From: Ben Giddings <bg-rubytalk@...>
Date: 2004-06-09T23:37:47+09:00
Subject: Re: oddities with select

Ara.T.Howard wrote:
> why not something along the lines of this
> 
>   buf = ''
>   t = Thread.new{ loop{ buf << io.getc } }
>   sleep n_seconds
>   t.kill
> 
>   case buf
>     when %r/^$/o
>       raise "command not accepted"
>     when %r/^\s+$/o
>       #
>       # handle command
>       #
>     else
>       raise "bad response <#{ buf.inspect }>"
>   end


What I'm actually using is pretty close to that:

    def internal_read(timeout=DEFAULT_TIMEOUT, stop_pattern=nil)
     retval = ""

     timed_out = false

     begin
       timeout(timeout) do
         while true
           if select([@sock], [], [], 0.1)
             retval += @sock.recv(256)
             if stop_pattern
               if retval =~ stop_pattern
                 break
               end
             end
           end
         end
       end
     rescue Timeout::Error
       timed_out = true
     end


#     if timed_out
#       puts "Timed out"
#       raise
#     end

     retval
   end

The problem is that although I've seen a newline go over the network to 
my PC, it is never spotted by the Ruby app, which sits there doing the 
'select' forever.

Your code looks slightly different, but I think it would do the exact 
same thing.

For some reason, the newline goes over the network, but doesn't make it 
far enough (in 5s) that the 'select()' call sees it.

Ben