make dining cache clearable (#415)

* make dining cache clearable

* Remove debug print statements

Removed debug print statements from test_views.py

Author: minghansun1

backend/dining/management/commands/load_next_menu.py

@@ -4,6 +4,7 @@
 from django.utils import timezone
 
 from dining.api_wrapper import DiningAPIWrapper
+from dining.utils.menu_view_cache import delete_menu_view_cache
 
 
 class Command(BaseCommand):
@@ -19,6 +20,7 @@ def load_one_menu(self, delta, *args, **kwargs):
         """
         d = DiningAPIWrapper()
         d.load_menu(timezone.now().date() + datetime.timedelta(days=delta))
+        delete_menu_view_cache(timezone.now().date() + datetime.timedelta(days=delta))
         self.stdout.write(
             "Loaded new Dining Menu for "
             + str(timezone.now().date() + datetime.timedelta(days=delta))

backend/dining/utils/__init__.py

@@ -0,0 +1,22 @@
+from django.core.cache import cache
+from django.utils import timezone
+
+
+VIEW_CACHE_KEY = "clearable_dining_menu_view_cache"
+VIEW_CACHE_TIMEOUT = 60 * 60 * 3  # 3 hours
+
+
+def _get_key(date_param):
+    return f"{VIEW_CACHE_KEY}_{date_param if date_param is not None else timezone.now().date()}"
+
+
+def get_menu_view_cache(date_param):
+    return cache.get(_get_key(date_param))
+
+
+def set_menu_view_cache(date_param, data):
+    cache.set(_get_key(date_param), data, timeout=VIEW_CACHE_TIMEOUT)
+
+
+def delete_menu_view_cache(date_param):
+    cache.delete(_get_key(date_param))

backend/dining/utils/menu_view_cache.py

@@ -15,6 +15,7 @@
 from dining.api_wrapper import APIError, DiningAPIWrapper
 from dining.models import DiningMenu, Venue
 from dining.serializers import DiningMenuSerializer
+from dining.utils.menu_view_cache import get_menu_view_cache, set_menu_view_cache
 from pennmobile.analytics import LabsAnalytics
 from utils.cache import Cache
 
@@ -77,6 +78,17 @@ def get_queryset(self):
 
         return latest
 
+    def get(self, request, *args, **kwargs):
+        try:
+            date_param = self.kwargs.get("date")
+            if get_menu_view_cache(date_param) is not None:
+                return Response(get_menu_view_cache(date_param))
+            res = super().get(request, *args, **kwargs)
+            set_menu_view_cache(date_param, res.data)
+            return res
+        except APIError as e:
+            return Response({"error": str(e)}, status=400)
+
 
 class Preferences(APIView):
     """

backend/dining/views.py

@@ -10,6 +10,10 @@
 import os
 
 import dj_database_url
+from dotenv import load_dotenv
+
+
+load_dotenv()
 
 
 DOMAINS = os.environ.get("DOMAINS", "example.com").split(",")

backend/pennmobile/settings/base.py

@@ -5,12 +5,15 @@
 from django.contrib.auth import get_user_model
 from django.core.management import call_command
 from django.test import TestCase
+from django.test.utils import override_settings
 from django.urls import reverse
+from django.utils import timezone
 from requests.exceptions import ConnectionError
 from rest_framework.test import APIClient
 
 from dining.api_wrapper import APIError, DiningAPIWrapper
 from dining.models import DiningMenu, Venue
+from dining.utils.menu_view_cache import get_menu_view_cache
 
 
 User = get_user_model()
@@ -35,7 +38,12 @@ def json(self):
         raise ValueError
 
     with open(file_path) as data:
-        return Mock(json.load(data), 200)
+        if len(args) > 0 and "menus" in args[0]:
+            res = json.load(data)
+            res["menus"]["days"][0]["date"] = str(timezone.now().date())
+            return Mock(res, 200)
+        else:
+            return Mock(json.load(data), 200)
 
 
 def mock_request_raise_error(*args, **kwargs):
@@ -137,7 +145,7 @@ def test_get_default(self):
         self.try_structure(response.json())
 
     def test_get_date(self):
-        response = self.client.get("/dining/menus/2022-10-04/")
+        response = self.client.get("/dining/menus/" + str(timezone.now().date()) + "/")
         self.try_structure(response.json())
 
     @mock.patch("requests.request", mock_dining_requests)
@@ -149,6 +157,25 @@ def test_skip_venue(self):
         self.assertEqual(DiningMenu.objects.count(), 0)
 
 
+@override_settings(
+    CACHES={
+        "default": {
+            "BACKEND": "django.core.cache.backends.locmem.LocMemCache",
+        }
+    }
+)
+class TestMenuViewCache(TestCase):
+    @mock.patch("requests.post", mock_dining_requests)
+    @mock.patch("requests.request", mock_dining_requests)
+    def test_cache_cleared_on_load_next_menu(self):
+        call_command("load_next_menu")
+        response = self.client.get(reverse("menus-with-date", args=[str(timezone.now().date())]))
+        self.assertEqual(response.status_code, 200)
+        self.assertIsNotNone(get_menu_view_cache(str(timezone.now().date())))
+        call_command("load_next_menu")
+        self.assertIsNone(get_menu_view_cache(str(timezone.now().date())))
+
+
 class TestPreferences(TestCase):
     def setUp(self):
         call_command("load_venues")