w_transport 2.5.0

Platform-agnostic transport library for sending and receiving data over HTTP and WebSocket. HTTP support includes plain-text, JSON, form-data, and multipart data, as well as custom encoding. WebSocket [...]

Changelog

2.5.0

June 15, 2015

• Bug Fix: WSocket extends Stream and StreamSink, but was not fulfilling those contracts in all scenarios. In particular:

  • After obtaining a StreamSubscription instance from a call to WSocket.listen(), reassigning the onData(), onError(), and onDone() handlers had no effect.

    var webSocket = await WSocket.connect(...);
    var subscription = webSocket.listen((data) { ... });
    
    // This does nothing:
    subscription.onData((data) { ... });
    // Same goes for onError() and onDone()
    

  • A subscription to a WSocket instance did not properly respect pause and resume signals. This could produce a memory leak by buffering WebSocket events indefinitely.

  • A WSocket instance was immediately listening to the underlying WebSocket and buffering events from the underlying WebSocket until a listener was registered. This is not how a standard Dart Stream works.

  • The SockJS configuration was not properly handling the fact that the SockJS Client produces WebSocket events with a broadcast stream.

  • All of these issues have been addressed, and every WSocket instance should now behave exactly as a standard Stream and StreamSink would, regardless of the platform (VM, browser, SockJS, or mock).

The WSocketCloseEvent class has been deprecated. This class was only used internally and should not have been exported as a part of the public API.

The WSocket implementations are no longer registering an onError handler for the underlying WebSocket stream. If an error occurs on the server, it will not add the error to the stream, it will just close the connection. As a result, the MockWSocket.triggerServerError() method has been deprecated - use MockWSocket.triggerServerClose() instead.

2.4.0

May 4, 2016

• Improvement: FormRequest now supports fields with multiple values.

  var request = new FormRequest()
    ..fields['multi'] = ['one', 'two'];
  

• SDK Compatibility: Dart 1.16 exposed a new Client class from the dart:html library that conflicted with the Client class in this library. This has been fixed by adjusting our imports internally, but it may still affect consumers of this library.

• Documentation: fixed inaccurate documentation around mocking & testing with WebSockets.

2.3.2

March 2, 2016

• Bug Fix: requests created from a Client now properly inherit all of the autoRetry configuration. Previously the backOff, forTimeouts, and maxRetries settings were missing.

2.3.0

February 11, 2016

Features

• Implemented retry back-off to allow fixed or exponential back-off between request retries. By default, there is no back-off.

  // Fixed back-off: 1 second between attempts.
  var request = new Request();
  request.autoRetry
    ..enabled = true
    ..backOff = new RetryBackOff.fixed(new Duration(seconds: 1));
  
  // Exponential back-off: 250ms, 500ms, 1s, 2s, etc (base*2^attempt)
  var request = new Request();
  request.autoRetry
    ..enabled = true
    ..backOff = new RetryBackOff.exponential(new Duration(milliseconds: 125));
  

• Added methods to all request classes for manually retrying failures. This is mainly useful for corner cases where the request's success is dependent on something else and where automatic retrying won't help.

  var request = new Request();
  // send request, catch failure
  
  var response = await request.retry(); // normal
  var response = await request.streamRetry(); // streamed
  

• Improved error messaging around failed requests. If automatic retrying is enabled, the error message for a failed request will include each individual attempt and why it failed.

2.2.0

February 8, 2016

Features

• Added an autoRetry.forTimeouts flag (defaults to true) to the Client class and all request classes. This flag determines whether or not requests that are canceled due to exceeding the timeout threshold should be retried.

  // This request will retry if the timeout is exceeded.
  var request = new Request()
    ..timeoutThreshold = new Duration(seconds: 10)
    ..autoRetry.enabled = true;
  
  // This request will NOT retry if the timeout is exceeded.
  var request = new Request()
    ..timeoutThreshold = new Duration(seconds: 10)
    ..autoRetry.enabled = true
    ..autoRetry.forTimeouts = false;
  

• Added a Duration sockJSTimeout config option to WSocket.connect().

  // browser only
  var socket = await WSocket.connect(Uri.parse('...'),
      useSockJS: true, sockJSTimeout: new Duration(seconds: 5));
  

2.1.0

January 7, 2016

Deprecation: SockJS global configuration

As of v2.0.0, this library could be configured to use SockJS under the hood when the WSocket class was used to establish WebSocket connections. This configuration occurred on a global basis (meaning it affected every WSocket instance) which is undesirable for applications with a mixed usage of native WebSockets and SockJS. This global configuration has been deprecated.

As of v2.1.0, passing useSockJS: true to the configureWTransportForBrowser() method will cause a deprecation warning to be printed to the console.

The SockJS configuration should now occur on a per-socket basis via the WSocket.connect() method:

Uri uri = Uri.parse('ws://echo.websocket.org');
WSocket webSocket = await WSocket.connect(uri,
   useSockJS: true, sockJSProtocolsWhitelist: ['websocket', 'xhr-streaming']);

Features

• Added a baseUri field to Client that all requests from the client will inherit.

• All request classes now support a timeout threshold via the timeoutTreshold field. This was also added to the Client class and all requests created from a client will inherit this value.

• Request and response interception is now supported. This can be done directly on a request instance, but more usefully through a Client instance. See "request & response interception" and "intercepting requests & responses from a client" in the README.

• All request classes and the Client class now include an API for automatic retrying via the autoRetry field. See "automatic request retrying" in the README.

• Added a replace method to Response and StreamedResponse to allow simple creation of new responses based on another response, while changing only the fields you specify. This is particularly useful during response interception.

Bug Fixes

• Headers passed into a request's dispatch method (ex: .get(headers: {...})) are now merged with any existing headers on the request (previously they were being ignored).

2.0.0

November 24, 2015

The 2.0.0 release is a major breaking release. While many of the patterns from 1.0.x were maintained, the HTTP API was broken up into several request classes and two response classes for a much more robust and useful API. As such, there is no backwards compatibility, but a migration guide is included below.

Features

• WebSockets

  • Single API for the browser and the Dart VM.
  • Option to use SockJS library in place of native WebSockets for the ability to fall back to XHR streaming (configuration only, no API usage difference).

• HTTP

  • Support for most commonly used request types:
    • Request (content-type: text/plain)
    • JsonRequest (content-type: application/json)
    • FormRequest (content-type: application/x-www-form-urlencoded)
    • MultipartRequest (content-type: multipart/form-data)
  • Synchronous access to response bodies as bytes, text, and JSON.
  • Asynchronous request bodies (StreamedRequest).
  • Asynchronous response bodies via streamGet(), streamPost(), etc. on any of the above request classes.
  • Automatic request encoding and response decoding.

• Mocks

  • Because this library is designed to be platform-agnostic, it's easy to introduce mocks simply by treating tests as another platform, just like the browser or the Dart VM.
  • Import package:w_transport/w_transport_mock.dart and call configureWTransportForTest() to configure w_transport to use mock implementations for every class.
  • No changes necessary to your source code!
  • Utilize the MockTransports class to control WebSocket connections and HTTP requests.

• Testing

  • A big initiative in this 2.0.0 release was to increase our test coverage - which we've done. With almost 1000 statements, w_transport has 99.7% coverage!
  • Since this library is concerned with transport protocols, it is imperative that our testing included rigorous integration tests. We have over 1000 integration tests that run in the browser and on the Dart VM against real servers.
  • Our test suites run against our mock implementations as well to ensure they are in parity with the real implementations.

Migration Guide

WRequest

The WRequest class attempted to cover all HTTP request use cases. Its closest analog now is Request - the class for sending plain-text requests. All other request classes share a similar base API with additional support for a specific type of request data (JSON, form, multipart, or streamed).

WResponse

The WResponse class made request meta data (status, headers) available as soon as the request had finished; however, in an attempt to unify the API between the dart:io HTTP requests and dart:html XHR requests, the response body was only available asynchronously (as a stream, an untyped future, or decoded to text). This meant two asynchronous steps were required for every request - one to get the response, and one to get the response body.

This has been greatly improved by switching to two different response classes:

• Response - response meta data and body available synchronously
• StreamedResponse - response meta data available synchronously, body available as a stream of bytes

1.0.1

June 23, 2015

Bug Fixes:

• Allow request data to be set to null.
• Canceling an in-flight request now properly results in the returned Future completing with an error.
• Request data type validation now happens when sending the request instead of upon assignment, allowing intermediate data assignments.
• Verify w_transport configuration has been set before constructing a WHttp instance.

1.0.0

May 21, 2015

• Initial version of w_transport: a fluent-style, platform-agnostic library with ready to use transport classes for sending and receiving data over HTTP.