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vue阻止重復(fù)請求實現(xiàn)示例詳解

 更新時間：2023年01月17日 08:34:49   作者：黃金林  
這篇文章主要為大家介紹了vue阻止重復(fù)請求實現(xiàn)示例詳解，有需要的朋友可以借鑒參考下，希望能夠有所幫助，祝大家多多進(jìn)步，早日升職加薪

背景

項目當(dāng)中前端代碼會遇到同一個請求向服務(wù)器發(fā)了多次的情況,我們要避免服務(wù)器資源浪費,同一個請求一定時間只允許發(fā)一次請求

思路

(1)如果業(yè)務(wù)簡單,例如同一個按鈕防止多次點擊,我們可以用定時器做防抖處理

(2)如果業(yè)務(wù)復(fù)雜,例如多個組件通過代碼,同一個請求發(fā)多次,這個時候防抖已經(jīng)不好處理了,最好是對重復(fù)的ajax請求統(tǒng)一做取消操作

方式1-通過定時器做防抖處理

(a)概述

效果:當(dāng)用戶連續(xù)點擊多次同一個按鈕,最后一次點擊之后,過小段時間后才發(fā)起一次請求
原理:每次調(diào)用方法后都產(chǎn)生一個定時器,定時器結(jié)束以后再發(fā)請求,如果重復(fù)調(diào)用方法,就取消當(dāng)前的定時器,創(chuàng)建新的定時器,等結(jié)束后再發(fā)請求,工作當(dāng)中可以用第三方封裝的工具函數(shù)例如lodash的debounce方法來簡化防抖的代碼

(b)代碼

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://lf26-cdn-tos.bytecdntp.com/cdn/expire-1-M/lodash.js/4.17.21/lodash.min.js" type="application/javascript"></script>
    <script src="https://lf26-cdn-tos.bytecdntp.com/cdn/expire-1-M/vue/2.6.14/vue.min.js" type="application/javascript"></script>
    <script src="https://lf9-cdn-tos.bytecdntp.com/cdn/expire-1-M/axios/0.26.0/axios.min.js" type="application/javascript"></script>
</head>
<body>
    <div id="app">
        <button @click="onClick">請求</button>
    </div>
</body>
<script>
// 定義請求接口
function sendPost(data){
    return axios({
        url: 'https://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test',
        method: 'post',
        data
    })
}
new Vue({
    el: '#app',
    methods: {
        // 調(diào)用lodash的防抖方法debounce,實現(xiàn)連續(xù)點擊按鈕多次,0.3秒后調(diào)用1次接口
        onClick: _.debounce(async function(){
            let res = await sendPost({username:'zs', age: 20})
            console.log('請求的結(jié)果', res.data)
        }, 300),
    },
})
</script>
</html>

(c)預(yù)覽

連接

(d)存在的問題

無法解決多個按鈕件的重復(fù)請求的發(fā)送問題,例如下面兩種情況

情況-在點擊事件上做防抖

按鈕事件間是相互獨立的,調(diào)用的是不同方法,做不到按鈕間防抖效果

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://lf26-cdn-tos.bytecdntp.com/cdn/expire-1-M/lodash.js/4.17.21/lodash.min.js" type="application/javascript"></script>
    <script src="https://lf26-cdn-tos.bytecdntp.com/cdn/expire-1-M/vue/2.6.14/vue.min.js" type="application/javascript"></script>
    <script src="https://lf9-cdn-tos.bytecdntp.com/cdn/expire-1-M/axios/0.26.0/axios.min.js" type="application/javascript"></script>
</head>
<body>
    <div id="app">
        <button @click="onClick1" ref="btn1">請求1</button>
        <button @click="onClick2" ref="btn2">請求2</button>
    </div>
</body>
<script>
let sendPost = function(data){
    return axios({
        url: 'http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test',
        method: 'post',
        data
    })
}
new Vue({
    el: '#app',
    mounted() {
        this.$refs.btn1.click()
        this.$refs.btn2.click()
    },
    methods: {
        // 使用lodash對請求方法做防抖
        //這里有問題,只是對每個按鈕的點擊事件單獨做了防抖,但是兩個按鈕之間做不到防抖的效果
        onClick1: _.debounce(async function(){
            let res = await sendPost({username:'zs', age: 20})
            console.log('請求1的結(jié)果', res.data)
        }, 300),
        onClick2: _.debounce(async function(){
            let res = await sendPost({username:'zs', age: 20})
            console.log('請求2的結(jié)果', res.data)
        }, 300),
    },
})
</script>
</html>

預(yù)覽

情況-在接口方法做防抖

按鈕間調(diào)用的方法是相同的,是可以對方法做防抖處理,但是處理本身對方法做了一次封裝,會影響到之前方法的返回值接收,需要對之前的方法做更多處理,變得更加復(fù)雜,不推薦

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://lf26-cdn-tos.bytecdntp.com/cdn/expire-1-M/lodash.js/4.17.21/lodash.min.js" type="application/javascript"></script>
    <script src="https://lf26-cdn-tos.bytecdntp.com/cdn/expire-1-M/vue/2.6.14/vue.min.js" type="application/javascript"></script>
    <script src="https://lf9-cdn-tos.bytecdntp.com/cdn/expire-1-M/axios/0.26.0/axios.min.js" type="application/javascript"></script>
</head>
<body>
    <div id="app">
        <button @click="onClick1" ref="btn1">請求1</button>
        <button @click="onClick2" ref="btn2">請求2</button>
    </div>
</body>
<script>
// 使用lodash對請求方法做防抖,    
let sendPost = _.debounce(function(data){
    //這里有問題,這里的返回值不能作為sendPost方法執(zhí)行的返回值,因為debounce內(nèi)部包裹了一層
    return axios({
        url: 'http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test',
        method: 'post',
        data
    })
}, 300)
new Vue({
    el: '#app',
    mounted() {
        this.$refs.btn1.click()
        this.$refs.btn2.click()
    },
    methods: {
        onClick1: async function(){
            //這里有問題,sendPost返回值不是promise,而是undefined
            let res = await sendPost({username:'zs', age: 20})
            console.log('請求1的結(jié)果', res)
        },
        onClick2: async function(){
            let res = await sendPost({username:'zs', age: 20})
            console.log('請求2的結(jié)果', res)
        },
    },
})
</script>
</html>

預(yù)覽

方式2-通過取消ajax請求

(a) 概述

直接對請求方法做處理,通過ajax庫的api方法把重復(fù)的請求給取消掉

(b)原理

原生ajax取消請求

通過調(diào)用XMLHttpRequest對象實例的abort方法把請求給取消掉

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
</body>
<script>
//原生ajax的語法    
let xhr = new XMLHttpRequest();
xhr.open("GET", "http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test?username=zs&age=20", true);
xhr.onload = function(){
    console.log(xhr.responseText)
}
xhr.send();
//在谷歌瀏覽器的低速3g下面測試
//通過XMLHttpRequest實例的abort方法取消請求
setTimeout(() => xhr.abort(), 100);
</script>
</html>

預(yù)覽

axios取消請求

通過axios的CancelToken對象實例cancel方法把請求給取消掉

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://lf9-cdn-tos.bytecdntp.com/cdn/expire-1-M/axios/0.26.0/axios.min.js" type="application/javascript"></script>
</head>
<body>
</body>
<script>
/*axios的取消的語法*/
// 方式1-通過axios.CancelToken.source產(chǎn)生cancelToken和cancel方法
/*
const source =  axios.CancelToken.source();
axios.get('http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test', {
    params: {username: 'zs', age: 20}, 
    cancelToken: source.token
}).then(res=>{
    console.log('res', res.data)
}).catch(err=>{
    console.log('err', err)
})
//在谷歌瀏覽器的低速3g下面測試
//通過調(diào)用source的cancel方法取消
setTimeout(() => source.cancel(), 100);
*/
/**/
// 方式2-通過new axios.CancelToken產(chǎn)生cancelToken和cancel方法
let cancelFn 
const cancelToken =  new axios.CancelToken(cancel=>{
    cancelFn = cancel
});
axios.get('http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test', {
    params: {username: 'zs', age: 20}, 
    cancelToken: cancelToken
}).then(res=>{
    console.log('res', res.data)
}).catch(err=>{
    console.log('err', err)
})
//在谷歌瀏覽器的低速3g下面測試
//通過調(diào)用cancelFn方法取消
setTimeout(() => cancelFn(), 100);
</script>
</html>

預(yù)覽

(c)代碼

步驟1-通過axios請求攔截器取消重復(fù)請求

通過axios請求攔截器,在每次請求前把請求信息和請求的取消方法放到一個map對象當(dāng)中,并且判斷map對象當(dāng)中是否已經(jīng)存在該請求信息的請求,如果存在取消上傳請求

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://lf26-cdn-tos.bytecdntp.com/cdn/expire-1-M/vue/2.6.14/vue.min.js" type="application/javascript"></script>
    <script src="https://lf9-cdn-tos.bytecdntp.com/cdn/expire-1-M/axios/0.26.0/axios.min.js" type="application/javascript"></script>
    <script src="https://lf3-cdn-tos.bytecdntp.com/cdn/expire-1-M/qs/6.10.3/qs.js" type="application/javascript"></script>
</head>
<body>
    <div id="app">
        <button @click="onClick1" ref="btn1">請求1</button>
        <button @click="onClick2" ref="btn2">請求2</button>
    </div>
</body>
<script>
//存儲請求信息和取消方法的的map對象    
const pendingRequest = new Map();  
//根據(jù)請求的信息(請求方式,url,請求get/post數(shù)據(jù)),產(chǎn)生map的key
function getRequestKey(config){
    const { method, url, params, data } = config;
    return [method, url, Qs.stringify(params), Qs.stringify(data)].join("&");
}   
//請求攔截器
axios.interceptors.request.use(
    function (config) {
    //根據(jù)請求的信息(請求方式,url,請求get/post數(shù)據(jù)),產(chǎn)生map的key
    let requestKey = getRequestKey(config)
    //判斷請求是否重復(fù)
    if(pendingRequest.has(requestKey)){
        //取消上次請求
        let cancel = pendingRequest.get(requestKey)
        cancel()
        //刪除請求信息
        pendingRequest.delete(requestKey) 
    }
    //把請求信息,添加請求到map當(dāng)中
    // 生成取消方法
    config.cancelToken = config.cancelToken || new axios.CancelToken(cancel => {
        // 把取消方法添加到map
        if (!pendingRequest.has(requestKey)) {
            pendingRequest.set(requestKey, cancel)
        }
    })
    return config;
  },
  (error) => {
     return Promise.reject(error);
  }
);
let sendPost = function(data){
    return axios({
        url: 'http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test',
        method: 'post',
        data
    })
}
new Vue({
    el: '#app',
    mounted() {
        this.$refs.btn1.click()
        this.$refs.btn2.click()
    },
    methods: {
        // 使用lodash對請求方法做防抖
        //這里有問題,只是對每個按鈕的點擊事件單獨做了防抖,但是兩個按鈕之間做不到防抖的效果
        onClick1: async function(){
            let res = await sendPost({username:'zs', age: 20})
            console.log('請求1的結(jié)果', res.data)
        },
        onClick2: async function(){
            let res = await sendPost({username:'zs', age: 20})
            console.log('請求2的結(jié)果', res.data)
        },
    },
})
</script>
</html>

預(yù)覽

步驟2-通過axios響應(yīng)攔截器處理請求成功

通過axios的響應(yīng)攔截器,在請求成功后在map對象當(dāng)中,刪除該請求信息的數(shù)據(jù)

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://lf26-cdn-tos.bytecdntp.com/cdn/expire-1-M/vue/2.6.14/vue.min.js" type="application/javascript"></script>
    <script src="https://lf9-cdn-tos.bytecdntp.com/cdn/expire-1-M/axios/0.26.0/axios.min.js" type="application/javascript"></script>
    <script src="https://lf3-cdn-tos.bytecdntp.com/cdn/expire-1-M/qs/6.10.3/qs.js" type="application/javascript"></script>
</head>
<body>
    <div id="app">
        <button @click="onClick1" ref="btn1">請求1</button>
        <button @click="onClick2" ref="btn2">請求2</button>
    </div>
</body>
<script>
//存儲請求信息和取消方法的的map對象    
const pendingRequest = new Map();  
//根據(jù)請求的信息(請求方式,url,請求get/post數(shù)據(jù)),產(chǎn)生map的key
function getRequestKey(config){
    const { method, url, params, data } = config;
    return [method, url, Qs.stringify(params), Qs.stringify(data)].join("&");
}   
//請求攔截器
axios.interceptors.request.use(
    function (config) {
    //根據(jù)請求的信息(請求方式,url,請求get/post數(shù)據(jù)),產(chǎn)生map的key
    let requestKey = getRequestKey(config)
    //判斷請求是否重復(fù)
    if(pendingRequest.has(requestKey)){
        //取消上次請求
        let cancel = pendingRequest.get(requestKey)
        cancel()
        //刪除請求信息
        pendingRequest.delete(requestKey) 
    }
    //把請求信息,添加請求到map當(dāng)中
    // 生成取消方法
    config.cancelToken = config.cancelToken || new axios.CancelToken(cancel => {
        // 把取消方法添加到map
        if (!pendingRequest.has(requestKey)) {
            pendingRequest.set(requestKey, cancel)
        }
    })
    return config;
  },
  (error) => {
     return Promise.reject(error);
  }
);
//響應(yīng)攔截器
axios.interceptors.response.use(
  (response) => {
        //請求成功
        //刪除請求的信息
        let requestKey = getRequestKey(response.config)
        if(pendingRequest.has(requestKey)){
            pendingRequest.delete(requestKey)   
        }
        return response;
   },
   (error) => {
        return Promise.reject(error);
   }
);
let sendPost = function(data){
    return axios({
        url: 'http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test',
        method: 'post',
        data
    })
}
new Vue({
    el: '#app',
    mounted() {
        this.$refs.btn1.click()
        this.$refs.btn2.click()
    },
    methods: {
        // 使用lodash對請求方法做防抖
        //這里有問題,只是對每個按鈕的點擊事件單獨做了防抖,但是兩個按鈕之間做不到防抖的效果
        onClick1: async function(){
            let res = await sendPost({username:'zs', age: 20})
            console.log('請求1的結(jié)果', res.data)
        },
        onClick2: async function(){
            let res = await sendPost({username:'zs', age: 20})
            console.log('請求2的結(jié)果', res.data)
        },
    },
})
</script>
</html>

預(yù)覽

步驟3-通過axios響應(yīng)攔截器處理請求失敗

通過axios的響應(yīng)攔截器,在請求失敗后在map對象當(dāng)中,刪除該請求信息的數(shù)據(jù)

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://lf26-cdn-tos.bytecdntp.com/cdn/expire-1-M/vue/2.6.14/vue.min.js" type="application/javascript"></script>
    <script src="https://lf9-cdn-tos.bytecdntp.com/cdn/expire-1-M/axios/0.26.0/axios.min.js" type="application/javascript"></script>
    <script src="https://lf3-cdn-tos.bytecdntp.com/cdn/expire-1-M/qs/6.10.3/qs.js" type="application/javascript"></script>
</head>
<body>
    <div id="app">
        <button @click="onClick1" ref="btn1">請求1</button>
        <button @click="onClick2" ref="btn2">請求2</button>
    </div>
</body>
<script>
//存儲請求信息和取消方法的的map對象    
const pendingRequest = new Map();  
//根據(jù)請求的信息(請求方式,url,請求get/post數(shù)據(jù)),產(chǎn)生map的key
function getRequestKey(config){
    const { method, url, params, data } = config;
    return [method, url, Qs.stringify(params), Qs.stringify(data)].join("&");
}   
//請求攔截器
axios.interceptors.request.use(
    function (config) {
    //根據(jù)請求的信息(請求方式,url,請求get/post數(shù)據(jù)),產(chǎn)生map的key
    let requestKey = getRequestKey(config)
    //判斷請求是否重復(fù)
    if(pendingRequest.has(requestKey)){
        //取消上次請求
        let cancel = pendingRequest.get(requestKey)
        cancel()
        //刪除請求信息
        pendingRequest.delete(requestKey) 
    }
    //把請求信息,添加請求到map當(dāng)中
    // 生成取消方法
    config.cancelToken = config.cancelToken || new axios.CancelToken(cancel => {
        // 把取消方法添加到map
        if (!pendingRequest.has(requestKey)) {
            pendingRequest.set(requestKey, cancel)
        }
    })
    return config;
  },
  (error) => {
     return Promise.reject(error);
  }
);
//刪除請求信息
function delPendingRequest(config){
    let requestKey = getRequestKey(config)
    if(pendingRequest.has(requestKey)){
        pendingRequest.delete(requestKey)   
    } 
}
//響應(yīng)攔截器
axios.interceptors.response.use(
  (response) => {
        //請求成功
        //刪除請求的信息
        delPendingRequest(response.config)
        return response;
   },
   (error) => {
        //請求失敗
        //不是取消請求的錯誤
        if (!axios.isCancel(error)){
            //服務(wù)器報400,500報錯,刪除請求信息
            delPendingRequest(error.config || {})
        } 
        return Promise.reject(error);
   }
);
let sendPost = function(data){
    return axios({
        url: 'http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test',
        method: 'post',
        data
    })
}
new Vue({
    el: '#app',
    mounted() {
        this.$refs.btn1.click()
        this.$refs.btn2.click()
    },
    methods: {
        // 使用lodash對請求方法做防抖
        //這里有問題,只是對每個按鈕的點擊事件單獨做了防抖,但是兩個按鈕之間做不到防抖的效果
        onClick1: async function(){
            let res = await sendPost({username:'zs', age: 20})
            console.log('請求1的結(jié)果', res.data)
        },
        onClick2: async function(){
            let res = await sendPost({username:'zs', age: 20})
            console.log('請求2的結(jié)果', res.data)
        },
    },
})
</script>
</html>

預(yù)覽

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