Google oAuth 2.0 PHP Curl Boilerplate

Google_oAuth2_PHP_Curl_Boilerplate.php

<?php
/*
 * Google oAuth 2.0 PHP Curl boilerplate
 * Google Tasks API example
 *
 *
 * Settings
 * 
 * scope         Space-delimited set of permissions that the application requests.
 * state         Provides any state that might be useful to your application upon receipt of the response.
 * redirect_uri  One of the redirect_uri values listed for this project in the Developers Console.
 * client_id     The client ID you obtain from the Developers Console.
 * client_secret The client secret obtained from the Developers Console.
 *
 * Documentation: https://developers.google.com/accounts/docs/OAuth2WebServer
 * Developers Console: https://console.developers.google.com
 *
 */
$scope = "email profile https://www.googleapis.com/auth/tasks";
$state = "auth_ok";
$redirect_uri = "http://localhost/google-oauth-php/";
$client_id = "YOUR_CLIENT_ID";
$client_secret = "YOUR_CLIENT_SECRET";


/* STEP 1 - Ask user to accept access */

// If no state
if(!$_GET['state']){

	// Build URL
	$auth_url  = "https://accounts.google.com/o/oauth2/auth";
	$auth_url .= "?";
	$auth_url .= "scope=$scope&";
	$auth_url .= "state=$state&";
	$auth_url .= "redirect_uri=$redirect_uri&";
	$auth_url .= "response_type=code&";
	$auth_url .= "client_id=$client_id";

	echo "<a href='$auth_url'>$auth_url</a>";

}

/* STEP 2 - Ask Google for token */

// If state is auth_ok
if($_GET['state'] == 'auth_ok'){

	// Build curl parameter array
	$params = array(
		"code" => $_GET['code'],
		"client_id" => $client_id,
		"client_secret" => $client_secret,
		"redirect_uri" => $redirect_uri,
		"grant_type" => "authorization_code"
	);

	// Init curl
	$ch = curl_init();

	// Set curl options
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
	curl_setopt($ch, CURLOPT_URL, 'https://accounts.google.com/o/oauth2/token');
	curl_setopt($ch, CURLOPT_POST, true);
	curl_setopt($ch, CURLOPT_POSTFIELDS, $params);
	curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);

	// Execute curl
	$r = curl_exec($ch);

	// Close connection
	curl_close($ch);

	// Decode json
	$returned_items = json_decode($r, true);

	// Token - Aww Yiss!
	$access_token = $returned_items['access_token'];

/* STEP 3 - Use access token with a Google API like Tasks */

	// Use this url to get task LISTS (So, a list of tasks lists, not tasks ;-) )
	// Note: @me represents the current user
	// Reference: https://developers.google.com/google-apps/tasks/v1/reference/
	$url = "https://www.googleapis.com/tasks/v1/users/@me/lists?access_token=$access_token";

	// Init, execute, close curl
	$ch = curl_init();
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
	curl_setopt($ch, CURLOPT_URL, $url);
	$r = curl_exec($ch);
	curl_close($ch);

	// Decode json
	$returned_items = json_decode($r,true);

	// Get lists 
	$task_lists = $returned_items['items'];

	// For each list
	foreach($task_lists as $k1=>$v1){
		
/* STEP 4 - Get tasks */
		
		// List ID
		$list_id = $v1['id'];

		// Use this url to get tasks from tasklist $list_id
		$url = "https://www.googleapis.com/tasks/v1/lists/$list_id/tasks?access_token=$access_token";

		// Init, execute, close curl
		$ch = curl_init();
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
		curl_setopt($ch, CURLOPT_URL, $url);
		$r = curl_exec($ch);
		curl_close($ch);

		// Decode json
		$returned_items = json_decode($r,true);

		// Get tasks
		$tasks = $returned_items['items'];

		// Echo each task to the browser
		echo '<pre>';
		foreach ($tasks as $k2=>$v2) {
			echo $v1['title'] . ' ' . $v2['updated'] . ' ' . $v2['title'] . ' ' . $v2['status'] . "\r\n" ;
		}
		echo '</pre>';

	} // end for each task list


} // end if state = auth_ok