PHP Extension

Get GMail SMTP OAuth2 Access Token for Desktop App

See more OAuth2 Examples

This example show how to obtain a Gmail SMTP OAuth2 access token from a desktop application or script, enabling the use of XOAUTH2 authentication. PHP Extension

<?php

include("chilkat.php");

$success = false;

// To further clarify, see OAuth 2.0 Authorization Flow

$oauth2 = new CkOAuth2();

// For Google OAuth2, set the listen port equal to the port used
// in the Authorized Redirect URL for the Client ID.
// For example, in this case the Authorized Redirect URL would be http://localhost:55568/
// Your app should choose a port not likely not used by any other application.
$oauth2->put_ListenPort(55568);

$oauth2->put_AuthorizationEndpoint('https://accounts.google.com/o/oauth2/v2/auth');
$oauth2->put_TokenEndpoint('https://www.googleapis.com/oauth2/v4/token');

// Replace these with actual values.
$oauth2->put_ClientId('GOOGLE-CLIENT-ID');
$oauth2->put_ClientSecret('GOOGLE-CLIENT-SECRET');

// To use Gmail's OAuth2 for sending emails via the SMTP protocol, you need to request the https://mail.google.com/ scope. 
// See About GMail SMTP OAuth2 Scopes
$oauth2->put_Scope('https://mail.google.com/');

// Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
$url = $oauth2->startAuth();
if ($oauth2->get_LastMethodSuccess() != true) {
    print $oauth2->lastErrorText() . "\n";
    exit;
}

// Launch the default browser on the system and navigate to the url.
// The LaunchBrowser method was added in Chilkat v10.1.2.
$success = $oauth2->LaunchBrowser($url);
if ($success == false) {
    print $oauth2->lastErrorText() . "\n";
    exit;
}

// Wait for the user to approve or deny authorization in the browser.
$numMsWaited = 0;
while (($numMsWaited < 90000) and ($oauth2->get_AuthFlowState() < 3)) {
    $oauth2->SleepMs(100);
    $numMsWaited = $numMsWaited + 100;
}

// If the browser does not respond within the specified time, AuthFlowState will be:
// 
// 1: Waiting for Redirect – The OAuth2 background thread is waiting for the browser's redirect request.
// 2: Waiting for Final Response – The thread is awaiting the final access token response.
// In either case, cancel the background task initiated by StartAuth.

if ($oauth2->get_AuthFlowState() < 3) {
    $oauth2->Cancel();
    print 'No response from the browser!' . "\n";
    exit;
}

// Check AuthFlowState to determine if authorization was granted, denied, or failed:
// 
// 3: Success – OAuth2 flow completed, the background thread exited, and the successful response is in AccessTokenResponse.
// 4: Access Denied – OAuth2 flow completed, the background thread exited, and the error response is in AccessTokenResponse.
// 5: Failure – OAuth2 flow failed before completion, the background thread exited, and error details are in FailureInfo.

if ($oauth2->get_AuthFlowState() == 5) {
    print 'OAuth2 failed to complete.' . "\n";
    print $oauth2->failureInfo() . "\n";
    exit;
}

if ($oauth2->get_AuthFlowState() == 4) {
    print 'OAuth2 authorization was denied.' . "\n";
    print $oauth2->accessTokenResponse() . "\n";
    exit;
}

if ($oauth2->get_AuthFlowState() != 3) {
    print 'Unexpected AuthFlowState:' . $oauth2->get_AuthFlowState() . "\n";
    exit;
}

// Save the full JSON access token response to a file.
$sbJson = new CkStringBuilder();
$sbJson->Append($oauth2->accessTokenResponse());
$sbJson->WriteFile('qa_data/tokens/_gmailSmtp.json','utf-8',false);

// The saved JSON response looks like this:

// 	{
// 	 "access_token": "ya39.Ci-XA_C5bGgRDC3UaD-h0_NeL-DVIQnI2gHtBBBHkZzrwlARkwX6R3O0PCDEzRlfaQ",
// 	 "token_type": "Bearer",
// 	 "expires_in": 3600,
// 	 "refresh_token": "1/r_2c_7jddspcdfesrrfKqfXtqo08D6Q-gUU0DsdfVMsx0c"
// 	}
// 
print 'OAuth2 authorization granted!' . "\n";
print 'Access Token = ' . $oauth2->accessToken() . "\n";

?>