flutter dio 请求封装（空安全）

小鱼儿 2024-02-23 08:12 41阅读 0赞

### 一、添加依赖 ###

dio: ^5.3.2

### 二、请求封装 ###

class HttpHelper {
        
      static Dio? mDio;
      static BaseOptions? options;
      static HttpHelper? httpHelper;
    
      CancelToken cancelToken = CancelToken();
    
      static const String GET = 'get';
      static const String POST = 'post';
      static const String PUT = 'put';
      static const String PATCH = 'patch';
      static const String DELETE = 'delete';
    
      static HttpHelper? get instance => getInstance();
    
      static Dio? get dio => getDio();
    
      static HttpHelper? getInstance() {
        
        httpHelper ??= HttpHelper();
        return httpHelper;
      }
    
      static Dio? getDio() {
        
        final token = GetStorage().read('token');
    
        final Map<String, dynamic> headerMap = {
        };
    
        if (token != null) {
        
          headerMap.putIfAbsent("Authorization", () => "Bearer $token");
        }
    
        options = BaseOptions(
          //请求基地址,可以包含子路径
          baseUrl: Api.BASE_URL,
          //连接服务器超时时间，单位是毫秒.
          connectTimeout: const Duration(seconds: 10),
          //2.x中为接收数据的最长时限
          receiveTimeout: const Duration(seconds: 5),
          //Http请求头.
          headers: headerMap,
          // 请求的Content-Type，默认值是"application/json; charset=utf-8".
          //   /// 如果您想以"application/x-www-form-urlencoded"格式编码请求数据,
          //   /// 可以设置此选项为 `Headers.formUrlEncodedContentType`,  这样[Dio]
          //   /// 就会自动编码请求体.
          contentType: Headers.jsonContentType,
    
          /// [responseType] 表示期望以那种格式(方式)接受响应数据。
          /// 目前 [ResponseType] 接受三种类型 `JSON`, `STREAM`, `PLAIN`.
          ///
          /// 默认值是 `JSON`, 当响应头中content-type为"application/json"时，dio 会自动将响应内容转化为json对象。
          /// 如果想以二进制方式接受响应数据，如下载一个二进制文件，那么可以使用 `STREAM`.
          ///
          /// 如果想以文本(字符串)格式接收响应数据，请使用 `PLAIN`.
          responseType: ResponseType.json,
        );
    
        mDio = Dio(options);
        mDio?.interceptors.add(interceptorsWrapper());
    
        mDio?.httpClientAdapter = IOHttpClientAdapter(
          createHttpClient: () {
        
            final client = HttpClient();
            // Config the client.
            client.findProxy = (uri) {
        
              // Forward all request to proxy "localhost:8888".
              // Be aware, the proxy should went through you running device,
              // not the host platform.
              return 'PROXY 192.168.0.191:8089';
            };
            // You can also create a new HttpClient for Dio instead of returning,
            // but a client must being returned here.
            return client;
          },
        );
    
        return mDio;
      }
    
      static InterceptorsWrapper interceptorsWrapper() {
        
        return InterceptorsWrapper(onRequest: (options, handler) {
        
          // Do something before request is sent
          return handler.next(options); //continue
          // 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。
        }, onResponse: (response, handler) {
        
          // Do something with response data
          return handler.next(response); // continue
          // 如果你想终止请求并触发一个错误,你可以 reject 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。
        }, onError: (DioError e, handler) {
        
          // Do something with response error
    
          if (e.response != null) {
        
            if (e.response?.statusCode == 401) {
        
              ToastMsg.show("当前登录已过期，请重新登录！");
              Future.delayed(const Duration(milliseconds: 1000), () {
        
                Get.offAllNamed(AppRoutes.LOGIN);
              });
            } else if (e.response?.statusCode == 403) {
        
              ToastMsg.show("暂无权限访问，请联系管理员！");
            } else {
        
              ToastMsg.show("系统内部异常！");
            }
          }
    
          return handler.next(e); //continue
          // 如果你想完成请求并返回一些自定义数据，可以resolve 一个`Response`,如`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.
        });
      }
    
      ///Get请求
      Future<BaseRes<T>> getHttp<T>(String url, parameters,{
        loading = true}) async {
        
        return await getResponse<T>(url, method: GET, parameters: parameters,loading:loading);
      }
    
      Future<BaseRes<T>> postHttp<T>(String url, parameters,{
        loading = true}) async {
        
        ///定义请求参数
        parameters = parameters ?? <String, dynamic>{
        };
    
        return await getResponse<T>(url, method: POST, parameters: parameters,loading:loading);
      }
    
      Future<BaseRes<T>> putHttp<T>(String url, parameters,{
        loading = true}) async {
        
        ///定义请求参数
        parameters = parameters ?? <String, dynamic>{
        };
    
        return await getResponse<T>(url, method: PUT, parameters: parameters,loading:loading);
      }
    
      Future<BaseRes<T>> deleteHttp<T>(String url, parameters,{
        loading = true}) async {
        
        ///定义请求参数
        parameters = parameters ?? <String, dynamic>{
        };
        return await getResponse<T>(url, method: DELETE, parameters: parameters,loading:loading);
      }
    
      /*
       * 下载文件
       */
      downloadFile(urlPath, savePath, onReceiveProgress) async {
        
        Response? response;
        try {
        
          response = await dio?.download(urlPath, savePath,
              onReceiveProgress: onReceiveProgress);
        } on DioError catch (e) {
        
          formatError(e);
        }
        return response?.data;
      }
    
      Future<BaseRes<T>> getResponse<T>(
        String url, {
        
        required String method,
        parameters,
        loading,
      }) async {
        
        //这里指定response自动转成map,不指定的话有可能是String类型
        Response<Map<String, dynamic>>? response;
    
    
        if(loading) {
        
          ToastMsg.showLoading();
        }
    
        switch (method) {
        
          case GET:
            response = await dio?.get(url,
                queryParameters: parameters ?? <String, dynamic>{
        });
            break;
          case PUT:
            response = await dio?.put(url,
                queryParameters: parameters ?? <String, dynamic>{
        });
            break;
          case DELETE:
            response = await dio?.delete(url,
                queryParameters: parameters ?? <String, dynamic>{
        });
            break;
          default:
            response =
                await dio?.post(url, data: parameters ?? <String, dynamic>{
        });
            break;
        }
    
        if(loading) {
        
          ToastMsg.cancelLoading();
        }
    
    
        //200代表网络请求成功
        if (response?.statusCode == 200) {
        
          /// 将后台的data字段转成自己想要的数据/数据集,code根据后端实际返回进行判断访问结果
          BaseRes<T> bean = BaseRes.fromJson(response?.data);
    
          return bean;
        } else if (response?.statusCode == 401) {
        
          ToastMsg.show("当前登录已过期，请重新登录！");
          Future.delayed(const Duration(milliseconds: 1000), () {
        
            Get.offAllNamed(AppRoutes.LOGIN);
          });
        } else if (response?.statusCode == 403) {
        
          ToastMsg.show("暂无权限访问，请联系管理员！");
        } else {
        
          ToastMsg.show("系统内部异常！");
        }
    
        throw Exception('${
          response?.statusCode}+${
          response?.statusMessage}');
      }
    
      void formatError(DioError e) {
        
        print(e.message);
      }
    
      /*
       * 取消请求
       * 同一个cancel token 可以用于多个请求，当一个cancel token取消时，所有使用该cancel token的请求都会被取消。
       */
      void cancelRequests(CancelToken token) {
        
        token.cancel("cancelled");
      }
    }

### 三、封装统一返回类 ###

@JsonSerializable()
    class BaseRes<T>{
        
    
      BaseRes(this.msg, this.code, this.data);
    
      late String msg;
      late int code;
      late T data;
    
    
      BaseRes.fromJson(Map<String, dynamic>? json) {
        
        if (json?['data'] != null && json?['data'] != 'null') {
        
          data = JsonConvert.fromJsonAsT<T>(json?['data']) as T;
        }
        msg = json?['msg'];
        code = json?['code'];
      }
    
    
    
      Map<String, dynamic> toJson() {
        
        final Map<String, dynamic> data = <String, dynamic>{
        };
        if (this.data != null) {
        
          data['data'] = this.data;
        }
        data['code'] = this.code;
        data['msg'] = this.msg;
        return data;
      }
    }

### 四、使用 ###

// Entity类使用的是JsonToDartBeanAction生成
     BaseRes<UserInfoEntity>? res = await HttpHelper.instance?.getHttp(Api.GET_USER_INGO,null,loading: false);
        if(res?.code == 200 && res?.data != null) {
        
          state.userInfo = res!.data.obs;
        }