nodejs: a simple file server

Simple File Server

Sometimes, we want to read some files on the server, but we don't want to write too complicated programs. We can consider using nodejs to write a file server easily.
Here's a simple file server I wrote with caching. Here's it. github links Or simply copy the following code to run, requiring the installation of mime dependencies

const port = 3004; // Port number
const http = require('http');
const url = require('url');
const fs = require('fs');
const path = require('path');
const mime = require('mime');

const STATIC_FOLDER = 'public'; // Read the files under the public folder by default
const IS_OPEN_CACHE = true; // Whether to turn on the caching function
const CACHE_TIME = 10;// Tell the browser how long you can avoid requesting the server in seconds.

const server = http.createServer((req, res) => {
  const obj = url.parse(req.url); // url for parsing requests
  let pathname = obj.pathname; // Path of request
  if (pathname === '/') {
    pathname = './index.html';
  const realPath = path.join(__dirname, STATIC_FOLDER, pathname); // Getting physical paths

  // Get basic information about files, including size, creation time, modification time, etc.
  fs.stat(realPath, (err, stats) => {
    let endFilePath = '', contentType = '';
    if (err || stats.isDirectory()) {
      // If an error is reported or the requested path is a folder, 404 is returned.
      res.writeHead(404, 'not found', {
        'Content-Type': 'text/plain'
      res.write(`the request ${pathname} is not found`);
    } else {
      let ext = path.extname(realPath).slice(1); // Get the file extension name
      contentType = mime.getType(ext) || 'text/plain';
      endFilePath = realPath;

      if (!IS_OPEN_CACHE) {
        // Unopened cache
        let raw = fs.createReadStream(endFilePath);
        res.writeHead(200, 'ok');
      } else {
        // Get the last modification time of the file and convert the time into a world time string
        let lastModified = stats.mtime.toUTCString();
        const ifModifiedSince = 'if-modified-since';

        // Tell the browser what time to use the browser cache without asking the server directly, but it seems that it is not effective, and needs to learn why.
        let expires = new Date();
        expires.setTime(expires.getTime() + CACHE_TIME * 1000);
        res.setHeader("Expires", expires.toUTCString());
        res.setHeader('Cache-Control', 'max-age=' + CACHE_TIME);

        if (req.headers[ifModifiedSince] && lastModified === req.headers[ifModifiedSince]) {
          // If the request header contains the request ifModifiedSince and the file is not modified, it returns 304
          res.writeHead(304, 'Not Modified');
        } else {
          // Return the header Last-Modified for the last modification time of the current request file
          res.setHeader('Last-Modified', lastModified);

          // Return file
          let raw = fs.createReadStream(endFilePath);
          res.writeHead(200, 'ok');

console.log(`server is running at http://localhost:${port}`)

However, there is still a problem at present. The server cache returns 304, and after modifying the file, the function that the request will return the latest file is not a problem at present. However, after setting up Cache-Control and Expires, the server will still be requested within the specified time. This still needs to see what happens. If anyone knows, please let me know. Thank you.

Keywords: node.js github

Added by reloj_alfred on Tue, 01 Oct 2019 19:04:25 +0300