Migrate to idiomatic error handling in app/websocket_router.go (#9708)

app/websocket_router.go

@@ -50,10 +50,11 @@ func (wr *WebSocketRouter) ServeWebSocket(conn *WebConn, r *model.WebSocketReque
 		}
 
 		session, err := wr.app.GetSession(token)
-
 		if err != nil {
 			conn.WebSocket.Close()
-		} else {
+			return
+		}
+
 		wr.app.Go(func() {
 			wr.app.SetStatusOnline(session.UserId, false)
 			wr.app.UpdateLastActivityAtIfNeeded(*session)
@@ -67,7 +68,6 @@ func (wr *WebSocketRouter) ServeWebSocket(conn *WebConn, r *model.WebSocketReque
 
 		resp := model.NewWebSocketResponse(model.STATUS_OK, r.Seq, nil)
 		conn.Send <- resp
-		}
 
 		return
 	}
@@ -78,13 +78,11 @@ func (wr *WebSocketRouter) ServeWebSocket(conn *WebConn, r *model.WebSocketReque
 		return
 	}
 
-	var handler webSocketHandler
+	handler, ok := wr.handlers[r.Action]
-	if h, ok := wr.handlers[r.Action]; !ok {
+	if !ok {
 		err := model.NewAppError("ServeWebSocket", "api.web_socket_router.bad_action.app_error", nil, "", http.StatusInternalServerError)
 		ReturnWebSocketError(conn, r, err)
 		return
-	} else {
-		handler = h
 	}
 
 	handler.ServeWebSocket(conn, r)