Node.js server without a framework

This article provides a simple static file server built with pure Node.js without the use of a framework.

Node.js has many frameworks to help you get your server up and running.

The most popular are:

Express: A widely used framework.
Hapi.js: A rich framework for building applications and services
Total: The all-in-one Node.js framework, which does not depend on any other framework, or module.

These will not suit every situation. A developer may need to build their own server without other dependencies.

Example

A simple static file server built with Node.js:

var http = require('http');
var fs = require('fs');
var path = require('path');

http.createServer(function (request, response) {
    console.log('request ', request.url);

    var filePath = '.' + request.url;
    if (filePath == './') {
        filePath = './index.html';
    }

    var extname = String(path.extname(filePath)).toLowerCase();
    var mimeTypes = {
        '.html': 'text/html',
        '.js': 'text/javascript',
        '.css': 'text/css',
        '.json': 'application/json',
        '.png': 'image/png',
        '.jpg': 'image/jpg',
        '.gif': 'image/gif',
        '.svg': 'image/svg+xml',
        '.wav': 'audio/wav',
        '.mp4': 'video/mp4',
        '.woff': 'application/font-woff',
        '.ttf': 'application/font-ttf',
        '.eot': 'application/vnd.ms-fontobject',
        '.otf': 'application/font-otf',
        '.wasm': 'application/wasm'
    };

    var contentType = mimeTypes[extname] || 'application/octet-stream';

    fs.readFile(filePath, function(error, content) {
        if (error) {
            if(error.code == 'ENOENT') {
                fs.readFile('./404.html', function(error, content) {
                    response.writeHead(404, { 'Content-Type': 'text/html' });
                    response.end(content, 'utf-8');
                });
            }
            else {
                response.writeHead(500);
                response.end('Sorry, check with the site admin for error: '+error.code+' ..\n');
            }
        }
        else {
            response.writeHead(200, { 'Content-Type': contentType });
            response.end(content, 'utf-8');
        }
    });

}).listen(8125);
console.log('Server running at http://127.0.0.1:8125/');

Breakdown

Lines 1 through 3 load modules provided by Node.js, roughly similar to imports.

var http = require('http');
var fs = require('fs');
var path = require('path');

Afterward is the function for creating the server. https.createServer returns a Server object, which we can start up by listening on port 8125.

http.createServer(function (request, response) {
    ...
}).listen(8125);
console.log('Server running at http://127.0.0.1:8125/');

The following lines deal with logging the request URL and fixing it if it does not specify a file.

console.log('request ', request.url);
var filePath = '.' + request.url;
if (filePath == './') {
    filePath = './index.html';
}

For example, if the URL sent is example.org, it will be interpreted as example.org/index.html.

Next, we lowercase and look for the extension of the file being requested to see if it matches with one of our MIME types. If no matches are found, we use the application/octet-stream as the default type.

var extname = String(path.extname(filePath)).toLowerCase();
var mimeTypes = {
    '.html': 'text/html',
    '.js': 'text/javascript',
    '.css': 'text/css',
    '.json': 'application/json',
    '.png': 'image/png',
    '.jpg': 'image/jpg',
    '.gif': 'image/gif',
    '.svg': 'image/svg+xml',
    '.wav': 'audio/wav',
    '.mp4': 'video/mp4',
    '.woff': 'application/font-woff',
    '.ttf': 'application/font-ttf',
    '.eot': 'application/vnd.ms-fontobject',
    '.otf': 'application/font-otf',
    '.wasm': 'application/wasm'
};

var contentType = mimeTypes[extname] || 'application/octet-stream';

Lastly, we respond to the client with the file information. This function reads the file using our previously prepared filePath variable.

fs.readFile(filePath, function(error, content) {
    ...
});

The first thing we do is to compensate for any possible errors.

if (error) {
  ..
} else {
  ..
}

Most often, the error will be ENOENT, in which case we reply with a 404 error.

if(error.code == 'ENOENT') {
    fs.readFile('./404.html', function(error, content) {
        response.writeHead(404, { 'Content-Type': 'text/html' });
        response.end(content, 'utf-8');
    });
}
else {
    response.writeHead(500);
    response.end('Sorry, check with the site admin for error: '+error.code+' ..\n');
}

Finally, if there are no errors, we send over the requested file.

response.writeHead(200, { 'Content-Type': contentType });
response.end(content, 'utf-8');