Cache invalidation for paginator implemented

README.md

@@ -11,8 +11,9 @@ Fast Paginator is a simple Django app to paginate Django Querysets. Core Django
         'fast_pagination'
     ]
 ```
-2. Import FastPaginator like this:
+2. In Django settings, you can set FAST_PAGINATION_TIMEOUT variable to invalidate cache. Default value is 1 hour.
+3. Import FastPaginator like this:
 ```python
     from fast_pagination.helpers import FastPaginator
 ```
-3. Then, you are ready. All you have to do is give your queryset and number of entries when creating FastPaginator object.
+4. Then, you are ready. All you have to do is give your queryset and number of entries when creating FastPaginator object.

fast_pagination/helpers.py

@@ -1,8 +1,10 @@
 import inspect
+from datetime import datetime
 
 from django.core.paginator import Paginator, Page
+from django.core.cache import cache
+from django.conf import settings
 from django.db.models.query import QuerySet
-from django.utils.functional import cached_property
 from django.utils.inspect import method_has_no_args
 
 
@@ -11,17 +13,27 @@ class FastPaginator(Paginator):
     def __init__(self, object_list, per_page, orphans=0,
                  allow_empty_first_page=True):
         super().__init__(object_list, per_page, orphans, allow_empty_first_page)
+        self.cache_key = self.get_paginator_cache_key()
+        self.timeout = getattr(settings, "FAST_PAGINATION_TIMEOUT", 3600)
         if isinstance(object_list, QuerySet):
             self.ids = list(object_list.values_list('id', flat=True))
 
-    @cached_property
+    def get_paginator_cache_key(self):
+        return datetime.now().isoformat()
+
+    @property
     def count(self):
-        c = getattr(self.object_list, 'count', None)
-        if callable(c) and not inspect.isbuiltin(c) \
-            and method_has_no_args(c) \
-            and not isinstance(self.object_list, QuerySet):
-            return c()
-        return len(self.ids)
+        result = cache.get(self.cache_key)
+        if result is None:
+            c = getattr(self.object_list, 'count', None)
+            if callable(c) and not inspect.isbuiltin(c) \
+                and method_has_no_args(c) \
+                and isinstance(self.object_list, QuerySet):
+                result = c()
+            else:
+                result = len(self.object_list)
+            cache.set(self.cache_key, result, timeout=self.timeout)
+        return result
 
     def page(self, number):
         number = self.validate_number(number)

setup.cfg

@@ -1,14 +1,14 @@
 [metadata]
 name = django-fast-paginator
-version = v1.0.0
+version = v1.0.1
 description = A Django app to paginate querysets faster.
 long_description = file: README.md
 long_description_content_type = text/markdown
 author = Tolga Bilbey
 author_email = [email protected]
 license = BSD-3-Clause
 url = https://github.com/bilbeyt/django-fast-pagination
-download_url = https://github.com/bilbeyt/django-fast-pagination/archive/v1.0.0.tar.gz
+download_url = https://github.com/bilbeyt/django-fast-pagination/archive/v1.0.1.tar.gz
 keywords =
     django
     pagination