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Node.js

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node.js
Original author(s)Ryan Dahl
Developer(s)Node.js Developers, Joyent, Github Contributors
Initial releaseMay 27, 2009 (2009-05-27)[1]
Stable release
0.10.33 / October 20, 2014 (2014-10-20)[2]
Preview release
0.11.14 / September 25, 2014 (2014-09-25)[2]
Repository
Written inC, C++, JavaScript
Operating systemOS X, Linux, Solaris, FreeBSD, OpenBSD, Microsoft Windows (older versions require Cygwin), webOS
TypeEvent-driven networking
LicenseMIT
Websitenodejs.org

Node.js is an open source, cross-platform runtime environment for server-side and networking applications. Node.js applications are written in JavaScript, and can be run within the Node.js runtime on OS X, Microsoft Windows, Linux and FreeBSD.

Node.js provides an event-driven architecture and a non-blocking I/O API that optimizes an application's throughput and scalability. These technologies are commonly used for real-time applications.

Node.js uses the Google V8 JavaScript engine to execute code, and a large percentage of the basic modules are written in JavaScript. Node.js contains a built-in library to allow applications to act as a Web server without software such as Apache HTTP Server or IIS.

Node.js is gaining adoption as a server-side platform[3] and is used by Groupon,[4] SAP,[5] LinkedIn,[6][7] Microsoft,[8][9] Yahoo!,[10] Walmart,[11] Rakuten and PayPal.[12][13]

History

Ryan Dahl, creator of Node.js

Node.js was created and first published for Linux use in 2009. Its development and maintenance was spearheaded by Ryan Dahl and sponsored by Joyent, the firm where Dahl worked.[14]

Dahl was inspired to create Node.js after seeing a file upload progress bar on Flickr. The browser did not know how much of the file had been uploaded and had to query the Web server. Dahl desired an easier way.[15]

It heralded international attention after its debut at the inaugural JSConf EU conference.[16][17]

npm, a package manager for Node.js libraries, was introduced in 2011.

In June 2011, Microsoft partnered with Joyent to create a native Windows version of Node.js.[18] The first Node.js build to support Windows was released in July.

In January 2012, Dahl stepped aside, promoting coworker and npm creator Isaac Schlueter to manage the project.[19]

In January 2014, Schlueter announced Timothy J Fontaine would be Node.js' new project lead.[20]

Technical

Overview

The creator of Node.js originally had the goal of creating Web sites with push capabilities such as those seen in Gmail. After trying solutions in several other programming languages, he chose JavaScript because of the lack of an existing I/O API. This allowed him to define a convention of asynchronous, event-driven I/O.[21]

JavaScript has no unified API for I/O, allowing the developers to think about the best way to implement a modern I/O interface. In Node.js, the fact that all I/O is implemented in an asynchronous and non-blocking way, combined with a single-threaded event-based loop, presented a novel way to implement real-time Web applications. Node.js can therefore keep many connections alive transparently without having to reject new incoming connections.

Node.js applications are designed to maximize throughput and efficiency, using non-blocking I/O and asynchronous events. It is commonly used for real-time applications due to its asynchronous nature. Node.js internally uses the Google V8 JavaScript engine to execute code, and a large percentage of the basic modules are written in JavaScript. Node.js contains a built-in asynchronous I/O library for file, socket, and HTTP communication, which allows applications to act as a Web server without software such as Apache HTTP Server or IIS.

Node.js is influenced by other models, such as the Ruby Event Machine and Python's Twisted model. The difference between alternatives is the implementation of the event loop as a language instead of a library. Unlike traditional models, which use blocking calls, Node.js does not have event-loop calls. Instead, Node.js enters the loop after executing the script, based on how JavaScript works. Ruby's Mongrel Web server was another source of inspiration.[22]

Node.js applications usually run single-threaded, although multi-threaded execution is supported on Node.js 0.10+ from JXcore. Node.js is based on single-threaded execution, although Node.js uses multiple threads for file and network events.

Node.js can be compiled locally or downloaded as a pre-compiled binary. Applications are executed from the command line with the command: "node <application name>.js"

Threading

Node.js operates on a single thread, using non-blocking I/O calls, allowing it to support tens of thousands of concurrent connections, without worrying about the cost of context-switching between threads. The design of sharing a single-thread between all the requests means it can be used to build highly concurrent applications. The design goal of a Node.js application is that any function performing I/O must use a callback.

A downside of this approach is that Node.js doesn't allow scaling with the number of CPU cores of the machine it is running on.

V8

V8 is the JavaScript execution engine built for Google Chrome, open-sourced by Google in 2008. Written in C++, V8 compiles JavaScript source code just-in-time to machine code instead of interpreting it in real time.

Node.js contains libuv to handle asynchronous events. V8 provides the run-time for JavaScript. Libuv is an abstraction layer for network and file system functionality on both Windows and POSIX-based systems like Linux, Mac OS X and Unix.

The core functionality of Node.js resides in a JavaScript library. The Node.js bindings, written in C++, connect these technologies to each other and to the operating system.

Package management

Npm is the pre-installed package manager for the Node.js server platform. It is used to install Node.js programs from the npm registry. By organizing the installation and management of third-party Node.js programs, it helps developers build faster. npm is not to be confused with the commonJS require() statement. It is not used to load code: instead, it is used to install code and manage code dependencies from the command line. The packages found in the npm registry can range from simple helper libraries like underscore.js to task runners like Grunt.

Unified API

Node.js combined with a browser, a document DB (such as MongoDB or CouchDB) and JSON offers a unified JavaScript development stack. With the increased attention to client-side frameworks and the adaptation of what were essentially server-side development patterns like MVC, MVP, MVVM, etc., Node.js allows the reuse of the same model and service interface between client-side and server-side.

Event loop

Node.js registers itself with the operating system so that it is notified when a connection is made. When a connection is made, the operating system will issue a callback. Within the Node.js runtime, each connection is a small heap allocation. Traditionally, relatively heavyweight OS processes or threads handled each connection. Node.js, however, uses an event loop, instead of processes or threads, to scale to millions of connections happening at the same time[citation needed]. In contrast to other event-driven servers, Node.js' event loop does not need to be called explicitly. Instead callbacks are defined, and the server automatically enters the event loop at the end of the callback definition. Node.js exits the event loop when there are no further callbacks to be performed.

Community

Node.js has a developer community primarily centered on two mailing lists and the IRC channel #node.js on freenode. The community gathers at NodeConf, an annual developer conference focused on Node.js.[23]

Tools

Desktop IDEs
Online code editors
Runtimes and debuggers
Application Performance Management
  • ruxit (cloud service, commercial) - SAAS based APM solution[26]

Alternatives

Similar environments available for other programming languages include:

See also

References

  1. ^ https://github.com/joyent/node/tags?after=v0.0.4. Retrieved 2 August 2014. {{cite web}}: Missing or empty |title= (help)
  2. ^ a b https://github.com/joyent/node/blob/master/ChangeLog. Retrieved 30 October 2014. {{cite web}}: Missing or empty |title= (help)
  3. ^ Industry Usage, Node.js Website
  4. ^ Geitgey, Adam (30 October 2013). "I-Tier: Dismantling the Monoliths". Groupon. Retrieved 30 April 2014.
  5. ^ "SAP AppBuilder". SAP. March 10, 2014. Retrieved March 10, 2014.
  6. ^ "You'll never believe how LinkedIn built its new iPad app". VentureBeat. May 2, 2012. Retrieved May 10, 2012.
  7. ^ http://engineering.linkedin.com/nodejs/blazing-fast-nodejs-10-performance-tips-linkedin-mobile. Retrieved 2 August 2014. {{cite web}}: Missing or empty |title= (help)
  8. ^ "Here's why you should be happy that Microsoft is embracing Node.js". The Guardian. November 9, 2011. Retrieved May 10, 2012.
  9. ^ "WebMatrix - Front End Web Developers take note (ASP.NET, PHP, node.js and more)". Retrieved 2 August 2014.
  10. ^ http://developer.yahoo.com/blogs/ydn/posts/2011/11/yahoo-announces-cocktails-%E2%80%93-shaken-not-stirred/. Retrieved 2 August 2014. {{cite web}}: Missing or empty |title= (help)
  11. ^ "Why Walmart is using Node.js". VentureBeat. January 24, 2012. Retrieved May 10, 2012.
  12. ^ "Clash of the Titans: Releasing the Kraken, NodeJS @paypal". fluentconf.com. May 28, 2013. Retrieved September 11, 2013.
  13. ^ "All such companies and their products in which Node.js is used". Retrieved 2 August 2014.
  14. ^ Alex Handy (2011-06-24). "Node.js pushes JavaScript to the server-side". SDTimes. Retrieved 2011-09-04.
  15. ^ Harris, Amber (April 1, 2012). "The Birth of Node: Where Did it Come From? Creator Ryan Dahl Shares the History". Devops Angle. Retrieved 26 October 2013.
  16. ^ "Ryan Dahl at JSConf EU 2009".
  17. ^ "Ryan Dahl at JSConf EU 2009 Video".
  18. ^ "Porting Node to Windows". Retrieved 2 August 2014.
  19. ^ Dahl, Ryan. "New gatekeeper". Retrieved 26 October 2013.
  20. ^ Schlueter, Isaac (January 15, 2014). "The Next Phase of Node.js". Retrieved 21 January 2014.
  21. ^ Hughes-Croucher, Tom; Wilson, Mike (2012). Up and Running with Node.js. Up and Running (1st ed.). Sebastopol: O'Reilly. p. vii. ISBN 978-1-4493-9858-3. I was concerned about the ability to program advanced push features into the website like I had seen in Gmail
  22. ^ Synodinos, Dio (December 13, 2010). "Deep inside Node.js with Ryan Dahl". InfoQ. Retrieved 26 October 2013.
  23. ^ Finley, Klint (April 7, 2011). "NodeConf Schedule Announced". ReadWriteHack. Retrieved 2 August 2014.
  24. ^ "Node.js Tools for Visual Studio". Codeplex. Retrieved 2 August 2014.
  25. ^ "Bergius: Flowhub and the GNOME Developer Experience". LWN.net. 2014-05-02. Retrieved 2014-05-24.
  26. ^ Mike Kopp (2014-11-27). "There's a new kid in town: node.js monitoring". blog.ruxit.com. Retrieved 2014-11-28.

Further reading

Wikimedia Commons has media related to Node.js.
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