simplest way to use select with sockets?

I’ve been playing recently with python and network programming. IMHO, writing a server that makes use of select seems to be the simplest select code I’ve ever read/wrote. Here’s how it goes:

import socket,select,sys,pdb

if(len(sys.argv) != 2):
	print "a port must be supplied"
sock = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
read_list = [sock]

while 1:
	current_data = ""	
	infds,outfds,errfds = select.select(read_list,[],read_list,0.05)
	if len(infds):
		for socket in infds:
			if socket==sock:
				clientsock,client_addr = sock.accept()
				current_data = socket.recv(4196)
				if(not len(current_data)):
					print "client disconnected"
		for socket in [socket for socket in read_list if socket != sock]:
			if current_data != "":
				socket.send("a client wrote:%s"%current_data)

The code illustrates a VERY basic messaging “application”, that will listen on a user-supplied port. Each time a client writes a message, the server sends the message to all connected sockets. The message doesn’t get sent to server again ( notice the socket != sock ). The deal with select is that you need to supply it with a list to check for available data, this is the read_list. I’m no socket guru, but this really looks simple, right?


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