From 05235c8df61b0cd6bf588ee15a924576cb10aa0a Mon Sep 17 00:00:00 2001
From: Olivier Gayot <olivier.gayot@sigexec.com>
Date: Wed, 27 May 2020 20:50:16 +0200
Subject: Don't use coroutines for functions sending notifications

Functions which generate notifications for clients were all making use
of await and async. This is not great because if we add a notification
somewhere, we need to change the function to a coroutine and update all
invocations (recursively changing all functions to coroutines).

Instead, we now add a task to the event loop whenever a notification
needs to be generated. This allows to drop the await and async
specifiers from mostly everywhere.

On the downside, it means that if we send a notification to n clients,
we have to register n tasks.

Signed-off-by: Olivier Gayot <olivier.gayot@sigexec.com>
---
 swiftstory/SwiftStory.py | 82 +++++++++++++++++++++++-------------------------
 1 file changed, 40 insertions(+), 42 deletions(-)

(limited to 'swiftstory/SwiftStory.py')

diff --git a/swiftstory/SwiftStory.py b/swiftstory/SwiftStory.py
index b252040..2aa1444 100644
--- a/swiftstory/SwiftStory.py
+++ b/swiftstory/SwiftStory.py
@@ -14,50 +14,48 @@ from swiftstory.Status import error
 game_manager = swiftstory.GameManager.GameManager()
 
 
-async def message_received_handler(client, message):
+def message_received_handler(client, message):
     try:
         json_msg = json.loads(message)
     except JSONDecodeError:
-        res = error('badly formatted json')
-    else:
-        op = json_msg['op']
-        if op == 'join_game':
-            try:
-                game_name = json_msg['game_name']
-            except KeyError:
-                res = error('field `game_name\' is required')
-            else:
-                lang = json_msg.get('lang')
-                res = await client.join_game(game_name, lang)
-        elif op == 'view_player_cards':
-            res = client.view_player_cards()
-        elif op == 'view_black_card':
-            res = client.view_black_card()
-        elif op == 'view_played_cards':
-            res = client.view_played_cards()
-        elif op == 'pick_black_card':
-            res = await client.pick_black_card()
-        elif op == 'designate_card':
-            card_id = None
-            try:
-                card_id = int(json_msg['card_id'])
-            except (KeyError, TypeError):
-                pass
-            finally:
-                res = await client.designate_card(card_id)
-        elif op == 'play_white_card':
-            try:
-                card_id = int(json_msg['card_id'])
-            except KeyError:
-                res = error('field `card_id\' is required')
-            else:
-                res = await client.play_white_card(card_id)
-        elif op == 'collect_cards':
-            res = await client.collect_cards()
+        return error('badly formatted json')
+
+    op = json_msg['op']
+    if op == 'join_game':
+        try:
+            game_name = json_msg['game_name']
+        except KeyError:
+            return error('field `game_name\' is required')
         else:
-            res = error('invalid command')
-
-    await client.socket.send(res)
+            lang = json_msg.get('lang')
+            return client.join_game(game_name, lang)
+    elif op == 'view_player_cards':
+        return client.view_player_cards()
+    elif op == 'view_black_card':
+        return client.view_black_card()
+    elif op == 'view_played_cards':
+        return client.view_played_cards()
+    elif op == 'pick_black_card':
+        return client.pick_black_card()
+    elif op == 'designate_card':
+        card_id = None
+        try:
+            card_id = int(json_msg['card_id'])
+        except (KeyError, TypeError):
+            pass
+        finally:
+            return client.designate_card(card_id)
+    elif op == 'play_white_card':
+        try:
+            card_id = int(json_msg['card_id'])
+        except KeyError:
+            return error('field `card_id\' is required')
+        else:
+            return client.play_white_card(card_id)
+    elif op == 'collect_cards':
+        return client.collect_cards()
+    else:
+        return error('invalid command')
 
 
 async def swiftstory(websocket, path):
@@ -65,9 +63,9 @@ async def swiftstory(websocket, path):
 
     with contextlib.suppress(websockets.exceptions.ConnectionClosed):
         async for message in client.socket:
-            await message_received_handler(client, message)
+            await client.socket.send(message_received_handler(client, message))
 
-    await client.disconnect()
+    client.disconnect()
 
 
 def main():
-- 
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