/**
  * @param RequestInterface $request
  * @param array            $options
  *
  * @return PromiseInterface
  */
 public function __invoke(RequestInterface $request, array $options)
 {
     $fn = $this->nextHandler;
     // Don't do anything if the request has no body.
     if (isset(self::$skipMethods[$request->getMethod()]) || $request->getBody()->getSize() === 0) {
         return $fn($request, $options);
     }
     $modify = [];
     // Add a default content-type if possible.
     if (!$request->hasHeader('Content-Type')) {
         if ($uri = $request->getBody()->getMetadata('uri')) {
             if ($type = Psr7\mimetype_from_filename($uri)) {
                 $modify['set_headers']['Content-Type'] = $type;
             }
         }
     }
     // Add a default content-length or transfer-encoding header.
     if (!isset(self::$skipMethods[$request->getMethod()]) && !$request->hasHeader('Content-Length') && !$request->hasHeader('Transfer-Encoding')) {
         $size = $request->getBody()->getSize();
         if ($size !== null) {
             $modify['set_headers']['Content-Length'] = $size;
         } else {
             $modify['set_headers']['Transfer-Encoding'] = 'chunked';
         }
     }
     // Add the expect header if needed.
     $this->addExpectHeader($request, $options, $modify);
     return $fn(Psr7\modify_request($request, $modify), $options);
 }

 /**
  * This method is invoked before every HTTP request is sent to the API. When this happens, it
  * checks to see whether a token is set and valid, and then sets the ``X-Auth-Token`` header
  * for the HTTP request before letting it continue on its merry way.
  *
  * @param RequestInterface $request
  * @param array            $options
  *
  * @return mixed|void
  */
 public function __invoke(RequestInterface $request, array $options)
 {
     $fn = $this->nextHandler;
     if ($this->shouldIgnore($request)) {
         return $fn($request, $options);
     }
     if (!$this->token || $this->token->hasExpired()) {
         $this->token = call_user_func($this->tokenGenerator);
     }
     $modify = ['set_headers' => ['X-Auth-Token' => $this->token->getId()]];
     return $fn(modify_request($request, $modify), $options);
 }

 /**
  * Set the middleware handlers for all requests using Oauth2
  *
  * @return HandlerStack|null
  */
 protected function returnHandlers()
 {
     // Create a handler stack that has all of the default middlewares attached
     $handler = HandlerStack::create();
     //Add the Authorization header to requests.
     $handler->push(Middleware::mapRequest(function (RequestInterface $request) {
         if ($this->getConfig('auth') == 'oauth2') {
             $token = $this->getAccessToken();
             if ($token !== null) {
                 $request = $request->withHeader('Authorization', 'Bearer ' . $token->getToken());
                 return $request;
             }
         }
         return $request;
     }), 'add_oauth_header');
     $handler->before('add_oauth_header', $this->retry_modify_request(function ($retries, RequestInterface $request, ResponseInterface $response = null, $error = null) {
         if ($retries > 0) {
             return false;
         }
         if ($response instanceof ResponseInterface) {
             if ($response->getStatusCode() == 401) {
                 return true;
             }
         }
         return false;
     }, function (RequestInterface $request, ResponseInterface $response) {
         if ($response instanceof ResponseInterface) {
             if ($response->getStatusCode() == 401) {
                 $token = $this->acquireAccessToken();
                 $this->setAccessToken($token, 'Bearer');
                 $modify['set_headers']['Authorization'] = 'Bearer ' . $token->getToken();
                 return Psr7\modify_request($request, $modify);
             }
         }
         return $request;
     }));
     return $handler;
 }

 public function modifyRequest()
 {
     return $this->retry_modify_request(function ($retries, RequestInterface $request, ResponseInterface $response = null, $error = null) {
         if ($retries > 0) {
             return false;
         }
         if ($response instanceof ResponseInterface) {
             if (in_array($response->getStatusCode(), [400, 401])) {
                 return true;
             }
         }
         return false;
     }, function (RequestInterface $request, ResponseInterface $response) {
         if ($response instanceof ResponseInterface) {
             if (in_array($response->getStatusCode(), [400, 401])) {
                 $token = $this->acquireAccessToken();
                 $this->setAccessToken($token, 'Bearer');
                 $modify['set_headers']['X-SFDC-Session'] = $token->getToken();
                 return Psr7\modify_request($request, $modify);
             }
         }
         return $request;
     });
 }

 /**
  * Applies the array of request options to a request.
  *
  * @param RequestInterface $request
  * @param array            $options
  *
  * @return RequestInterface
  */
 private function applyOptions(RequestInterface $request, array &$options)
 {
     $modify = [];
     if (isset($options['form_params'])) {
         if (isset($options['multipart'])) {
             throw new \InvalidArgumentException('You cannot use ' . 'form_params and multipart at the same time. Use the ' . 'form_params option if you want to send application/' . 'x-www-form-urlencoded requests, and the multipart ' . 'option to send multipart/form-data requests.');
         }
         $options['body'] = http_build_query($options['form_params'], '', '&');
         unset($options['form_params']);
         $options['_conditional']['Content-Type'] = 'application/x-www-form-urlencoded';
     }
     if (isset($options['multipart'])) {
         $options['body'] = new Psr7\MultipartStream($options['multipart']);
         unset($options['multipart']);
     }
     if (isset($options['json'])) {
         $options['body'] = \GuzzleHttp\json_encode($options['json']);
         unset($options['json']);
         $options['_conditional']['Content-Type'] = 'application/json';
     }
     if (!empty($options['decode_content']) && $options['decode_content'] !== true) {
         $modify['set_headers']['Accept-Encoding'] = $options['decode_content'];
     }
     if (isset($options['headers'])) {
         if (isset($modify['set_headers'])) {
             $modify['set_headers'] = $options['headers'] + $modify['set_headers'];
         } else {
             $modify['set_headers'] = $options['headers'];
         }
         unset($options['headers']);
     }
     if (isset($options['body'])) {
         if (is_array($options['body'])) {
             $this->invalidBody();
         }
         $modify['body'] = Psr7\stream_for($options['body']);
         unset($options['body']);
     }
     if (!empty($options['auth']) && is_array($options['auth'])) {
         $value = $options['auth'];
         $type = isset($value[2]) ? strtolower($value[2]) : 'basic';
         switch ($type) {
             case 'basic':
                 $modify['set_headers']['Authorization'] = 'Basic ' . base64_encode("{$value['0']}:{$value['1']}");
                 break;
             case 'digest':
                 // @todo: Do not rely on curl
                 $options['curl'][CURLOPT_HTTPAUTH] = CURLAUTH_DIGEST;
                 $options['curl'][CURLOPT_USERPWD] = "{$value['0']}:{$value['1']}";
                 break;
         }
     }
     if (isset($options['query'])) {
         $value = $options['query'];
         if (is_array($value)) {
             $value = http_build_query($value, null, '&', PHP_QUERY_RFC3986);
         }
         if (!is_string($value)) {
             throw new \InvalidArgumentException('query must be a string or array');
         }
         $modify['query'] = $value;
         unset($options['query']);
     }
     // Ensure that sink is not an invalid value.
     if (isset($options['sink'])) {
         // TODO: Add more sink validation?
         if (is_bool($options['sink'])) {
             throw new \InvalidArgumentException('sink must not be a boolean');
         }
     }
     $request = Psr7\modify_request($request, $modify);
     if ($request->getBody() instanceof Psr7\MultipartStream) {
         // Use a multipart/form-data POST if a Content-Type is not set.
         $options['_conditional']['Content-Type'] = 'multipart/form-data; boundary=' . $request->getBody()->getBoundary();
     }
     // Merge in conditional headers if they are not present.
     if (isset($options['_conditional'])) {
         // Build up the changes so it's in a single clone of the message.
         $modify = [];
         foreach ($options['_conditional'] as $k => $v) {
             if (!$request->hasHeader($k)) {
                 $modify['set_headers'][$k] = $v;
             }
         }
         $request = Psr7\modify_request($request, $modify);
         // Don't pass this internal value along to middleware/handlers.
         unset($options['_conditional']);
     }
     return $request;
 }

 public function testAddsQueryToUri()
 {
     $r1 = new Psr7\Request('GET', 'http://foo.com');
     $r2 = Psr7\modify_request($r1, ['query' => 'foo=bar']);
     $this->assertNotSame($r1, $r2);
     $this->assertEquals('foo=bar', $r2->getUri()->getQuery());
 }

 private function createRequestFromFollow(Step $step, ValueBag $values, RequestInterface $request = null, ResponseInterface $response = null, Crawler $crawler = null)
 {
     if (null === $request || null === $response) {
         throw new CrawlException('Unable to follow when no previous page.');
     }
     if ('3' !== substr($response->getStatusCode(), 0, 1) || !$response->hasHeader('Location')) {
         throw new CrawlException('Unable to follow when no previous page is not a redirect.');
     }
     // logic from Guzzle\RedirectMiddleware
     // Request modifications to apply.
     $modify = [];
     // Use a GET request if this is an entity enclosing request and we are
     // not forcing RFC compliance, but rather emulating what all browsers
     // would do.
     $statusCode = $response->getStatusCode();
     if ($statusCode == 303 || $statusCode <= 302 && $request->getBody()) {
         $modify['method'] = 'GET';
         $modify['body'] = '';
     }
     $modify['uri'] = Psr7\Uri::resolve($request->getUri(), $response->getHeaderLine('Location'));
     Psr7\rewind_body($request);
     // Add the Referer header only if we are not redirecting from https to http
     if ($modify['uri']->getScheme() === $request->getUri()->getScheme()) {
         $modify['set_headers']['Referer'] = (string) $request->getUri()->withUserInfo('', '');
     } else {
         $modify['remove_headers'][] = 'Referer';
     }
     // Remove Authorization header if host is different
     if ($request->getUri()->getHost() !== $modify['uri']->getHost()) {
         $modify['remove_headers'][] = 'Authorization';
     }
     return Psr7\modify_request($request, $modify);
 }

 public function testModifyRequestKeepInstanceOfRequest()
 {
     $r1 = new Psr7\Request('GET', 'http://foo.com');
     $r2 = Psr7\modify_request($r1, ['remove_headers' => ['non-existent']]);
     $this->assertTrue($r2 instanceof Psr7\Request);
     $r1 = new Psr7\ServerRequest('GET', 'http://foo.com');
     $r2 = Psr7\modify_request($r1, ['remove_headers' => ['non-existent']]);
     $this->assertTrue($r2 instanceof ServerRequestInterface);
 }

 /**
  * Sign the request.
  *
  * @param RequestInterface $request Psr7 request.
  * @return RequestInterface
  */
 private function signRequest(RequestInterface $request)
 {
     $headers = ['User-Agent' => 'gcloud-php/' . ServiceBuilder::VERSION, 'Authorization' => 'Bearer ' . $this->getToken()];
     return Psr7\modify_request($request, ['set_headers' => $headers]);
 }

 /**
  * Applies the array of request options to a request.
  *
  * @param RequestInterface $request
  * @param array            $options
  *
  * @return RequestInterface
  */
 private function applyOptions(RequestInterface $request, array &$options)
 {
     $modify = [];
     if (isset($options['form_params'])) {
         $options['body'] = http_build_query($options['form_params']);
         unset($options['form_params']);
         $options['_conditional']['Content-Type'] = 'application/x-www-form-urlencoded';
     }
     if (isset($options['multipart'])) {
         $elements = $options['multipart'];
         unset($options['multipart']);
         $options['body'] = new Psr7\MultipartStream($elements);
         // Use a multipart/form-data POST if a Content-Type is not set.
         $options['_conditional']['Content-Type'] = 'multipart/form-data; boundary=' . $options['body']->getBoundary();
     }
     if (!empty($options['decode_content']) && $options['decode_content'] !== true) {
         $modify['set_headers']['Accept-Encoding'] = $options['decode_content'];
     }
     if (isset($options['headers'])) {
         if (isset($modify['set_headers'])) {
             $modify['set_headers'] = $options['headers'] + $modify['set_headers'];
         } else {
             $modify['set_headers'] = $options['headers'];
         }
         unset($options['headers']);
     }
     if (isset($options['body'])) {
         if (is_array($options['body'])) {
             $this->invalidBody();
         }
         $modify['body'] = Psr7\stream_for($options['body']);
         unset($options['body']);
     }
     if (!empty($options['auth'])) {
         $value = $options['auth'];
         $type = is_array($value) ? isset($value[2]) ? strtolower($value[2]) : 'basic' : $value;
         $config['auth'] = $value;
         switch (strtolower($type)) {
             case 'basic':
                 $modify['set_headers']['Authorization'] = 'Basic ' . base64_encode("{$value['0']}:{$value['1']}");
                 break;
             case 'digest':
                 // @todo: Do not rely on curl
                 $options['curl'][CURLOPT_HTTPAUTH] = CURLAUTH_DIGEST;
                 $options['curl'][CURLOPT_USERPWD] = "{$value['0']}:{$value['1']}";
                 break;
         }
     }
     if (isset($options['query'])) {
         $value = $options['query'];
         if (is_array($value)) {
             $value = http_build_query($value, null, '&', PHP_QUERY_RFC3986);
         }
         if (!is_string($value)) {
             throw new Iae('query must be a string or array');
         }
         $modify['query'] = $value;
         unset($options['query']);
     }
     if (isset($options['json'])) {
         $modify['body'] = Psr7\stream_for(json_encode($options['json']));
         $options['_conditional']['Content-Type'] = 'application/json';
         unset($options['json']);
     }
     $request = Psr7\modify_request($request, $modify);
     // Merge in conditional headers if they are not present.
     if (isset($options['_conditional'])) {
         // Build up the changes so it's in a single clone of the message.
         $modify = [];
         foreach ($options['_conditional'] as $k => $v) {
             if (!$request->hasHeader($k)) {
                 $modify['set_headers'][$k] = $v;
             }
         }
         $request = Psr7\modify_request($request, $modify);
         // Don't pass this internal value along to middleware/handlers.
         unset($options['_conditional']);
     }
     return $request;
 }

 /**
  * @param RequestInterface  $request
  * @param array             $options
  * @param ResponseInterface $response
  *
  * @return RequestInterface
  */
 public function modifyRequest(RequestInterface $request, array $options, ResponseInterface $response)
 {
     // Request modifications to apply.
     $modify = [];
     $protocols = $options['allow_redirects']['protocols'];
     // Use a GET request if this is an entity enclosing request and we are
     // not forcing RFC compliance, but rather emulating what all browsers
     // would do.
     $statusCode = $response->getStatusCode();
     if ($statusCode == 303 || $statusCode <= 302 && $request->getBody() && !$options['allow_redirects']['strict']) {
         $modify['method'] = 'GET';
         $modify['body'] = '';
     }
     $modify['uri'] = $this->redirectUri($request, $response, $protocols);
     Psr7\rewind_body($request);
     // Add the Referer header if it is told to do so and only
     // add the header if we are not redirecting from https to http.
     if ($options['allow_redirects']['referer'] && $modify['uri']->getScheme() === $request->getUri()->getScheme()) {
         $uri = $request->getUri()->withUserInfo('', '');
         $modify['set_headers']['Referer'] = (string) $uri;
     } else {
         $modify['remove_headers'][] = 'Referer';
     }
     return Psr7\modify_request($request, $modify);
 }

 /**
  * Concurrently delete the files.
  *
  * @param array $files
  *   Array of file ID's.
  * @param OutputInterface $output
  *   Console output interface.
  */
 protected function deleteFiles(array $files, OutputInterface $output)
 {
     $requests = function ($files) {
         $uri = "https://slack.com/api/files.delete";
         foreach ($files as $file_id) {
             $req = new Request('POST', $uri);
             $modify['body'] = Psr7\stream_for(http_build_query(['file' => $file_id, 'token' => getenv('SLACK_AUTH_TOKEN')]));
             $modify['set_headers']['Content-Type'] = 'application/x-www-form-urlencoded';
             $modify['set_headers']['Cache-Control'] = 'no-cache';
             $request = Psr7\modify_request($req, $modify);
             (yield $request);
         }
     };
     $pool = new Pool($this->client, $requests($files), ['concurrency' => self::CONCURRENT_REQUESTS, 'fulfilled' => function ($response, $index) use($output) {
         $output->writeln("<info>File deleted</info>");
     }, 'rejected' => function ($reason, $index) use($output) {
         $output->writeln("<error>Error deleting file {$reason}</error>");
     }]);
     $promise = $pool->promise();
     $promise->wait();
 }