node.js 实现一个简单的 web 服务器还是比较简单的，以前利用 express 框架实现过『nodeJS搭一个简单的(代理)web服务器』。代码量很少，可是使用时需要安装依赖，多处使用难免有点不方便。于是便有了完全使用原生 api 来重写的想法，也当作一次 node.js 复习。
1、静态 web 服务器
'use strict'
const http = require('http')
const url = require('url')
const fs = require('fs')
const path = require('path')
const cp = require('child_process')
const port = 8080
const hostname = 'localhost'
// 创建 http 服务
let httpServer = http.createServer(processStatic)
// 设置监听端口
httpServer.listen(port, hostname, () => {
console.log(`app is running at port:${port}`)
console.log(`url: http://${hostname}:${port}`)
cp.exec(`explorer http://${hostname}:${port}`, () => {})
})
// 处理静态资源
function processStatic(req, res) {
const mime = {
css: 'text/css',
gif: 'image/gif',
html: 'text/html',
ico: 'image/x-icon',
jpeg: 'image/jpeg',
jpg: 'image/jpeg',
js: 'text/javascript',
json: 'application/json',
pdf: 'application/pdf',
png: 'image/png',
svg: 'image/svg+xml',
woff: 'application/x-font-woff',
woff2: 'application/x-font-woff',
swf: 'application/x-shockwave-flash',
tiff: 'image/tiff',
txt: 'text/plain',
wav: 'audio/x-wav',
wma: 'audio/x-ms-wma',
wmv: 'video/x-ms-wmv',
xml: 'text/xml'
}
const requestUrl = req.url
let pathName = url.parse(requestUrl).pathname
// 中文乱码处理
pathName = decodeURI(pathName)
let ext = path.extname(pathName)
// 特殊 url 处理
if (!pathName.endsWith('/') && ext === '' && !requestUrl.includes('?')) {
pathName += '/'
const redirect = `http://${req.headers.host}${pathName}`
redirectUrl(redirect, res)
}
// 解释 url 对应的资源文件路径
let filePath = path.resolve(__dirname + pathName)
// 设置 mime
ext = ext ? ext.slice(1) : 'unknown'
const contentType = mime[ext] || 'text/plain'
// 处理资源文件
fs.stat(filePath, (err, stats) => {
if (err) {
res.writeHead(404, { 'content-type': 'text/html;charset=utf-8' })
res.end('<h1>404 Not Found</h1>')
return
}
// 处理文件
if (stats.isFile()) {
readFile(filePath, contentType, res)
}
// 处理目录
if (stats.isDirectory()) {
let html = "<head><meta charset = 'utf-8'/></head><body><ul>"
// 遍历文件目录，以超链接返回，方便用户选择
fs.readdir(filePath, (err, files) => {
if (err) {
res.writeHead(500, { 'content-type': contentType })
res.end('<h1>500 Server Error</h1>')
return
} else {
for (let file of files) {
if (file === 'index.html') {
const redirect = `http://${req.headers.host}${pathName}index.html`
redirectUrl(redirect, res)
}
html += `<li><a href='${file}'>${file}</a></li>`
}
html += '</ul></body>'
res.writeHead(200, { 'content-type': 'text/html' })
res.end(html)
}
})
}
})
}
// 重定向处理
function redirectUrl(url, res) {
url = encodeURI(url)
res.writeHead(302, {
location: url
})
res.end()
}
// 文件读取
function readFile(filePath, contentType, res) {
res.writeHead(200, { 'content-type': contentType })
const stream = fs.createReadStream(filePath)
stream.on('error', function() {
res.writeHead(500, { 'content-type': contentType })
res.end('<h1>500 Server Error</h1>')
})
stream.pipe(res)
}
2、代理功能
// 代理列表
const proxyTable = {
'/api': {
target: 'http://127.0.0.1:8090/api',
changeOrigin: true
}
}
// 处理代理列表
function processProxy(req, res) {
const requestUrl = req.url
const proxy = Object.keys(proxyTable)
let not_found = true
for (let index = 0; index < proxy.length; index++) {
const k = proxy[index]
const i = requestUrl.indexOf(k)
if (i >= 0) {
not_found = false
const element = proxyTable[k]
const newUrl = element.target + requestUrl.slice(i + k.length)
if (requestUrl !== newUrl) {
const u = url.parse(newUrl, true)
const options = {
hostname : u.hostname,
port : u.port || 80,
path : u.path,
method : req.method,
headers : req.headers,
timeout : 6000
}
if(element.changeOrigin){
options.headers['host'] = u.hostname + ':' + ( u.port || 80)
}
const request = http
.request(options, response => {
// cookie 处理
if(element.changeOrigin && response.headers['set-cookie']){
response.headers['set-cookie'] = getHeaderOverride(response.headers['set-cookie'])
}
res.writeHead(response.statusCode, response.headers)
response.pipe(res)
})
.on('error', err => {
res.statusCode = 503
res.end()
})
req.pipe(request)
}
break
}
}
return not_found
}
function getHeaderOverride(value){
if (Array.isArray(value)) {
for (var i = 0; i < value.length; i++ ) {
value[i] = replaceDomain(value[i])
}
} else {
value = replaceDomain(value)
}
return value
}
function replaceDomain(value) {
return value.replace(/domain=[a-z.]*;/,'domain=.localhost;').replace(/secure/, '')
}
3、完整版
服务器接收到 http 请求，首先处理代理列表 proxyTable，然后再处理静态资源。虽然这里面只有二个步骤，但如果按照先后顺序编码，这种方式显然不够灵活，不利于以后功能的扩展。koa 框架的中间件就是一个很好的解决方案。完整代码如下：
'use strict'
const http = require('http')
const url = require('url')
const fs = require('fs')
const path = require('path')
const cp = require('child_process')
// 处理静态资源
function processStatic(req, res) {
const mime = {
css: 'text/css',
gif: 'image/gif',
html: 'text/html',
ico: 'image/x-icon',
jpeg: 'image/jpeg',
jpg: 'image/jpeg',
js: 'text/javascript',
json: 'application/json',
pdf: 'application/pdf',
png: 'image/png',
svg: 'image/svg+xml',
woff: 'application/x-font-woff',
woff2: 'application/x-font-woff',
swf: 'application/x-shockwave-flash',
tiff: 'image/tiff',
txt: 'text/plain',
wav: 'audio/x-wav',
wma: 'audio/x-ms-wma',
wmv: 'video/x-ms-wmv',
xml: 'text/xml'
}
const requestUrl = req.url
let pathName = url.parse(requestUrl).pathname
// 中文乱码处理
pathName = decodeURI(pathName)
let ext = path.extname(pathName)
// 特殊 url 处理
if (!pathName.endsWith('/') && ext === '' && !requestUrl.includes('?')) {
pathName += '/'
const redirect = `http://${req.headers.host}${pathName}`
redirectUrl(redirect, res)
}
// 解释 url 对应的资源文件路径
let filePath = path.resolve(__dirname + pathName)
// 设置 mime
ext = ext ? ext.slice(1) : 'unknown'
const contentType = mime[ext] || 'text/plain'
// 处理资源文件
fs.stat(filePath, (err, stats) => {
if (err) {
res.writeHead(404, { 'content-type': 'text/html;charset=utf-8' })
res.end('<h1>404 Not Found</h1>')
return
} // 处理文件
if (stats.isFile()) {
readFile(filePath, contentType, res)
} // 处理目录
if (stats.isDirectory()) {
let html = "<head><meta charset = 'utf-8'/></head><body><ul>"
// 遍历文件目录，以超链接返回，方便用户选择
fs.readdir(filePath, (err, files) => {
if (err) {
res.writeHead(500, { 'content-type': contentType })
res.end('<h1>500 Server Error</h1>')
return
} else {
for (let file of files) {
if (file === 'index.html') {
const redirect = `http://${req.headers.host}${pathName}index.html`
redirectUrl(redirect, res)
}
html += `<li><a href='${file}'>${file}</a></li>`
}
html += '</ul></body>'
res.writeHead(200, { 'content-type': 'text/html' })
res.end(html)
}
})
}
})
}
// 重定向处理
function redirectUrl(url, res) {
url = encodeURI(url)
res.writeHead(302, {
location: url
})
res.end()
}
// 文件读取
function readFile(filePath, contentType, res) {
res.writeHead(200, { 'content-type': contentType })
const stream = fs.createReadStream(filePath)
stream.on('error', function() {
res.writeHead(500, { 'content-type': contentType })
res.end('<h1>500 Server Error</h1>')
})
stream.pipe(res)
}
// 处理代理列表
function processProxy(req, res) {
const requestUrl = req.url
const proxy = Object.keys(proxyTable)
let not_found = true
for (let index = 0; index < proxy.length; index++) {
const k = proxy[index]
const i = requestUrl.indexOf(k)
if (i >= 0) {
not_found = false
const element = proxyTable[k]
const newUrl = element.target + requestUrl.slice(i + k.length)
if (requestUrl !== newUrl) {
const u = url.parse(newUrl, true)
const options = {
hostname : u.hostname,
port : u.port || 80,
path : u.path,
method : req.method,
headers : req.headers,
timeout : 6000
};
if(element.changeOrigin){
options.headers['host'] = u.hostname + ':' + ( u.port || 80)
}
const request =
http.request(options, response => {
// cookie 处理
if(element.changeOrigin && response.headers['set-cookie']){
response.headers['set-cookie'] = getHeaderOverride(response.headers['set-cookie'])
}
res.writeHead(response.statusCode, response.headers)
response.pipe(res)
})
.on('error', err => {
res.statusCode = 503
res.end()
})
req.pipe(request)
}
break
}
}
return not_found
}
function getHeaderOverride(value){
if (Array.isArray(value)) {
for (var i = 0; i < value.length; i++ ) {
value[i] = replaceDomain(value[i])
}
} else {
value = replaceDomain(value)
}
return value}
function replaceDomain(value) {
return value.replace(/domain=[a-z.]*;/,'domain=.localhost;').replace(/secure/, '')
}
function compose (middleware) {
if (!Array.isArray(middleware)) throw new TypeError('Middleware stack must be an array!')
for (const fn of middleware) {
if (typeof fn !== 'function') throw new TypeError('Middleware must be composed of functions!')
}
return function (context, next) {
// 记录上一次执行中间件的位置
let index = -1
return dispatch(0)
function dispatch (i) {
// 理论上 i 会大于 index，因为每次执行一次都会把 i递增，
// 如果相等或者小于，则说明next()执行了多次
if (i <= index) return Promise.reject(new Error('next() called multiple times'))
index = i
let fn = middleware[i]
if (i === middleware.length) fn = next
if (!fn) return Promise.resolve()
try {
return Promise.resolve(fn(context, function next () {
return dispatch(i + 1)
}))
} catch (err) {
return Promise.reject(err)
}
}
}
}
function Router(){
this.middleware = []
}
Router.prototype.use = function (fn){
if (typeof fn !== 'function') throw new TypeError('middleware must be a function!')
this.middleware.push(fn)
return this}
Router.prototype.callback= function() {
const fn = compose(this.middleware)
const handleRequest = (req, res) => {
const ctx = {req, res}
return this.handleRequest(ctx, fn)
}
return handleRequest
}
Router.prototype.handleRequest= function(ctx, fn) {
fn(ctx)
}
// 代理列表
const proxyTable = {
'/api': {
target: 'http://127.0.0.1:8090/api',
changeOrigin: true
}
}
const port = 8080
const hostname = 'localhost'
const appRouter = new Router()
// 使用中间件
appRouter.use(async(ctx,next)=>{
if(processProxy(ctx.req, ctx.res)){
next()
}
}).use(async(ctx)=>{
processStatic(ctx.req, ctx.res)
})
// 创建 http 服务
let httpServer = http.createServer(appRouter.callback())
// 设置监听端口
httpServer.listen(port, hostname, () => {
console.log(`app is running at port:${port}`)
console.log(`url: http://${hostname}:${port}`)
cp.exec(`explorer http://${hostname}:${port}`, () => {})
})
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