do make cache invalidation from product model

shop/admin/product.py

@@ -1,15 +1,17 @@
 # -*- coding: utf-8 -*-
 from __future__ import unicode_literals
 
-import warnings
-
 from django import forms
-from django.core.cache import cache
 from django.core.exceptions import ImproperlyConfigured
 from django.contrib import admin
 from django.contrib.sites.models import Site
 from django.utils.translation import ugettext_lazy as _
 
+try:
+    from django_elasticsearch_dsl.registries import registry as elasticsearch_registry
+except ImportError:
+    elasticsearch_registry = type('DocumentRegistry', (), {'get_documents': lambda *args: []})()
+
 from adminsortable2.admin import SortableInlineAdminMixin
 
 from cms.models import Page
@@ -100,33 +102,26 @@ def save_related(self, request, form, formsets, change):
         return super(CMSPageAsCategoryMixin, self).save_related(request, form, formsets, change)
 
 
-class InvalidateProductCacheMixin(object):
+class SearchProductIndexMixin:
     """
-    If caching is enabled, add this class as the first mixin to Django's model admin for the
-    corresponding product.
+    If Elasticsearch is used to create a full text search index, add this mixin class to Django's
+    ``ModelAdmin`` backend for the corresponding product model.
     """
-    def __init__(self, *args, **kwargs):
-        if not hasattr(cache, 'delete_pattern'):
-            warnings.warn("\n"
-                "Your caching backend does not support deletion by key patterns.\n"
-                "Please use 'django-redis-cache', or wait until the product's HTML\n"
-                "snippet cache expires by itself.")
-        super(InvalidateProductCacheMixin, self).__init__(*args, **kwargs)
+    def save_model(self, request, product, form, change):
+        super().save_model(request, product, form, change)
+        if change:
+            product.update_search_index()
 
+
+class InvalidateProductCacheMixin:
+    """
+    If Redis caching is used to create a HTML snippets for product representation, add this mixin
+    class to Django's ``ModelAdmin`` backend for the corresponding product model.
+    """
     def save_model(self, request, product, form, change):
         if change:
-            self.invalidate_cache(product)
-        super(InvalidateProductCacheMixin, self).save_model(request, product, form, change)
-
-    def invalidate_cache(self, product):
-        """
-        The method ``ProductCommonSerializer.render_html`` caches the rendered HTML snippets.
-        Invalidate them after changing something in the product.
-        """
-        try:
-            cache.delete_pattern('product:{}|*'.format(product.id))
-        except AttributeError:
-            pass
+            product.invalidate_cache()
+        return super().save_model(request, product, form, change)
 
 
 class UnitPriceMixin(object):

shop/apps.py

@@ -1,15 +1,19 @@
+import warnings
+
 from django.apps import AppConfig
+from django.core.cache import cache
 from django.utils.translation import ugettext_lazy as _
 
 
 class ShopConfig(AppConfig):
     name = 'shop'
     verbose_name = _("Shop")
+    cache_supporting_wildcard = False
 
     def ready(self):
-        from shop.models.fields import JSONField
         from rest_framework.serializers import ModelSerializer
         from shop.deferred import ForeignKeyBuilder
+        from shop.models.fields import JSONField
         from shop.rest.fields import JSONSerializerField
         from shop.patches import PageAttribute
         from cms.templatetags import cms_tags
@@ -21,3 +25,11 @@ def ready(self):
         ForeignKeyBuilder.check_for_pending_mappings()
 
         cms_tags.register.tags['page_attribute'] = PageAttribute
+
+        if callable(getattr(cache, 'delete_pattern', None)):
+            self.cache_supporting_wildcard = True
+        else:
+            warnings.warn("\n"
+                "Your caching backend does not support invalidation by key pattern.\n"
+                "Please use `django-redis-cache`, or wait until the product's HTML\n"
+                "snippet cache expires by itself.")

shop/models/product.py

@@ -6,8 +6,9 @@
 import operator
 from cms import __version__ as CMS_VERSION
 
+from django.apps import apps
 from django.conf import settings
-from django.core import checks
+from django.core import cache, checks
 from django.db import models
 from django.db.models.aggregates import Sum
 from django.db.models.functions import Coalesce
@@ -351,11 +352,11 @@ def check(cls, **kwargs):
             errors.append(checks.Error(msg.format(cls.__name__)))
         return errors
 
-    def save(self, *args, **kwargs):
-        super().save(*args, **kwargs)
-        self.update_search_index()
-
     def update_search_index(self):
+        """
+        Update the document model inside the Elasticsearch index after changing relevant parts
+        of the product.
+        """
         documents = elasticsearch_registry.get_documents([ProductModel])
         if settings.USE_I18N:
             for language, _ in settings.LANGUAGES:
@@ -368,6 +369,15 @@ def update_search_index(self):
             document = next(doc for doc in documents)
             document().update(self)
 
+    def invalidate_cache(self):
+        """
+        Method ``ProductCommonSerializer.render_html()`` caches the rendered HTML snippets.
+        Invalidate this HTML snippet after changing relevant parts of the product.
+        """
+        shop_app = apps.get_app_config('shop')
+        if shop_app.cache_supporting_wildcard:
+            cache.delete_pattern('product:{}|*'.format(self.id))
+
 ProductModel = deferred.MaterializedModel(BaseProduct)