Node.js动手撸一个静态资源服务器的方法

const http = require("http");
const url = require("url");
const fs = require("fs");
const path = require("path");

const item = (name, parentPath) => {
  let path = parentPath = `${parentPath}/${name}`.slice(1);
  return `<div><a href="${path}" rel="external nofollow" >${name}</a></div>`;
}

const list = (arr, parentPath) => {
  return arr.map(name => item(name, parentPath)).join("");
}

const server = http.createServer((req, res) => {
  let _path = url.parse(req.url).pathname;//去掉search
  let parentPath = _path;
  _path = path.join(__dirname, _path);
  try {
    //拿到路径所对应的文件描述对象
    let stats = fs.statSync(_path);
    if (stats.isFile()) {
      //是文件，返回文件内容
      let file = fs.readFileSync(_path);
      res.end(file);
    } else if (stats.isDirectory()) {
      //是目录，返回目录列表，让用户可以继续点击
      let dirArray = fs.readdirSync(_path);
      res.end(list(dirArray, parentPath));
    } else {
      res.end();
    }
  } catch (err) {
    res.writeHead(404, "Not Found");
    res.end();
  }
});

const port = 2234;
const hostname = "127.0.0.1";
server.listen(port, hostname, () => {
  console.log(`server is running on http://${hostname}:${port}`);
});

if (stats.isFile()) {
  //是文件，返回文件内容
  //在createServer时传入的回调函数被添加到了"request"事件上，回调函数的两个形参req和res
  //分别为http.IncomingMessage对象和http.ServerResponse对象
  //并且它们都实现了流接口
  let readStream = fs.createReadStream(_path);
  readStream.pipe(res);
}

const zlib = require("zlib");

if (stats.isFile()) {
  //是文件，返回文件内容

  res.setHeader("content-encoding", "gzip");
  
  const gzip = zlib.createGzip();
  let readStream = fs.createReadStream(_path);
  readStream.pipe(gzip).pipe(res);
}

if (stats.isFile()) {
  //是文件，返回文件内容
  
  //增加判断文件是否有改动，没有改动返回304的逻辑
  
  //从请求头获取modified时间
  let IfModifiedSince = req.headers["if-modified-since"];
  //获取文件的修改日期——时间戳格式
  let mtime = stats.mtime;
  //如果服务器上的文件修改时间小于等于请求头携带的修改时间，则认定文件没有变化
  if (IfModifiedSince && mtime <= new Date(IfModifiedSince).getTime()) {
    //返回304
    res.writeHead(304, "not modify");
    return res.end();
  }
  //第一次请求或文件被修改后，返回给客户端新的修改时间
  res.setHeader("last-modified", new Date(mtime).toString());
  res.setHeader("content-encoding", "gzip");
  let reg = /\.html$/;
  //不同的文件类型设置不同的cache-control
  if (reg.test(_path)) {
    //我们对html文件执行每次必须向服务器验证资源有效性的策略
    res.setHeader("cache-control", "no-cache");
  } else {
    //我们对其余的静态资源文件采取强缓存策略，一个月内无需向服务器索取
    res.setHeader("cache-control", `max-age=${1 * 60 * 60 * 24 * 30}`);
  }
  
  //执行gzip压缩
  const gzip = zlib.createGzip();
  let readStream = fs.createReadStream(_path);
  readStream.pipe(gzip).pipe(res);
}

const config = {
  //从命令行中获取端口号，如果未设置采用默认
  port: process.argv[2] || 2234,
  hostname: "127.0.0.1"
}
server.listen(config.port, config.hostname, () => {
  console.log(`server is running on http://${config.hostname}:${config.port}`);
});

const exec = require("child_process").exec;
server.listen(config.port, config.hostname, () => {
  console.log(`server is running on http://${config.hostname}:${config.port}`);
  exec(`open http://${config.hostname}:${config.port}`);
});

//__dirname是当前文件的目录地址，process.cwd()返回的是脚本执行的路径
_path = path.join(process.cwd(), _path);

{
  "name": "here11",
  "version": "0.0.13",
  "private": false,
  "description": "a node static assets server",
  "bin": {
    "here": "./bin/index.js"
  },
  "repository": {
    "type": "git",
    "url": "https://github.com/gww666/here.git"
  },
  "scripts": {
    "test": "node bin/index.js"
  },
  "keywords": [
    "node"
  ],
  "author": "gw666",
  "license": "ISC"
}

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