EventMachine Cheat Sheet

eventmachine.cheat

EventMachine
============

Installation:
$ gem install eventmachine

Synchronous Ruby code (Not EM appropriate):
ret = operation(); do_something_with(ret)

Evented, asynchronous code (EM appropriate):
operation{ |ret| do_something_with(ret) }

Start the reactor:
EM.run {...} | EventMachine.run do ... end

Check that the reactor is running:
EM.reactor_running?

Start a server:
EM.run do
  EM.start_server '0.0.0.0', 6666, FooServer 
end

Stop the reactor:
EM.stop | EM.run{ puts "reactor started!"; EM.stop; }; puts "this will happen"

Queue a proc to be executed on the next iteration of the reactor loop:
EM.next_tick | do_work = proc{...}; EM.next_tick(&do_work)

Iterate over multiple ticks of the reactor:
EM::Iterator.new(0..10, 2).each(proc{ |num,iter| iter.next }, proc{ puts 'All done' })

Set the size of the worker thread pool:
EM.threadpool_size

Push a job onto the thread pool:
EM.defer(proc{ result = long_blocking_call_on_worker_thread; result }, proc{|result| use_reactor_thread(result) })

Schedule/defer something for specified seconds:
EventMachine.add_timer(1) { puts "hello one second from #{time}!" }

Create interval timing:
EM::PeriodicTimer.new(0.25) { foo_every_quarter_second() }

Specify event handlers:
operation{ do_something } | operation(proc{ do_something }) | operation(&method(:do_something)) | operation(obj.method(:do_something))

Standard EM:Callback interface:
def operation(*args, &blk) { handler = EM::Callback(*args, &blk); handler.call }


EM.schedule
EM::Deferrable
EM::Queue
EM::Channel
EM.system
EM.start_server (and EM.stop_server): TCP Server
EM.connect (and EM.bind_connect): TCP Client
EM.open_datagram_socket: UDP Socket
EM::Protocols
EM.watch and EM.attach
EM.watch_file
EM.watch_process
EM.open_keyboard