prevent double-play through race condition

views/player.py

@@ -2,7 +2,7 @@ from app_instance import api
 
 from wiz_game import the_game
 from starlette.websockets import WebSocketDisconnect
-
+import asyncio
 
 @api.route("/player/{player}")
 def show(req, resp, player: str):
@@ -31,19 +31,28 @@ def show(req, resp, player: str):
 
 @api.route("/player/{player}/play/{card}")
 async def play(req, resp, player: str, card: str):
+    lock = asyncio.Lock()
     p = int(player)
     c = int(card)
-    the_game.play_card(p, c)
-    if the_game.is_hand_finished():
-        print("hand finished")
-        trick_winner, highest_card = the_game.get_trick_winner()
-        trick_winner.take_trick()
-        #the_game.next_hand()
-    elif the_game.is_trick_finished():
-        print("trick finished")
-        trick_winner, highest_card = the_game.get_trick_winner()
-        trick_winner.take_trick()
-        the_game.next_trick()
+
+    async with lock:
+        try:
+            isActive = the_game.players_ordered[the_game.active_player].id == p
+        except IndexError:
+            isActive = False
+            print("show p: {} | {}".format('None', p))
+        if isActive:
+            the_game.play_card(p, c)
+            if the_game.is_hand_finished():
+                print("hand finished")
+                trick_winner, highest_card = the_game.get_trick_winner()
+                trick_winner.take_trick()
+                #the_game.next_hand()
+            elif the_game.is_trick_finished():
+                print("trick finished")
+                trick_winner, highest_card = the_game.get_trick_winner()
+                trick_winner.take_trick()
+                the_game.next_trick()
 
     url = '/player/'+player
     for ws in the_game.websockets: