<?php
/*
* Copyright 2012 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
if (!defined('ABSPATH')) die('No direct access allowed');
if (!class_exists('UDP_Google_Client')) {
require_once dirname(__FILE__) . '/../autoload.php';
}
/**
* Credentials object used for OAuth 2.0 Signed JWT assertion grants.
*/
class Google_Auth_AssertionCredentials
{
const MAX_TOKEN_LIFETIME_SECS = 3600;
public $serviceAccountName;
public $scopes;
public $privateKey;
public $privateKeyPassword;
public $assertionType;
public $sub;
/**
* @deprecated
* @link http://tools.ietf.org/html/draft-ietf-oauth-json-web-token-06
*/
public $prn;
private $useCache;
/**
* @param $serviceAccountName
* @param $scopes array List of scopes
* @param $privateKey
* @param string $privateKeyPassword
* @param string $assertionType
* @param bool|string $sub The email address of the user for which the
* application is requesting delegated access.
* @param bool useCache Whether to generate a cache key and allow
* automatic caching of the generated token.
*/
public function __construct(
$serviceAccountName,
$scopes,
$privateKey,
$privateKeyPassword = 'notasecret',
$assertionType = 'http://oauth.net/grant_type/jwt/1.0/bearer',
$sub = false,
$useCache = true
) {
$this->serviceAccountName = $serviceAccountName;
$this->scopes = is_string($scopes) ? $scopes : implode(' ', $scopes);
$this->privateKey = $privateKey;
$this->privateKeyPassword = $privateKeyPassword;
$this->assertionType = $assertionType;
$this->sub = $sub;
$this->prn = $sub;
$this->useCache = $useCache;
}
/**
* Generate a unique key to represent this credential.
* @return string
*/
public function getCacheKey()
{
if (!$this->useCache) {
return false;
}
$h = $this->sub;
$h .= $this->assertionType;
$h .= $this->privateKey;
$h .= $this->scopes;
$h .= $this->serviceAccountName;
return md5($h);
}
public function generateAssertion()
{
$now = time();
$jwtParams = array(
'aud' => Google_Auth_OAuth2::OAUTH2_TOKEN_URI,
'scope' => $this->scopes,
'iat' => $now,
'exp' => $now + self::MAX_TOKEN_LIFETIME_SECS,
'iss' => $this->serviceAccountName,
);
if ($this->sub !== false) {
$jwtParams['sub'] = $this->sub;
} else if ($this->prn !== false) {
$jwtParams['prn'] = $this->prn;
}
return $this->makeSignedJwt($jwtParams);
}
/**
* Creates a signed JWT.
* @param array $payload
* @return string The signed JWT.
*/
private function makeSignedJwt($payload)
{
$header = array('typ' => 'JWT', 'alg' => 'RS256');
$payload = json_encode($payload);
// Handle some overzealous escaping in PHP json that seemed to cause some errors
// with claimsets.
$payload = str_replace('\/', '/', $payload);
$segments = array(
Google_Utils::urlSafeB64Encode(json_encode($header)),
Google_Utils::urlSafeB64Encode($payload)
);
$signingInput = implode('.', $segments);
$signer = new Google_Signer_P12($this->privateKey, $this->privateKeyPassword);
$signature = $signer->sign($signingInput);
$segments[] = Google_Utils::urlSafeB64Encode($signature);
return implode(".", $segments);
}
}