feat: change cache condition for plate order query api

api_v1/views/printing/views.py

@@ -10,6 +10,7 @@ from rest_framework.parsers import MultiPartParser, FormParser, JSONParser
 from django.db.models import CharField, Prefetch
 from django.db.models.functions import Cast, Coalesce
 from django.views.decorators.cache import cache_page
+from django.views.decorators.http import condition
 from django.utils.decorators import method_decorator
 from django_filters.rest_framework import DjangoFilterBackend
 from django_filters import rest_framework as django_filters
@@ -556,7 +557,16 @@ class PlateOrderFilterSet(django_filters.FilterSet):
         fields = ['customer', 'salesperson', 'merchandiser', 'urgency_level', 'is_invalid', 'is_ordered']
 
 
-@method_decorator(cache_page(20), name='list')
+def _plate_order_last_modified(request, *args, **kwargs):
+    """
+    返回 PlateOrder 表中最新的 updated_at 时间。
+    用于条件请求（304 Not Modified）判断。
+    """
+    latest = models.PlateOrder.objects.order_by('-updated_at').values_list('updated_at', flat=True).first()
+    return latest
+
+
+@method_decorator(condition(last_modified_func=_plate_order_last_modified), name='list')
 class PlateOrderViewSet(LimitedModelViewSet):
     """
     开版订单 ViewSet