Flutter网络请求库Dio的封装（单例、动态baseUrl、拦截器、日志、请求loading）

封装网络请求的几个好处：

Demo地址 https://github.com/po1arbear/Flutter-Net.git
如果觉得有帮助，希望能给个star鼓励下，如果不能满足你的需求，欢迎提issue : )

1. 便于统一配置请求参数，如header，公共参数，加密规则等
2. 方便调试，详细的日志打印信息
3. 优化代码性能，避免到处滥new对象，构建全局单例
4. 简化请求步骤，只暴露需要的响应数据，而对错误的响应统一回调
5. 对接口数据的基类封装，简化解析流程
6. 无侵入的，灵活的请求loading配置

请求loading自动化

只需要传递一个参数，就可以为请求加上Loading效果，没有任何的代码入侵

  var params = DataHelper.getBaseMap();
    params.clear();
    params["apikey"] = "0df993c66c0c636e29ecbb5344252a4a";
    params["start"] = "0";
    params["count"] = "10";
//withLoading也可以省略，默认就加上，会更简洁
    ResultData res = await HttpManager.getInstance()
        .get(Address.TEST_API, params: params, withLoading: true);

清晰全面的日志打印

再也不需要额外地配置抓包了，接口调试效率大大提升

下面通过关键源码介绍下封装过程

HttpManager的定义

构造全局单例，配置请求参数，配置通用的GET\POST，支持baseUrl的切换

import 'package:dio/dio.dart';
import 'package:flutter_net/code.dart';
import 'package:flutter_net/dio_log_interceptor.dart';
import 'package:flutter_net/loading_utils.dart';
import 'response_interceptor.dart';
import 'result_data.dart';
import 'address.dart';

class HttpManager {
  static HttpManager _instance = HttpManager._internal();
  Dio _dio;

  static const CODE_SUCCESS = 200;
  static const CODE_TIME_OUT = -1;

  factory HttpManager() => _instance;

  ///通用全局单例，第一次使用时初始化
  HttpManager._internal({String baseUrl}) {
    if (null == _dio) {
      _dio = new Dio(
          new BaseOptions(baseUrl: Address.BASE_URL, connectTimeout: 15000));
      _dio.interceptors.add(new DioLogInterceptor());
//      _dio.interceptors.add(new PrettyDioLogger());
      _dio.interceptors.add(new ResponseInterceptors());
    }
  }

  static HttpManager getInstance({String baseUrl}) {
    if (baseUrl == null) {
      return _instance._normal();
    } else {
      return _instance._baseUrl(baseUrl);
    }
  }

  //用于指定特定域名
  HttpManager _baseUrl(String baseUrl) {
    if (_dio != null) {
      _dio.options.baseUrl = baseUrl;
    }
    return this;
  }

  //一般请求，默认域名
  HttpManager _normal() {
    if (_dio != null) {
      if (_dio.options.baseUrl != Address.BASE_URL) {
        _dio.options.baseUrl = Address.BASE_URL;
      }
    }
    return this;
  }

  ///通用的GET请求
  get(api, {params, withLoading = true}) async {
    if (withLoading) {
      LoadingUtils.show();
    }

    Response response;
    try {
      response = await _dio.get(api, queryParameters: params);
      if (withLoading) {
        LoadingUtils.dismiss();
      }
    } on DioError catch (e) {
      if (withLoading) {
        LoadingUtils.dismiss();
      }
      return resultError(e);
    }

    if (response.data is DioError) {
      return resultError(response.data['code']);
    }

    return response.data;
  }

  ///通用的POST请求
  post(api, {params, withLoading = true}) async {
    if (withLoading) {
      LoadingUtils.show();
    }

    Response response;

    try {
      response = await _dio.post(api, data: params);
      if (withLoading) {
        LoadingUtils.dismiss();
      }
    } on DioError catch (e) {
      if (withLoading) {
        LoadingUtils.dismiss();
      }
      return resultError(e);
    }

    if (response.data is DioError) {
      return resultError(response.data['code']);
    }

    return response.data;
  }
}

ResultData resultError(DioError e) {
  Response errorResponse;
  if (e.response != null) {
    errorResponse = e.response;
  } else {
    errorResponse = new Response(statusCode: 666);
  }
  if (e.type == DioErrorType.CONNECT_TIMEOUT ||
      e.type == DioErrorType.RECEIVE_TIMEOUT) {
    errorResponse.statusCode = Code.NETWORK_TIMEOUT;
  }
  return new ResultData(
      errorResponse.statusMessage, false, errorResponse.statusCode);
}

响应基类

默认200的情况isSuccess为true，响应为response.data,赋值给data

class ResultData {
  var data;
  bool isSuccess;
  int code;
  var headers;

  ResultData(this.data, this.isSuccess, this.code, {this.headers});
}

Api的封装

请求的集中管理

class Api {
  ///示例请求
  static request(String param) {
    var params = DataHelper.getBaseMap();
    params['param'] = param;
    return HttpManager.getInstance().get(Address.TEST_API, params);
  }
}

公共参数和加密等

class DataHelper{
  static SplayTreeMap getBaseMap() {
    var map = new SplayTreeMap<String, dynamic>();
    map["platform"] = AppConstants.PLATFORM;
    map["system"] = AppConstants.SYSTEM;
    map["channel"] = AppConstants.CHANNEL;
    map["time"] = new DateTime.now().millisecondsSinceEpoch.toString();
    return map;
  }
  
  static string2MD5(String data) {
    var content = new Utf8Encoder().convert(data);
    var digest = md5.convert(content);
    return hex.encode(digest.bytes);
  }
}

地址的配置

方便地址管理

class Address {
  static const String TEST_API =  "test_api";
}

响应拦截器

过滤正确的响应数据，对数据进行初步封装

import 'package:dio/dio.dart';
import 'package:exchange_flutter/common/net/code.dart';
import 'package:flutter/material.dart';
import '../result_data.dart';

class ResponseInterceptors extends InterceptorsWrapper {
  @override
  onResponse(Response response) {
    RequestOptions option = response.request;
    try {
      if (option.contentType != null &&
          option.contentType.primaryType == "text") {
        return new ResultData(response.data, true, Code.SUCCESS);
      }
      ///一般只需要处理200的情况，300、400、500保留错误信息
      if (response.statusCode == 200 || response.statusCode == 201) {
        int code = response.data["code"];
        if (code == 0) {
          return new ResultData(response.data, true, Code.SUCCESS,
              headers: response.headers);
        } else if (code == 100006 || code == 100007) {

        } else {
          Fluttertoast.showToast(msg: response.data["msg"]);
          return new ResultData(response.data, false, Code.SUCCESS,
              headers: response.headers);
        }
      }
    } catch (e) {
      print(e.toString() + option.path);

      return new ResultData(response.data, false, response.statusCode,
          headers: response.headers);
    }

    return new ResultData(response.data, false, response.statusCode,
        headers: response.headers);
  }
}

日志拦截器

打印请求参数和返回参数

import 'package:dio/dio.dart';

///日志拦截器
class DioLogInterceptor extends Interceptor {
  @override
  Future onRequest(RequestOptions options) async {
    String requestStr = "\n==================== REQUEST ====================\n"
        "- URL:\n${options.baseUrl + options.path}\n"
        "- METHOD: ${options.method}\n";

    requestStr += "- HEADER:\n${options.headers.mapToStructureString()}\n";

    final data = options.data;
    if (data != null) {
      if (data is Map)
        requestStr += "- BODY:\n${data.mapToStructureString()}\n";
      else if (data is FormData) {
        final formDataMap = Map()
          ..addEntries(data.fields)
          ..addEntries(data.files);
        requestStr += "- BODY:\n${formDataMap.mapToStructureString()}\n";
      } else
        requestStr += "- BODY:\n${data.toString()}\n";
    }
    print(requestStr);
    return options;
  }

  @override
  Future onError(DioError err) async {
    String errorStr = "\n==================== RESPONSE ====================\n"
        "- URL:\n${err.request.baseUrl + err.request.path}\n"
        "- METHOD: ${err.request.method}\n";

    errorStr +=
        "- HEADER:\n${err.response.headers.map.mapToStructureString()}\n";
    if (err.response != null && err.response.data != null) {
      print('╔ ${err.type.toString()}');
      errorStr += "- ERROR:\n${_parseResponse(err.response)}\n";
    } else {
      errorStr += "- ERRORTYPE: ${err.type}\n";
      errorStr += "- MSG: ${err.message}\n";
    }
    print(errorStr);
    return err;
  }

  @override
  Future onResponse(Response response) async {
    String responseStr =
        "\n==================== RESPONSE ====================\n"
        "- URL:\n${response.request.uri}\n";
    responseStr += "- HEADER:\n{";
    response.headers.forEach(
        (key, list) => responseStr += "\n  " + "\"$key\" : \"$list\",");
    responseStr += "\n}\n";
    responseStr += "- STATUS: ${response.statusCode}\n";

    if (response.data != null) {
      responseStr += "- BODY:\n ${_parseResponse(response)}";
    }
    printWrapped(responseStr);
    return response;
  }

  void printWrapped(String text) {
    final pattern = new RegExp('.{1,800}'); // 800 is the size of each chunk
    pattern.allMatches(text).forEach((match) => print(match.group(0)));
  }

  String _parseResponse(Response response) {
    String responseStr = "";
    var data = response.data;
    if (data is Map)
      responseStr += data.mapToStructureString();
    else if (data is List)
      responseStr += data.listToStructureString();
    else
      responseStr += response.data.toString();

    return responseStr;
  }
}

extension Map2StringEx on Map {
  String mapToStructureString({int indentation = 2}) {
    String result = "";
    String indentationStr = " " * indentation;
    if (true) {
      result += "{";
      this.forEach((key, value) {
        if (value is Map) {
          var temp = value.mapToStructureString(indentation: indentation + 2);
          result += "\n$indentationStr" + "\"$key\" : $temp,";
        } else if (value is List) {
          result += "\n$indentationStr" +
              "\"$key\" : ${value.listToStructureString(indentation: indentation + 2)},";
        } else {
          result += "\n$indentationStr" + "\"$key\" : \"$value\",";
        }
      });
      result = result.substring(0, result.length - 1);
      result += indentation == 2 ? "\n}" : "\n${" " * (indentation - 1)}}";
    }

    return result;
  }
}

extension List2StringEx on List {
  String listToStructureString({int indentation = 2}) {
    String result = "";
    String indentationStr = " " * indentation;
    if (true) {
      result += "$indentationStr[";
      this.forEach((value) {
        if (value is Map) {
          var temp = value.mapToStructureString(indentation: indentation + 2);
          result += "\n$indentationStr" + "\"$temp\",";
        } else if (value is List) {
          result += value.listToStructureString(indentation: indentation + 2);
        } else {
          result += "\n$indentationStr" + "\"$value\",";
        }
      });
      result = result.substring(0, result.length - 1);
      result += "\n$indentationStr]";
    }

    return result;
  }
}

示例请求

dart的json解析推荐使用json_serializable，其他的有些坑，慎用

void request() async {
    ResultData res = await Api.request("param");
    if (res.isSuccess) {
       //拿到res.data就可以进行Json解析了，这里一般用来构造实体类
            TestBean bean = TestBean.fromMap(res.data);

    }else{
      //处理错误
    }
  }

Demo地址 https://github.com/po1arbear/Flutter-Net.git

如果觉得有帮助，希望能给个star鼓励下，如果不能满足你的需求，欢迎提issue : )