<?php
 use Google\Auth\CredentialsLoader;
 use Google\Auth\HttpHandler\HttpHandlerFactory;
 use Google\Auth\FetchAuthTokenCache;
 use Google\Auth\Subscriber\AuthTokenSubscriber;
 use Google\Auth\Subscriber\ScopedAccessTokenSubscriber;
 use Google\Auth\Subscriber\SimpleSubscriber;
 use GuzzleHttp\Client;
 use GuzzleHttp\ClientInterface;
 use Psr\Cache\CacheItemPoolInterface;
 class Google_AuthHandler_Guzzle5AuthHandler {
 protected $cache;
 protected $cacheConfig;
 public function __construct(CacheItemPoolInterface $cache = null, array $cacheConfig = []) {
 $this->cache = $cache;
 $this->cacheConfig = $cacheConfig;
 }
 public function attachCredentials( ClientInterface $http, CredentialsLoader $credentials, callable $tokenCallback = null ) {
 if ($this->cache) {
 $credentials = new FetchAuthTokenCache( $credentials, $this->cacheConfig, $this->cache );
 }
 $authHttp = $this->createAuthHttp($http);
 $authHttpHandler = HttpHandlerFactory::build($authHttp);
 $subscriber = new AuthTokenSubscriber( $credentials, $authHttpHandler, $tokenCallback );
 $http->setDefaultOption('auth', 'google_auth');
 $http->getEmitter()->attach($subscriber);
 return $http;
 }
 public function attachToken(ClientInterface $http, array $token, array $scopes) {
 $tokenFunc = function ($scopes) use ($token) {
 return $token['access_token'];
 }
;
 $subscriber = new ScopedAccessTokenSubscriber( $tokenFunc, $scopes, $this->cacheConfig, $this->cache );
 $http->setDefaultOption('auth', 'scoped');
 $http->getEmitter()->attach($subscriber);
 return $http;
 }
 public function attachKey(ClientInterface $http, $key) {
 $subscriber = new SimpleSubscriber(['key' => $key]);
 $http->setDefaultOption('auth', 'simple');
 $http->getEmitter()->attach($subscriber);
 return $http;
 }
 private function createAuthHttp(ClientInterface $http) {
 return new Client( [ 'base_url' => $http->getBaseUrl(), 'defaults' => [ 'exceptions' => true, 'verify' => $http->getDefaultOption('verify'), 'proxy' => $http->getDefaultOption('proxy'), ] ] );
 }
 }
 