Node.js Application

Go back to Tutorial

Following are the areas where Node.js is proving itself as a perfect technology partner.

• I/O bound Applications
• Data Streaming Applications
• Data Intensive Real-time Applications (DIRT)
• JSON APIs based Applications
• Single Page Applications

It is not advisable to use Node.js for CPU intensive applications.

Node is part of the Server Side JavaScript environnement and extend JavaScript API to offer usual server side functionalities. Node base API can be extended by using the CommonJS module system.

Node’s spirit is similar to Twisted for Python and EventMachine for Ruby.

Node’s Features

It’s features are offering an easy and safe way to build high performance and scalable network applications in JavaScript. Those goals are achieved thanks it’s architecture:

• Single Threaded : Node use a single thread to run instead of other server like Apache HTTP who spawn a thread per request, this approach result in avoiding CPU context switching and massive execution stacks in memory. This is also the method used by nginx and other servers developed to counter the C10K problem.
• Event Loop : Written in C++ using the Marc Lehman’s libev library, the event loop use epoll or kqueue for scalable event notification mechanism.
• Non blocking I/O : Node avoid CPU time loss usually made by waiting for an input or an output response (database, file system, web service, …) thanks to the full-featured asynchronous I/O provided by Marc Lehmann’s libeio library.

These characteristics allow Node to handle a large amount of traffic by handling as quickly as possible a request to free the thread for the next one.

Node has a built-in support for most important protocols like TCP, DNS, and HTTP (the one that we will focus on). The design goal of a Node application is that any function performing an I/O must use a callback. That’s why there is no blocking methods provided in Node’s API.

The HTTP implementation offered by Node is very complete and natively support chunked request and response (very useful since we are going to use the twitter streaming api) and hanging request for comet applications. The Node’s footprint for each http stream is only 36 bytes.

Go back to Tutorial