[尚硅谷React笔记]——第4章 React ajax

目录：

1. 脚手架配置代理_方法一
   1. server1.js
   2. 开启服务器server1:
   3. App.js
   4. 解决跨域问题：
2. 脚手架配置代理_方法二
   1. ​​​​​​​server2.js
   2. 开启服务器server2
   3. 第一步：创建代理配置文件
   4. 编写setupProxy.js配置具体代理规则：
   5. App.js
   6. 运行结果：
   7. 说明：
3. github用户搜索案例
   1. github搜索案例_静态组件
   2. github搜索案例_axios发送请求
   3. github搜索案例_展示数据
   4. github搜索案例_完成案例
4. 消息订阅与发布_pubsub
5. fetch发送请求

1.脚手架配置代理_方法一

server1.js

const express = require('express')
const app = express()app.use((request,response,next)=>{console.log('有人请求服务器1了');console.log('请求来自于',request.get('Host'));console.log('请求的地址',request.url);next()
})app.get('/students',(request,response)=>{const students = [{id:'001',name:'tom',age:18},{id:'002',name:'jerry',age:19},{id:'003',name:'tony',age:120},]response.send(students)
})app.listen(5000,(err)=>{if(!err) console.log('服务器1启动成功了,请求学生信息地址为：http://localhost:5000/students');
})

开启服务器server1:

App.js

import React, {Component} from 'react';
import axios from "axios";class App extends Component {getStudentData = () => {axios.get('http://localhost:5000/students').then(response => {console.log('成功了', response.data);},error => {console.log('失败了', error);})}render() {return (<div><button onClick={this.getStudentData}>点我获取学生数据</button></div>);}
}export default App;

解决跨域问题：

package.json

{"name": "20231003","version": "0.1.0","private": true,"dependencies": {"@testing-library/jest-dom": "^5.17.0","@testing-library/react": "^13.4.0","@testing-library/user-event": "^13.5.0","axios": "^1.5.1","nanoid": "^5.0.1","prop-types": "^15.8.1","react": "^18.2.0","react-dom": "^18.2.0","react-scripts": "5.0.1","web-vitals": "^2.1.4"},"scripts": {"start": "react-scripts start","build": "react-scripts build","test": "react-scripts test","eject": "react-scripts eject"},"eslintConfig": {"extends": ["react-app","react-app/jest"]},"browserslist": {"production": [">0.2%","not dead","not op_mini all"],"development": ["last 1 chrome version","last 1 firefox version","last 1 safari version"],"proxy": "http://localhost:5000"}
}

使用方法一遇到了bug,去stackoverflow解决一下，能解决，但是有更好的方法，方法一不在继续了.node.js - Invalid options object. Dev Server has been initialized using an options object that does not match the API schema - Stack Overflow

2.脚手架配置代理_方法二

server2.js

const express = require('express')
const app = express()app.use((request,response,next)=>{console.log('有人请求服务器2了');next()
})app.get('/cars',(request,response)=>{const cars = [{id:'001',name:'奔驰',price:199},{id:'002',name:'马自达',price:109},{id:'003',name:'捷达',price:120},]response.send(cars)
})app.listen(5001,(err)=>{if(!err) console.log('服务器2启动成功了,请求汽车信息地址为：http://localhost:5001/cars');
})

开启服务器server2

访问端口：

第一步：创建代理配置文件

在src下创建配置文件：src/setupProxy.js

编写setupProxy.js配置具体代理规则：

这个适合低版本

const proxy = require('http-proxy-middleware')

module.exports = function(app) {
  app.use(
    proxy('/api1', {  //api1是需要转发的请求(所有带有/api1前缀的请求都会转发给5000)
      target: 'http://localhost:5000', //配置转发目标地址(能返回数据的服务器地址)
      changeOrigin: true, //控制服务器接收到的请求头中host字段的值
      /*
          changeOrigin设置为true时，服务器收到的请求头中的host为：localhost:5000
          changeOrigin设置为false时，服务器收到的请求头中的host为：localhost:3000
          changeOrigin默认值为false，但我们一般将changeOrigin值设为true
      */
      pathRewrite: {'^/api1': ''} //去除请求前缀，保证交给后台服务器的是正常请求地址(必须配置)
    }),
    proxy('/api2', { 
      target: 'http://localhost:5001',
      changeOrigin: true,
      pathRewrite: {'^/api2': ''}
    })
  )
}

我使用的node是：v18.18.0 

//react 18版本写法
const {createProxyMiddleware} = require('http-proxy-middleware')module.exports = function (app) {app.use(createProxyMiddleware('/api1', {target: 'http://localhost:5000',changeOrigin: true,pathRewrite: {'^/api1': ''}}),createProxyMiddleware('/api2', {target: 'http://localhost:5001',changeOrigin: true,pathRewrite: {'^/api2': ''}}),)
}

App.js 

import React, {Component} from 'react';
import axios from "axios";class App extends Component {getStudentData = () => {axios.get('http://localhost:3000/api1/students').then(response => {console.log('成功了', response.data);},error => {console.log('失败了', error);})}getCarData = () => {axios.get('http://localhost:3000/api2/cars').then(response => {console.log('成功了', response.data);},error => {console.log('失败了', error);})}render() {return (<div><button onClick={this.getStudentData}>点我获取学生数据</button><button onClick={this.getCarData}>点我获取汽车数据</button></div>);}
}export default App;

运行结果：

说明：

1. 优点：可以配置多个代理，可以灵活的控制请求是否走代理。

2. 缺点：配置繁琐，前端请求资源时必须加前缀。

3.github用户搜索案例

github搜索案例_静态组件

App.js

import React, {Component} from 'react';
import Search from './components/Search/Search'
import List from "./components/List/List";class App extends Component {render() {return (<div><div className="container"><Search></Search><List></List></div></div>);}
}export default App;

index.js

import React from 'react';
import ReactDOM from 'react-dom/client';
import App from './App';const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(<App/>);

 List.jsx

import React, {Component} from 'react';
import './List.css'class List extends Component {render() {return (<div><div className="row"><div className="card"><a rel="noreferrer" href="https://github.com/reactjs" target="_blank"><img alt="head_protrait" src="https://avatars.githubusercontent.com/u/6412038?v=3" style={{width:'100px'}}/></a><p className="card-text">reactjs</p></div></div></div>);}
}export default List;

 List.css

.album {min-height: 50rem; /* Can be removed; just added for demo purposes */padding-top: 3rem;padding-bottom: 3rem;background-color: #f7f7f7;
}.card {float: left;width: 33.333%;padding: .75rem;margin-bottom: 2rem;border: 1px solid #efefef;text-align: center;
}.card > img {margin-bottom: .75rem;border-radius: 100px;
}.card-text {font-size: 85%;
}

Search.jsx

import React, {Component} from 'react';class Search extends Component {render() {return (<div><section className="jumbotron"><h3 className="jumbotron-heading">Search Github Users</h3><div><input type="text" placeholder="enter the name you search"/>&nbsp;<button>Search</button></div></section></div>);}
}export default Search;

运行结果：

 

github搜索案例_axios发送请求

demo.html

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<script type="text/javascript">let obj = {a: {b: {c: 1}}}let obj2 = {a: {b: 1}}console.log(obj.a.b.c)const {a: {b: {c}}} = objconsole.log(c)const {a: {b: data}} = obj2console.log(data)
</script>
</body>
</html>

server.js

const express = require("express")
const axios = require("axios")
const app = express()/*请求地址： http://localhost:3000/search/users?q=aa后台路由key： /search/usersvalue： function () {}
*/
app.get("/search/users", function (req, res) {const {q} = req.queryaxios({url: 'https://api.github.com/search/users',params: {q}}).then(response => {res.json(response.data)})
})app.get("/search/users2", function (req, res) {res.json({items: [{login: "yyx990803",html_url: "https://github.com/yyx990803",avatar_url:"https://avatars3.githubusercontent.com/u/499550?s=460&u=de41ec9325e8a92e281b96a1514a0fd1cd81ad4a&v=4",id: 1,},{login: "ruanyf",html_url: "https://github.com/ruanyf",avatar_url: "https://avatars2.githubusercontent.com/u/905434?s=460&v=4",id: 2,},{login: "yyx9908032",html_url: "https://github.com/yyx990803",avatar_url:"https://avatars3.githubusercontent.com/u/499550?s=460&u=de41ec9325e8a92e281b96a1514a0fd1cd81ad4a&v=4",id: 3,},{login: "ruanyf2",html_url: "https://github.com/ruanyf",avatar_url: "https://avatars2.githubusercontent.com/u/905434?s=460&v=4",id: 4,},{login: "yyx9908033",html_url: "https://github.com/yyx990803",avatar_url:"https://avatars3.githubusercontent.com/u/499550?s=460&u=de41ec9325e8a92e281b96a1514a0fd1cd81ad4a&v=4",id: 5,},{login: "ruanyf3",html_url: "https://github.com/ruanyf",avatar_url: "https://avatars2.githubusercontent.com/u/905434?s=460&v=4",id: 6,},{login: "yyx9908034",html_url: "https://github.com/yyx990803",avatar_url:"https://avatars3.githubusercontent.com/u/499550?s=460&u=de41ec9325e8a92e281b96a1514a0fd1cd81ad4a&v=4",id: 7,},{login: "ruanyf4",html_url: "https://github.com/ruanyf",avatar_url: "https://avatars2.githubusercontent.com/u/905434?s=460&v=4",id: 8,},{login: "yyx9908035",html_url: "https://github.com/yyx990803",avatar_url:"https://avatars3.githubusercontent.com/u/499550?s=460&u=de41ec9325e8a92e281b96a1514a0fd1cd81ad4a&v=4",id: 9,},],});
});app.listen(5000, "localhost", (err) => {if (!err){console.log("服务器启动成功")console.log("请求github真实数据请访问：http://localhost:5000/search/users")console.log("请求本地模拟数据请访问：http://localhost:5000/search/users2")} else console.log(err);
})

启动服务器：

node .\server.js

 App.js

import React, {Component} from 'react';
import Search from './components/Search/Search'
import List from "./components/List/List";class App extends Component {render() {return (<div><div className="container"><Search></Search><List></List></div></div>);}
}export default App;

index.js

import React from 'react';
import ReactDOM from 'react-dom/client';
import App from './App';const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(<App/>);

List.jsx

import React, {Component} from 'react';
import './List.css'class List extends Component {render() {return (<div><div className="row"><div className="card"><a rel="noreferrer" href="https://github.com/reactjs" target="_blank"><img alt="head_protrait" src="https://avatars.githubusercontent.com/u/6412038?v=3" style={{width:'100px'}}/></a><p className="card-text">reactjs</p></div></div></div>);}
}export default List;

List.css

.album {min-height: 50rem; /* Can be removed; just added for demo purposes */padding-top: 3rem;padding-bottom: 3rem;background-color: #f7f7f7;
}.card {float: left;width: 33.333%;padding: .75rem;margin-bottom: 2rem;border: 1px solid #efefef;text-align: center;
}.card > img {margin-bottom: .75rem;border-radius: 100px;
}.card-text {font-size: 85%;
}

Search.jsx

import React, {Component} from 'react';
import axios from "axios";class Search extends Component {search = () => {//连续结构+重命名const {keyWordElement: {value: keyWord}} = thisaxios.get(`http://localhost:3000/api1/search/users2?q=${keyWord}`).then(response => {console.log('成功了', response.data);},error => {console.log('失败了', error);})}render() {return (<div><section className="jumbotron"><h3 className="jumbotron-heading">搜索github用户</h3><div><input ref={c => this.keyWordElement = c} type="text" placeholder="输入关键词点击搜索"/>&nbsp;<button onClick={this.search}>搜索</button></div></section></div>);}
}export default Search;

 setupProxy.js

//react 18版本写法
const {createProxyMiddleware} = require('http-proxy-middleware')module.exports = function (app) {app.use(createProxyMiddleware('/api1', {target: 'http://localhost:5000',changeOrigin: true,pathRewrite: {'^/api1': ''}}),)
}

 

运行结果：

 

github搜索案例_展示数据

App.js

import React, {Component} from 'react';
import Search from './components/Search/Search'
import List from "./components/List/List";class App extends Component {state = {users: []}saveUsers = (users) => {this.setState({users})}render() {const {users} = this.statereturn (<div><div className="container"><Search saveUsers={this.saveUsers}></Search><List users={users}></List></div></div>);}
}export default App;

List.jsx

import React, {Component} from 'react';
import './List.css'class List extends Component {render() {return (<div><div className="row">{this.props.users.map((userObj) => {return (<div className="card" key={userObj.id}><a rel="noreferrer" href={userObj.html_url} target="_blank"><img alt="head_protrait"src={userObj.avatar_url}style={{width: '100px'}}/></a><p className="card-text">{userObj.login}</p></div>)})}</div></div>);}
}export default List;

 Search.jsx

import React, {Component} from 'react';
import axios from "axios";class Search extends Component {search = () => {//连续结构+重命名const {keyWordElement: {value: keyWord}} = thisaxios.get(`http://localhost:3000/api1/search/users2?q=${keyWord}`).then(response => {console.log('成功了', response.data.items);this.props.saveUsers(response.data.items)},error => {console.log('失败了', error);})}render() {return (<div><section className="jumbotron"><h3 className="jumbotron-heading">搜索github用户</h3><div><input ref={c => this.keyWordElement = c} type="text" placeholder="输入关键词点击搜索"/>&nbsp;<button onClick={this.search}>搜索</button></div></section></div>);}
}export default Search;

运行结果：

github搜索案例_完成案例

App.js

import React, {Component} from 'react';
import Search from './components/Search/Search'
import List from "./components/List/List";class App extends Component {state = {users: [], isFirst: true, isLoading: false, err: ''}saveUsers = (users) => {this.setState({users})}updateAppState = (stateObj) => {this.setState(stateObj)}render() {const {users} = this.statereturn (<div><div className="container"><Search updateAppState={this.updateAppState}></Search><List {...this.state}></List></div></div>);}
}export default App;

Search.jsx

import React, {Component} from 'react';
import axios from "axios";class Search extends Component {search = () => {//连续结构+重命名const {keyWordElement: {value: keyWord}} = thisconsole.log(keyWord)this.props.updateAppState({isFirst: false, isLoading: true})axios.get(`http://localhost:3000/api1/search/users2?q=${keyWord}`).then(response => {console.log('成功了', response.data.items);this.props.updateAppState({isLoading: false, users: response.data.items})},error => {console.log('失败了', error);this.props.updateAppState({isLoading: false, err: error.message})})}render() {return (<div><section className="jumbotron"><h3 className="jumbotron-heading">搜索github用户</h3><div><input ref={c => this.keyWordElement = c} type="text" placeholder="输入关键词点击搜索"/>&nbsp;<button onClick={this.search}>搜索</button></div></section></div>);}
}export default Search;

List.jsx

import React, {Component} from 'react';
import './List.css'class List extends Component {render() {const {users, isFirst, isLoading, err} = this.propsreturn (<div><div className="row">{isFirst ? <h2>欢迎使用,输入关键字，然后点击搜索</h2> :isLoading ? <h2>加载中...</h2> :err ? <h2 style={{color: 'red'}}>{err}</h2> :users.map((userObj) => {return (<div className="card" key={userObj.id}><a rel="noreferrer" href={userObj.html_url} target="_blank"><img alt="head_protrait"src={userObj.avatar_url}style={{width: '100px'}}/></a><p className="card-text">{userObj.login}</p></div>)})}</div></div>);}
}export default List;

 setProxy.js

//react 18版本写法
const {createProxyMiddleware} = require('http-proxy-middleware')module.exports = function (app) {app.use(createProxyMiddleware('/api1', {target: 'http://localhost:5000',changeOrigin: true,pathRewrite: {'^/api1': ''}}),)
}

index.js

import React from 'react';
import ReactDOM from 'react-dom/client';
import App from './App';const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(<App/>);

运行结果：

4.消息订阅与发布_pubsub

App.js

import React, {Component} from 'react';
import Search from './components/Search/Search'
import List from "./components/List/List";class App extends Component {render() {return (<div><div className="container"><Search></Search><List></List></div></div>);}
}export default App;

List.jsx

import React, {Component} from 'react';
import './List.css'
import PubSub from 'pubsub-js'class List extends Component {state = {users: [], isFirst: true, isLoading: false, err: ''}componentDidMount() {this.token = PubSub.subscribe('atguigu', (_, stateObj) => {console.log(stateObj);this.setState(stateObj);})}componentWillUnmount() {PubSub.unsubscribe(this.token)}render() {const {users, isFirst, isLoading, err} = this.statereturn (<div><div className="row">{isFirst ? <h2>欢迎使用,输入关键字，然后点击搜索</h2> :isLoading ? <h2>加载中...</h2> :err ? <h2 style={{color: 'red'}}>{err}</h2> :users.map((userObj) => {return (<div className="card" key={userObj.id}><a rel="noreferrer" href={userObj.html_url} target="_blank"><img alt="head_protrait"src={userObj.avatar_url}style={{width: '100px'}}/></a><p className="card-text">{userObj.login}</p></div>)})}</div></div>);}
}export default List;

 Search.jsx

import React, {Component} from 'react';
import axios from "axios";
import PubSub from "pubsub-js";class Search extends Component {search = () => {//连续结构+重命名const {keyWordElement: {value: keyWord}} = thisconsole.log(keyWord)// this.props.updateAppState({isFirst: false, isLoading: true})PubSub.publish('atguigu', {isFirst: false, isLoading: true})axios.get(`http://localhost:3000/api1/search/users2?q=${keyWord}`).then(response => {console.log('成功了', response.data.items);// this.props.updateAppState({isLoading: false, users: response.data.items})PubSub.publish('atguigu', {isLoading: false, users: response.data.items})},error => {console.log('失败了', error);// this.props.updateAppState({isLoading: false, err: error.message})PubSub.publish('atguigu', {isLoading: false, err: error.message})})}render() {return (<div><section className="jumbotron"><h3 className="jumbotron-heading">搜索github用户</h3><div><input ref={c => this.keyWordElement = c} type="text" placeholder="输入关键词点击搜索"/>&nbsp;<button onClick={this.search}>搜索</button></div></section></div>);}
}export default Search;

setupProxy.js

//react 18版本写法
const {createProxyMiddleware} = require('http-proxy-middleware')module.exports = function (app) {app.use(createProxyMiddleware('/api1', {target: 'http://localhost:5000',changeOrigin: true,pathRewrite: {'^/api1': ''}}))
}

运行结果：

5.fetch发送请求

Search.jsx

import React, {Component} from 'react';
import axios from "axios";
import PubSub from "pubsub-js";class Search extends Component {search = async () => {//连续结构+重命名const {keyWordElement: {value: keyWord}} = thisPubSub.publish('atguigu', {isFirst: false, isLoading: true})try {const response = await fetch(`http://localhost:3000/api1/search/users2?q=${keyWord}`)const data = await response.json()console.log(data)PubSub.publish('atguigu', {isLoading: false, users: data.items})} catch (error) {console.log('请求出错', error)PubSub.publish('atguigu', {isLoading: false, err: error.message})}}render() {return (<div><section className="jumbotron"><h3 className="jumbotron-heading">搜索github用户</h3><div><input ref={c => this.keyWordElement = c} type="text" placeholder="输入关键词点击搜索"/>&nbsp;<button onClick={this.search}>搜索</button></div></section></div>);}
}export default Search;

ajax,fetch,xhr,axios,jquery之间的关系 

 

运行结果：