(PHP ActiveX) OAuth2 for a GMail using a P12 Service Account Key

See more GMail REST API Examples

Note: This example does not work for Personal Google Accounts where the email domain is @gmail.com

For more information, see https://www.chilkatsoft.com/google_workspace_setup_smtp_gmail.asp

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows Note: The php_com_dotnet.dll may need to be enabled inside of php.ini.

<?php

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

$http = new COM("Chilkat.Http");

// --------------------------------------------------------------------------------
// 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
// --------------------------------------------------------------------------------
// Begin by loading your Google service account key (.p12)
$cert = new COM("Chilkat.Cert");
$success = $cert->LoadPfxFile('c:/someDirectory/keys/chilkat25-cbd7b42afbd8.p12','notasecret');
if ($success != 1) {
    print $cert->LastErrorText . "\n";
    exit;
}

// 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 = 'bob@yourcompany.com';

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

$accessToken = $http->g_SvcOauthAccessToken($iss,$scope,$oauth_sub,$numSec,$cert);
if ($http->LastMethodSuccess != 1) {
    print $http->LastErrorText . "\n";
    exit;
}
else {
    print 'access token: ' . $accessToken . "\n";
}

// The access token allows us to send unlimited emails while it's valid. Once it expires, we must obtain and use a new one.

// -----------------------------------------------------------------------
$mailman = new COM("Chilkat.MailMan");

// Set the properties for the GMail SMTP server:
$mailman->SmtpHost = 'smtp.gmail.com';
$mailman->SmtpPort = 587;
$mailman->StartTLS = 1;

$mailman->SmtpUsername = 'bob@yourcompany.com';
$mailman->OAuth2AccessToken = $accessToken;

// Create a new email object
$email = new COM("Chilkat.Email");

$email->Subject = 'This is a test';
$email->Body = 'This is a test';
$email->From = 'Bob <bob@yourcompany.com>';
$success = $email->AddTo('Recipient','recipient@example.com');
// To add more recipients, call AddTo, AddCC, or AddBcc once per recipient.

$success = $mailman->SendEmail($email);
if ($success != 1) {
    print $mailman->LastErrorText . "\n";
    exit;
}

$success = $mailman->CloseSmtpConnection();
if ($success != 1) {
    print 'Connection to SMTP server not closed cleanly.' . "\n";
}

print 'Successfully sent email using Gmail with a service account key.' . "\n";

?>