EM-Proxy

EventMachine Proxy DSL for writing high-performance transparent / intercepting proxies in Ruby.

Getting started

# install & configure gemcutter repos
gem update --system
gem install gemcutter
gem tumble

gem install em-proxy

irb:0> require 'em-proxy'

Simple port forwarding proxy

Proxy.start(:host => "0.0.0.0", :port => 80, :debug => true) do |conn|
  conn.server :srv, :host => "127.0.0.1", :port => 81

  # modify / process request stream
  conn.on_data do |data|
    p [:on_data, data]
    data
  end

  # modify / process response stream
  conn.on_response do |backend, resp|
    p [:on_response, backend, resp]
    resp
  end

  # termination logic
  conn.on_finish do |backend|
    p [:on_finish, name]

    # terminate connection (in duplex mode, you can terminate when prod is done)
    unbind if backend == :srv
  end
end

For more examples see the /examples directory.

  • SMTP Spam Filtering

  • Duplicating traffic

  • Selective forwarding

  • Beanstalkd interceptor

  • etc.