HTTP Integration Patterns

HTTP Provider Pattern

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

class UserProvider { final http.Client _client; final String _baseUrl;

UserProvider(this._client, {String? baseUrl}) : _baseUrl = baseUrl ?? 'https://api.example.com';

Map<String, String> get _headers => { 'Content-Type': 'application/json', 'Accept': 'application/json', };

Future<UserModel> fetchUser(String id) async { final response = await _client.get( Uri.parse('$_baseUrl/users/$id'), headers: _headers, ).timeout(Duration(seconds: 10));

if (response.statusCode == 200) {
  return UserModel.fromJson(json.decode(response.body));
} else if (response.statusCode == 404) {
  throw ServerException(message: 'User not found');
} else {
  throw ServerException(
    message: 'Failed to fetch user',
    statusCode: response.statusCode,
  );
}

}

Future<List<UserModel>> fetchAllUsers() async { final response = await _client.get( Uri.parse('$_baseUrl/users'), headers: _headers, ).timeout(Duration(seconds: 10));

if (response.statusCode == 200) {
  final List<dynamic> data = json.decode(response.body);
  return data.map((json) => UserModel.fromJson(json)).toList();
} else {
  throw ServerException(message: 'Failed to fetch users');
}

}

Future<UserModel> createUser(Map<String, dynamic> data) async { final response = await _client.post( Uri.parse('$_baseUrl/users'), headers: _headers, body: json.encode(data), ).timeout(Duration(seconds: 10));

if (response.statusCode == 201) {
  return UserModel.fromJson(json.decode(response.body));
} else {
  throw ServerException(message: 'Failed to create user');
}

}

Future<void> deleteUser(String id) async { final response = await _client.delete( Uri.parse('$_baseUrl/users/$id'), headers: _headers, ).timeout(Duration(seconds: 10));

if (response.statusCode != 204) {
  throw ServerException(message: 'Failed to delete user');
}

} }

Authenticated HTTP Client

class AuthenticatedClient extends http.BaseClient { final http.Client _inner; final String Function() _getToken;

AuthenticatedClient(this._inner, this._getToken);

@override Future<http.StreamedResponse> send(http.BaseRequest request) async { final token = _getToken(); if (token.isNotEmpty) { request.headers['Authorization'] = 'Bearer $token'; } request.headers['Content-Type'] = 'application/json'; request.headers['Accept'] = 'application/json';

return _inner.send(request);

} }

// Usage in bindings Get.lazyPut<http.Client>( () => AuthenticatedClient( http.Client(), () => Get.find<StorageService>().token ?? '', ), );

Error Handling

try { final response = await _client.get(url); return parseResponse(response); } on SocketException { throw NetworkException(); } on TimeoutException { throw ServerException(message: 'Request timeout'); } on FormatException { throw ServerException(message: 'Invalid response format'); } catch (e) { throw ServerException(message: e.toString()); }