一文聊聊vue怎麼阻止重複請求-Vue.js-PHP中文網

vue怎麼阻止重複請求？以下這篇文章跟大家介紹vue阻止重複請求的兩種方式，希望對大家有幫助！

一文聊聊vue怎麼阻止重複請求

專案當中前端程式碼會遇到同一個請求向伺服器發了多次的情況,我們要避免伺服器資源浪費,同一個請求一定時間只允許發一次請求

思路

(1)如果業務簡單,例如同一個按鈕防止多次點擊,我們可以用定時器做防手震處理
(2 )如果業務複雜,例如多個組件通過代碼,同一個請求發多次,這個時候防抖已經不好處理了,最好是對重複的ajax請求統一做取消操作

實作

方式1-透過計時器做防手震處理

(a)概述

效果:當使用者連續點擊多次同一個按鈕,最後一次點擊之後,過小段時間後才發起一次請求
原理:每次呼叫方法後都產生一個定時器,定時器結束以後再發請求,如果重複調用方法,就取消當前的定時器,創建新的定時器,等結束後再發請求,工作當中可以用第三方封裝的工具函數例如lodash的debounce方法來簡化防手震的程式碼【相關推薦：vuejs影片教學、web前端開發】

(b)程式碼

<!DOCTYPE html>
<html>
<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">请求</button>
    </div>
</body>
<script>
// 定义请求接口
function sendPost(data){
    return axios({
        url: &#39;https://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test&#39;,
        method: &#39;post&#39;,
        data
    })
}
new Vue({
    el: &#39;#app&#39;,
    methods: {
        // 调用lodash的防抖方法debounce,实现连续点击按钮多次,0.3秒后调用1次接口
        onClick: _.debounce(async function(){
            let res = await sendPost({username:&#39;zs&#39;, age: 20})
            console.log(&#39;请求的结果&#39;, res.data)
        }, 300),
    },
})
</script>
</html>

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(c)預覽

#連接

(d)存在的問題

無法解決多個按鈕件的重複請求的發送問題,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,調用的是不同方法,做不到按鈕間防抖效果

<!DOCTYPE html>
<html>
<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">请求1</button>
        <button @click="onClick2" ref="btn2">请求2</button>
    </div>
</body>
<script>
  
let sendPost = function(data){
    return axios({
        url: &#39;http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test&#39;,
        method: &#39;post&#39;,
        data
    })
}
new Vue({
    el: &#39;#app&#39;,
    mounted() {
        this.$refs.btn1.click()
        this.$refs.btn2.click()
    },
    methods: {
        // 使用lodash对请求方法做防抖
        //这里有问题,只是对每个按钮的点击事件单独做了防抖,但是两个按钮之间做不到防抖的效果
        onClick1: _.debounce(async function(){
            let res = await sendPost({username:&#39;zs&#39;, age: 20})
            console.log(&#39;请求1的结果&#39;, res.data)
        }, 300),
        onClick2: _.debounce(async function(){
            let res = await sendPost({username:&#39;zs&#39;, age: 20})
            console.log(&#39;请求2的结果&#39;, res.data)
        }, 300),
    },
})
</script>
</html>

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預覽

情況2-在介面方法做防手震

#按鈕間呼叫的方法是相同的,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,變得更加複雜,不推薦

<!DOCTYPE html>
<html>
<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">请求1</button>
        <button @click="onClick2" ref="btn2">请求2</button>
    </div>
</body>
<script>
// 使用lodash对请求方法做防抖,    
let sendPost = _.debounce(function(data){
    //这里有问题,这里的返回值不能作为sendPost方法执行的返回值,因为debounce内部包裹了一层
    return axios({
        url: &#39;http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test&#39;,
        method: &#39;post&#39;,
        data
    })
}, 300)
new Vue({
    el: &#39;#app&#39;,
    mounted() {
        this.$refs.btn1.click()
        this.$refs.btn2.click()
    },
    methods: {
        onClick1: async function(){
            //这里有问题,sendPost返回值不是promise,而是undefined
            let res = await sendPost({username:&#39;zs&#39;, age: 20})
            console.log(&#39;请求1的结果&#39;, res)
        },
        onClick2: async function(){
            let res = await sendPost({username:&#39;zs&#39;, age: 20})
            console.log(&#39;请求2的结果&#39;, res)
        },
    },
})
</script>
</html>

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#預覽

#方式2-透過取消ajax請求

(a) 概述

直接對請求方法做處理,透過ajax函式庫的api方法把重複的請求給取消掉

(b)原理

原生ajax取消請求

透過呼叫XMLHttpRequest物件實例的abort方法把請求給取消掉

<!DOCTYPE html>
<html>
<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的语法    
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();
//在谷歌浏览器的低速3g下面测试
//通过XMLHttpRequest实例的abort方法取消请求
setTimeout(() => xhr.abort(), 100);
</script>
</html>

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axios取消請求

透過axios的CancelToken物件實例cancel

方法把請求給取消掉

<!DOCTYPE html>
<html>
<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的取消的语法*/
// 方式1-通过axios.CancelToken.source产生cancelToken和cancel方法
/*
const source =  axios.CancelToken.source();
axios.get(&#39;http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test&#39;, {
    params: {username: &#39;zs&#39;, age: 20}, 
    cancelToken: source.token
}).then(res=>{
    console.log(&#39;res&#39;, res.data)
}).catch(err=>{
    console.log(&#39;err&#39;, err)
})
//在谷歌浏览器的低速3g下面测试
//通过调用source的cancel方法取消
setTimeout(() => source.cancel(), 100);
*/

/**/
// 方式2-通过new axios.CancelToken产生cancelToken和cancel方法
let cancelFn 
const cancelToken =  new axios.CancelToken(cancel=>{
    cancelFn = cancel
});
axios.get(&#39;http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test&#39;, {
    params: {username: &#39;zs&#39;, age: 20}, 
    cancelToken: cancelToken
}).then(res=>{
    console.log(&#39;res&#39;, res.data)
}).catch(err=>{
    console.log(&#39;err&#39;, err)
})
//在谷歌浏览器的低速3g下面测试
//通过调用cancelFn方法取消
setTimeout(() => cancelFn(), 100);

</script>
</html>

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預覽

(c)代碼

#步驟1-透過axios請求攔截器取消重複請求

#透過axios

請求攔截器,在每次請求前把請求資訊和請求的取消方法放到一個map對象當中,並且判斷map對象當中是否已經存在該請求信息的請求,如果存在取消上傳請求

<!DOCTYPE html>
<html>
<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">请求1</button>
        <button @click="onClick2" ref="btn2">请求2</button>
    </div>
</body>
<script>
//存储请求信息和取消方法的的map对象    
const pendingRequest = new Map();  
//根据请求的信息(请求方式,url,请求get/post数据),产生map的key
function getRequestKey(config){
    const { method, url, params, data } = config;
    return [method, url, Qs.stringify(params), Qs.stringify(data)].join("&");
}   
//请求拦截器
axios.interceptors.request.use(
    function (config) {
    //根据请求的信息(请求方式,url,请求get/post数据),产生map的key
    let requestKey = getRequestKey(config)
    //判断请求是否重复
    if(pendingRequest.has(requestKey)){
        //取消上次请求
        let cancel = pendingRequest.get(requestKey)
        cancel()
        //删除请求信息
        pendingRequest.delete(requestKey) 
    }
    //把请求信息,添加请求到map当中
    // 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: &#39;http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test&#39;,
        method: &#39;post&#39;,
        data
    })
}
new Vue({
    el: &#39;#app&#39;,
    mounted() {
        this.$refs.btn1.click()
        this.$refs.btn2.click()
    },
    methods: {
        // 使用lodash对请求方法做防抖
        //这里有问题,只是对每个按钮的点击事件单独做了防抖,但是两个按钮之间做不到防抖的效果
        onClick1: async function(){
            let res = await sendPost({username:&#39;zs&#39;, age: 20})
            console.log(&#39;请求1的结果&#39;, res.data)
        },
        onClick2: async function(){
            let res = await sendPost({username:&#39;zs&#39;, age: 20})
            console.log(&#39;请求2的结果&#39;, res.data)
        },
    },
})
</script>
</html>

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預覽

步驟2-透過axios回應攔截器處理請求成功

透過axios

的回應攔截器,在請求成功後在map物件當中,刪除該請求資訊的資料

<!DOCTYPE html>
<html>
<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">请求1</button>
        <button @click="onClick2" ref="btn2">请求2</button>
    </div>
</body>
<script>
//存储请求信息和取消方法的的map对象    
const pendingRequest = new Map();  
//根据请求的信息(请求方式,url,请求get/post数据),产生map的key
function getRequestKey(config){
    const { method, url, params, data } = config;
    return [method, url, Qs.stringify(params), Qs.stringify(data)].join("&");
}   
//请求拦截器
axios.interceptors.request.use(
    function (config) {
    //根据请求的信息(请求方式,url,请求get/post数据),产生map的key
    let requestKey = getRequestKey(config)
    //判断请求是否重复
    if(pendingRequest.has(requestKey)){
        //取消上次请求
        let cancel = pendingRequest.get(requestKey)
        cancel()
        //删除请求信息
        pendingRequest.delete(requestKey) 
    }
    //把请求信息,添加请求到map当中
    // 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);
  }
);

//响应拦截器
axios.interceptors.response.use(
  (response) => {
        //请求成功
        //删除请求的信息
        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: &#39;http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test&#39;,
        method: &#39;post&#39;,
        data
    })
}
new Vue({
    el: &#39;#app&#39;,
    mounted() {
        this.$refs.btn1.click()
        this.$refs.btn2.click()
    },
    methods: {
        // 使用lodash对请求方法做防抖
        //这里有问题,只是对每个按钮的点击事件单独做了防抖,但是两个按钮之间做不到防抖的效果
        onClick1: async function(){
            let res = await sendPost({username:&#39;zs&#39;, age: 20})
            console.log(&#39;请求1的结果&#39;, res.data)
        },
        onClick2: async function(){
            let res = await sendPost({username:&#39;zs&#39;, age: 20})
            console.log(&#39;请求2的结果&#39;, res.data)
        },
    },
})
</script>
</html>

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#預覽

####

步骤3-通过axios响应拦截器处理请求失败

通过axios的响应拦截器,在请求失败后在map对象当中,删除该请求信息的数据

<!DOCTYPE html>
<html>
<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">请求1</button>
        <button @click="onClick2" ref="btn2">请求2</button>
    </div>
</body>
<script>
//存储请求信息和取消方法的的map对象    
const pendingRequest = new Map();  
//根据请求的信息(请求方式,url,请求get/post数据),产生map的key
function getRequestKey(config){
    const { method, url, params, data } = config;
    return [method, url, Qs.stringify(params), Qs.stringify(data)].join("&");
}   
//请求拦截器
axios.interceptors.request.use(
    function (config) {
    //根据请求的信息(请求方式,url,请求get/post数据),产生map的key
    let requestKey = getRequestKey(config)
    //判断请求是否重复
    if(pendingRequest.has(requestKey)){
        //取消上次请求
        let cancel = pendingRequest.get(requestKey)
        cancel()
        //删除请求信息
        pendingRequest.delete(requestKey) 
    }
    //把请求信息,添加请求到map当中
    // 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);
  }
);
//删除请求信息
function delPendingRequest(config){
    let requestKey = getRequestKey(config)
    if(pendingRequest.has(requestKey)){
        pendingRequest.delete(requestKey)   
    } 
}
//响应拦截器
axios.interceptors.response.use(
  (response) => {
        //请求成功
        //删除请求的信息
        delPendingRequest(response.config)
        return response;
   },
   (error) => {
        //请求失败
        //不是取消请求的错误
        if (!axios.isCancel(error)){
            //服务器报400,500报错,删除请求信息
            delPendingRequest(error.config || {})
        } 
        return Promise.reject(error);
   }
);
let sendPost = function(data){
    return axios({
        url: &#39;http://nodejs-cloud-studio-demo-bkzxs.nodejs-cloud-studio-demo.50185620.cn-hangzhou.fc.devsapp.net/test&#39;,
        method: &#39;post&#39;,
        data
    })
}
new Vue({
    el: &#39;#app&#39;,
    mounted() {
        this.$refs.btn1.click()
        this.$refs.btn2.click()
    },
    methods: {
        // 使用lodash对请求方法做防抖
        //这里有问题,只是对每个按钮的点击事件单独做了防抖,但是两个按钮之间做不到防抖的效果
        onClick1: async function(){
            let res = await sendPost({username:&#39;zs&#39;, age: 20})
            console.log(&#39;请求1的结果&#39;, res.data)
        },
        onClick2: async function(){
            let res = await sendPost({username:&#39;zs&#39;, age: 20})
            console.log(&#39;请求2的结果&#39;, res.data)
        },
    },
})
</script>
</html>

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