Perl

Get Google API Access Token using JSON Private Key using NIST Time Server Date/Time

Demonstrates how to get a Google API access token using a JSON service account private key, using the NIST time server date/time rather than the local system date/time. Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# First, let's get the current date/time from time-c.nist.gov
my $socket = Chilkat2::Socket->new;

# Connect to an NIST time server and read the current date/time
my $maxWaitMs = 8000;
my $useTls = 0;
my $success = $socket->Connect('time-c.nist.gov', 37, $useTls, $maxWaitMs);
if (!$success) {
    print $socket->LastErrorText, "\n";
    exit;
}

# The time server will send a big-endian 32-bit integer representing
# the number of seconds since since 00:00 (midnight) 1 January 1900 GMT.
# The ReceiveInt32 method will receive a 4-byte integer, but returns
# 1 or 0 to indicate success.  If successful, the integer
# is obtained via the ReceivedInt property.
my $bigEndian = 1;
$success = $socket->ReceiveInt32($bigEndian);
if (!$success) {
    print $socket->LastErrorText, "\n";
    exit;
}

my $dt = Chilkat2::DateTime->new;
$dt->SetFromNtpTime($socket->ReceivedInt);

# Show the current local date/time
my $bLocalTime = 1;
print 'Current local date/time: ', $dt->GetAsRfc822($bLocalTime), "\n";

$maxWaitMs = 10;
$socket->Close($maxWaitMs);

# ------------------------------------------------------------------------
# OK, we have the current date/time.  We'll use it to set the IAT property
# in the code below.

# First load the JSON key into a string.
my $fac = Chilkat2::FileAccess->new;
my $jsonKey = $fac->ReadEntireTextFile('qa_data/googleApi/ChilkatTest-ab2ecd52ef98.json', 'utf-8');
if (!$fac->LastMethodSuccess) {
    print $fac->LastErrorText, "\n";
    exit;
}

# A JSON private key should look like this:

#     {
#       "type": "service_account",
#       "project_id": "chilkattest-1350",
#       "private_key_id": "fa2e36ee26986eab628b59868af8bec1d1c64c38",
#       "private_key": "-----BEGIN PRIVATE KEY-----\nMIIEvgIjFa...28N64N2n1E4FYzBZjSdy\n-----END PRIVATE KEY-----\n",
#       "client_email": "598922945226-00rb0ppfg0sndajo6bhvd4v17jtj2d3a@developer.gserviceaccount.com",
#       "client_id": "598922945226-00rb0ppfg0snd9jo7bhvd4v17jtj2d3a.apps.googleusercontent.com",
#       "auth_uri": "https://accounts.google.com/o/oauth2/auth",
#       "token_uri": "https://accounts.google.com/o/oauth2/token",
#       "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
#       "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/598922945226-00rb0ppfg0sndajo6bhvd4v17jtj2d3a%40developer.gserviceaccount.com"
#     }

my $gAuth = Chilkat2::AuthGoogle->new;
$gAuth->JsonKey($jsonKey);

# Choose a scope.
$gAuth->Scope('https://www.googleapis.com/auth/cloud-platform');

# Request an access token that is valid for this many seconds.
$gAuth->ExpireNumSeconds(3600);

# If the application is requesting delegated access:
# The email address of the user for which the application is requesting delegated access,
# then set the email address here. (Otherwise leave it empty.)
$gAuth->SubEmailAddress('');

# ------------------------------------------------------------------------
# Set the IAT using the date/time from the NIST time server.
my $unixTime = $dt->GetAsUnixTime(0);
print 'unixTime = ', $unixTime, "\n";
$gAuth->Iat($unixTime);

# Connect to www.googleapis.com using TLS (TLS 1.2 is the default.)
# The Chilkat socket object is used so that the connection can be established
# through proxies or an SSH tunnel if desired.
my $tlsSock = Chilkat2::Socket->new;
$success = $tlsSock->Connect('www.googleapis.com', 443, 1, 5000);
if (!$success) {
    print $tlsSock->LastErrorText, "\n";
    exit;
}

# Send the request to obtain the access token.
$success = $gAuth->ObtainAccessToken($tlsSock);
if (!$success) {
    print $gAuth->LastErrorText, "\n";
    exit;
}

# Examine the access token:
print 'Access Token: ', $gAuth->AccessToken, "\n";