Login with Google in CakePHP

login.ctp

<?php
//HTML page start
echo '<h1>Login with Google</h1>';

if(isset($authUrl)) //user is not logged in, show login button
{
  echo '<a class="login" href="'.$authUrl.'"><img src="'.WEB_ROOT.'google-login-button.png" /></a>';
}
else
{
	echo $msg;
	echo '<p><a class="logout" href="?reset=1">Logout</a></p>';
}
?>

routes.php

if (!defined('WEB_ROOT'))
  {
		define('WEB_ROOT', "http://".$_SERVER['HTTP_HOST']."/creativepeople/images/");
	}

User.php

<?php
class User extends AppModel
{
    var $name = 'User';
  /* The $useTable keyword is reserved in cakePHP
	This is used to define the custom new table name */
	var $useTable = 'google_users';
}
?>

UsersController.php

<?php
class UsersController extends AppController
{
  function login()
	{
		########## Google Settings.. Client ID, Client Secret #############
		$google_client_id 		= 'xxxxxxxxxxxx.apps.googleusercontent.com';
		$google_client_secret 	= 'XXXXXXXXXXXXXXXXXXXXXXXX';
		$google_redirect_url 	= 'http://localhost/google-login/';
		$google_developer_key 	= 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX';
		
		//include google api files
		require_once 'src/Google_Client.php';
		require_once 'src/contrib/Google_Oauth2Service.php';
		
		$gClient = new Google_Client();
		$gClient->setApplicationName('Login to localhost');
		$gClient->setClientId($google_client_id);
		$gClient->setClientSecret($google_client_secret);
		$gClient->setRedirectUri($google_redirect_url);
		$gClient->setDeveloperKey($google_developer_key);
		
		$google_oauthV2 = new Google_Oauth2Service($gClient);
		
		//If user wish to log out, we just unset Session variable
		if (isset($_REQUEST['reset'])) 
		{
		 	$this->set('msg', 'Logout');
		  //unset($_SESSION['token']);
		  $this->Session->delete('token');
		  $gClient->revokeToken();
		  header('Location: ' . filter_var($google_redirect_url, FILTER_SANITIZE_URL));
		}
		
		//Redirect user to google authentication page for code, if code is empty.
		//Code is required to aquire Access Token from google
		//Once we have access token, assign token to session variable
		//and we can redirect user back to page and login.
		if (isset($_REQUEST['code'])) 
		{ 
			$gClient->authenticate($_REQUEST['code']);
			$this->Session->write('token', $gClient->getAccessToken());
			$this->redirect(filter_var($google_redirect_url, FILTER_SANITIZE_URL), null, false);
			//header('Location: ' . filter_var($google_redirect_url, FILTER_SANITIZE_URL));
			return;
		}
		
		if ($this->Session->read('token')) 
		{ 
			$gClient->setAccessToken($this->Session->read('token'));
		}
		
		if ($gClient->getAccessToken()) 
		{
			  //Get user details if user is logged in
			  $user 				= $google_oauthV2->userinfo->get();
			  $user_id 				= $user['id'];
			  $user_name 			= filter_var($user['name'], FILTER_SANITIZE_SPECIAL_CHARS);
			  $email 				= filter_var($user['email'], FILTER_SANITIZE_EMAIL);
			  $profile_url 			= filter_var($user['link'], FILTER_VALIDATE_URL);
			  $profile_image_url 	= filter_var($user['picture'], FILTER_VALIDATE_URL);
			  $personMarkup 		= "$email<div><img src='$profile_image_url?sz=50'></div>";
			  $this->Session->write('token', $gClient->getAccessToken());
		}
		else 
		{
			//get google login url
			$authUrl = $gClient->createAuthUrl();
		}
		
		if(isset($authUrl)) //user is not logged in, show login button
		{
			$this->set('authUrl', $authUrl);
		} 
		else // user logged in 
		{
		   /* Save data in db */
		   /* And set variables for to display or redirect some where else */ 
			
			$result = $this->User->find('count', array('conditions' => array('google_id' => $user_id)));
			if($result > 0)
			{
				$msg = 'Welcome back '.$user_name.'!<br />';
				$msg .= '<br />';
				$msg .= '<img src="'.$profile_image_url.'" width="100" align="left" hspace="10" vspace="10" />';
				$msg .= '<br />';
				$msg .= '&nbsp;Name: '.$user_name.'<br />';
				$msg .= '&nbsp;Email: '.$email.'<br />';
				$msg .= '<br />';
				$this->set('msg', $msg);
			}
			else
			{
				$msg1  = 'Hi '.$user_name.', Thanks for Registering!';
				$msg1 .= '<br />';
				$msg1 .= '<img src="'.$profile_image_url.'" width="100" align="left" hspace="10" vspace="10" />';
				$msg1 .= '<br />';
				$msg1 .= '&nbsp;Name: '.$user_name.'<br />';
				$msg1 .= '&nbsp;Email: '.$email.'<br />';
				$msg1 .= '<br />';
				$this->set('msg', $msg1);
				$this->User->query("INSERT INTO google_users (google_id, google_name, google_email, google_link, google_picture_link) VALUES ($user_id, '$user_name', '$email', '$profile_url', '$profile_image_url')");
			}
		}
	}
}