The LWP::UserAgent module can be used to issue a request to a REST API. This is handled differently in a GET request vs. a POST request.

GET request

Let's say a GET request to www.example.com/api should return "Hello World".

The $request->header option can be used to include headers.

#!/usr/bin/perl
use strict;
use warning;
use LWP::UserAgent;
use Data::Dumper;

my $ua = LWP::UserAgent->new;
my $request = HTTP::Request->new(GET => "http://www.example.com/api");
$request->header( "Accept" => "application/json" );
my $response = $ua->request($request);

print Dumper $response;

Dumper can be used to display the response. Something like this should be returned.

$VAR1 = bless( {
                 '_protocol' => 'HTTP/1.1',
                 '_content' => 'Hello World',
                 '_rc' => '200'
});

And here is how you would print all headers.

print $response->headers()->as_string;

Or a specific header.

print $response->header('Content-Type');

Or a previous header, such as when there is a 302 redirect.

print $response->previous->header('location');

POST request

And here is how you would include the Accept => application/json header in a POST request.

#!/usr/bin/perl
use strict;
use warning;
use LWP::UserAgent;

my $ua = LWP::UserAgent->new;
my $request = $ua->post( "http://www.example.com/api", "Accept" => "application/json", \@array );

if ( $request->is_success ) {
  print $request->decoded_content;
}
else {
  print "failed";
}