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How to implement react backend request data

藏色散人
藏色散人Original
2022-12-29 13:48:303103browse

React backend request data implementation method: 1. Configure ""proxy":"http://localhost:5000"" in package.json; 2. Create "setupProxy.js" in the src directory " file; 3. Call the function configured in "setupProxy.js", the code is such as "createProxyMiddleware('/api2',{target:...}".

How to implement react backend request data

The operating environment of this tutorial: Windows 10 system, react version 18.0.0, Dell G3 computer.

How to request data from the react backend?

react -ajax request background data method

##react-ajax

axios

Method 1: Configure
 "proxy":"http://localhost:5000"

    in package.json so that localhost:5000 is the server we want to proxy to
  getStudentData = () => {
    axios.get('/students').then(
      (result) => { console.log(result.data); },
      (reason) => { console.log(reason); })
  }
    Get the data of /students in
  • localhost:5000
**Advantages: **Simple configuration, front-end request resources are not required Any prefix required

**Disadvantage: **Cannot configure multiple proxy servers

Method 2: Create the setupProxy.js file in the src directory

  • Step one: webpack is configured to call the function configured in setupProxy.js

  • setupProxy.js

  • Step 2: Configuration

//const proxy=require("http-proxy-middleware")   :视频中请求的包,引用它出现了无法访问的问题//应该使用以下写法*******const { createProxyMiddleware } = require("http-proxy-middleware");module.exports=function(app){
    app.use(
        createProxyMiddleware('/api1',{//遇见/api1前缀的请求,就会触发该代理配置
            target:"http://localhost:5000",//请求转发给谁
            changeOrigin:true,//控制服务器收到的请求头中Host字段的值:host就是主机名+端口号
            	//true:后端接收到的host:localhost:5000
            	//false:后端接收到的host:localhost:3000
            	//系统默认为false,一般会设为true
            pathRewrite:{"^/api1":""}//重写请求路径(必须要写)
            //不写:后台接收到的请求路径:/api1/student
            //写了:后台请求的路径:/student
        }),
        createProxyMiddleware('/api2',{
            target:"http://localhost:5001",
            changeOrigin:true,
            pathRewrite:{"^/api2":""}
        }),
    )}
  • Solution link: https://www.csdn.net/tags/OtTaIg0sNzE3OC1ibG9n.html

  • Cross-domain request real interface case

    • App.jsx

    import React, { Component } from 'react'
    import Search from './components/Search'
    import List from './components/List'
    import './App.css'
    
    export default class App extends Component {
    state={users:[]}
    getSearchResult=(result)=>{
      this.setState({users:result})
    }
    
      render() {
        return (
          <div>
            <search></search>
            <list></list>
          </div>
        )
      }
    }
  • Search.jsx

  • import React, { Component } from 'react'
    import axios from 'axios'
    import './index.css'
    
    export default class Search extends Component {
    
      search = () => {
        //获取输入框中的值
        const { value } = this.keyWordElement;
        //发送请求
        axios.get(`/api1/search/users?q=${value}`).then(
          result => {
            this.props.getSearchResult(result.data.items)
          },
          reason => {
            console.log(reason);
          })
      }
    
    
    
      render() {
        return (
          <section>
            <h3>搜索github用户</h3>
            <div>
              <input> this.keyWordElement = c} type="text" placeholder="enter the name you search" /> <button>搜索</button>
            </div>
          </section>
        )
      }
    }
  • List.jsx

  • import React, { Component } from 'react'
    
    import './index.css'
    export default class List extends Component {
      render() {
        return (
          <div>
            {this.props.users.map(item=>{
                return    <div>
                    <a>
                      <img  alt="How to implement react backend request data" >
                    </a>
                    <p>{item.login}</p>
                  </div>
            })}
      
           
          </div>  
        )
      }
    }

    react-Communication between any components

    Message subscription and publishing mechanism

    PubSubJs:

    ##pub:( publish) publish
    • sub:(subscribe) subscribe
    pubsub-js

    : It is used to implement publish and subscribe. You can see it in vue. eventBus, regarded as the carrier of the function

      Subscriber: Create a function and pass this function to pubsub for hosting
    • var token=PubSub.subscribe("myTopic",myFunction[托管的函数])//token,是当前订阅函数的唯一id,可以用来取消订阅
    • Publisher: Publishing means to realize the function of passing parameters or performing operations by calling the function specified by the subscriber
    • PubSub.publish('myTopic','需要发送给订阅者的内容')
    Step 1

    : Add pubsub-js

    yarn add pubsub-js
    • **Step 2:**In Import

    import PubSub from 'pubsub-js'
    • into the component **Step 3: **Call the PubSub subscription function (usually subscribed in the componentDidMount hook function)

      componentDidMount(){
        this.token=PubSub.subscribe("changeState",this.changeStateObj)
      }

    demo

    List.jsx
    import React, { Component } from 'react'
    import PubSub from 'pubsub-js'
    import './index.css'
    export default class List extends Component {
      state={
        users:[],//拿到的用户信息
        isFirst:true,//是否第一次访问
        isLoading:false,//是否正在加载
        err:"",//返回的错误信息
      
      }
    
      changeStateObj=(msg,value)=>{
        this.setState(value)
      }
    
      componentDidMount(){
        this.token=PubSub.subscribe("changeState",this.changeStateObj)
      }
      componentWillUnmount(){
        PubSub.unsubscribe(this.token)
      }
     
      render() {
        let {users,isFirst,isLoading,err}=this.state
        return (
            
        )
      }
    }

    Search. jsx
    import React, { Component } from 'react'
    import axios from 'axios'
    import './index.css'
    import PubSub from 'pubsub-js'
    
    export default class Search extends Component {
      
    
      search = () => {
        //获取输入框中的值
        const { value } = this.keyWordElement;
        PubSub.publish('changeState',{isFirst:false,isLoading:true})
        //发送请求
        axios.get(`/api1/search/users2?q=${value}`).then(
          result => {
            PubSub.publish('changeState',{isLoading:false,users:result.data.items})
    
          },
          reason => {
            PubSub.publish('changeState',{isLoading:false,err:reason.message})
    
          })
      }
    
    
    
      render() {
        return (
          <section>
            <h3>搜索github用户</h3>
            <div>
              <input> this.keyWordElement = c} type="text" placeholder="enter the name you search" /> <button>搜索</button>
            </div>
          </section>
        )
      }
    }

    App.jsx
    import React, { Component } from 'react'
    import Search from './components/Search'
    import List from './components/List'
    import './App.css'
    
    export default class App extends Component {
    
    
    
      render() {
        return (
          <div>
            <search></search>
            <list></list>
          </div>
        )
      }
    }

    What are the ways to send ajax requests?

    xhr:xmlHttpRequest: traditional ajax
    • jQuery: encapsulated xhr
      • axios: encapsulated xhr
      **fetch (fetch)?* Built-in in window, no need to borrow third-party libraries, use it directly
    • Disadvantages: It is not very useful at the moment, there is no request sending interceptor

    xhr

    How to implement react backend request data

    fetch

      Disadvantages
    • : Low compatibility
    • Advantages
    • : No need to use xhr, no need to install third-party libraries, native

    How to implement react backend request data

    ##The best way to write fetch

    let getData=async()=>{	
    	try{
            let result=await fetch(url);
            let data=await result.json();
        }catch(error){
            console.log('请求错误',error)
        }
    }
    recommends learning: "react video tutorial"

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