Update oAuth credentail

oAuth Credentials

<?php
$url = "https://accounts.google.com/o/oauth2/token";
$fields = array(
		'grant_type' => 'refresh_token',
		'client_id' => 'CLIENT_ID',
		'client_secret' => 'CLIENT_SECRET',
		'refresh_token' => 'REFRESH_TOKEN'
	);

$ch = curl_init();
curl_setopt($ch,CURLOPT_URL,$url);
curl_setopt($ch,CURLOPT_POSTFIELDS, $fields);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$output = curl_exec($ch);
$info = curl_getinfo($ch);
curl_close($ch);
$key = json_decode($output);
$key = $key->access_token;
echo $key . "\n";
?>