leech

Leech

Leech is simple TCP client/server framework. Server is similar to rack, but is designed for asynchronously handling a short text commands. It can be used for some monitoring purposes or simple communication between few machines.

Installation

You can install Leach directly from rubygems:

gem install leach 

Gettings started

Leech is using simple TCP client/server architecture. It's a simple processor for text commands passed through TCP socket.

Server

Server can be created in two ways:

server = Leech::Server.new :port => 666
server.use :auth
server.run

...or using block style:

Leech::Server.new do 
  port 666
  use :auth
  run
end

Server configuration

You can pass frew configuration options when you are creating new server, eg:

Leech::Server.new(port => 666, :host => 'myhost.com', :timeout => 60)

For more information about allowed parameters visit This doc page.

Handlers

Handlers are extending functionality of server by defining custom command handling callbacks or server instance methods.

For simple commands handling you can use inline handler, which is automatically used by server, eg.

Leech::Server.new do 
  handle(/^PRINT) (.*)$/ {|env,params| print params[0]}
  handle(/^DELETE FILE (.*)$/) {|env,params| File.delete(params[0])}
end 

For advanced tasks, you can write own handler, which will add new functionality to server instance.

class CustomHandler < Leech::Handler
  # This method is automaticaaly called when server will use this handler
  def self.used(server)
    server.instance_eval { extend ServerMethods }
  end
  
  module ServerMethods
    def say_hello
      answer("Hello!")
    end
  end

  handle /^Hello server!$/, :say_hello
  handle /^Bye!$/ do |env,params|
    env.answer("Take care!")
  end
end

To enable this handler in the server you can simply type:

Leech::Server.new do 
  use CustomHandler
end

You should notice that block-style callbacks are passing two arguments: env - instance of server which is using this handler for processing, and params - array of strings fetched from matched command.

Answering

For sending answers to clients server have the #answer method. It can be used like here:

Leech::Server.new do
  handle /^HELLO$/ do |env,params| env.answer("HELLO MY FRIEND!\n")
end 

Running / Listening

Server is partialy acting as Thread. You can join it's instance so application will be waiting to interrupt or some unhandled server error:

server = Leech::Server.new
server.run
server.join # on server.acceptor.join

You can also simple use:

server.run.join

Client

Client will be implemented in 0.2.0 version.

Links

• Author blog
• YARD documentation
• Changelog

Note on Patches/Pull Requests

• Fork the project.
• Make your feature addition or bug fix.
• Add tests for it. This is important so I don't break it in a future version unintentionally.
• Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
• Send me a pull request. Bonus points for topic branches.

Copyright

Copyright (c) 2010 Kriss Kowalik. See LICENSE for details.