Node. js Static file Server improved version

First of all, I would like to thank github, github provided this source code author. Last night's static file server was a little more complex than today's, and you can learn a lot of new things.

You'll notice that this time the code has one more fs.stat function and one more pipe function for the ReadStream object, which is used to fetch file information. The first parameter is the path to the file, the second is the callback function, and the second parameter, stats, has the attributes of the basic information of the file. The pipe function is used to connect this readable stream to the destination target writable stream, and data passed into this stream will be written to the destination stream. The source and destination streams are kept in sync by pausing and resuming the stream if necessary.

The static file server is improved by using Last-ES18en and ES19en-ES20en-ES21en headers, so that it is not necessary to return its existing files to the browser. By the way, gzip or deflate compression can be returned to the resource according to the compression method requested by the browser.

var PORT = 8000;
var http = require("http");
var url = require("url");
var fs = require("fs");
var path = require("path");
var mime = require("./mime").types;
var config = require("./config");
var zlib = require("zlib");
var server = http.createServer(function(request, response) {
 response.setHeader("Server", "Node/V5");
 var pathname = url.parse(request.url).pathname;
 console.log("url = " + pathname);
 if (pathname.slice(-1) === "/") {
  pathname = pathname + config.Welcome.file;
 }
 var realPath = __dirname + "/" + path.join("assets", path.normalize(pathname.replace(/\.\./g, "")));
 console.log("realPath = " + realPath);
 var pathHandle = function (realPath) {
  fs.stat(realPath, function (err, stats) {
   if (err) {
    response.writeHead(404, "Not Found", {'Content-Type': 'text/plain'});
    response.write("stats = " + stats);
    response.write("This request URL " + pathname + " was not found on this server.");
    response.end();
   } else {
    if (stats.isDirectory()) {
     realPath = path.join(realPath, "/", config.Welcome.file);
     pathHandle(realPath);
    } else {
     var ext = path.extname(realPath);
     ext = ext ? ext.slice(1) : 'unknown';
     var contentType = mime[ext] || "text/plain";
     response.setHeader("Content-Type", contentType);
     // Get the modification time of the file  
     var lastModified = stats.mtime.toUTCString();
     var ifModifiedSince = "If-Modified-Since".toLowerCase();
     // Set up the Last-Modified
     // The server returns the last file to the browser 1 Secondary modification time Last-Modified
     response.setHeader("Last-Modified", lastModified);

     if (ext.match(config.Expires.fileMatch)) {
      var expires = new Date();
      expires.setTime(expires.getTime() + config.Expires.maxAge * 1000);
      response.setHeader("Expires", expires.toUTCString());
      response.setHeader("Cache-Control", "max-age=" + config.Expires.maxAge);
     }
     // The server receives the message from the browser If-Modified-Since Message header 
     // The same date means that the resource has not changed 304
     // Tell the browser that you already have the resource , There's no need to ask 
     if (request.headers[ifModifiedSince] && lastModified == request.headers[ifModifiedSince]) {
      response.writeHead(304, "Not Modified");
      response.end();
     } else {
      var raw = fs.createReadStream(realPath);
      var acceptEncoding = request.headers['accept-encoding'] || "";
      var matched = ext.match(config.Compress.match); 
      if (matched && acceptEncoding.match(/\bgzip\b/)) {
       response.writeHead(200, "Ok", {'Content-Encoding': 'gzip'});
       raw.pipe(zlib.createGzip()).pipe(response);
      } else if (matched && acceptEncoding.match(/\bdeflate\b/)) {
       response.writeHead(200, "Ok", {'Content-Encoding': 'deflate'});
       raw.pipe(zlib.createDeflate()).pipe(response);
      } else {
       response.writeHead(200, "Ok");
       raw.pipe(response);
      }
     }
    }
   }
  });
 };

 pathHandle(realPath);
});
server.listen(PORT);
console.log("Server runing at port: " + PORT + ".");

The Expires field states the time after which a web page or URL address is no longer cached by the browser. Once that time has passed, the browser should contact the original server. The failure time is set to be 1 year.

exports.Expires = {
 fileMatch: /^(gif|png|jpg|js|css)$/ig,
 maxAge: 60*60*24*365
};
exports.Compress = {
 match: /css|js|html/ig
};
exports.Welcome = {
 file: "index.html"
};

Enumerates the types of various resources, and you can set ES32en-ES33en by extension.

exports.types = {
 "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",
 "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"
};