HTTP

代码示例：

// server.js

const http = require('http')

// 创建Web服务

http.createServer((req, res) => {  // 接收浏览器传输过来的参数，返回渲染的内容
    //req：接收浏览器传过来的参数，res：返回渲染的内容
    // res.write('Hello World!')  // 往浏览器中输出内容
    res.writeHead(200, {'Content-Type':'text/html;charset=utf-8'})  // 状态码与响应内容的数据类型
    res.write(`
    <html lang="zh-CN">
        <h1>小时雨</h1>
    </html>
    `)  // 响应的内容
    res.end()  // 结束本次会话
}).listen(3000, () => {  // 端口
    console.log('server start')  // 创建成功时执行
})

// module/renderHTML.js

function renderHTML(url) {
    switch (url) {
        case '/home':
            return `
            <html lang="zh-CN">
                <h1>h1</h1>
            </html>
            `
        case '/list':
            return `
            <html lang="zh-CN">
                <h2>h2</h2>
            </html>
            `
        case '/api/list':
            return `['aaa', 'bbb', 'ccc']`
        case '/api/home':
            return `{name: '时雨'}`
        default:
            return `
            <html lang="zh-CN">
                <h1>404</h1>
            </html>
            `
    }
}

module.exports = {
    renderHTML
}

// module/renderStatus.js

function renderStatus(url) {
    let arr = ['/home', '/list', '/api/list', '/api/home']
    return arr.includes(url) ? 200 : 404
}

module.exports = {
    renderStatus
}

// server.js

const http = require('http')
const moduleRenderHTML = require('./module/renderHTML')
const moduleRenderStatus = require('./module/renderStatus')

http.createServer((req, res) => {
    res.writeHead(moduleRenderStatus.renderStatus(req.url), {'Content-Type': 'text/html;charset=utf-8'})
    if (req.url === '/favicon.ico') {  // 当请求此路径时
        return  // 处理不了此路径
    }
    res.write(moduleRenderHTML.renderHTML(req.url))
    res.end()
}).listen(3000, () => {
    console.log('server start')
})


// 第二种写法
// const server = http.createServer()
//
// server.on('request', (req, res) => {
//     res.writeHead(moduleRenderStatus.renderStatus(req.url), {'Content-Type': 'text/html;charset=utf-8'})
//     if (req.url === '/favicon.ico') {
//         return
//     }
//     res.write(moduleRenderHTML.renderHTML(req.url))
//     res.end()
// })
//
// server.listen(3000, () => {
//     console.log('server start')
// })

补充

代码示例：

// server.js

const http = require('http')
const url = require("url")

http.createServer((req, res) => {
    const urlObj = url.parse(req.url, true)
    // console.log(urlObj.query.callback)
    switch (urlObj.pathname) {
        case '/api/foo':
            return res.end(`${urlObj.query.callback}(${JSON.stringify({name: 'HQSY'})})`)
        default:
            res.end('404')
    }
}).listen(3000)

// server.js

const http = require('http')
const url = require("url")

http.createServer((req, res) => {
    const urlObj = url.parse(req.url, true)
    res.writeHead(200, {
        'Content-Type': 'application/json;charset=utf-8',
        'access-control-allow-origin': '*'  // 允许任何域请求
    })
    switch (urlObj.pathname) {
        case '/api/foo':
            return res.end(`${JSON.stringify({name: 'HQSY'})}`)
        default:
            res.end('404')
    }
}).listen(3000)

<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <script>
        const oscript = document.createElement('script')
        oscript.src = 'http://localhost:3000/api/foo?callback=test'
        document.body.appendChild(oscript)
        function foo(obj) {  // 提前定义
            console.log(obj)
        }
    </script>
</body>
</html>

<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <script>
        fetch('http://localhost:3000/api/foo')
            .then(res => res.json())
            .then(res => console.log(res))
            .catch(err => console.log(err))
    </script>
</body>
</html>

get

代码示例：

// server.js

const http = require('http')
const https = require('https')
const url = require("url")

function httpGet(cb) {
    let data = ''
    https.get(``,
        (res) => {
            res.on('data', (chunk) => {  // 逐帧收集数据
                data += chunk
            })
            res.on('end', () => {
                console.log(data)
                cb(data)
            })
        })
}

http.createServer((req, res) => {
    const urlObj = url.parse(req.url, true)
    res.writeHead(200, {
        'Content-Type': 'application/json;charset=utf-8',
        'access-control-allow-origin': '*'
    })
    switch (urlObj.pathname) {
        case '/api/foo':
            // 扮演中间人（请求另一个域的数据）
            return httpGet((data) => {
                res.end(data)
            })
        default:
            res.end('404')
    }
}).listen(3000)

<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <script>
        fetch('http://localhost:3000/api/foo')
            .then(res => res.json())
            .then(res => console.log(res))
            .catch(err => console.log(err))
    </script>
</body>
</html>

post

代码示例：

// server.js

const http = require('http')
const https = require('https')
const url = require("url")

function httpPost(cb) {
    let data = ''
    const options = {
        hostname: '',
        post: '443',
        path: '/foo',
        method: 'POST',
        headers: {
            'Content-Type': 'application/json'  // 发送的数据格式
        }
    }
    const req = https.request(options, (res) => {
        res.on('data', chunk => {
            data += chunk
        })
        res.on('end', () => {
            cb(data)
        })
    })
    // req.write('name=HQSY&age=24')
    req.write(JSON.stringify([{},{"foo":{"bar":1}}]))  // 发出请求
    req.end()
}

http.createServer((req, res) => {
    const urlObj = url.parse(req.url, true)
    res.writeHead(200, {
        'Content-Type': 'application/json;charset=utf-8',
        'access-control-allow-origin': '*'
    })
    switch (urlObj.pathname) {
        case '/api/foo':
            return httpPost((data) => {
                res.end(data)
            })
        default:
            res.end('404')
    }
}).listen(3000)

<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <script>
        fetch('http://localhost:3000/api/foo')
            .then(res => res.json())
            .then(res => console.log(res))
            .catch(err => console.log(err))
    </script>
</body>
</html>

爬虫

代码示例：

// server.js

const http = require('http')
const https = require('https')
const url = require("url")

const cheerio = require('cheerio')

function httpGet(cb) {
    let data = ''
    https.get(``,
        (res) => {
            res.on('data', (chunk) => {
                data += chunk
            })
            res.on('end', () => {
                console.log(data)
                cb(data)
            })
        })
}

function spider(data) {
    let $ = cheerio.load(data)
    let $moviewList = $('.column.content')
    // console.log($moviewList)
    let movies = []
    $moviewList.each((index, value) => {
        movies.push({
            title: $(value).find('.title').text(),
            grade: $(value).find('.grade').text(),
            actor: $(value).find('.actor').text()
        })
    })
    console.log(movies)
    return JSON.stringify(movies)
}

http.createServer((req, res) => {
    const urlObj = url.parse(req.url, true)
    res.writeHead(200, {
        'Content-Type': 'application/json;charset=utf-8',
        'access-control-allow-origin': '*'
    })
    switch (urlObj.pathname) {
        case '/api/foo':
            return httpGet((data) => {
                res.end(spider(data))
            })
        default:
            res.end('404')
    }
}).listen(3000)

<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <script>
        fetch('http://localhost:3000/api/foo')
            .then(res => res.json())
            .then(res => console.log(res))
            .catch(err => console.log(err))
    </script>
</body>
</html>