 'entity_name' => undef,
'contact_method_value' => 'example#example.com',
'contact_method_type_id' => '1',
'contact_method_id' => '24061',
'entity_id' => undef,
'contact_method_type_name' => 'Email'
}
],
'country_name' => undef,
'longitude' => undef,
'country_abbr_name' => undef,
'full_name' => 'NAME',
'networks' => [
{ 'network_name' => 'NET',
'network_id' => 'X'
}
],
'timezone_id' => undef,
'zip' => undef,
'timezone_name' => undef,
'title' => 'MAC/Network Specialist',
'first_name' => 'Terri'
},
{ 'contact_type_name' => 'Primary Technical Contact',
'street' => 'STREET',
'state_id' => undef,
'state_name' => undef,
'last_name' => 'NAME',
'entities' => [
{ 'entity_name' => 'NAME',
'entity_id' => '2679'
}
],
'state_abbr_name' => undef,
'city' => 'CITY',
'country_id' => undef,
'latitude' => undef,
'contact_id' => '7896',
'contact_type_id' => '1',
'roles' => [],
'contact_methods' => [
{ 'entity_name' => undef,
'contact_method_value' => 'example#example.com',
'contact_method_type_id' => '1',
'contact_method_id' => '16796',
'entity_id' => undef,
'contact_method_type_name' => 'Email'
},
{ 'entity_name' => undef,
'contact_method_value' => 'number',
'contact_method_type_id' => '2',
'contact_method_id' => '16797',
'entity_id' => undef,
'contact_method_type_name' => 'Office Phone'
}
],
'country_name' => undef,
'longitude' => undef,
'country_abbr_name' => undef,
'full_name' => 'NAME',
'networks' => [
{ 'network_name' => 'net',
'network_id' => '17'
}
],
'timezone_id' => undef,
'zip' => 'zip',
'timezone_name' => undef,
'title' => 'Infrastructure Manager',
'first_name' => 'name'
}
],
'offset' => '0'
},
...
This looks suspiciously like something that XML::Simple would have generated.
Assuming this is the case, then I would suggest that you've fallen for the classic mistake of assuming XML::Simple actually helps.
Under that assumption, if you instead use XML::Twig:
Taking your $VAR1. Although - ideally you'll just parse the original source with parse or parsefile:
use XML::Twig;
use XML::Simple;
my $twig = XML::Twig->parse( XMLout($VAR1) );
print $_->att('contact_method_value'), "\n" for $twig->findnodes('//contact_methods[#contact_method_type_name="Email"]');
Which given your sample (as $VAR1):
example#example.com
example#example.com
Edit: Because you've commented that it's JSON then I wouldn't necessarily do this (Although - it does actually work, despite that).
If the data structures are all of the same kind, this is very trivial. You just need to iterate all the outer hashrefs (I called those resultsets). Inside those, you need to look at all results, and in each result you need to look at all the contact methods. If one of them has a contact_method_type_id of 1, you take the contact_method_value. And that's it.
my #email_addresses;
foreach my $resultset ( #{$data} ) {
foreach my $result ( #{ $resultset->{results} } ) {
foreach my $contact ( #{ $result->{contact_methods} } ) {
push #email_addresses , [ $contact->{contact_method_value} ]
if $contact->{contact_method_type_id} == 1;
}
}
}
This code assumes your structure is called $data. #email_addresses looks like this when output.
[
[ 'EMAIL' ],
[ 'EMAIL' ]
];
If you have this on a database then you should use an SQL query to retrieve it, rather than fetching everything into memory and processing what you have
The output from Data::Dumper shows the contents of your data, but it doesn't explain what you're dealing with in your code. Specifically, you don't have a $VAR1 in your code, but I have no idea what you do have
In the end, I think I wouldn't start from here. But since it's the only starting point I have to work with, it's a simple matter of recursing through the data structure
I've assumed that you want
$VAR1->[*]{results}[*]{contact_methods}[*]{contact_method_value}
where
$VAR1->[*]{results}[*]{contact_methods}[*]{contact_method_type_name} eq 'Email'
Update
Since your comments I've altered my code to select the same values where
$VAR1->[*]{results}[*]{contact_methods}[*]{contact_method_type_id} == 1
Since you said nothing about your code at all, I've had to assume a variable $data which contains a reference to the array that you show in your question
for my $item ( #$data ) {
my $results = $item->{results};
for my $result ( #$results ) {
my $methods = $result->{contact_methods} or die;
for my $method ( #$methods ) {
#my $type_name = $method->{contact_method_type_name};
#next unless $type_name eq 'Email';
my $type_id = $method->{contact_method_type_id};
next unless $type_id == 1; ## Email
my $value = $method->{contact_method_value};
print "$value\n";
}
}
}
output
example#example.com
example#example.com

Perl extracting data from a hash

I am trying to extract data from a hash value.
my $triggers = $zabbix->raw('trigger','get', $options);
print Dumper($triggers);
foreach my $trigger (#{$triggers} )
{
push #triggerid,$trigger->{'triggerid'};
my #t=$trigger->{'hosts'};
my $lt = localtime($trigger->{'lastchange'});
print "$trigger->{'description'} $lt \n";
}
Output of Dumper is
[
{
'hosts' => [
{
'hostid' => '19914',
'host' => 'pc10bcf18.syd.sf.priv'
}
],
'priority' => '2',
'status' => '0',
'templateid' => '10652913',
'comments' => '',
'state' => '0',
'triggerid' => '10653191',
'expression' => '{15070357}#1',
'error' => '',
'url' => '',
'flags' => '0',
'value' => '1',
'name' => 'pc10_BizX_A_CF',
'description' => 'pc10bcf18.syd.sf.priv: Core Path not \'/dumps/java/core\' (Path=/export/home/jboss/j...)',
'value_flags' => '0',
'lastchange' => '1429181103',
'type' => '0'
},
]
From my above code, i was able to print 'description'. How do i access and print the value of 'host' value?
To maintain the for / push pattern that you have already coded, you can write this
my $triggers = $zabbix->raw('trigger', 'get', $options);
my #triggerid;
for my $trigger ( #$triggers ) {
push #triggerid, $trigger->{triggerid};
my #hosts;
my $hosts = $trigger->{hosts};
for my $host ( #$hosts ) {
push #hosts, $host->{host};
}
my $lt = localtime($trigger->{lastchange});
print "$trigger->{description} $lt\n";
}
Looks like there can be more than one host, so
my #hosts =
map { $_->{host} }
#{ $trigger->{hosts} };
To get the first one (assuming there will always be at least one),
my $first_host = $trigger->{hosts}[0]{host};
$triggers->{'hosts'}->[0]->{'host'}

How to access individual elements of perl Hashed object?

I'm a non-programmer attemting to retrieve useful info from our InfoBlox DHCP boxes. I've installed the Perl API and can make some use of it.
I've got an output from the Data::Dumper "thingie" that appears to have some of the info I want. I'd like to directly reference some of that data but I'm unsure how.
print Dumper(\$object)
Here is part of the Data::Dumper output;
$VAR1 = \bless( {
'network' => '10.183.1.0/24',
'override_lease_scavenge_time' => 'false',
'enable_ifmap_publishing' => 'false',
'low_water_mark_reset' => '10',
'use_lease_time' => 0,
'use_enable_option81' => 0,
'network_container' => '/',
'override_ddns_ttl' => 'false',
'rir' => 'NONE',
'network_view' => bless( {
<snip> --------------------------------------
'extattrs' => {
'Use' => bless( {
'value' => 'Voip'
}, 'Infoblox::Grid::Extattr' )
},
<snip> --------------------------------------
'members' => [
bless( {
'ipv4addr' => '10.85.9.242',
'name' => 'ig3-app3.my.net'
}, 'Infoblox::DHCP::Member' ),
bless( {
'ipv4addr' => '10.85.9.210',
'name' => 'ig3-app1.my.net'
}, 'Infoblox::DHCP::Member' ),
bless( {
'ipv4addr' => '10.85.9.226',
'name' => 'ig3-app2.my.net'
}, 'Infoblox::DHCP::Member' )
],
'override_ignore_client_identifier' => 'false',
'email_list' => undef,
'rir_registration_status' => '??
}, 'Infoblox::DHCP::Network' );
How do I view the elements? ie ...
print $object{members->name};
print $object{members->ipv4addr};
print $object{extattrs->Use->value};
I've found the API dox insufficiant for my skill level:) The data I'd like to pull remains just out of reach.
my #retrieved_objs = $session->search (
object => "Infoblox::DHCP::Network",
network => '.*\.*\.*\..*',
);
foreach $object ( #retrieved_objs ) {
my $network = $object->network;
my $comment = $object->comment;
my $extattrs = $object->extattrs;
my $options = $object->options;
print $network, " network ", $comment, " ", $extattrs, " ", $options, "\n";
}
-------- output ---
10.183.2.0/24 network HASH(0x6a2f038) ARRAY(0x1d20eb0)
10.192.1.0/24 network HASH(0x9df6540) ARRAY(0x9df5468)
10.192.2.0/24 network HASH(0xa088fc8) ARRAY(0xa089718)
You shouldn't try to access the internal values of an object directly. The module - in this case Infoblox::DHCP::Network will provide methods that allow you to read or manipulate the values properly.

How do I access values in the data structure returned by XML::Simple?

Hi everyone,
This is very simple for perl programmers but not beginners like me,
I have one xml file and I processed using XML::Simple like this
my $file="service.xml";
my $xml = new XML::Simple;
my $data = $xml->XMLin("$file", ForceArray => ['Service','SystemReaction',
'Customers', 'Suppliers','SW','HW'],);
Dumping out $data, it looks like this:
$data = {
'Service' => [{
'Suppliers' => [{
'SW' => [
{'Path' => '/work/service.xml', 'Service' => 'b7a'},
{'Path' => '/work/service1.xml', 'Service' => 'b7b'},
{'Path' => '/work/service2.xml', 'Service' => 'b5'}]}
],
'Id' => 'SKRM',
'Customers' =>
[{'SW' => [{'Path' => '/work/service.xml', 'Service' => 'ASOC'}]}],
'Des' => 'Control the current through the pipe',
'Name' => ' Control unit'
},
{
'Suppliers' => [{
'HW' => [{
'Type' => 'W',
'Path' => '/work/hardware.xml',
'Nr' => '18',
'Service' => '1'
},
{
'Type' => 'B',
'Path' => '/work/hardware.xml',
'Nr' => '7',
'Service' => '1'
},
{
'Type' => 'k',
'Path' => '/work/hardware.xml',
'Nr' => '1',
'Service' => '1'
}]}
],
'Id' => 'ADTM',
'Customers' =>
[{'SW' => [{'Path' => '/work/service.xml', 'Service' => 'SDCR'}]}],
'Des' => 'It delivers actual motor speed',
'Name' => ' Motor Drivers and Diognostics'
},
# etc.
],
'Systemreaction' => [
# etc.
],
};
How to access each elements in the service and systemReaction(not provided). because I am using "$data" in further processing. So I need to access each Id,customers, suppliers values in each service. How to get particular value from service to do some process with that value.for example I need to get all Id values form service and create nodes for each id values.
To get Type and Nr value I tried like this
foreach my $service (#{ $data->{Service}[1]{Suppliers}[0]{HW}[0] }) {
say $service->{Nr};
}
foreach my $service (#{ $data->{Service}[1]{Suppliers}[0]{HW}[0] }) {
say $service->{Type};
}
can you help me how to get all Nr and Type values from Supplier->HW.
I suggest reading perldocs Reference Tutorial and References and Nested Data Structures. They contain an introduction and full explanation of how to access data like that.
But, for example, you can access the service ID by doing:
say $data->{Service}[0]{Id} # prints SKRM
You could go through all the services, printing their ID, with a loop:
foreach my $service (#{ $data->{Service} }) {
say $service->{Id};
}
In response to your edit
$data->{Service}[1]{Suppliers}[0]{HW}[0] is an hash reference (you can check this quickly by either using Data::Dumper or Data::Dump on it, or just the ref function). In particular, it is { Nr => 18, Path => "/work/hardware.xml", Service => 1, Type => "W" }
In other words, you've almost got it—you just went one level too deep. It should be:
foreach my $service (#{ $data->{Service}[1]{Suppliers}[0]{HW} }) {
say $service->{Nr};
}
Note the lack of the final [0] that you had.