API Communication with Dio and Retrofit in Flutter

dependencies:
	retrofit: ^4.4.2
	dio: ^5.7.0
	json_annotation: ^4.9.0
 
dev_dependencies:
	build_runner: ^2.4.13
	retrofit_generator: ^9.1.5
	json_serializable: ^6.9.0

[
	{
		"id": 1,
		"name": "Leanne Graham",
		"username": "Bret",
		"email": "Sincere@april.biz",
		"address": {
			"street": "Kulas Light",
			"suite": "Apt. 556",
			"city": "Gwenborough",
			"zipcode": "92998-3874",
			"geo": {
				"lat": "-37.3159",
				"lng": "81.1496"
			}
		},
		"phone": "1-770-736-8031 x56442",
		"website": "hildegard.org",
		"company": {
			"name": "Romaguera-Crona",
			"catchPhrase": "Multi-layered client-server neural-net",
			"bs": "harness real-time e-markets"
		}
	},
	// ...
]

import 'package:json_annotation/json_annotation.dart';
part 'user_dto.g.dart';
 
@JsonSerializable()
class UserDto {
	final int id;
	final String name;
	final String username;
	final String email;
	final Address address;
	final String phone;
	final String website;
	final Company company;
 
	UserDto({
		required this.id,
		required this.name,
		required this.username,
		required this.email,
		required this.address,
		required this.phone,
		required this.website,
		required this.company,
	});
 
	factory UserDto.fromJson(Map<String, dynamic> json) => _$UserDtoFromJson(json);
	Map<String, dynamic> toJson() => _$UserDtoToJson(this);
} 
 
@JsonSerializable()
class Address {
	final String street;
	final String suite;
	final String city;
	final String zipcode;
	final Geo geo;
 
	Address({
		required this.street,
		required this.suite,
		required this.city,
		required this.zipcode,
		required this.geo,
	});
 
	factory Address.fromJson(Map<String, dynamic> json) => _$AddressFromJson(json);
	Map<String, dynamic> toJson() => _$AddressToJson(this);
}
 
@JsonSerializable()
class Geo {
	final String lat;
	final String lng;
 
	Geo({
		required this.lat,
		required this.lng,
	});
 
	factory Geo.fromJson(Map<String, dynamic> json) => _$GeoFromJson(json);
	Map<String, dynamic> toJson() => _$GeoToJson(this);
}
 
@JsonSerializable()
class Company {
	final String name;
	final String catchPhrase;
	final String bs;
 
	Company({
		required this.name,
		required this.catchPhrase,
		required this.bs,
	});
 
	factory Company.fromJson(Map<String, dynamic> json) => _$CompanyFromJson(json);
	Map<String, dynamic> toJson() => _$CompanyToJson(this);
}

import 'package:dio/dio.dart';
import 'package:retrofit/retrofit.dart';
import 'user_dto.dart';
 
part 'user.g.dart'; // 생성될 파일
 
@RestApi(baseUrl: "https://jsonplaceholder.typicode.com") // base url
abstract class UserApi {
	factory UserApi(Dio dio, {String baseUrl}) = _UserApi;
 
	@GET("/users") // 요청할 API
	Future<List<UserDto>> getUsers(); // 요청할 API의 응답을 받을 모델 클래스
}

import 'dart:developer';
 
import 'package:dio/dio.dart';
import 'package:retrofit/retrofit.dart';
import 'package:{project명}/model/user/user.dart'; // 작성한 프로젝트의 경로에 맞게 수정해주세요.
 
void runApiExample() {
  final dio = Dio();
  final client = GetUserApi(dio);
 
  client.getUsers().then((userList) => {
        for (final user in userList) {log(user.toJson().toString())}
      });
}
 

@GET('/users/{id}')
Future<UserDto> getUserByPathId(@Path() int id); // 파라미터 전달

@GET('/users')
Future<List<UserDto>> getUserByQueryId(
	@Query('id') int id,
); // 쿼리 파라미터 전달

@GET('/users')
@Headers(<String, dynamic>{
	'Content-Type': 'application/json',
	'Authorization': 'Bearer {token}',
})
Future<List<UserDto>> getUsers(); // 헤더 전달

@GET('/users')
Future<List<UserDto>> getUsers(
	@Header('Content-Type') String content_type, 
	@Header('Authorization') String authorization,
); // 헤더 전달

@POST('/users')
Future<UserDto> createUser(@Body() UserDto user); // 바디 전달