Rack (web server interface)

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Rack, a Ruby Webserver Interface
Original author(s) Christian Neukirchen
Developer(s) James Tucker, Josh Peek, José Valim, Michael Fellinger, Aaron Patterson, Santiago Pastorino, Konstantin Haase
Stable release 1.5.1 / January 28, 2013 (2013-01-28)
Operating system Cross-platform
Type Middleware
License MIT License
Website rack.github.io

Rack provides a modular and adaptable interface for developing web applications in Ruby. By wrapping HTTP requests and responses it unifies the API for web servers, web frameworks, and software in between (called middleware) into a single method call.

Rack is used by many Ruby web frameworks and libraries, such as Ruby On Rails and Sinatra. It is available as a Ruby Gem.

Rack has already inspired a JavaScript framework[1] (jackjs) and a Perl one (Plack), a Common Lisp one[2] (Clack), and has resulted in the Ruby developer quasi-standard of "rack-compliant".[3]

It was also cited as an inspiration for OWIN.[4]

Example application[edit]

A Rack-compatible "Hello World" application in Ruby syntax:

app = lambda do |env|
  body = "Hello, World!"
  [200, {"Content-Type" => "text/plain", "Content-Length" => body.length.to_s}, [body]]

run app

See also[edit]


  1. ^ jack - introduction. Jackjs.org. Retrieved on 2013-09-20.
  2. ^ clacklisp.org. Retrieved on 2014-10-17.
  3. ^ Pancake: How To Stack and Loosely Couple Rack-Based Webapps Together. Rubyinside.com (2009-12-04). Retrieved on 2013-09-20.
  4. ^ http://www.asp.net/aspnet/overview/owin-and-katana/an-overview-of-project-katana. Asp.net. Retrieved on 2014-10-01.

External links[edit]