1.8 dio 封装

参考

https://pub.dev/packages/dio

https://github.com/flutterchina/dio/blob/master/README-ZH.md

实现步骤：

---

开始之前请阅读 API 设计规范说明

第 1 步：安装插件 dio

flutter pub add dio
# flutter pub add dio_cookie_manager
# flutter pub add cookie_jar

dio_cookie_manager cookie_jar 这两个我暂时没用上

第 2 步：常量定义

lib/common/values/constants.dart

/// 常量
class Constants {
  // wp 服务器
  static const wpApiBaseUrl = 'https://wpapi.ducafecat.tech';

第 3 步：单例初始

lib/common/services/wp_http.dart

import 'dart:io';

import 'package:dio/dio.dart';
import 'package:get/get.dart' hide Response, FormData, MultipartFile;

import '../index.dart';

class WPHttpService extends GetxService {
  static WPHttpService get to => Get.find();

  late final Dio _dio;
  // final CancelToken _cancelToken = CancelToken(); // 默认去掉

  @override
  void onInit() {
    super.onInit();

    // 初始 dio
    var options = BaseOptions(
      baseUrl: Constants.wpApiBaseUrl,
      connectTimeout: 10000, // 10秒
      receiveTimeout: 5000, // 5秒
      headers: {},
      contentType: 'application/json; charset=utf-8',
      responseType: ResponseType.json,
    );
    _dio = Dio(options);

    // 拦截器
    _dio.interceptors.add(RequestInterceptors());
  }

}

第 4 步：方法 get/post/put/delete

lib/common/services/wp_http.dart

Future<Response> get(
  String url, {
  Map<String, dynamic>? params,
  Options? options,
  CancelToken? cancelToken,
}) async {
  Options requestOptions = options ?? Options();
  Response response = await _dio.get(
    url,
    queryParameters: params,
    options: requestOptions,
    cancelToken: cancelToken,
  );
  return response;
}

Future<Response> post(
  String url, {
  dynamic data,
  Options? options,
  CancelToken? cancelToken,
}) async {
  var requestOptions = options ?? Options();
  Response response = await _dio.post(
    url,
    data: data ?? {},
    options: requestOptions,
    cancelToken: cancelToken,
  );
  return response;
}

Future<Response> put(
  String url, {
  dynamic data,
  Options? options,
  CancelToken? cancelToken,
}) async {
  var requestOptions = options ?? Options();
  Response response = await _dio.put(
    url,
    data: data ?? {},
    options: requestOptions,
    cancelToken: cancelToken,
  );
  return response;
}

Future<Response> delete(
  String url, {
  dynamic data,
  Options? options,
  CancelToken? cancelToken,
}) async {
  var requestOptions = options ?? Options();
  Response response = await _dio.delete(
    url,
    data: data ?? {},
    options: requestOptions,
    cancelToken: cancelToken,
  );
  return response;
}

第 5 步：错误拦截处理

lib/common/services/wp_http.dart

/// 拦截
class RequestInterceptors extends Interceptor {
  @override
  void onRequest(RequestOptions options, RequestInterceptorHandler handler) {
    // super.onRequest(options, handler);
    // if (UserService.to.hasToken) {
    //   options.headers['Authorization'] = 'Bearer ${UserService.to.token}';
    // }
    return handler.next(options);
    // 如果你想完成请求并返回一些自定义数据，你可以resolve一个Response对象 `handler.resolve(response)`。
    // 这样请求将会被终止，上层then会被调用，then中返回的数据将是你的自定义response.
    //
    // 如果你想终止请求并触发一个错误,你可以返回一个`DioError`对象,如`handler.reject(error)`，
    // 这样请求将被中止并触发异常，上层catchError会被调用。
  }

  @override
  void onResponse(Response response, ResponseInterceptorHandler handler) {
    // 200 请求成功, 201 添加成功
    if (response.statusCode != 200 && response.statusCode != 201) {
      handler.reject(
        DioError(
          requestOptions: response.requestOptions,
          response: response,
          type: DioErrorType.response,
        ),
        true,
      );
    } else {
      handler.next(response);
    }
  }

  /// 退出并重新登录
  // Future<void> _errorNoAuthLogout() async {
  //   await UserService.to.logout();
  //   Get.toNamed(RouteNames.systemLogin);
  // }

  @override
  Future<void> onError(DioError err, ErrorInterceptorHandler handler) async {
    final exception = HttpException(err.message);
    switch (err.type) {
      case DioErrorType.response: // 服务端自定义错误体处理
        {
          // final response = err.response;
          // final errorMessage = ErrorMessageModel.fromJson(response?.data);
          // switch (errorMessage.statusCode) {
          //   case 401:
          //     _errorNoAuthLogout();
          //     break;
          //   case 404:
          //     break;
          //   case 500:
          //     break;
          //   case 502:
          //     break;
          //   default:
          //     break;
          // }
          // Loading.error(errorMessage.message);
        }
        break;
      case DioErrorType.other:
        break;
      case DioErrorType.cancel:
        break;
      case DioErrorType.connectTimeout:
        break;
      default:
        break;
    }
    err.error = exception;
    handler.next(err);
  }
}

最后 Global 载入

lib/global.dart

class Global {
  static Future<void> init() async {
    WidgetsBinding widgetsBinding = WidgetsFlutterBinding.ensureInitialized();
    ...

    // 初始化服务
    ...
    Get.put<WPHttpService>(WPHttpService());

提交代码到 git