ged / io-reactor

= IO-Reactor

An implementation of the Reactor design pattern for multiplexed asynchronous
single-thread IO.

== Authors

* Michael Granger <ged@FaerieMUD.org>


== Description

This module is a pure-Ruby implementation of an asynchronous multiplexed IO
Reactor which is based on the Reactor design pattern found in _Pattern-Oriented
Software Architecture, Volume 2: Patterns for Concurrent and Networked
Objects_. It allows a single thread to demultiplex and dispatch events from one
or more IO objects to the appropriate handler.

I would greatly appreciate feedback on any aspect of this software. Suggestions,
feature requests, questions, design critiques, and bug reports are most
welcome. Relevant patches and minimal test cases are particularly helpful. I may
be reached by email at <ged@FaerieMUD.org>, or you can file a ticket at the 
project's Trac:

http://deveiate.org/projects/IO-Reactor/


== Trivial Example

This is a very trivial example -- in most circumstances you'd only use a Reactor
when you're trying to manage reading and writing on more than a single IO 
object.

  require 'io/reactor'
  
  reactor = IO::Reactor.new
  data_to_send = "some stuff to send"
  
  reader, writer = IO.pipe
  
  # Read from the reader end of the pipe until the writer finishes
  reactor.register( reader, :read ) do |io,event|
      if io.eof?
          reactor.unregister( io )
          io.close
      else
          puts io.read( 256 )
      end
  end
  
  # Write to the writer end of the pipe until there's no data left
  reactor.register( writer, :write ) do |io,event|
      bytes = io.write( data_to_send )
      data_to_send.slice!( 0, bytes )
  
      if data_to_send.empty?
          reactor.unregister( io )
          io.close
      end
  end
  
  # Now pump the reactor until both sides are done
  puts "Starting IO"
  reactor.poll until reactor.empty?
  puts "done, exiting."

See the examples/ directory for some working, more full-featured examples.


== Requirements

* Ruby >= 1.8.6

Optional:

* RSpec, if you want to run the tests.


== Installation

If you use RubyGems, you can install via:

  $ sudo gem install io-reactor

You can also install as a site library via the Rakefile:

  $ wget http://deveiate.org/code/io-reactor-x.y.z.tar.gz
  $ tar xzvf io-reactor-x.y.z.tar.gz
  $ cd io-reactor-x.y.z
  $ sudo rake install


== More Information

You can find more information about IO-Reactor, including the latest
distribution and API documentation, at its project page:

http://deveiate.org/projects/IO-Reactor/


== Legal

Copyright (c) 2001-2008, Michael Granger
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

* Neither the name of the author/s, nor the names of the project's
  contributors may be used to endorse or promote products derived from this
  software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 $Id$