Professional Node.js: Building Javascript Based Scalable Software

Chapter 11

Building HTTP Servers

WHAT’S IN THIS CHAPTER?

• Creating an HTTP server
• Making an HTTP server listen on a port
• Handling HTTP requests
• Observing request headers
• Listening for and piping request data
• Replying with a status code and headers
• Replying with a body
• Using HTTP chunked responses to stream the response body

HTTP is an application-level protocol for content and application delivery. It uses TCP as its transport protocol, and it is the foundation of data communication for the World Wide Web. One of the preferred application deployment mechanisms is to provide an HTTP service on the Internet that answers HTTP client requests.

You can easily create an HTTP server in Node. Here is the famous “Hello World!” HTTP server example, as seen in Listing 11-1.

LISTING 11-1: A “Hello World!” HTTP server.

var http = require('http');
 
var server = http.createServer();
 
server.on('request', function(req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.write('Hello World!');
  res.end();
});
server.listen(4000);

On line 1 you obtain the http module, from which you can create a server object by calling http.createServer() (line 3).

You then listen for request events, which happen when a new client connects. The event callback you provide gets called with two arguments: the request and the response objects. You can then use the request object to learn details about this request and use the response object to write back to the client.

On line 6 you write a header ('ContentType': ...