' */ class ScopedAccessTokenMiddleware { use CacheTrait; const DEFAULT_CACHE_LIFETIME = 1500; /** * @var callable */ private $tokenFunc; /** * @var array|string */ private $scopes; /** * Creates a new ScopedAccessTokenMiddleware. * * @param callable $tokenFunc a token generator function * @param array|string $scopes the token authentication scopes * @param array $cacheConfig configuration for the cache when it's present * @param CacheItemPoolInterface $cache an implementation of CacheItemPoolInterface */ public function __construct( callable $tokenFunc, $scopes, array $cacheConfig = null, CacheItemPoolInterface $cache = null ) { $this->tokenFunc = $tokenFunc; if (!(is_string($scopes) || is_array($scopes))) { throw new \InvalidArgumentException( 'wants scope should be string or array' ); } $this->scopes = $scopes; if (!is_null($cache)) { $this->cache = $cache; $this->cacheConfig = array_merge([ 'lifetime' => self::DEFAULT_CACHE_LIFETIME, 'prefix' => '', ], $cacheConfig); } } /** * Updates the request with an Authorization header when auth is 'scoped'. * * E.g this could be used to authenticate using the AppEngine * AppIdentityService. * * use google\appengine\api\app_identity\AppIdentityService; * use Google\Auth\Middleware\ScopedAccessTokenMiddleware; * use GuzzleHttp\Client; * use GuzzleHttp\HandlerStack; * * $scope = 'https://www.googleapis.com/auth/taskqueue' * $middleware = new ScopedAccessTokenMiddleware( * 'AppIdentityService::getAccessToken', * $scope, * [ 'prefix' => 'Google\Auth\ScopedAccessToken::' ], * $cache = new Memcache() * ); * $stack = HandlerStack::create(); * $stack->push($middleware); * * $client = new Client([ * 'handler' => $stack, * 'base_url' => 'https://www.googleapis.com/taskqueue/v1beta2/projects/', * 'auth' => 'scoped' // authorize all requests * ]); * * $res = $client->get('myproject/taskqueues/myqueue'); * * @param callable $handler * @return \Closure */ public function __invoke(callable $handler) { return function (RequestInterface $request, array $options) use ($handler) { // Requests using "auth"="scoped" will be authorized. if (!isset($options['auth']) || $options['auth'] !== 'scoped') { return $handler($request, $options); } $request = $request->withHeader('authorization', 'Bearer ' . $this->fetchToken()); return $handler($request, $options); }; } /** * @return string */ private function getCacheKey() { $key = null; if (is_string($this->scopes)) { $key .= $this->scopes; } elseif (is_array($this->scopes)) { $key .= implode(':', $this->scopes); } return $key; } /** * Determine if token is available in the cache, if not call tokenFunc to * fetch it. * * @return string */ private function fetchToken() { $cacheKey = $this->getCacheKey(); $cached = $this->getCachedValue($cacheKey); if (!empty($cached)) { return $cached; } $token = call_user_func($this->tokenFunc, $this->scopes); $this->setCachedValue($cacheKey, $token); return $token; } }