Serving Static Resources

Education is not limited to just classrooms. It can be gained anytime, anywhere... - Ravi Ranjan (M.Tech-NIT)

In this section, you will learn how to serve static resources like images, css, JavaScript or other static files using Express.js and node-static module.

Serve Static Resources using Express.js:

It is easy to serve static files using built-in middleware in Express.js called express.static. Using express.static() method, you can server static resources directly by specifying the folder name where you have stored your static resources.

The following example serves static resources from the public folder under the root folder of your application.

server.js


var express = require('express');
var app = express();

//setting middleware
app.use(express.static(__dirname + 'public')); //Serves resources from public folder


var server = app.listen(5000);

Specify absolute path in express.static() by prepending __dirname. This will not break your application even if you run the express app from another directory.

In the above example, app.use() method mounts the middleware express.static for every request. The express.static middleware is responsible for serving the static assets of an Express.js application. The express.static() method specifies the folder from which to serve all static resources.

Now, run the above code using node server.js command and point your browser to http://localhost:5000/myImage.jpg and it will display myImage.jpg from the public folder (public folder should have myImage.jpg).

If you have different folders for different types of resources then you can set express.static middleware as shown below.

Example: Serve resources from different folders


var express = require('express');
var app = express();

app.use(express.static('public'));

//Serves all the request which includes /images in the url from Images folder
app.use('/images', express.static(__dirname + '/Images'));

var server = app.listen(5000);

In the above example, app.use() method mounts the express.static middleware for every request that starts with "/images". It will serve images from images folder for every HTTP requests that starts with "/images". For example, HTTP request http://localhost:5000/images/myImage.png will get myImage.png as a response. All other resources will be served from public folder.

Now, run the above code using node server.js and point your browser to http://localhost:5000/images/myImage.jpgand it will display myImage.jpg from the images folder, whereas http://localhost:5000/myJSFile.js request will be served from public folder. (images folder must include myImage.png and public folder must include myJSFile.js)

You can also create a virtual path in case you don't want to show actual folder name in the url.

Example: Setting virtual path


app.use('/resources',express.static(__dirname + '/images'));

So now, you can use http://localhost:5000/resources/myImage.jpg to serve all the images instead of http://localhost:5000/images/myImage.jpg.

In this way, you can use Express.js to server static resources such as images, CSS, JavaScript or other files.

Serve Static Resources using Node-static Module:

In your node application, you can use node-static module to serve static resources. The node-static module is an HTTP static-file server module with built-in caching.

First of all, install node-static module using NPM as below.

npm install node-static

After installing node-static module, you can create static file server in Node.js which serves static files only.

The following example demonstrates serving static resources using node-static module.

Example: Serving static resources using node-static


var http = require('http');

var nStatic = require('node-static');

var fileServer = new nStatic.Server('./public');

http.createServer(function (req, res) {
    
    fileServer.serve(req, res);

}).listen(5000);

In the above example, node-static will serve static files from public folder by default. So, an URL request will automatically map to the file in the public folder and will send it as a response.

Now, run the above example using node server.js command and point your browser to http://localhost:5000/myImage.jpg (assuming that public folder includes myImage.jpg file) and it will display the image on your browser. You don't need to give "/public/myImage.jpg" because it will automatically serve all the static files from the public folder.

Visit Github to learn about node-static in detail.