Creating non-blocking socket in python

Question

I was trying to understand how non-blocking sockets work ,so I wrote this simple server in python .

import socket

s=socket.socket(socket.AF_INET, socket.SOCK_STREAM)

s.bind(('127.0.0.1',1000))
s.listen(5)
s.setblocking(0)
while True:
      try:
            conn, addr = s.accept()
            print ('connection from',addr)
            data=conn.recv(100)
            print ('recived: ',data,len(data))

      except:
          pass  

Then I tried to connect to this server from multiple instances of this client

import socket

s=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('127.0.0.1',1000))
while True:
    continue

But for some reason putting blocking to 0 or 1 dose not seem to have an effect and server's recv method always block the execution. So, dose creating non-blocking socket in python require more than just setting the blocking flag to 0.

Answer 1

setblocking only affects the socket you use it on. So you have to add conn.setblocking(0) to see an effect: The recv will then return immediately if there is no data available.