vue阻止重复请求实现示例详解
目录
- 背景
- 思路
- 方式1-通过定时器做防抖处理
- (a)概述
- (b)代码
- (c)预览
- (d)存在的问题
- 情况-在点击事件上做防抖
- 情况-在接口方法做防抖
- 方式2-通过取消ajax请求
- (a) 概述
- (b)原理
- 原生ajax取消请求
- axios取消请求
- (c)代码
- 步骤1-通过axios请求拦截器取消重复请求
- 步骤2-通过axios响应拦截器处理请求成功
- 步骤3-通过axios响应拦截器处理请求失败
背景
项目当中前端代码会遇到同一个请求向服务器发了多次的情况,我们要避免服务器资源浪费,同一个请求一定时间只允许发一次请求
思路
(1)如果业务简单,例如同一个按钮防止多次点击,我们可以用定时器做防抖处理
(2)如果业务复杂,例如多个组件通过代码,同一个请求发多次,这个时候防抖已经不好处理了,最好是对重复的ajax请求统一做取消操作
方式1-通过定时器做防抖处理
(a)概述
效果:当用户连续点击多次同一个按钮,最后一次点击之后,过小段时间后才发起一次请求
原理:每次调用方法后都产生一个定时器,定时器结束以后再发请求,如果重复调用方法,就取消当前的定时器,创建新的定时器,等结束后再发请求,工作当中可以用第三方封装的工具函数例如lodash的debounce方法来简化防抖的代码
(b)代码
!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">
请求/button>
/div>
/body>
script>
// 定义请求接口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: {
// 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:'zs', age: 20}
) console.LOG('请求的结果', res.data) }
, 300), }
,}
)/script>
/html>
(c)预览
连接
(d)存在的问题
无法解决多个按钮件的重复请求的发送问题,例如下面两种情况
情况-在点击事件上做防抖
按钮事件间是相互独立的,调用的是不同方法,做不到按钮间防抖效果
!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">
请求1/button>
button @click="onClick2" ref="btn2">
请求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:'zs', age: 20}
) console.log('请求1的结果', res.data) }
, 300), onClick2: _.debounce(async function(){
let res = await sendPost({
username:'zs', age: 20}
) console.log('请求2的结果', res.data) }
, 300), }
,}
)/script>
/html>
预览
情况-在接口方法做防抖
按钮间调用的方法是相同的,是可以对方法做防抖处理,但是处理本身对方法做了一次封装,会影响到之前方法的返回值接收,需要对之前的方法做更多处理,变得更加复杂,不推荐
!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">
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: '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(){
//这里有问题,sendPost返回值不是promise,而是undefined let res = await sendPost({
username:'zs', age: 20}
) console.log('请求1的结果', res) }
, onClick2: async function(){
let res = await sendPost({
username:'zs', age: 20}
) console.log('请求2的结果', res) }
, }
,}
)/script>
/html>
预览
方式2-通过取消ajax请求
(a) 概述
直接对请求方法做处理,通过ajax库的api方法把重复的请求给取消掉
(b)原理
原生ajax取消请求
通过调用XMLHttPRequest对象实例的abort方法把请求给取消掉
!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>
预览
axios取消请求
通过axios的CancelToken对象实例cancel方法把请求给取消掉
!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的取消的语法*/// 方式1-通过axios.CancelToken.source产生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('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>
预览
(c)代码
步骤1-通过axios请求拦截器取消重复请求
通过axios请求拦截器,在每次请求前把请求信息和请求的取消方法放到一个map对象当中,并且判断map对象当中是否已经存在该请求信息的请求,如果存在取消上传请求
!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">
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keyfunction 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: '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:'zs', age: 20}
) console.log('请求1的结果', res.data) }
, onClick2: async function(){
let res = await sendPost({
username:'zs', age: 20}
) console.log('请求2的结果', res.data) }
, }
,}
)/script>
/html>
预览
步骤2-通过axios响应拦截器处理请求成功
通过axios的响应拦截器,在请求成功后在map对象当中,删除该请求信息的数据
!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">
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keyfunction 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: '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:'zs', age: 20}
) console.log('请求1的结果', res.data) }
, onClick2: async function(){
let res = await sendPost({
username:'zs', age: 20}
) console.log('请求2的结果', res.data) }
, }
,}
)/script>
/html>
预览
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 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">
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keyfunction 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: '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:'zs', age: 20}
) console.log('请求1的结果', res.data) }
, onClick2: async function(){
let res = await sendPost({
username:'zs', age: 20}
) console.log('请求2的结果', res.data) }
, }
,}
)/script>
/html>
预览
以上就是vue阻止重复请求实现示例详解的详细内容,更多关于vue阻止重复请求的资料请关注其它相关文章!
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