feat: 站内信 (#6183)

* 添加站内信

* s

* s

* 添加接口

* fix

* fix

* 重构了一些

* 完成

* 完善

* s

* s

* s

* s

* s

* s

* 测试ok

* 替换业务中发送消息的方式

* 修改

* s

* 去掉 update 兼容 create

* 添加 unread total 接口

* 调整json字段

Co-authored-by: xinwen <coderWen@126.com>

apps/notifications/serializers/notifications.py

@@ -0,0 +1,29 @@
+from rest_framework import serializers
+
+from common.drf.serializers import BulkModelSerializer
+from notifications.models import SystemMsgSubscription
+
+
+class SystemMsgSubscriptionSerializer(BulkModelSerializer):
+    receive_backends = serializers.ListField(child=serializers.CharField())
+
+    class Meta:
+        model = SystemMsgSubscription
+        fields = (
+            'message_type', 'message_type_label',
+            'users', 'groups', 'receive_backends', 'receivers'
+        )
+        read_only_fields = (
+            'message_type', 'message_type_label', 'receivers'
+        )
+        extra_kwargs = {
+            'users': {'allow_empty': True},
+            'groups': {'allow_empty': True},
+            'receive_backends': {'required': True}
+        }
+
+
+class SystemMsgSubscriptionByCategorySerializer(serializers.Serializer):
+    category = serializers.CharField()
+    category_label = serializers.CharField()
+    children = SystemMsgSubscriptionSerializer(many=True)