Perl get value of nested hash - perl

Question

I have spent couple hours trying to get the value of 'Auth-Token' out of REST api response header, I just don't understand the meaning of bless({ key=> value })
is this a hashref inside an array? How can I loop through it.
$VAR1 = bless( {
'access-control-allow-credentials' => 'true',
'connection' => 'keep-alive',
'x-powered-by' => 'restheart.org',
'client-response-num' => 1,
'access-control-allow-origin' => '*',
'date' => 'Thu, 05 May 2016 22:54:44 GMT',
'client-peer' => '172.18.18.122:8080',
'content-length' => '469',
'access-control-expose-headers' => 'Location, ETag, Auth-Token, Auth-Token-Valid-Until, Auth-Token-Location, X-Powered-By',
'::std_case' => {
'access-control-allow-credentials' => 'Access-Control-Allow-Credentials',
'x-powered-by' => 'X-Powered-By',
'client-response-num' => 'Client-Response-Num',
'access-control-allow-origin' => 'Access-Control-Allow-Origin',
'client-peer' => 'Client-Peer',
'access-control-expose-headers' => 'Access-Control-Expose-Headers',
'client-date' => 'Client-Date',
'auth-token-valid-until' => 'Auth-Token-Valid-Until',
'auth-token-location' => 'Auth-Token-Location',
'auth-token' => 'Auth-Token'
},
'client-date' => 'Thu, 05 May 2016 22:55:00 GMT',
'content-type' => 'application/hal+json',
'auth-token-valid-until' => '2016-05-05T23:09:44.471Z',
'auth-token-location' => '/_authtokens/test',
'auth-token' => 'fbbb0215-cedd-4a10-9f89-93fdf1e84fdc'
}, 'HTTP::Headers' );

Answer 1

That's a hash that's been blessed into an HTTP::Headers object. You can access what you need by using its API:
my $token = $VAR1->header('auth-token');
I wouldn't recommend accessing it via the hash directly (breaking encapsulation), in case the internals of HTTP::Headers ever changes.

Answer 2

Its common in perl5 to use a hash for objects. In this case, you have a 'HTTP::Headers' object in $VAR1. Under the hood, the object is a blessed HashRef, so what your are seeing are the ordinary "guts" of a hash. To the left of the "fat commas" are the keys and to the right are the values.
So, your question boils down to - given a hashref in a variable, how do I get the value for key 'x'? Now, here is how you do that - but DONT do it.
print $VAR1->{ auth-token };
The reason why I say "dont do it" is that you're breaking a fundamental principle of OO programming called encapsulation. The details of the object are not supposed to be any of your business. Instead use the methods provided by the class (ie, provided by the module HTTP::Headers)
Reading the HTTP::Heders doco, you can get the header for 'auth token' like so;
print $VAR1->header( 'auth-token' )
This is what you need to do.