<?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.
*/
/**
* Credentials object used for OAuth 2.0 Signed JWT assertion grants.
*
* @author Chirag Shah <chirags@google.com>
*/
class Google_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;
/**
* @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.
*/
public function __construct(
$serviceAccountName,
$scopes,
$privateKey,
$privateKeyPassword = 'notasecret',
$assertionType = 'http://oauth.net/grant_type/jwt/1.0/bearer',
$sub = false) {
$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;
}
public function generateAssertion() {
$now = time();
$jwtParams = array(
'aud' => Google_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');
$segments = array(
Google_Utils::urlSafeB64Encode(wp_json_encode($header)),
Google_Utils::urlSafeB64Encode(wp_json_encode($payload))
);
$signingInput = implode('.', $segments);
$signer = new Google_P12Signer($this->privateKey, $this->privateKeyPassword);
$signature = $signer->sign($signingInput);
$segments[] = Google_Utils::urlSafeB64Encode($signature);
return implode(".", $segments);
}
}