Mastering HTTP Requests with Dart's http Package

The http package in Dart provides a comprehensive library for making HTTP requests efficiently and effectively. This guide will delve into its features, usage, and configuration, empowering you to effortlessly interact with web resources.

Using Top-Level Functions

For straightforward HTTP requests, top-level functions offer an easy way to get started.

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

var url = Uri.https('example.com', 'whatsit/create');
var response = await http.post(url, body: {'name': 'doodle', 'color': 'blue'});
print('Response status: ${response.statusCode}');
print('Response body: ${response.body}');
print(await http.read(Uri.https('example.com', 'foobar.txt')));

Using a Client

If you need to make multiple requests to the same server, consider using a Client instance:

var client = http.Client();
try {
  var response = await client.post(
      Uri.https('example.com', 'whatsit/create'),
      body: {'name': 'doodle', 'color': 'blue'});
  var decodedResponse = jsonDecode(utf8.decode(response.bodyBytes)) as Map;
  var uri = Uri.parse(decodedResponse['uri'] as String);
  print(await client.get(uri));
} finally {
  client.close();
}

Configuring the HTTP Client

To use a specific HTTP client implementation, you can configure it through the httpClient function:

Client httpClient() {
  if (Platform.isAndroid) {
    return CronetClient.defaultCronetEngine();
  }
  if (Platform.isIOS || Platform.isMacOS) {
    return CupertinoClient.defaultSessionConfiguration();
  }
  return IOClient();
}

Retrying Requests

The retry subpackage provides RetryClient to automatically retry failed requests:

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

Future main() async {
  final client = RetryClient(http.Client());
  try {
    print(await client.read(Uri.http('example.org', '')));
  } finally {
    client.close();
  }
}

Summary

The http package empowers Dart developers to efficiently make HTTP requests. Whether using top-level functions or a Client instance, the package simplifies the process of interacting with web resources. Furthermore, its configurability allows for tailoring to specific needs, such as retrying requests or choosing a desired HTTP client implementation.