(PHP Extension) Get Google API Access Token using P12 Service Account Key

Demonstrates how to get a Google API access token using a P12 service account key.

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<?php

include("chilkat.php");

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

// --------------------------------------------------------------------------------
// For a step-by-step guide for setting up your Google Workspace service account,
// see Setup Google Workspace Account for Sending SMTP GMail from a Service Account
// --------------------------------------------------------------------------------

// First load the PKCS12 (.p12 / .pfx) into a PFX object.
$pfx = new CkPfx();
$success = $pfx->LoadPfxFile('qa_data/pfx/chilkat25-cbd7b42afbd8.p12','notasecret');
if ($success != true) {
    print $pfx->lastErrorText() . "\n";
    exit;
}

$gAuth = new CkAuthGoogle();
$success = $gAuth->SetP12($pfx);

// The ISS is your service account email address ending in gserviceaccount.com.
$iss = 'chilkatsvc@chilkat25.iam.gserviceaccount.com';

// The scope is always the following string:
$scope = 'https://mail.google.com/';

// The sub is your company email address
$oauth_sub = 'info@chilkat.xyz';

// The access token is valid for this number of seconds.
$numSec = 3600;

$gAuth->put_EmailAddress($iss);
$gAuth->put_Scope($scope);
$gAuth->put_ExpireNumSeconds($numSec);
$gAuth->put_SubEmailAddress($oauth_sub);

// Connect to www.googleapis.com
$tlsSock = new CkSocket();
$success = $tlsSock->Connect('www.googleapis.com',443,true,5000);
if ($success != true) {
    print $tlsSock->lastErrorText() . "\n";
    exit;
}

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

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

?>