From: Peter Yu <roger_callisto@...>
Date: 2001-01-01T16:40:02+09:00
Subject: [ruby-talk:8455] Proper Usage of recv(from)?

After poking around the documentation a bit, I managed to do a little
test server program.   However, I've run into a little problem:

I wanted to keep all the connections within the same thread and simply
use select() and loops to service all the various connections; however,
the sample server's socket.gets will block the thread until after it
finds a newline.  So, I tried using socket.recv(), and it complains
about "recv for buffered IO (IOError)"  Socket.gets() did finally work,
but it does seem rather inefficient to read/echo one single character
at a time...

Anyone know what I'm doing wrong?

The stuff below is the test program.

Thanks in advance,
Peter Yu

require "socket"
class DUCKSOCK
  @@connections = []
  @@handle = nil
  def initialize(port)
    @@handle = TCPServer.open(port)
    @@connections = [@@handle]
  end
  def poll(pause)
    sock = select(@@connections, nil, nil, pause)
    return if sock == nil
    for s in sock[0]
      if (s == @@handle)
        conn = s.accept
        @@connections.push(conn)
        printf ("Connection from %s(%s) on port %s\n", conn.addr[2],
                                                       conn.addr[3],
                                                       conn.addr[1])
      else
        if s.eof?
          printf("Connection from %s(%s) on port %s lost\n", s.addr[2],
                                                             s.addr[3],
                                                             s.addr[1])
          s.close
          @@connections.delete(s)
        else
         #str = s.gets          #This'll block until a newline...
          str=s.recvfrom(100)[0]#Complains about "recv for buffered IO"
         #char = s.getc         #Works, but exceedingly slow.
   	  s.write(str)
        end
      end
    end
  end
end

ds = DUCKSOCK.new(2000)
diff = 0
while true
  time1 = Time.new
  ds.poll(2.0+diff)
  time2 = Time.new
  elapsed = (time2.to_f-time1.to_f)
  diff = 2.0 - elapsed
  while (diff < -2.0)
    diff += 2.0
    printf("Extra!\n");
  end
  print "Elaspsed %10.20f\n" % elapsed
  print time2, "\n"
end


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