446 lines
14 KiB
PHP
446 lines
14 KiB
PHP
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<?php
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/*
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* Copyright 2008 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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require_once "Google_Verifier.php";
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require_once "Google_LoginTicket.php";
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require_once "service/Google_Utils.php";
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/**
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* Authentication class that deals with the OAuth 2 web-server authentication flow
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*
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* @author Chris Chabot <chabotc@google.com>
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* @author Chirag Shah <chirags@google.com>
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*
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*/
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class Google_OAuth2 extends Google_Auth {
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public $clientId;
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public $clientSecret;
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public $developerKey;
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public $token;
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public $redirectUri;
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public $state;
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public $accessType = 'offline';
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public $approvalPrompt = 'force';
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/** @var Google_AssertionCredentials $assertionCredentials */
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public $assertionCredentials;
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const OAUTH2_REVOKE_URI = 'https://accounts.google.com/o/oauth2/revoke';
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const OAUTH2_TOKEN_URI = 'https://accounts.google.com/o/oauth2/token';
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const OAUTH2_AUTH_URL = 'https://accounts.google.com/o/oauth2/auth';
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const OAUTH2_FEDERATED_SIGNON_CERTS_URL = 'https://www.googleapis.com/oauth2/v1/certs';
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const CLOCK_SKEW_SECS = 300; // five minutes in seconds
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const AUTH_TOKEN_LIFETIME_SECS = 300; // five minutes in seconds
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const MAX_TOKEN_LIFETIME_SECS = 86400; // one day in seconds
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/**
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* Instantiates the class, but does not initiate the login flow, leaving it
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* to the discretion of the caller (which is done by calling authenticate()).
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*/
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public function __construct() {
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global $apiConfig;
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if (! empty($apiConfig['developer_key'])) {
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$this->developerKey = $apiConfig['developer_key'];
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}
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if (! empty($apiConfig['oauth2_client_id'])) {
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$this->clientId = $apiConfig['oauth2_client_id'];
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}
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if (! empty($apiConfig['oauth2_client_secret'])) {
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$this->clientSecret = $apiConfig['oauth2_client_secret'];
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}
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if (! empty($apiConfig['oauth2_redirect_uri'])) {
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$this->redirectUri = $apiConfig['oauth2_redirect_uri'];
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}
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if (! empty($apiConfig['oauth2_access_type'])) {
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$this->accessType = $apiConfig['oauth2_access_type'];
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}
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if (! empty($apiConfig['oauth2_approval_prompt'])) {
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$this->approvalPrompt = $apiConfig['oauth2_approval_prompt'];
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}
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}
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/**
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* @param $service
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* @param string|null $code
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* @throws Google_AuthException
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* @return string
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*/
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public function authenticate($service, $code = null) {
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if (!$code && isset($_GET['code'])) {
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$code = $_GET['code'];
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}
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if ($code) {
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// We got here from the redirect from a successful authorization grant, fetch the access token
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$request = Google_Client::$io->makeRequest(new Google_HttpRequest(self::OAUTH2_TOKEN_URI, 'POST', array(), array(
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'code' => $code,
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'grant_type' => 'authorization_code',
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'redirect_uri' => $this->redirectUri,
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'client_id' => $this->clientId,
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'client_secret' => $this->clientSecret
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)));
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if ($request->getResponseHttpCode() == 200) {
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$this->setAccessToken($request->getResponseBody());
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$this->token['created'] = time();
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return $this->getAccessToken();
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} else {
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$response = $request->getResponseBody();
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$decodedResponse = json_decode($response, true);
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if ($decodedResponse != null && $decodedResponse['error']) {
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$response = $decodedResponse['error'];
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}
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throw new Google_AuthException("Error fetching OAuth2 access token, message: '$response'", $request->getResponseHttpCode());
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}
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}
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$authUrl = $this->createAuthUrl($service['scope']);
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header('Location: ' . $authUrl);
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return true;
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}
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/**
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* Create a URL to obtain user authorization.
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* The authorization endpoint allows the user to first
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* authenticate, and then grant/deny the access request.
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* @param string $scope The scope is expressed as a list of space-delimited strings.
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* @return string
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*/
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public function createAuthUrl($scope) {
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$params = array(
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'response_type=code',
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'redirect_uri=' . urlencode($this->redirectUri),
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'client_id=' . urlencode($this->clientId),
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'scope=' . urlencode($scope),
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'access_type=' . urlencode($this->accessType),
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'approval_prompt=' . urlencode($this->approvalPrompt),
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);
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if (isset($this->state)) {
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$params[] = 'state=' . urlencode($this->state);
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}
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$params = implode('&', $params);
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return self::OAUTH2_AUTH_URL . "?$params";
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}
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/**
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* @param string $token
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* @throws Google_AuthException
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*/
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public function setAccessToken($token) {
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$token = json_decode($token, true);
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if ($token == null) {
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throw new Google_AuthException('Could not json decode the token');
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}
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if (! isset($token['access_token'])) {
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throw new Google_AuthException("Invalid token format");
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}
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$this->token = $token;
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}
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public function getAccessToken() {
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return json_encode($this->token);
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}
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public function setDeveloperKey($developerKey) {
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$this->developerKey = $developerKey;
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}
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public function setState($state) {
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$this->state = $state;
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}
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public function setAccessType($accessType) {
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$this->accessType = $accessType;
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}
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public function setApprovalPrompt($approvalPrompt) {
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$this->approvalPrompt = $approvalPrompt;
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}
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public function setAssertionCredentials(Google_AssertionCredentials $creds) {
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$this->assertionCredentials = $creds;
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}
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/**
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* Include an accessToken in a given apiHttpRequest.
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* @param Google_HttpRequest $request
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* @return Google_HttpRequest
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* @throws Google_AuthException
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*/
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public function sign(Google_HttpRequest $request) {
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// add the developer key to the request before signing it
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if ($this->developerKey) {
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$requestUrl = $request->getUrl();
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$requestUrl .= (strpos($request->getUrl(), '?') === false) ? '?' : '&';
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$requestUrl .= 'key=' . urlencode($this->developerKey);
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$request->setUrl($requestUrl);
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}
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// Cannot sign the request without an OAuth access token.
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if (null == $this->token && null == $this->assertionCredentials) {
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return $request;
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}
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// Check if the token is set to expire in the next 30 seconds
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// (or has already expired).
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if ($this->isAccessTokenExpired()) {
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if ($this->assertionCredentials) {
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$this->refreshTokenWithAssertion();
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} else {
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if (! array_key_exists('refresh_token', $this->token)) {
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throw new Google_AuthException("The OAuth 2.0 access token has expired, "
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. "and a refresh token is not available. Refresh tokens are not "
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. "returned for responses that were auto-approved.");
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}
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$this->refreshToken($this->token['refresh_token']);
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}
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}
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// Add the OAuth2 header to the request
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$request->setRequestHeaders(
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array('Authorization' => 'Bearer ' . $this->token['access_token'])
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);
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return $request;
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}
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/**
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* Fetches a fresh access token with the given refresh token.
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* @param string $refreshToken
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* @return void
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*/
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public function refreshToken($refreshToken) {
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$this->refreshTokenRequest(array(
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'client_id' => $this->clientId,
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'client_secret' => $this->clientSecret,
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'refresh_token' => $refreshToken,
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'grant_type' => 'refresh_token'
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));
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}
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/**
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* Fetches a fresh access token with a given assertion token.
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* @param Google_AssertionCredentials $assertionCredentials optional.
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* @return void
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*/
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public function refreshTokenWithAssertion($assertionCredentials = null) {
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if (!$assertionCredentials) {
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$assertionCredentials = $this->assertionCredentials;
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}
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$this->refreshTokenRequest(array(
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'grant_type' => 'assertion',
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'assertion_type' => $assertionCredentials->assertionType,
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'assertion' => $assertionCredentials->generateAssertion(),
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));
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}
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private function refreshTokenRequest($params) {
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$http = new Google_HttpRequest(self::OAUTH2_TOKEN_URI, 'POST', array(), $params);
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$request = Google_Client::$io->makeRequest($http);
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$code = $request->getResponseHttpCode();
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$body = $request->getResponseBody();
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if (200 == $code) {
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$token = json_decode($body, true);
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if ($token == null) {
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throw new Google_AuthException("Could not json decode the access token");
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}
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if (! isset($token['access_token']) || ! isset($token['expires_in'])) {
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throw new Google_AuthException("Invalid token format");
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}
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$this->token['access_token'] = $token['access_token'];
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$this->token['expires_in'] = $token['expires_in'];
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$this->token['created'] = time();
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} else {
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throw new Google_AuthException("Error refreshing the OAuth2 token, message: '$body'", $code);
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}
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}
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/**
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* Revoke an OAuth2 access token or refresh token. This method will revoke the current access
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* token, if a token isn't provided.
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* @throws Google_AuthException
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* @param string|null $token The token (access token or a refresh token) that should be revoked.
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* @return boolean Returns True if the revocation was successful, otherwise False.
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*/
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public function revokeToken($token = null) {
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if (!$token) {
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$token = $this->token['access_token'];
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}
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$request = new Google_HttpRequest(self::OAUTH2_REVOKE_URI, 'POST', array(), "token=$token");
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$response = Google_Client::$io->makeRequest($request);
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$code = $response->getResponseHttpCode();
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if ($code == 200) {
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$this->token = null;
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return true;
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}
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return false;
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}
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/**
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* Returns if the access_token is expired.
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* @return bool Returns True if the access_token is expired.
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*/
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public function isAccessTokenExpired() {
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if (null == $this->token) {
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return true;
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}
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// If the token is set to expire in the next 30 seconds.
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$expired = ($this->token['created']
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+ ($this->token['expires_in'] - 30)) < time();
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return $expired;
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}
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// Gets federated sign-on certificates to use for verifying identity tokens.
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// Returns certs as array structure, where keys are key ids, and values
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// are PEM encoded certificates.
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private function getFederatedSignOnCerts() {
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// This relies on makeRequest caching certificate responses.
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$request = Google_Client::$io->makeRequest(new Google_HttpRequest(
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self::OAUTH2_FEDERATED_SIGNON_CERTS_URL));
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if ($request->getResponseHttpCode() == 200) {
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$certs = json_decode($request->getResponseBody(), true);
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if ($certs) {
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return $certs;
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}
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}
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throw new Google_AuthException(
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"Failed to retrieve verification certificates: '" .
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$request->getResponseBody() . "'.",
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$request->getResponseHttpCode());
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}
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/**
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* Verifies an id token and returns the authenticated apiLoginTicket.
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* Throws an exception if the id token is not valid.
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* The audience parameter can be used to control which id tokens are
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* accepted. By default, the id token must have been issued to this OAuth2 client.
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*
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* @param $id_token
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* @param $audience
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* @return Google_LoginTicket
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*/
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public function verifyIdToken($id_token = null, $audience = null) {
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if (!$id_token) {
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$id_token = $this->token['id_token'];
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}
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$certs = $this->getFederatedSignonCerts();
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if (!$audience) {
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$audience = $this->clientId;
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}
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return $this->verifySignedJwtWithCerts($id_token, $certs, $audience);
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}
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// Verifies the id token, returns the verified token contents.
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// Visible for testing.
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function verifySignedJwtWithCerts($jwt, $certs, $required_audience) {
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$segments = explode(".", $jwt);
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if (count($segments) != 3) {
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throw new Google_AuthException("Wrong number of segments in token: $jwt");
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}
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$signed = $segments[0] . "." . $segments[1];
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$signature = Google_Utils::urlSafeB64Decode($segments[2]);
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|
||
|
|
// Parse envelope.
|
||
|
|
$envelope = json_decode(Google_Utils::urlSafeB64Decode($segments[0]), true);
|
||
|
|
if (!$envelope) {
|
||
|
|
throw new Google_AuthException("Can't parse token envelope: " . $segments[0]);
|
||
|
|
}
|
||
|
|
|
||
|
|
// Parse token
|
||
|
|
$json_body = Google_Utils::urlSafeB64Decode($segments[1]);
|
||
|
|
$payload = json_decode($json_body, true);
|
||
|
|
if (!$payload) {
|
||
|
|
throw new Google_AuthException("Can't parse token payload: " . $segments[1]);
|
||
|
|
}
|
||
|
|
|
||
|
|
// Check signature
|
||
|
|
$verified = false;
|
||
|
|
foreach ($certs as $keyName => $pem) {
|
||
|
|
$public_key = new Google_PemVerifier($pem);
|
||
|
|
if ($public_key->verify($signed, $signature)) {
|
||
|
|
$verified = true;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!$verified) {
|
||
|
|
throw new Google_AuthException("Invalid token signature: $jwt");
|
||
|
|
}
|
||
|
|
|
||
|
|
// Check issued-at timestamp
|
||
|
|
$iat = 0;
|
||
|
|
if (array_key_exists("iat", $payload)) {
|
||
|
|
$iat = $payload["iat"];
|
||
|
|
}
|
||
|
|
if (!$iat) {
|
||
|
|
throw new Google_AuthException("No issue time in token: $json_body");
|
||
|
|
}
|
||
|
|
$earliest = $iat - self::CLOCK_SKEW_SECS;
|
||
|
|
|
||
|
|
// Check expiration timestamp
|
||
|
|
$now = time();
|
||
|
|
$exp = 0;
|
||
|
|
if (array_key_exists("exp", $payload)) {
|
||
|
|
$exp = $payload["exp"];
|
||
|
|
}
|
||
|
|
if (!$exp) {
|
||
|
|
throw new Google_AuthException("No expiration time in token: $json_body");
|
||
|
|
}
|
||
|
|
if ($exp >= $now + self::MAX_TOKEN_LIFETIME_SECS) {
|
||
|
|
throw new Google_AuthException(
|
||
|
|
"Expiration time too far in future: $json_body");
|
||
|
|
}
|
||
|
|
|
||
|
|
$latest = $exp + self::CLOCK_SKEW_SECS;
|
||
|
|
if ($now < $earliest) {
|
||
|
|
throw new Google_AuthException(
|
||
|
|
"Token used too early, $now < $earliest: $json_body");
|
||
|
|
}
|
||
|
|
if ($now > $latest) {
|
||
|
|
throw new Google_AuthException(
|
||
|
|
"Token used too late, $now > $latest: $json_body");
|
||
|
|
}
|
||
|
|
|
||
|
|
// TODO(beaton): check issuer field?
|
||
|
|
|
||
|
|
// Check audience
|
||
|
|
$aud = $payload["aud"];
|
||
|
|
if ($aud != $required_audience) {
|
||
|
|
throw new Google_AuthException("Wrong recipient, $aud != $required_audience: $json_body");
|
||
|
|
}
|
||
|
|
|
||
|
|
// All good.
|
||
|
|
return new Google_LoginTicket($envelope, $payload);
|
||
|
|
}
|
||
|
|
}
|