111 lines
4.0 KiB
Markdown
111 lines
4.0 KiB
Markdown
# About EventMachine [](https://travis-ci.org/eventmachine/eventmachine) [](https://codeclimate.com/github/eventmachine/eventmachine/maintainability)
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## What is EventMachine ##
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EventMachine is an event-driven I/O and lightweight concurrency library for Ruby.
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It provides event-driven I/O using the [Reactor pattern](http://en.wikipedia.org/wiki/Reactor_pattern),
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much like [JBoss Netty](http://www.jboss.org/netty), [Apache MINA](http://mina.apache.org/),
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Python's [Twisted](http://twistedmatrix.com), [Node.js](http://nodejs.org), libevent and libev.
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EventMachine is designed to simultaneously meet two key needs:
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* Extremely high scalability, performance and stability for the most demanding production environments.
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* An API that eliminates the complexities of high-performance threaded network programming,
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allowing engineers to concentrate on their application logic.
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This unique combination makes EventMachine a premier choice for designers of critical networked
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applications, including Web servers and proxies, email and IM production systems, authentication/authorization
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processors, and many more.
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EventMachine has been around since the early 2000s and is a mature and battle-tested library.
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## What EventMachine is good for? ##
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* Scalable event-driven servers. Examples: [Thin](http://code.macournoyer.com/thin/) or [Goliath](https://github.com/postrank-labs/goliath/).
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* Scalable asynchronous clients for various protocols, RESTful APIs and so on. Examples: [em-http-request](https://github.com/igrigorik/em-http-request) or [amqp gem](https://github.com/ruby-amqp/amqp).
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* Efficient network proxies with custom logic. Examples: [Proxymachine](https://github.com/mojombo/proxymachine/).
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* File and network monitoring tools. Examples: [eventmachine-tail](https://github.com/jordansissel/eventmachine-tail) and [logstash](https://github.com/logstash/logstash).
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## What platforms are supported by EventMachine? ##
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EventMachine supports Ruby 1.8.7 through 2.6, REE, JRuby and **works well on Windows** as well
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as many operating systems from the Unix family (Linux, Mac OS X, BSD flavors).
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## Install the gem ##
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Install it with [RubyGems](https://rubygems.org/)
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gem install eventmachine
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or add this to your Gemfile if you use [Bundler](http://gembundler.com/):
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gem "eventmachine"
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## Getting started ##
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For an introduction to EventMachine, check out:
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* [blog post about EventMachine by Ilya Grigorik](http://www.igvita.com/2008/05/27/ruby-eventmachine-the-speed-demon/).
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* [EventMachine Introductions by Dan Sinclair](http://everburning.com/news/eventmachine-introductions.html).
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### Server example: Echo server ###
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Here's a fully-functional echo server written with EventMachine:
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```ruby
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require 'eventmachine'
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module EchoServer
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def post_init
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puts "-- someone connected to the echo server!"
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end
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def receive_data data
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send_data ">>>you sent: #{data}"
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close_connection if data =~ /quit/i
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end
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def unbind
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puts "-- someone disconnected from the echo server!"
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end
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end
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# Note that this will block current thread.
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EventMachine.run {
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EventMachine.start_server "127.0.0.1", 8081, EchoServer
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}
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```
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## EventMachine documentation ##
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Currently we only have [reference documentation](http://rdoc.info/github/eventmachine/eventmachine/frames) and a [wiki](https://github.com/eventmachine/eventmachine/wiki).
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## Community and where to get help ##
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* Join the [mailing list](http://groups.google.com/group/eventmachine) (Google Group)
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* Join IRC channel #eventmachine on irc.freenode.net
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## License and copyright ##
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EventMachine is copyrighted free software made available under the terms
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of either the GPL or Ruby's License.
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Copyright: (C) 2006-07 by Francis Cianfrocca. All Rights Reserved.
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## Alternatives ##
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If you are unhappy with EventMachine and want to use Ruby, check out [Celluloid](https://celluloid.io/).
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