refactor(system): 重构消息中心功能

- 移除 WebSocket相关代码
- 新增 SSE (Server-Sent Events) 实现消息推送
- 优化消息中心未读数量展示和更新逻辑- 调整消息中心相关 API 和前端展示

backend/dvadmin/system/apps.py

@@ -4,3 +4,7 @@ from django.apps import AppConfig
 class SystemConfig(AppConfig):
     default_auto_field = 'django.db.models.BigAutoField'
     name = 'dvadmin.system'
+
+    def ready(self):
+        # 注册信号
+        import dvadmin.system.signals  # 确保路径正确

backend/dvadmin/system/signals.py

@@ -1,4 +1,10 @@
-from django.dispatch import Signal
+import time
+
+from django.db.models.signals import post_save, post_delete
+from django.dispatch import Signal, receiver
+from django.core.cache import cache
+from dvadmin.system.models import MessageCenterTargetUser
+
 # 初始化信号
 pre_init_complete = Signal()
 detail_init_complete = Signal()
@@ -10,3 +16,12 @@ post_tenants_init_complete = Signal()
 post_tenants_all_init_complete = Signal()
 # 租户创建完成信号
 tenants_create_complete = Signal()
+
+# 全局变量用于标记最后修改时间
+last_db_change_time = time.time()
+
+
+@receiver(post_save, sender=MessageCenterTargetUser)
+@receiver(post_delete, sender=MessageCenterTargetUser)
+def update_last_change_time(sender, **kwargs):
+    cache.set('last_db_change_time', time.time(), timeout=None)  # 设置永不超时的键值对

backend/dvadmin/system/views/download_center.py

@@ -44,6 +44,11 @@ class DownloadCenterViewSet(CustomModelViewSet):
     extra_filter_class = []
 
     def get_queryset(self):
+        # 判断是否是 Swagger 文档生成阶段，防止报错
+        if getattr(self, 'swagger_fake_view', False):
+            return self.queryset.model.objects.none()
+
+        # 正常请求下的逻辑
         if self.request.user.is_superuser:
             return super().get_queryset()
         return super().get_queryset().filter(creator=self.request.user)

backend/dvadmin/system/views/message_center.py

@@ -36,7 +36,7 @@ class MessageCenterSerializer(CustomModelSerializer):
         return serializer.data
 
     def get_user_info(self, instance, parsed_query):
-        if instance.target_type  in (1,2,3):
+        if instance.target_type in (1, 2, 3):
             return []
         users = instance.target_user.all()
         # You can do what ever you want in here
@@ -108,7 +108,7 @@ class MessageCenterTargetUserListSerializer(CustomModelSerializer):
         return serializer.data
 
     def get_user_info(self, instance, parsed_query):
-        if instance.target_type  in (1,2,3):
+        if instance.target_type in (1, 2, 3):
             return []
         users = instance.target_user.all()
         # You can do what ever you want in here
@@ -139,21 +139,6 @@ class MessageCenterTargetUserListSerializer(CustomModelSerializer):
         read_only_fields = ["id"]
 
 
-def websocket_push(user_id, message):
-    """
-    主动推送消息
-    """
-    username = "user_" + str(user_id)
-    channel_layer = get_channel_layer()
-    async_to_sync(channel_layer.group_send)(
-        username,
-        {
-            "type": "push.message",
-            "json": message
-        }
-    )
-
-
 class MessageCenterCreateSerializer(CustomModelSerializer):
     """
     消息中心-新增-序列化器
@@ -182,10 +167,6 @@ class MessageCenterCreateSerializer(CustomModelSerializer):
         targetuser_instance = MessageCenterTargetUserSerializer(data=targetuser_data, many=True, request=self.request)
         targetuser_instance.is_valid(raise_exception=True)
         targetuser_instance.save()
-        for user in users:
-            unread_count = MessageCenterTargetUser.objects.filter(users__id=user, is_read=False).count()
-            websocket_push(user, message={"sender": 'system', "contentType": 'SYSTEM',
-                                          "content": '您有一条新消息~', "unread": unread_count})
         return data
 
     class Meta:
@@ -225,10 +206,6 @@ class MessageCenterViewSet(CustomModelViewSet):
             queryset.save()
         instance = self.get_object()
         serializer = self.get_serializer(instance)
-        # 主动推送消息
-        unread_count = MessageCenterTargetUser.objects.filter(users__id=user_id, is_read=False).count()
-        websocket_push(user_id, message={"sender": 'system', "contentType": 'TEXT',
-                                         "content": '您查看了一条消息~', "unread": unread_count})
         return DetailResponse(data=serializer.data, msg="获取成功")
 
     @action(methods=['GET'], detail=False, permission_classes=[IsAuthenticated])