| // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| library http_throttle; |
| |
| import 'dart:async'; |
| |
| import 'package:http/http.dart'; |
| import 'package:pool/pool.dart'; |
| |
| /// A middleware client that throttles the number of concurrent requests. |
| /// |
| /// As long as the number of requests is within the limit, this works just like |
| /// a normal client. If a request is made beyond the limit, the underlying HTTP |
| /// request won't be sent until other requests have completed. |
| class ThrottleClient extends BaseClient { |
| final Pool _pool; |
| final Client _inner; |
| |
| /// Creates a new client that allows no more than [maxActiveRequests] |
| /// concurrent requests. |
| /// |
| /// If [inner] is passed, it's used as the inner client for sending HTTP |
| /// requests. It defaults to `new http.Client()`. |
| ThrottleClient(int maxActiveRequests, [Client inner]) |
| : _pool = new Pool(maxActiveRequests), |
| _inner = inner == null ? new Client() : inner; |
| |
| Future<StreamedResponse> send(BaseRequest request) { |
| return _pool.request().then((resource) { |
| return _inner.send(request).then((response) { |
| var stream = response.stream.transform( |
| new StreamTransformer.fromHandlers(handleDone: (sink) { |
| resource.release(); |
| sink.close(); |
| })); |
| return new StreamedResponse(stream, response.statusCode, |
| contentLength: response.contentLength, |
| request: response.request, |
| headers: response.headers, |
| isRedirect: response.isRedirect, |
| persistentConnection: response.persistentConnection, |
| reasonPhrase: response.reasonPhrase); |
| }); |
| }); |
| } |
| |
| void close() => _inner.close(); |
| } |