Google REST API with Perl JSON::WebToken

jwt.pl

use strict;
use warnings;

require JSON::XS;
require JSON::WebToken;
require LWP::UserAgent;

my $google_ua = signin_with_google(
    service_account_id => $SERVICE_AC_ID,
    private_key => $PRIVATE_KEY,
    scopes => [
        'https://www.googleapis.com/auth/plus.login',
        'https://www.googleapis.com/auth/fusiontables',
        'https://www.googleapis.com/auth/drive',
    ]
);

my $api_response = $google_ua->get(
    'https://www.googleapis.com/fusiontables/v2/tables'
);

if ($api_response->is_success) {
    die $api_response->code .' - '. $api_response->message, "\n\n", $api_response->content, "\n\n ... ";
} else {
    require Data::Dumper;
    warn Data::Dumper::Dumper JSON::XS::decode_json($api_response->content);
}

sub signin_with_google {
    my $args = ref($_[0])? shift : {@_};
    $args->{duration} ||= 60 * 10;
    $args->{scopes} = ref($args->{scopes})? join(' ', @{$args->{scopes}}) : $args->{scopes};
    my $time = time;

    my $res = LWP::UserAgent->new()->post('https://accounts.google.com/o/oauth2/token', {
        grant_type => 'urn:ietf:params:oauth:grant-type:jwt-bearer',
        assertion => JSON::WebToken->encode(
            {
                iss => $args->{service_account_id},
                scope => $args->{scopes},
                aud => 'https://accounts.google.com/o/oauth2/token',
                exp => $time + $args->{duration},
                iat => $time
            },
            $args->{private_key},
            'RS256', {typ => 'JWT'}
        )
    });

    unless ($res->is_success()) {
        die $res->code .' - '. $res->content;
    }

    my $google_ua = LWP::UserAgent->new();
    $google_ua->default_header(
        Authorization => 'Bearer ' . JSON::XS::decode_json($res->content)->{access_token}
    );

    warn 'Ready to call API...';
    return $google_ua;
}