HTTP client

Introduction

The HttpClient is responsible for sending all requests made by Beagle. Beagle already uses a default implementation of the HttpClient which makes the requests as they come from the JSON (DefaultHttpClient). If you need to change the default behavior, you must implement your own HttpClient, i.e., you must implement the following interface:

abstract class HttpClient {
  Future<Response> sendRequest(BeagleRequest req);
}

In the sendRequest method, you can create the rules for your network layer. You can add headers to your requests, change the HTTP method, request body, response, run cryptography, etc.

The sendRequest receives a single parameter of type BeagleRequest and returns an object of type Response. See below what each of these types does:

BeagleRequest

It’s the class for configuring HTTP requests.

Response

It’s used to return the data retrieved by the request.

The response also has a method toJson which returns a String with the status, body and headers encoded.

Create a custom HTTP client

See below an example of a custom HttpClient that adds the header platform to every GET request:

import 'dart:async';
import 'package:beagle/beagle.dart';
import 'dart:io';
import 'package:http/http.dart' as http;

class MyHttpClient implements HttpClient {
  const MyHttpClient();
  @override
  Future<Response> sendRequest(BeagleRequest req) async {
    final uri = Uri.parse(req.url);
    final handlers = {
      BeagleHttpMethod.get: () => http.get(uri, headers: {...req.headers, 'platform': Platform.operatingSystem}),
      BeagleHttpMethod.post: () => http.post(uri, headers: req.headers, body: req.body),
      BeagleHttpMethod.put: () => http.put(uri, headers: req.headers, body: req.body),
      BeagleHttpMethod.patch: () => http.patch(uri, headers: req.headers, body: req.body),
      BeagleHttpMethod.delete: () => http.delete(uri, headers: req.headers),
    };
    final response = await handlers[req.method]!();
    return Response(response.statusCode, response.body, response.headers, response.bodyBytes);
  }
}

This is a very simple example and, to implement this, it would be easier to extend the DefaultHttpClient instead, which already contains most of the implementation. Nonetheless, in most scenarios, the entire implementation will need to be replaced, hence the example.

Use a custom HTTP client

To use your client, pass it in the Beagle initialization method BeagleSdk.init just like the example below:

final beagleService = BeagleService(
  httpClient: const MyHttpClient(),
  // ...
);

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