A pure Ruby library for event-driven IO.

This library is designed with portability as the highest priority, which is why it's written in pure Ruby. Consider EventMachine if you need a solution that's faster, more mature, and scalable.


Install the gem:

gem install backport

Or add it to your application's Gemfile:

gem 'backport'



A simple echo server:

require 'backport'

module MyAdapter
  def opening
    puts "Opening a connection"

  def closing
    puts "Closing a connection"

  def receiving data
    write "Client sent: #{data}"
end do
  Backport.prepare_tcp_server(host: 'localhost', port: 8000, adapter: MyAdapter)

An interval server that runs once per second:

require 'backport' do
  Backport.prepare_interval 1 do
    puts "tick"

Using Adapters

Backport servers that handle client connections, such as TCP servers, use an adapter to provide an application interface to the client. Developers can provide their own adapter implementations in two ways: a Ruby module that will be used to extend a Backport::Adapter object, or a class that extends Backport::Adapter. In either case, the adapter should provide the following methods:

  • opening: A callback triggered when the client connection is accepted
  • closing: A callback triggered when the client connection is closed
  • receiving(data): A callback triggered when the server receives data from the client

Backport::Adapter also provides the following methods:

  • write(data): Send raw data to the client
  • write_line(data): Send a line of data to the client
  • close: Disconnect the client from the server
  • closed?: True if the connection is closed
  • remote: A hash of data about the client, e.g., the remote IP address