Disabled FilterCls cache by default and fixed cache related bugs

Author: maxipavlovic

dj_rql/drf/backend.py

@@ -35,29 +35,32 @@ def filter_queryset(self, request, queryset, view):
         filter_instance = self._get_filter_instance(filter_class, queryset, view)
         query = self.get_query(filter_instance, request, view)
 
-        def apply_filters_lazy():
-            return filter_instance.apply_filters(query, request, view)
-
-        if filter_class.QUERIES_CACHE_BACKEND and request.method in ('GET', 'HEAD', 'OPTIONS'):
+        can_query_be_cached = all((
+            filter_class.QUERIES_CACHE_BACKEND,
+            filter_class.QUERIES_CACHE_SIZE,
+            request.method in ('GET', 'HEAD', 'OPTIONS'),
+        ))
+        if can_query_be_cached:
             # We must use the combination of queryset and query to make a cache key as
             #  queryset can already contain some filters (e.x. based on authentication)
-            cache_key = hash(str(queryset.query) + query)
+            cache_key = str(queryset.query) + query
 
             query_cache = self._get_or_init_cache(filter_class, view)
             filters_result = query_cache.get(cache_key)
             if not filters_result:
-                filters_result = apply_filters_lazy()
+                filters_result = filter_instance.apply_filters(query, request, view)
                 query_cache[cache_key] = filters_result
+
         else:
-            filters_result = apply_filters_lazy()
+            filters_result = filter_instance.apply_filters(query, request, view)
 
         rql_ast, queryset = filters_result
 
         request.rql_ast = rql_ast
         if queryset.select_data:
             request.rql_select = queryset.select_data
 
-        return queryset
+        return queryset.all()
 
     def get_schema_operation_parameters(self, view):
         spec = []
@@ -84,14 +87,14 @@ def get_query(cls, filter_instance, request, view):
 
     @classmethod
     def _get_or_init_cache(cls, filter_class, view):
-        qual_name = cls._get_filter_cls_qual_name(filter_class, view)
+        qual_name = cls._get_filter_cls_qual_name(view)
         return cls._CACHES.setdefault(
             qual_name, filter_class.QUERIES_CACHE_BACKEND(int(filter_class.QUERIES_CACHE_SIZE)),
         )
 
     @classmethod
     def _get_filter_instance(cls, filter_class, queryset, view):
-        qual_name = cls._get_filter_cls_qual_name(filter_class, view)
+        qual_name = cls._get_filter_cls_qual_name(view)
 
         filter_instance = _FilterClassCache.CACHE.get(qual_name)
         if filter_instance:
@@ -102,5 +105,5 @@ def _get_filter_instance(cls, filter_class, queryset, view):
         return filter_instance
 
     @staticmethod
-    def _get_filter_cls_qual_name(filter_class, view):
-        return '{0}.{1}'.format(view.basename, filter_class.__name__)
+    def _get_filter_cls_qual_name(view):
+        return '{0}.{1}'.format(view.__class__.__module__, view.__class__.__name__)

dj_rql/filter_cls.py

@@ -6,8 +6,6 @@
 from datetime import datetime
 from uuid import uuid4
 
-from cachetools import LFUCache
-
 from dj_rql._dataclasses import FilterArgs, OptimizationArgs
 from dj_rql.constants import (
     ComparisonOperators,
@@ -64,8 +62,8 @@ class RQLFilterClass:
     OPENAPI_SPECIFICATION = RQLFilterClassSpecification
     """Class for OpenAPI specifications generation."""
 
-    QUERIES_CACHE_BACKEND = LFUCache
-    """Class for query caching (can be `None`)."""
+    QUERIES_CACHE_BACKEND = None
+    """Class for query caching."""
 
     QUERIES_CACHE_SIZE = 20
     """Default number of cached queries."""

tests/dj_rf/filters.py

@@ -1,7 +1,7 @@
 #
 #  Copyright © 2021 Ingram Micro Inc. All rights reserved.
 #
-from cachetools import LRUCache
+from cachetools import LFUCache, LRUCache
 
 from dj_rql.constants import FilterLookups, RQL_NULL
 from dj_rql.drf.fields import SelectField
@@ -35,6 +35,7 @@
 
 class BooksFilterClass(RQLFilterClass):
     MODEL = Book
+    QUERIES_CACHE_BACKEND = LFUCache
     FILTERS = ['id', {
         'filter': 'title',
         'null_values': {RQL_NULL, 'NULL_ID'},

tests/test_drf/test_common_drf_backend.py

@@ -103,7 +103,7 @@ def test_filter_cls_cache(api_client, clear_cache):
     response = api_client.get('{0}?{1}'.format(reverse('book-list'), 'title=F'))
     assert response.data == [{'id': books[0].pk}]
 
-    expected_cache_key = 'book.BooksFilterClass'
+    expected_cache_key = 'tests.dj_rf.view.DRFViewSet'
     assert expected_cache_key in _FilterClassCache.CACHE
     cache_item_id = id(_FilterClassCache.CACHE[expected_cache_key])
 
@@ -118,15 +118,16 @@ def test_filter_cls_cache(api_client, clear_cache):
 
 
 @pytest.mark.django_db
-def test_query_cache(api_client, clear_cache):
+def test_query_cache(api_client, clear_cache, django_assert_num_queries):
     books = [
         Book.objects.create(title='F'),
         Book.objects.create(title='G'),
     ]
 
     for _ in range(4):
-        response = api_client.get('{0}?{1}'.format(reverse('book-list'), 'title=F'))
-        assert response.data == [{'id': books[0].pk}]
+        with django_assert_num_queries(2):
+            response = api_client.get('{0}?{1}'.format(reverse('book-list'), 'title=F'))
+            assert response.data == [{'id': books[0].pk}]
 
         response = api_client.get('{0}?{1}'.format(reverse('book-list'), 'title=X'))
         assert response.data == []
@@ -136,12 +137,12 @@ def test_query_cache(api_client, clear_cache):
         assert 'id' not in response.data[0]
 
     caches = RQLFilterBackend._CACHES
-    assert isinstance(caches['book.BooksFilterClass'], LFUCache)
-    assert caches['book.BooksFilterClass'].currsize == 2
-    assert caches['book.BooksFilterClass'].maxsize == 20
-    assert isinstance(caches['select.SelectBooksFilterClass'], LRUCache)
-    assert caches['select.SelectBooksFilterClass'].currsize == 1
-    assert caches['select.SelectBooksFilterClass'].maxsize == 100
+    assert isinstance(caches['tests.dj_rf.view.DRFViewSet'], LFUCache)
+    assert caches['tests.dj_rf.view.DRFViewSet'].currsize == 2
+    assert caches['tests.dj_rf.view.DRFViewSet'].maxsize == 20
+    assert isinstance(caches['tests.dj_rf.view.SelectViewSet'], LRUCache)
+    assert caches['tests.dj_rf.view.SelectViewSet'].currsize == 1
+    assert caches['tests.dj_rf.view.SelectViewSet'].maxsize == 100
 
 
 @pytest.mark.django_db