Rack 0.3, a modular Ruby webserver interface


Today I’m proud to release Rack 0.3.

= Rack, a modular Ruby webserver interface

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

The exact details of this are described in the Rack specification,
which all Rack applications should conform to.

== Supported web servers

The included handlers connect all kinds of web servers to Rack:

  • Mongrel
  • Mongrel/Swiftcore (require it before requiring rack)
  • WEBrick
  • FCGI
  • CGI
  • SCGI
  • LiteSpeed

These web servers include Rack handlers in their distributions:

  • Ebb
  • Fuzed
  • Thin

Any valid Rack app will run the same on all these handlers, without
changing anything.

== Supported web frameworks

The included adapters connect Rack with existing Ruby web frameworks:

  • Camping

These frameworks include Rack adapters in their distributions:

  • Coset
  • Halcyon
  • Maveric
  • Merb
  • Racktools::SimpleApplication
  • Ramaze
  • Sinatra
  • Vintage

Ruby on Rails can be run with the adapter included with Thin, which
will be merged into a later Rack version.

Current links to these projects can be found at

== Available middleware

Between the server and the framework, Rack can be customized to your
applications needs using middleware, for example:

  • Rack::URLMap, to route to multiple applications inside the same
  • Rack::CommonLogger, for creating Apache-style logfiles.
  • Rack::ShowException, for catching unhandled exceptions and
    presenting them in a nice and helpful way with clickable backtrace.
  • Rack::File, for serving static files.
  • …many others!

All these components use the same interface, which is described in
detail in the Rack specification. You can choose to use them exactly
in the way you want.

== Convenience

If you want to develop outside of existing frameworks, implement your
own ones, or develop middleware, Rack provides many helpers to create
Rack applications quickly and without doing the same web stuff all

  • Rack::Request, which also provides query string parsing and
    multipart handling.
  • Rack::Response, for convenient generation of HTTP replies and
    cookie handling.
  • Rack::MockRequest and Rack::MockResponse for efficient and quick
    testing of Rack application without real HTTP round-trips.

== rackup

rackup is a useful tool for running Rack applications, which uses the
Rack::Builder DSL to configure middleware and build up applications

rackup automatically figures out the environment it is run in, and
runs your application as FastCGI, CGI, or standalone with Mongrel or
WEBrick—all from the same configuration.

== Where can I get it?

You can download Rack 0.3 at


Alternatively, you can checkout from the development repository with:

       darcs get http://chneukirchen.org/repos/rack

(Patches using “darcs send” are most welcome.)

== Installing with RubyGems

A Gem of Rack is available. You can install it with:

gem install rack

I also provide a local mirror of the gems (and development snapshots)
at my site:

gem install rack --source http://chneukirchen.org/releases/gems

== History

  • March 3rd, 2007: First public release 0.1.

  • May 16th, 2007: Second public release 0.2.

    • HTTP Basic authentication.
    • Cookie Sessions.
    • Static file handler.
    • Improved Rack::Request.
    • Improved Rack::Response.
    • Added Rack::ShowStatus, for better default error messages.
    • Bug fixes in the Camping adapter.
    • Removed Rails adapter, was too alpha.
  • February 26th, 2008: Third public release 0.3.

    • LiteSpeed handler, by Adrian M…
    • SCGI handler, by Jeremy E…
    • Pool sessions, by blink.
    • OpenID authentication, by blink.
    • :Port and :File options for opening FastCGI sockets, by blink.
    • Last-Modified HTTP header for Rack::File, by blink.
    • Rack::Builder#use now accepts blocks, by Corey J…
      (See example/protectedlobster.ru)
    • HTTP status 201 can contain a Content-Type and a body now.
    • Many bugfixes, especially related to Cookie handling.

== Contact

Please mail bugs, suggestions and patches to
mailto:[email protected].

Darcs repository (“darcs send” is welcome for patches):

You are also welcome to join the #rack channel on irc.freenode.net.

== Thanks to

  • Michael F., for the helpful discussion, bugfixes and a better
    Rack::Request interface.
  • Adrian M., for the LiteSpeed handler.
  • Christoffer S., for the Rails adapter.
  • Tim F., for the HTTP authentication code.
  • Luc H. for the Cookie sessions, the static file handler and
  • blink for the Pool sessions, OpenID support, various tweaks, and
  • Armin Ronacher, for the logo and racktools.
  • Aredridel, for bug fixing.
  • Gary W., for proposing a better Rack::Response interface.
  • Jonathan B., for improvements regarding Rack::Response.
  • Armin Röhrl, for tracking down bugs in the Cookie generator.
  • Alexander Kellett for testing the Gem and reviewing the announce.
  • Marcus Rückert, for help with configuring and debugging lighttpd.
  • The WSGI team for the well-done and documented work they’ve done and
    Rack builds up on.

== Copyright

Copyright (C) 2007, 2008 Christian N.

Rack is freely distributable under the terms of an MIT-style license.

== Links

Rack:: http://rack.rubyforge.org/
Rack’s Rubyforge project:: http://rubyforge.org/projects/rack

Christian N.:: http://chneukirchen.org/

Happy hacking and have a nice day,
Christian N.

5e92f2901d2dc77eb0453fc3acdd6c4a07fc167a rack-0.3.0.tar.gz
fedf79e0fb9a41b2c442b982fa0546d2fd3ebec0 rack-0.3.0.gem

On 2008-02-26, Christian N. [email protected] wrote:

I also provide a local mirror of the gems (and development snapshots)
at my site:

gem install rack --source http://chneukirchen.org/releases/gems

gem install rack --source Index of /releases/gems/
with rubygems 0.9.5.