Use compact encoding for JSON websocket messages (#67148)

Co-authored-by: Paulus Schoutsen <balloob@gmail.com>

homeassistant/components/websocket_api/commands.py

@@ -480,7 +480,9 @@ async def handle_subscribe_trigger(
             msg["id"], {"variables": variables, "context": context}
         )
         connection.send_message(
-            json.dumps(message, cls=ExtendedJSONEncoder, allow_nan=False)
+            json.dumps(
+                message, cls=ExtendedJSONEncoder, allow_nan=False, separators=(",", ":")
+            )
         )
 
     connection.subscriptions[msg["id"]] = (

homeassistant/components/websocket_api/const.py

@@ -53,4 +53,6 @@ SIGNAL_WEBSOCKET_DISCONNECTED: Final = "websocket_disconnected"
 # Data used to store the current connection list
 DATA_CONNECTIONS: Final = f"{DOMAIN}.connections"
 
-JSON_DUMP: Final = partial(json.dumps, cls=JSONEncoder, allow_nan=False)
+JSON_DUMP: Final = partial(
+    json.dumps, cls=JSONEncoder, allow_nan=False, separators=(",", ":")
+)

tests/components/websocket_api/test_messages.py

@@ -83,13 +83,13 @@ async def test_message_to_json(caplog):
 
     json_str = message_to_json({"id": 1, "message": "xyz"})
 
-    assert json_str == '{"id": 1, "message": "xyz"}'
+    assert json_str == '{"id":1,"message":"xyz"}'
 
     json_str2 = message_to_json({"id": 1, "message": _Unserializeable()})
 
     assert (
         json_str2
-        == '{"id": 1, "type": "result", "success": false, "error": {"code": "unknown_error", "message": "Invalid JSON in response"}}'
+        == '{"id":1,"type":"result","success":false,"error":{"code":"unknown_error","message":"Invalid JSON in response"}}'
     )
     assert "Unable to serialize to JSON" in caplog.text