JavaScript is quickly becoming the go-to language for web developers. Front-end web developers use JavaScript to add user interface enhancements, add interactivity, and talk to back-end web services using AJAX. Web developers who work on the server-side are also flocking to JavaScript because of the efficiencies and speed offered by JavaScript’s event-driven, non-blocking nature.
In fact, concentrating on JavaScript as your language of choice offers the opportunity to master a single language while still being able to develop “full-stack” web applications. The key to this server-side JavaScript revolution is Node.js® — a version of Chrome’s V8 JavaScript runtime engine — which makes it possible to run JavaScript on the server-side.
Node.js is also used for developing desktop applications and for deploying tools that make developing web sites simpler. For example, by installing Node.js® on your desktop machine, you can quickly convert CoffeeScript to JavaScript, SASS to CSS, and shrink the size of your HTML, JavaScript and graphic files. Using NPM — a tool that makes installing and managing Node modules — it’s quite easy to add many useful tools to your web development toolkit.
Advantages of Node.js
- js is an open-source framework under MIT license. (MIT license is a free software license originating at the Massachusetts Institute of Technology (MIT).)
- Uses JavaScript to build entire server side application.
- Lightweight framework that includes bare minimum modules. Other modules can be included as per the need of an application.
- Asynchronous by default. So it performs faster than other frameworks.
- Cross-platform framework that runs on Windows, MAC or Linux
Node.js Application
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