Dart Cancellation Token: HTTP

A fork of Dart's HTTP package with request cancellation using cancellation_token.

Currently based on version 1.2.2 of the HTTP package.

Features

• Retains all original functionality of the HTTP package.
• Cancel HTTP requests using CancellationTokens.
• Pair with the cancellation_token package to make a cancellable API request and parse the response JSON in a cancellable isolate using a single token.

Using

This package keeps the same APIs as the base HTTP package, but with the addition of optional cancellationToken parameters. For more information on CancellationTokens, refer to CancellationTokens.

import 'package:cancellation_token_http/http.dart' as http;

var token = http.CancellationToken();
try {
  // A single CancellationToken can be used for multiple requests
  var readResponse = await http.read(
    Uri.parse('https://example.com/foobar.txt'),
    cancellationToken: token,
  );
  var postResponse = await http.post(
    Uri.parse('https://example.com/whatsit/create'),
    body: {'name': 'doodle', 'color': 'blue'},
    cancellationToken: token,
  );
  print('Read response: $readReponse');
  print('Post response status: ${postResponse.statusCode}');
  print('Post response body: ${postResponse.body}');
} on http.CancelledException {
  // If `token.cancel()` is called, the request will be cancelled and a
  // CancelledException will be thrown
  print('Request cancelled');
}

Parsing JSON in an isolate

To parse JSON responses in a cancellable isolate, add the cancellation_token package to your project and use the same CancellationToken for both the API request and cancellableCompute():

import 'package:cancellation_token/cancellation_token.dart';
import 'package:cancellation_token_http/http.dart' as http;

Future<void> makeRequest() async {
  var token = CancellationToken();
  try {
    var response = await http.get(
      Uri.parse('https://example.com/bigjson'),
      cancellationToken: token,
    );
    var parsedResponse = cancellableCompute(
      _readAndParseJson,
      response.body,
      token,
    );
    print('Request and parse complete');
  } on CancelledException {
    // If `token.cancel()` is called, the request and response parsing will be
    // cancelled and a CancelledException will be thrown
    print('Request and parse cancelled');
  }
}

static ChunkyApiResponse _readAndParseJson(String json) {
  final Map<String, dynamic> decodedJson = jsonDecode(json);
  return ChunkyApiResponse.fromJson(decodedJson);
}