Python CODE——Nonblocking I/O client AND Delaying Server

 #!Nonblocking I/O - Chapter 5 -pollclient.py
 import socket,sys,select
 port=51423
 host='localhost'

 spinsize=10
 spinpos=0
 spindir=1

 def spin():
     global spinsize,spinpos,spindir
     spinstr='.'*spinpos+'|'+'.'*(spinsize-spinpos-1)
     sys.stdout.write('\r'+spinstr+'  ')
     sys.stdout.flush()

     spinpos+=spindir
     if spinpos<0:
         spindir=1
         spinpos=1
     elif spinpos>=spinsize:
         spinpos-=2
         spindir=-1

 sock=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
 sock.connect((host,port))

 p=select.poll()
 p.register(sock.fileno(),select.POLLIN|select.POLLERR|select.POLLHUP)

 while True:
     results=p.poll(2002)
     if len(results):
         if results[0][1]==select.POLLIN:
             data=sock.recv(4096).decode()
             if not len(data):
                 print("\rRemote end closed connection; exiting.")
                 break
         sys.stdout.write("\rReceived :"+data)
         sys.stdout.flush()
         spin()
     else:
         print("\rProblem occurred; exiting")
         sys.exit(0)

 #!Delaying Server - Chapter 5 -delayserver.py
 import socket,traceback,time

 host=""
 port=51423

 sock=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
 sock.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
 sock.bind((host,port))
 sock.listen(1)

 while True:
     try:
         clientsock,clientaddr= sock.accept()
     except KeyboardInterrupt:
         raise
     except:
         traceback.print_exc()
         continue

     try:
         print("Got connection from ",clientsock.getpeername)
         while True:
             try:
                 print(time.asctime().encode())
                 clientsock.sendall(time.asctime().encode()+b"\n")
             except:
                 break
             time.sleep(2)
     except (KeyboardInterrupt,SystemExit):
         raise
     except:
         traceback.print_exc()

     try:
         clientsock.close()
     except KeyboardInterrupt:
         raise
     except:
         traceback.print_exc()