Merge pull request #821 from uktrade/cache-draft

Cache draft pages

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Implemented enhancements
 - CI-677 - Add CTA link field to Capital Investment homepage hero
+- no ticket - Add cache supoort to draft pages
 
 ## Hotfix
 - No ticket - v3-cipipeline manifest.yml file fix

core/cache.py

@@ -129,6 +129,18 @@ def populate_sync(cls, instance):
                         data=serializer.data,
                         lang=language_code,
                     )
+                    if instance.has_unpublished_changes:
+                        draft_instance = instance.get_latest_nested_revision_as_page()
+                        draft_serializer = serializer_class(
+                            instance=draft_instance,
+                            context={'is_draft': True}
+                        )
+                        page_cache.set(
+                            page_id=instance.id,
+                            data=draft_serializer.data,
+                            lang=language_code,
+                            draft_version=True
+                        )
 
     @classmethod
     def delete(cls, instance):
@@ -138,6 +150,11 @@ def delete(cls, instance):
                     page_id=instance.id,
                     lang=language_code,
                 )
+                page_cache.delete(
+                    page_id=instance.id,
+                    lang=language_code,
+                    draft_version=True
+                )
 
 
 class PageIDCache:

core/fields.py

@@ -15,17 +15,13 @@ def to_representation(self, instance):
 class MetaDictField(fields.DictField):
 
     def get_attribute(self, instance):
-        if 'request' in self.context:
-            is_draft = helpers.is_draft_requested(self.context['request'])
-        else:
-            is_draft = False
         return {
             'languages': [
                 (code, label) for (code, label) in settings.LANGUAGES_LOCALIZED
                 if code in instance.specific.translated_languages
             ],
             'url': instance.specific.get_url(
-                is_draft=is_draft,
+                is_draft=self.context.get('is_draft', False),
                 language_code=settings.LANGUAGE_CODE,
             ),
             'slug': instance.slug,

core/views.py

@@ -1,3 +1,5 @@
+from logging import getLogger
+
 from django_filters.rest_framework import DjangoFilterBackend
 from rest_framework.exceptions import ValidationError
 from rest_framework.renderers import JSONRenderer
@@ -22,6 +24,9 @@
 from core.serializer_mapping import MODELS_SERIALIZERS_MAPPING
 
 
+logger = getLogger(__name__)
+
+
 class PageNotSerializableError(NotImplementedError):
     pass
 
@@ -89,14 +94,13 @@ def detail_view(self, request, **kwargs):
         # Exit early if there are any issues
         self.check_parameter_validity()
 
+        variation_kwargs = {'lang': translation.get_language()}
+
         if helpers.is_draft_requested(request):
-            return super().detail_view(request, pk=None)
+            variation_kwargs['draft_version'] = True
 
         # Return a cached response if one is available
-        cached_data = cache.PageCache.get(
-            page_id=self.object_id,
-            lang=translation.get_language(),
-        )
+        cached_data = cache.PageCache.get(page_id=self.object_id, **variation_kwargs)
         if cached_data:
             cached_response = helpers.CachedResponse(cached_data)
             cached_response['etag'] = cached_data.get('etag', None)
@@ -108,15 +112,22 @@ def detail_view(self, request, **kwargs):
 
         # No cached response available
         response = super().detail_view(request, pk=None)
+
         if response.status_code == 200:
             # Reuse the already-fetched object to populate the cache
             cache.CachePopulator.populate_async(self.get_object())
 
+        logger.warn(f'Page cache miss')
         # No etag is set for this response because creating one is expensive.
         # If API caching is enabled, one will be added to the cached version
         # created above.
         return response
 
+    def get_serializer_context(self):
+        context = super().get_serializer_context()
+        context['is_draft'] = helpers.is_draft_requested(self.request)
+        return context
+
 
 class PagesOptionalDraftAPIEndpoint(APIEndpointBase):
     def listing_view(self, request):

tests/core/test_cache.py

@@ -160,16 +160,23 @@ class TestSubscriber(cache.DatabaseCacheSubscriber):
         model_classes = [Page]
 
     instance = mock.Mock(
-        id=1, slug='some-slug', service_name='thing',
+        id=2, slug='some-slug', service_name='thing',
         translated_languages=['en-gb']
     )
     TestSubscriber.delete(sender=None, instance=instance)
 
-    assert mock_delete.call_count == 1
-    assert mock_delete.call_args == mock.call(
-        page_id=1,
-        lang='en-gb',
-    )
+    assert mock_delete.call_count == 2
+    assert mock_delete.call_args_list == [
+        mock.call(
+            page_id=2,
+            lang='en-gb',
+        ),
+        mock.call(
+            page_id=2,
+            lang='en-gb',
+            draft_version=True,
+        )
+    ]
 
 
 @mock.patch('django.core.cache.cache.set')

tests/core/test_fields.py

@@ -5,7 +5,6 @@
 from wagtail.core.fields import StreamField
 
 from core import fields
-from core import permissions
 from great_international.serializers import InternationalSectorPageSerializer, InternationalArticlePageSerializer
 from tests.great_international.factories import InternationalSectorPageFactory
 
@@ -103,10 +102,9 @@ def test_meta_field_draft(international_root_page, rf):
         parent=international_root_page,
         slug='test-slug',
     )
-    request = rf.get('/', {permissions.DraftTokenPermisison.TOKEN_PARAM: '1'})
     serializer = InternationalSectorPageSerializer(
         instance=sector_page,
-        context={'request': request}
+        context={'is_draft': True}
     )
 
     assert serializer.data['meta']['url'] == sector_page.get_url(is_draft=True)