Flutter dio http 封装指南说明

视频

https://youtu.be/YJBC0ZNEv0Q

https://www.bilibili.com/video/BV1qy41187y3/

前言

原文 https://ducafecat.com/blog/building-a-powerful-flutter-dio-wr...

本文介绍了如何实现一个通用、可重构的 Dio 基础类,包括单例访问、日志记录、常见操作封装以及请求、输出、报错拦截等功能。

Flutter, Dio, 网络请求, 封装, 重构, 可扩展

参考

https://pub.dev/packages/dio

https://pub.dev/packages/pretty_dio_logger

https://github.com/cfug/dio/blob/main/dio/README-ZH.md

步骤

第一步：安装 dio 插件

pubspec.yaml

dependencies:
    ...
  dio: ^5.4.3+1

dev_dependencies:
  ...
  pretty_dio_logger: ^1.3.1

第二步：编写单例工具类

lib/utils/woo_http.dart

常量

const String APPLICATION_JSON = "application/json";
const String CONTENT_TYPE = "content-type";
const String ACCEPT = "accept";
const String AUTHORIZATION = "authorization";
const String DEFAULT_LANGUAGE = "en";
const String TOKEN = "Bearer token";
const String BASE_URL = "https://wpapi.ducafecat.tech";

单例类

/// woo 电商 api 请求工具类
class WooHttpUtil {
  static final WooHttpUtil _instance = WooHttpUtil._internal();
  factory WooHttpUtil() => _instance;

  late Dio _dio;

  /// 单例初始
  WooHttpUtil._internal() {
    // header 头
    Map<String, String> headers = {
      CONTENT_TYPE: APPLICATION_JSON,
      ACCEPT: APPLICATION_JSON,
      AUTHORIZATION: TOKEN,
      DEFAULT_LANGUAGE: DEFAULT_LANGUAGE
    };

    // 初始选项
    var options = BaseOptions(
      baseUrl: BASE_URL,
      headers: headers,
      connectTimeout: const Duration(seconds: 5), // 5秒
      receiveTimeout: const Duration(seconds: 3), // 3秒
      responseType: ResponseType.json,
    );

    // 初始 dio
    _dio = Dio(options);

    // 拦截器 - 日志打印
    if (!kReleaseMode) {
      _dio.interceptors.add(PrettyDioLogger(
        requestHeader: true,
        requestBody: true,
        responseHeader: true,
      ));
    }
  }

}

第三步：加入操作方法

常用的 get post put delete

  /// get 请求
  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;
  }

  /// post 请求
  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;
  }

  /// put 请求
  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;
  }

  /// delete 请求
  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;
  }

第四步：拦截器

安装拦截器

class WooHttpUtil {
  ...
    
  /// 单例初始
  WooHttpUtil._internal() {
    ...

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

拦截类

/// 拦截
class RequestInterceptors extends Interceptor {
  //

  /// 发送请求
  /// 我们这里可以添加一些公共参数，或者对参数进行加密
  @override
  void onRequest(RequestOptions options, RequestInterceptorHandler handler) {
    // super.onRequest(options, handler);

    // http header 头加入 Authorization
    // 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。
  }

  /// 响应
  @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(
        DioException(
          requestOptions: response.requestOptions,
          response: response,
          type: DioExceptionType.badResponse,
        ),
        true,
      );
    } else {
      handler.next(response);
    }
  }

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

  /// 错误
  @override
  Future<void> onError(
      DioException err, ErrorInterceptorHandler handler) async {
    final exception = HttpException(err.message ?? "error message");
    switch (err.type) {
      case DioExceptionType.badResponse: // 服务端自定义错误体处理
        {
          final response = err.response;
          final errorMessage = ErrorMessageModel.fromJson(response?.data);
          switch (errorMessage.statusCode) {
            // 401 未登录
            case 401:
              // 注销 并跳转到登录页面
              // _errorNoAuthLogout();
              break;
            case 404:
              break;
            case 500:
              break;
            case 502:
              break;
            default:
              break;
          }
          // 显示错误信息
          // if(errorMessage.message != null){
          //   Loading.error(errorMessage.message);
          // }
        }
        break;
      case DioExceptionType.unknown:
        break;
      case DioExceptionType.cancel:
        break;
      case DioExceptionType.connectionTimeout:
        break;
      default:
        break;
    }
    DioException errNext = err.copyWith(
      error: exception,
    );
    handler.next(errNext);
  }
}

自定义错误消息 entity 类

lib/models/error_message_model.dart

/// 错误体信息
class ErrorMessageModel {
  int? statusCode;
  String? error;
  String? message;

  ErrorMessageModel({this.statusCode, this.error, this.message});

  factory ErrorMessageModel.fromJson(Map<String, dynamic> json) {
    return ErrorMessageModel(
      statusCode: json['statusCode'] as int?,
      error: json['error'] as String?,
      message: json['message'] as String?,
    );
  }

  Map<String, dynamic> toJson() => {
        'statusCode': statusCode,
        'error': error,
        'message': message,
      };
}

第五步：准备 entity 类

安装插件

https://marketplace.visualstudio.com/items?itemName=hirantha....

json to dart

复制你的输出 json 数据

执行 json to dart 命令，转换来自于剪贴板

json to dart from clipboard

保存输出结果 lib/models/product_model

第六步：编写 api 类

lib/apis/product.dart

/// 商品 api
class ProductApi {
  /// 商品列表
  static Future<List<ProductModel>> list({int? page, int? prePage}) async {
    var res = await WooHttpUtil().get('/products', params: {
      'page': page ?? 1,
      'per_page': prePage ?? 20,
    });

    List<ProductModel> items = [];
    for (var item in res.data) {
      items.add(ProductModel.fromJson(item));
    }

    return items;
  }
}

最后：拉取数据

lib/pages/first.dart

class FirstPage extends StatefulWidget {
  const FirstPage({super.key});

  @override
  State<FirstPage> createState() => _FirstPageState();
}

class _FirstPageState extends State<FirstPage> {
  List<ProductModel> _products = [];

  Future<void> _getProducts() async {
    var products = await ProductApi.list();
    if (mounted) {
      setState(() {
        _products = products;
      });
    }
  }

  @override
  void initState() {
    super.initState();
    _getProducts();
  }

  Widget _buildView() {
    return ListView.builder(
      itemCount: _products.length,
      itemBuilder: (context, index) {
        return ListTile(
          title: Text(_products[index].name ?? ""),
          subtitle: Text(_products[index].description ?? ""),
        );
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('First Page'),
      ),
      body: _buildView(),
    );
  }
}

代码

https://github.com/ducafecat/flutter_develop_tips/tree/main/flutter_application_dio

小结

本文详细介绍了如何构建一个通用、可重构的 Flutter Dio 基础类,包括单例访问、日志记录、常见操作封装以及请求、输出、报错拦截等功能。通过这种封装,可以大大提高网络请求的可维护性和扩展性,并且可以轻松应对各种网络请求场景。希望本文能为您在 Flutter 开发中的网络请求部分提供有价值的参考和指导。

感谢阅读本文

如果有什么建议，请在评论中让我知道。我很乐意改进。

flutter 学习路径

Flutter 优秀插件推荐 https://flutter.ducafecat.com
Flutter 基础篇1 - Dart 语言学习 https://ducafecat.com/course/dart-learn
Flutter 基础篇2 - 快速上手 https://ducafecat.com/course/flutter-quickstart-learn
Flutter 实战1 - Getx Woo 电商APP https://ducafecat.com/course/flutter-woo
Flutter 实战2 - 上架指南 Apple Store、Google Play https://ducafecat.com/course/flutter-upload-apple-google
Flutter 基础篇3 - 仿微信朋友圈 https://ducafecat.com/course/flutter-wechat
Flutter 实战3 - 腾讯即时通讯第一篇 https://ducafecat.com/course/flutter-tim
Flutter 实战4 - 腾讯即时通讯第二篇 https://ducafecat.com/course/flutter-tim-s2

end

Flutter dio http 封装指南说明