Exchanging real-time messages using WebSockets

Before HTML5 Web Sockets, web applications that needed to implement real-time updates, such as chat messages and game moves, had to resort to inefficient methods.

The most popular method was to use long polling, where a connection to the server is kept open until an event arrives. Another popular method was streaming chunked blocks of JavaScript to an iframe element, also known as comet streaming .

HTML5 WebSockets enable the exchange of real-time messages with the web server. The API is much cleaner and easier to use, less error-prone, and provides lower message latency.

In this recipe, we're going to implement a simple chat system based on WebSockets. To make the system easier to extend, we're going to use dnode on top of the underlying WebSockets. The dnode library provides full callback-based RPC for multiple languages and platforms: Node.js, Ruby, Java, and Perl. Essentially, it enables us to call server-side code as if it were executing on...