(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.

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

# 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
$socket = chilkat::CkSocket->new();

# Connect to an NIST time server and read the current date/time
$maxWaitMs = 8000;
$useTls = 0;
$success = $socket->Connect("time-c.nist.gov",37,$useTls,$maxWaitMs);
if ($success != 1) {
    print $socket->lastErrorText() . "\r\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.
$bigEndian = 1;
$success = $socket->ReceiveInt32($bigEndian);
if ($success != 1) {
    print $socket->lastErrorText() . "\r\n";
    exit;
}

$dt = chilkat::CkDateTime->new();
$dt->SetFromNtpTime($socket->get_ReceivedInt());

# Show the current local date/time
$bLocalTime = 1;
print "Current local date/time: " . $dt->getAsRfc822($bLocalTime) . "\r\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.
$fac = chilkat::CkFileAccess->new();
$jsonKey = $fac->readEntireTextFile("qa_data/googleApi/ChilkatTest-ab2ecd52ef98.json","utf-8");
if ($fac->get_LastMethodSuccess() != 1) {
    print $fac->lastErrorText() . "\r\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"
# 	}

$gAuth = chilkat::CkAuthGoogle->new();
$gAuth->put_JsonKey($jsonKey);

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

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

# ------------------------------------------------------------------------
# Set the IAT using the date/time from the NIST time server.
$unixTime = $dt->GetAsUnixTime(0);
print "unixTime = " . $unixTime . "\r\n";
$gAuth->put_Iat($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.
$tlsSock = chilkat::CkSocket->new();
$success = $tlsSock->Connect("www.googleapis.com",443,1,5000);
if ($success != 1) {
    print $tlsSock->lastErrorText() . "\r\n";
    exit;
}

# Send the request to obtain the access token.
$success = $gAuth->ObtainAccessToken($tlsSock);
if ($success != 1) {
    print $gAuth->lastErrorText() . "\r\n";
    exit;
}

# Examine the access token:
print "Access Token: " . $gAuth->accessToken() . "\r\n";