http module in node.js

The http module is a module officially provided by Node.js to create a web server .

Through the http.createServer() method provided by the http module , an ordinary computer can be conveniently turned into a web server to provide web resource services to the outside world.

Create the most basic web server

1. import http module
2. Create a web server instance
3. Bind the request event to the server instance and listen to the client's request
4. start server

sample code

//1.导入http模块
const http = require('http')

//2.创建web服务器实例
const server = http.createServer()

//3.为服务器实例绑定request事件，监听客户端的请求
server.on('request',function(req,res){
    console.log('Someone visit our web server')

    //获取请求的url地址
    const url = req.url

    //设置默认的响应内容为404 Not found
    let content = '404 Not found'

    //判断用户请求的是否为/ 或 /index.html首页
    //判断用户请求的是否为/about.html关于页面
    if(url === '/' || url==='/index.html'){
        content = '<h1>首页</h1>'
    }else if(url==='/about.html'){
        content = '<h1>关于页面</h1>'
    }

    //设置Content-Type响应头，防止中文乱码
    res.setHeader('Content-Type','text/html;charset=utf-8')

    //使用res.end()把内容响应给客户端
    res.end(content)

})

//启动服务器
server.listen(8080,function(){
    console.log('server running at http://127.0.0.1:8080')
})

Application examples:

There is a clock folder on the local disk, which contains html, css, and js files. When the html file is opened on the browser, a clock pattern is displayed. Requirement: Create a web server, use the content in the clock folder as the server resource, and when the client accesses the server, enter /index.html to load the clock pattern.

My local folder structure is as follows:

 

//1.1导入http模块
const http = require('http')
//1.2导入fs模块
const fs = require('fs')
//1.3导入path模块
const path = require('path')

//2.1创建web服务器
const server = http.createServer()

//2.2监听web服务器的request事件
server.on('request',(req,res) => {
    // 3.1获取到客户端请求的url地址
    //    /clock/index.html
    //    /clock/index.css
    //    /clock/index.js
    const url = req.url
    // 3.2 把请求的url地址映射为具体文件的存放路径
    let fpath = ''
    if (url === '/'){
        fpath = path.join(__dirname,'../clock/index.html')
    }else{
        fpath = path.join(__dirname,'../clock',url)
    }

    // 4.1 根据映射过来的文件路径读取文件的内容
    fs.readFile(fpath,'utf8',(err,dataStr) => {
        //4.2 读取失败，向客户端响应固定的"错误消息"
        if (err) return res.end('404 Not found')
        //4.3 读取文件成功，将读取成功的内容，响应给客户端
        res.end(dataStr)
    })
})

//2.3启动服务器
server.listen(8080, () => {
    console.log('server running at http://127.0.0.1')
})