axios处理重复请求的方法小结

import { type AxiosRequestConfig } from 'axios'

const getDataType = (obj: unknown) => {
  let res = Object.prototype.toString.call(obj).split(' ')[1]
  res = res.substring(0, res.length - 1).toLowerCase()
  return res
}

const getKey = (config: AxiosRequestConfig) => {
  const { method, url, data, params } = config;
  let key = `${method}-${url}`;

  try {
    if (data && getDataType(data) === 'object') {
      key += `-${JSON.stringify(data)}`;
    } else if (getDataType(data) === 'formdata') {
      for (const [k, v] of data.entries()) {
        if (v instanceof Blob) {
          continue;
        }

        key += `-${k}-${v}`;
      }
    }
    
    if (params && getDataType(params) === 'object') {
      key += `-${JSON.stringify(params)}`;
    }
  } catch (e) {console.error(e);}
  
  return key;
};

import axios from 'axios';

const historyRequests = new Map<string, number>()

axios.interceptors.request.use(
  (config) => {
    // 生成key
    const key = createKey(config);
    // 响应拦截器中需要用到
    config.headers.key = key;
    // 缓存请求信息
    historyRequests.set(key, 1);

    return config;
  },
  (error) => {
    return Promise.reject(error);
  }
);

instance.interceptors.response.use(
  (res) => {
    // 请求完成，删除缓存信息
    const key = res.config.headers.key as string;
    if (historyRequests.has(key)) {
      historyRequests.delete(key);
    }

    return res;
  },
  (error) => {
    return Promise.reject(error);
  }
);

export default class EventBus<T extends Record<string | symbol, any>> {
  private listeners: Record<keyof T, ((...args: any[]) => void)[]> = {} as any

  $on<K extends keyof T>(event: K, callback: T[K]) {
    if (!this.listeners[event]) {
      this.listeners[event] = []
    }
    this.listeners[event].push(callback)
  }

  $emit<K extends keyof T>(event: K, ...args: Parameters<T[K]>) {
    const callbacks = this.listeners[event]
    if (!callbacks || callbacks?.length === 0) {
      return
    }

    callbacks.forEach((callback) => {
      callback(...args)
    })
  }

  $off<K extends keyof T>(event: K, listener?: T[K]) {
    if (!listener) {
      delete this.listeners[event]
      return
    }

    const fns = this.listeners[event]
    if (!fns || !fns.length) {
      return
    }

    const idx = fns.indexOf(listener)
    if (idx !== -1) {
      fns.splice(idx, 1)
    }
  }

  clear() {
    this.listeners = {} as any
  }
}

import axios, {
  type AxiosRequestConfig,
  AxiosError,
  type AxiosResponse
} from 'axios';
import { getDataType } from './utils';
import { EventBus } from './event/eventBus';

interface IBaseResponse {
  code: number;
  msg: string;
  data?: unknown;
}

const createKey = (config: AxiosRequestConfig) => {
  const { method, url, data, params } = config;
  let key = `${method}-${url}`;

  try {
    if (data && getDataType(data) === 'object') {
      key += `-${JSON.stringify(data)}`;
    } else if (getDataType(data) === 'formdata') {
      for (const [k, v] of data.entries()) {
        if (v instanceof Blob) {
          continue
        }
        key += `-${k}-${v}`;
      }
    }
    if (params && getDataType(params) === 'object') {
      key += `-${JSON.stringify(params)}`;
    }
  } catch (e) {console.error(e);}
  return key;
};

const instance = axios.create({
  baseURL: '',
  timeout: 5000,
  withCredentials: true,
  headers: {
    'Content-Type': 'application/json;'
  }
});

const historyRequests = new Map<string, number>();
instance.interceptors.request.use(
  (config) => {
    const key = createKey(config);
    // 在响应拦截器中需要用到该key发布/订阅事件
    config.headers.key = key;
    // 判断是否存在相同请求，存在则中断请求
    if (historyRequests.has(key)) {
      // 为了后续方便处理中断请求超时
      config.headers.requestTime = Date.now();
      
      // 抛出错误并传递相应参数
      return Promise.reject(
        new AxiosError('Redundant request', 'ERR_REPEATED', config)
      );
    }
    historyRequests.set(key, 1);
    return config;
  },
  (error: AxiosError) => {
    return Promise.reject(error);
  }
);

const responseInterceptor = (res: AxiosResponse<IBaseResponse | Blob>) => {
  const result: [
    AxiosResponse<IBaseResponse | Blob> | undefined,
    AxiosError | undefined
  ] = [undefined, undefined];
  const data = res.data;
  // 可根据你的接口响应数据作处理，这里假设code不为200都为错误
  if (data instanceof Blob || data.code === 200) {
    result[0] = res;
  } else {
    result[1] = new AxiosError(data.msg);
  }
  return result;
};

const eventBus = new EventBus<{
  [key: string]: (
    data?: AxiosResponse<IBaseResponse | Blob>,
    error?: AxiosError
  ) => void;
}>();

instance.interceptors.response.use(
  (res) => {
    const [data, error] = responseInterceptor(res);

    // 如果存在重复请求，则发布结果，执行订阅事件
    const key = res.config.headers.key as string;
    if (historyRequests.has(key)) {
      historyRequests.delete(key);
      eventBus.$emit(key, data, error);
    }

    return data !== undefined ? data : Promise.reject(error);
  },
  (error: AxiosError) => {
    // 处理中断的重复请求
    if (error.code === 'ERR_REPEATED') {
      return new Promise((resolve, reject) => {
        const config = error.config!;
        const key = config.headers.key as string;
        const callback = (
          res?: AxiosResponse<IBaseResponse | Blob>,
          err?: AxiosError
        ) => {
          res ? resolve(res) : reject(err);
          eventBus.$off(key, callback);
        };
        // 订阅事件
        eventBus.$on(key, callback);

        // 处理超时
        const timeout = config.timeout || 5000;
        const requestTime = config.headers.requestTime as number;
        const now = Date.now();
        if (now - requestTime > timeout) {
          historyRequests.delete(key);
          const error = new AxiosError(
            `timeout of ${timeout}ms exceeded`,
            'ECONNABORTED',
            config
          );
          error.name = 'AxiosError';
          eventBus.$emit(key, undefined, error);
        }
      });
    }

    return Promise.reject(error);
  }
);