TCP server with "selectors"

TCP_select.py

@@ -13,18 +13,18 @@ def upper(msg):
     return msg.upper()
 
 
-def ChildHandler(s):
-    data = s.recv(32)
+def child_handler(sock):
+    data = sock.recv(32)
     if not data:
-        socks.remove(s)
-        s.close()
+        socks.remove(sock)
+        sock.close()
         return
 
-    s.sendall(upper(data))
+    sock.sendall(upper(data))
 
 
-def ParentHandler(s):
-    child_sock, client = s.accept()
+def master_handler(sock):
+    child_sock, client = sock.accept()
     socks.append(child_sock)
     print("+ Client connected: {}, Total {} sockets".format(
         client, len(socks)))
@@ -58,8 +58,8 @@ def socket_peer(sock):
 
     for i in read_ready:
         if i == ss:
-            ParentHandler(i)
+            master_handler(i)
         else:
-            ChildHandler(i)
+            child_handler(i)
 
     show_status(socks, read_ready)

TCP_selectors.py

@@ -0,0 +1,46 @@
+#!/usr/bin/python3
+# Copyright: See AUTHORS and COPYING
+"Usage: {0} <port>"
+
+import sys
+import socket
+import selectors
+import time
+
+
+def upper(msg):
+    time.sleep(1)  # simulates a complex job
+    return msg.upper()
+
+
+def child_handler(sock):
+    data = sock.recv(32)
+    if not data:
+        selector.unregister(sock)
+        sock.close()
+        return
+
+    sock.sendall(upper(data))
+
+
+def master_handler(sock):
+    conn, client = sock.accept()
+    selector.register(conn, selectors.EVENT_READ, child_handler)
+    print("+ Client connected: {}".format(client))
+
+
+if len(sys.argv) != 2:
+    print(__doc__.format(sys.argv[0]))
+    sys.exit(1)
+
+ss = socket.socket()
+ss.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+ss.bind(('', int(sys.argv[1])))
+ss.listen(30)
+
+selector = selectors.DefaultSelector()
+selector.register(ss, selectors.EVENT_READ, master_handler)
+
+while True:
+    for key, mask in selector.select():
+        key.data(key.fileobj)