add a player class for buffer splitting etc.

main.py

@@ -2,35 +2,31 @@
 
 import selectors
 import socket
+import atexit
+from player import Player
 
 sel = selectors.DefaultSelector()
+players = []
 
 def accept(sock, mask):
 	conn, addr = sock.accept()  # Should be ready
-	print('accepted', conn, 'from', addr)
-	conn.setblocking(False)
-	sel.register(conn, selectors.EVENT_READ, read)
-
-def read(conn, mask):
-	data = conn.recv(1000)  # Should be ready
-	if data:
-		print('echoing', repr(data), 'to', conn)
-		conn.send(data)  # Hope it won't block
-		conn.send('Danke für Ihre Nachricht!'.encode("utf-8"))
-	else:
-		print('closing', conn)
-		sel.unregister(conn)
-		conn.close()
+	player = Player(sel, conn)
+	players.append(player)
+	sel.register(conn, selectors.EVENT_READ, player.read)
 
 sock = socket.socket()
 sock.bind(('0.0.0.0', 1234))
 sock.listen(100)
-sock.setblocking(False)
 sel.register(sock, selectors.EVENT_READ, accept)
 
-while True:
-	events = sel.select()
-	for key, mask in events:
-		callback = key.data
-		callback(key.fileobj, mask)
+try:
+    while True:
+        events = sel.select()
+        for key, mask in events:
+            callback = key.data
+            callback(key.fileobj, mask)
+finally:
+    sock.close()
+    for player in players:
+        player.close()
 

player.py

+from util import *
+
+class Player:
+    def __init__(self, sel, conn):
+        self.buffer = b""
+        self.sel = sel
+        self.conn = conn
+    
+    # low-level functions
+    def send(self, data):
+        assert type(data) == str
+        send_async(self.conn, (data+"\n").encode('utf-8'))
+    
+    def close(self):
+        self.conn.close()
+    
+    def read(self, conn, mask):
+        assert self.conn == conn, "The player's connection changed?"
+        data = conn.recv(1024)  # Should be ready
+        if data:
+            self.buffer += data
+            pos = self.buffer.find(b'\n')
+            if pos >= 0:
+                cmd = self.buffer[:pos]
+                self.buffer = self.buffer[pos+1:]
+                self.readCmd(cmd.decode('utf-8'))
+        else:
+            log_stdout('closing', conn)
+            self.sel.unregister(conn)
+            conn.close()
+    
+    # high(er)-level functions
+    def readCmd(self, cmd):
+        self.send("Selber "+cmd)

util.py

+import threading, traceback, sys
+
+# run a Python command asynchronously
+def fire_and_forget(f):
+    def _fire_and_forget():
+        try:
+            f()
+        except Exception:
+            log_stderr("fire_and_forget: Got exception out of callback:\n%s" % traceback.format_exc())
+    t = threading.Thread(target=_fire_and_forget)
+    t.start()
+
+def send_async(conn, data):
+    fire_and_forget(lambda: conn.send(data))
+
+def log_stdout(*args):
+    print(*args, file=sys.stdout, flush=True)
+def log_stderr(*args):
+    print(*args, file=sys.stdout, flush=True)