場景:
項目開發過程中有時會遇到這種情況:兩次查詢請求相隔時間很短時,由於接口異步,第一次請求可能會覆蓋第二次請求返回數據,所以需要在第二次請求前先將第一次請求中止,話不多說,實現如下:
關於axios取消請求網上有很多,可自信百度,本文主要針對於fetch請求,由於fetch並沒有 “取消請求” 方法,目前通過AbortController()實現
項目:Ant.Design Pro + umijs + dva
新建一個abortDispath.js文件
export const abortDispatch = (payload, dispatch) => {
if (payload && payload.signal) {
const error = 'success! request is aborted';
if (payload.signal.aborted) {
// eslint-disable-next-line prefer-promise-reject-errors
return Promise.reject(error); // 通過reject達到中止請求目的
}
const cancellation = new Promise((_, reject) => {
payload.signal.addEventListener('abort', () => {
// eslint-disable-next-line prefer-promise-reject-errors
reject(error);
});
});
return Promise.race([cancellation, dispatch(payload)]); //Promise.race比較中止和接口請求快慢,誰快返回誰
}
return dispatch(payload);
};
新建一個擴展Component
import React from 'react';
/**
* 用於組件卸載時自動cancel所有註冊的promise
*/
export default class EnhanceComponent extends React.Component {
constructor(props) {
super(props);
this.abortSignalControllers = [];
}
componentWillUnmount() {
this.abortSignalControl(); // 頁面卸載後自動中止所有請求
}
/**
* 註冊control
*/
bindSignalControl = () => {
let registerSignal = '';
if ('AbortController' in window) {
const controller = new AbortController();
const { signal } = controller;
registerSignal = signal;
this.abortSignalControllers.push(controller);
}
return registerSignal;
};
/**
* 取消signal對應的Promise的請求
* @param {*} signal
*/
abortSignalControl(signal) {
if (signal !== undefined) {
const idx = this._findSignalControl(signal);
if (idx !== -1) {
const control = this.abortSignalControllers[idx];
control.abort();
this.abortSignalControllers.splice(idx, 1);
}
} else {
this.abortSignalControllers.forEach(control => {
control.abort();
});
this.abortSignalControllers = [];
}
}
_findSignalControl(signal) {
const idx = this.abortSignalControllers.findIndex(controller => controller.signal === signal);
return idx;
}
}
demo.js
export default class Demo extends EnhanceComponent{
constructor(props) {
super(props);
this.state = {
signal: this.bindSignalControl(),
};
}
search = () => {
this.abortSignalControl(this.state.signal); // 請求前先中止上一次的請求
const payload = {
...其他參數
signal: this.bindSignalControl()
}
this.setState({
signal: payload.signal, // 保存最新的signal
});
abortDispatch(payload, query =>
dispatch({
type: 'xxx',
payload: {...query},
callback: (data, aborted) => {
if (!aborted) {
// !aborted避免頁面卸載後或者中止請求後進行this.setState
}
}
})
}
}
request.js文件中需要將signal放在options中,例如
在errorHandler方法中對Aborted接口進行特殊處理
const errorHandler = error => {
const { response, data, name } = error || {};
const { status, url = '', statusText } = response || {};
// 如果是終止請求,默認返回成功
if (name === 'AbortError') {
return {
code: 0, // 請求成功
aborted: true, // callback頁面是否中止請求成功
};
}
......
return { response, data };
}
const request = extend({
errorHandler,
prefix: '/api',
});
request.interceptors.request.use((url, options) => {
return {
url,
options: {
...options,
signal: options.signal
},
};
})