Cinch

Pub

A powerful HTTP client library for Dart/Flutter that uses code generation to create type-safe API clients with minimal boilerplate code.

Features

  • 🚀 Code Generation: Automatically generates HTTP client code using build_runner
  • 🔧 Type Safety: Full type safety with compile-time validation
  • 📝 Multiple Content Types: Support for JSON, form data, and multipart uploads
  • 🛡️ Custom Validation: Flexible HTTP status code validation
  • 🌐 Dynamic URLs: Multiple ways to configure base URLs
  • 📊 Rich Annotations: Comprehensive set of annotations for different use cases

🚀 Migration Guide to v6.0.0

Version 6.0.0 introduces a significant breaking change in how generic types are deserialized. The new implementation aligns with the genericArgumentFactories pattern used by freezed and json_serializable, removing the old fromNestedGenericJson method.

What You Need to Do

If you use custom generic classes for your API responses (e.g., BaseResponse<T>), you must update them to be compatible with the new generator.

1. Update Your Generic Model:

Modify your generic class to include a fromJson factory that accepts a T Function(Object?) fromJsonT argument. This function is responsible for deserializing the nested generic type T.

Before (Old Way):

// This approach is no longer supported.
class BaseResponse<T> {
  final T data;
  BaseResponse(this.data);

  factory BaseResponse.fromNestedGenericJson(Map<String, dynamic> json, List<Type> types) {
    // ... old logic ...
  }
}

After (New Way with freezed):

We strongly recommend using freezed to generate your data classes. It handles the genericArgumentFactories pattern automatically.

import 'package:freezed_annotation/freezed_annotation.dart';

part 'base_response.freezed.dart';
part 'base_response.g.dart';

@Freezed(genericArgumentFactories: true)
sealed class BaseResponse<T> with _$BaseResponse<T> {
  const factory BaseResponse({
    required T data,
    // Add other fields like message, code, etc.
  }) = _BaseResponse;

  factory BaseResponse.fromJson(
    Map<String, dynamic> json,
    T Function(Object?) fromJsonT,
  ) =>
      _$BaseResponseFromJson(json, fromJsonT);
}

2. Update Your pubspec.yaml:

Make sure your dependencies are updated to the latest version.

dependencies:
  cinch: ^6.0.1

dev_dependencies:
  cinch_gen: ^6.0.0
  build_runner: ^2.0.0
  # Add freezed and json_serializable if you use them
  freezed: <latest_version>
  json_serializable: <latest_version>

3. Regenerate Your Code:

After updating your models and dependencies, run the build runner to regenerate the Cinch client code.

dart run build_runner build --delete-conflicting-outputs

By following these steps, your project will be aligned with the new, more robust deserialization mechanism.

Quick Start

Installation

Add the following dependencies to your pubspec.yaml:

dependencies:
  cinch: ^6.0.0

dev_dependencies:
  cinch_gen: ^6.0.0
  build_runner: ^2.0.0

Basic Usage

  1. Create your API service (test.dart):

    import 'package:cinch/cinch.dart';
part 'test.cinch.dart';

@ApiService('https://api.example.com/')
class TestApi extends _$TestApi {
  TestApi() : super();

  @Get('users/{id}')
  Future<Response> getUser(@Path('id') String userId) async {
    return _$getUser(userId);
  }

  @Get('users')
  Future<Response> getUsers(@Query('page') int page) async {
    return _$getUsers(page);
  }
}

  2. Generate the code:

    Run the following command in your terminal:

    dart run build_runner build

  3. Use your API:

    final api = TestApi();
final response = await api.getUser('123');
final users = await api.getUsers(1);

Supported HTTP Methods

Cinch supports all major HTTP methods:

  • GET - Retrieve data
  • POST - Create new resources
  • PUT - Update existing resources
  • DELETE - Remove resources

Advanced Features

Form URL Encoded Requests

For application/x-www-form-urlencoded content type:

@ApiService('https://api.example.com/')
class AuthApi extends _$AuthApi {
  @formUrlEncoded
  @Post('auth/login')
  Future<Response<LoginResponse>> login(
    @Field('username') String username,
    @Field('password') String password,
  ) async {
    return _$login(username, password);
  }
}

Path Parameters

Use path parameters for dynamic URLs:

@ApiService('https://api.example.com/')
class UserApi extends _$UserApi {
  @Get('users/{userId}/posts/{postId}')
  Future<Response> getUserPost(
    @Path('userId') String userId,
    @Path('postId') String postId,
  ) async {
    return _$getUserPost(userId, postId);
  }
}

Dynamic URL Configuration

Method 1: Custom ApiService Class

import 'package:cinch/cinch.dart';
part 'api.cinch.dart';

class ProductionApi extends ApiService {
  const ProductionApi() : super("https://api.production.com/");
}

@ProductionApi()
class UserApi extends _$UserApi {
  UserApi() : super();
  
  @Get('users')
  Future<Response> getUsers() async {
    return _$getUsers();
  }
}

Method 2: ApiUrlMixin

import 'package:cinch/cinch.dart';
part 'api.cinch.dart';

class ApiConfig with ApiUrlMixin {
  @override
  String get url => 'https://api.example.com/';
}

@ApiService.emptyUrl()
class UserApi extends _$UserApi with ApiConfig {
  UserApi() : super();
  
  @Get('users')
  Future<Response> getUsers() async {
    return _$getUsers();
  }
}

File Upload (Multipart)

Single File Upload

@ApiService('https://api.example.com/')
class FileApi extends _$FileApi {
  @Post('upload')
  @multipart
  Future<Response> uploadFile(@Part('file') MultipartFile file) {
    return _$uploadFile(file);
  }
}

// Usage
void uploadExample() {
  final api = FileApi();
  
  // From file path
  api.uploadFile(MultipartFile.fromFileSync(
    '/path/to/file.txt', 
    filename: 'document.txt'
  ));
  
  // From bytes
  api.uploadFile(MultipartFile.fromBytes(
    bytes, 
    filename: 'document.txt'
  ));
}

Multiple File Upload with PartMap

@ApiService('https://api.example.com/')
class FileApi extends _$FileApi {
  @Post('multi-upload')
  @multipart
  Future<Response> multiUpload(
    @Part('description') String description,
    @partMap Map<String, MultipartFile> files,
  ) {
    return _$multiUpload(description, files);
  }
}

// Usage
void multiUploadExample() {
  final api = FileApi();
  
  api.multiUpload('My files', {
    "file1": MultipartFile.fromFileSync('/path/file1.txt', filename: 'doc1.txt'),
    "file2": MultipartFile.fromFileSync('/path/file2.txt', filename: 'doc2.txt'),
  });
  
  // Dynamic file list
  api.multiUpload('Batch upload', {
    for (var i = 0; i < 5; i++)
      "file$i": MultipartFile.fromFileSync(
        '/path/file$i.txt', 
        filename: 'document$i.txt'
      ),
  });
}

Custom Status Code Validation

Service-Level Validation

@ApiService('https://api.example.com/')
class CustomApi extends _$CustomApi {
  // Accept only 404 as valid response
  CustomApi() : super(validateStatus: (status) => status == 404);

  @Get('maybe-missing')
  Future<Response> checkResource() async {
    return _$checkResource();
  }
}

Method-Level Validation

Method-level validation overrides service-level validation:

@ApiService('https://api.example.com/')
class CustomApi extends _$CustomApi {
  CustomApi() : super(validateStatus: (status) => status == 404);

  // This method will only accept 403 as valid, ignoring the service-level validation
  @Get('restricted')
  @Get('api/restricted', validateStatus: [403, 200])
  Future<Response> getRestricted() async {
    return _$getRestricted();
  }
}

Custom Headers

Add custom headers to your requests:

import 'dart:io';

@ApiService('https://api.example.com/')
class SecureApi extends _$SecureApi {
  @Get('protected-resource')
  Future<Response> getProtectedResource(
    @Header(HttpHeaders.authorizationHeader) String bearerToken,
    @Header('X-API-Version') String apiVersion,
  ) async {
    return _$getProtectedResource(bearerToken, apiVersion);
  }
}

// Usage
void secureApiExample() {
  final api = SecureApi();
  api.getProtectedResource('Bearer your-token-here', '2.0');
}

Request Body

Send complex objects as JSON request body:

@ApiService('https://api.example.com/')
class DataApi extends _$DataApi {
  @Post('users')
  Future<Response> createUser(@Body() CreateUserRequest userData) async {
    return _$createUser(userData);
  }
}

class CreateUserRequest {
  final String name;
  final String email;
  final int age;
  final List<String> interests;

  CreateUserRequest({
    required this.name,
    required this.email,
    required this.age,
    required this.interests,
  });

  Map<String, dynamic> toJson() => {
        'name': name,
        'email': email,
        'age': age,
        'interests': interests,
      };
}

// Usage
void createUserExample() {
  final api = DataApi();
  
  api.createUser(CreateUserRequest(
    name: 'John Doe',
    email: 'john@example.com',
    age: 30,
    interests: ['programming', 'reading'],
  ));
}

Best Practices

  1. Organize your APIs: Group related endpoints into separate service classes
  2. Use meaningful names: Make your method and parameter names descriptive
  3. Handle errors: Always wrap API calls in try-catch blocks
  4. Type safety: Define response models for better type safety
  5. Documentation: Add comments to your API methods for better maintainability

Error Handling

try {
  final response = await api.getUser('123');
  // Handle successful response
} on DioException catch (e) {
  // Handle Dio-specific errors
  if (e.response?.statusCode == 404) {
    print('User not found');
  } else {
    print('API Error: ${e.message}');
  }
} catch (e) {
  // Handle other errors
  print('Unexpected error: $e');
}

License

MIT License

Copyright (c) 2020 tatsuyuki

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Libraries

cinch