Re: Using Kgio::TCPSocket.start with EventMachine (in non blocking way)

[Eric Wong <normalperson@yhbt.net>]

Iñaki Baz Castillo <ibc@aliax.net> wrote:
> Now the first issue is: how to do a non-blocking TCP connection
> (needed within EM environment)? So I found
> "Kgio::TCPSocket.start('127.0.0.1', 80)":

> I basically need a callback "on_connected" to be called when such a
> TCP connection is completed, but honestly I have no idea since it
> seems to require using select/poll (at Ruby level) working on top of a
> EventMachine code, really complex IMHO. Or maybe I miss something.

Kgio::TCPSocket.start is correct.  I'm not sure what you need the
"on_connected" callback for, but you can just do whatever you want
to do on the initial write.  You can keep track of the initial write
vs subsequent writes with an instance variable.

Just try writing, and if you get :wait_writable, tell EM to have it
watch for writability somehow.


  sock = Kgio::TCPSocket.start(...)
  buf = "TEST"
  case buf = sock.kgio_trywrite(buf)
  when :wait_writable
    # Tell EM to wait for sock to be writable
    # It's been a while since I've used EM
    # so I'm not familiar with the API anymore.
  when nil
    # initial write completed

    # otherwise, keep looping if we have an unwritten string
    # (we'll probably hit :wait_writable at the next iteration)
  end while String === buf