Gmail Account Authentication from php - php

Question

I am trying to authenticate the google account using this tutorial. I am passing just my username and password but it returning false. I am new to it. Here is the function i am calling
function googleAuthenticate($username, $password, $source = 'your_google_app', $service = 'lh2') {
$session_token = $source . '_' . $service . '_auth_token';
// get an authorization token
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://www.google.com/accounts/ClientLogin");
$post_fields = "accountType=" . urlencode('GOOGLE')
. "&Email=" . urlencode($username)
. "&Passwd=" . urlencode($password)
. "&source=" . urlencode($source)
. "&service=" . urlencode($service);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_fields);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($ch, CURLOPT_HEADER, TRUE);
curl_setopt($ch, CURLINFO_HEADER_OUT, true); // for debugging the request
curl_setopt($ch, CURLOPT_VERBOSE, true); // for debugging the request
var_dump(curl_getinfo($ch,CURLINFO_HEADER_OUT));
echo "<br>";
var_dump($post_fields);
echo "<br>";
$response = curl_exec($ch);
curl_close($ch);
var_dump($response);
exit();
if (strpos($response, '200 OK') === false) {
return false;
}
// find the auth code
preg_match("/(Auth=)([\w|-]+)/", $response, $matches);
if (!$matches[2]) {
return false;
}
$_SESSION[$session_token] = $matches[2];
return $matches[2];
}