Node.js

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node.js
Node.js logo.svg
Original author(s) Ryan Dahl
Developer(s) Node.js Developers, Joyent, Github Contributors
Initial release May 27, 2009 (2009-05-27)[1]
Stable release 0.10.31 / August 19, 2014 (2014-08-19)[2]
Preview release 0.11.13 / May 1, 2014 (2014-05-01)[2]
Development status Active
Written in C, C++, JavaScript
Operating system OS X, Linux, Solaris, FreeBSD, OpenBSD, Microsoft Windows (older versions require Cygwin), webOS
Type Event-driven networking
License MIT
Website http://www.nodejs.org

Node.js is a 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 and Linux with no changes.

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

History[edit]

Ryan Dahl, creator of Node.js

Node.js was created by Ryan Dahl, starting in 2009. Its development and maintenance was 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 wanted an easier way.[15]

Originally Dahl had several failed projects in C, Lua, and Haskell, but when Google's V8 JavaScript engine was released as open-source, Dahl began to examine JavaScript.[16]

Node.js was first published by Dahl in 2009 and could only run on Linux. It reached international attention after Dahl presented at the inaugural JSConf EU conference.[17][18]

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

In June 2011, Microsoft partnered with Joyent to help create a native Windows version of Node.js.[19] The first Node.js build to support Windows was released in July.

On January 30, 2012 Dahl stepped aside, promoting coworker and npm creator Isaac Schlueter to the gatekeeper position.[20]

On January 15, 2014 Schlueter announced he was making npm his main focus and Timothy J Fontaine would be Node.js' new project lead.[21] The next day, January 16, 2014, Timothy J Fontaine made a followup post outlining the road ahead where he mentioned bug fixing, performance tuning, staying up to date with the V8 engine and tooling as priorities.[22]

Technical[edit]

Overview[edit]

Ryan Dahl, 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.[23]

The goal of Node.js is to offer an easy and safe way to build high performance and scalable network applications in JavaScript. Node.js is part of the Server Side JavaScript environment and extends the JavaScript API to offer server side features. Node.js is able to do this by handling many client connections at the same time. The Node.js API can be extended using the CommonJS module system.

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 is influenced by other models, such as the Ruby Event Machine and Python's Twisted model. Node.js builds on this further by providing the event loop as a language instead of a library[clarification needed]. Unlike the 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.[clarification needed][citation needed] Ruby's Mongrel Web server was another source of inspiration for Dahl.[24]

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[edit]

Traditional Web-serving techniques require each connection (request) to create a new thread, taking up system RAM and eventually maxing-out at the amount of RAM available. Node.js is different. It operates on a single-thread, using non-blocking I/O calls, allowing it to support tens of thousands of concurrent connections, without worrying about RAM limitations and 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 an I/O must use a callback.

V8[edit]

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++, are the glue-layer connecting these technologies to each other and to the operating system.

Package management[edit]

Npm is the package manager that comes pre-installed with 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.js.

Unified API[edit]

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[edit]

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[edit]

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.[25]

Tools[edit]

Desktop IDEs
Online code editors
Runtimes and debuggers

Alternatives[edit]

Similar environments available for other programming languages include:

See also[edit]

References[edit]

  1. ^ https://github.com/joyent/node/tags?after=v0.0.4. Retrieved 2 August 2014.  Missing or empty |title= (help)
  2. ^ a b https://github.com/joyent/node/blob/master/ChangeLog. Retrieved 2 August 2014.  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.  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.  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. ^ McCarthy, Kevin (January 31, 2011). "Node.js Interview: 4 Questions with Creator Ryan Dahl". Streetwise Media. Retrieved 26 October 2013. 
  17. ^ "Ryan Dahl at JSConf EU 2009". 
  18. ^ "Ryan Dahl at JSConf EU 2009 Video". 
  19. ^ "Porting Node to Windows". Retrieved 2 August 2014. 
  20. ^ Dahl, Ryan. "New gatekeeper". Retrieved 26 October 2013. 
  21. ^ Schlueter, Isaac (January 15, 2014). "The Next Phase of Node.js". Retrieved 21 January 2014. 
  22. ^ Fontaine, Timothy (January 16, 2014). "Node.js and the Road Ahead". Retrieved 21 January 2014. 
  23. ^ 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" 
    See the book's Foreword at OReilly.com
  24. ^ Synodinos, Dio (December 13, 2010). "Deep inside Node.js with Ryan Dahl". InfoQ. Retrieved 26 October 2013. 
  25. ^ Finley, Klint (April 7, 201). "NodeConf Schedule Announced". ReadWriteHack. Retrieved 2 August 2014. 
  26. ^ "Node.js Tools for Visual Studio". Codeplex. Retrieved 2 August 2014. 
  27. ^ "Bergius: Flowhub and the GNOME Developer Experience". LWN.net. 2014-05-02. Retrieved 2014-05-24. 

Further reading[edit]

External links[edit]