From 39defa2bd9ca0d1eeffa7ee4f3c7a701db6b385d Mon Sep 17 00:00:00 2001
From: Mitchell Kotler <mitch@mitchellkotler.net>
Date: Sat, 19 Nov 2016 12:13:35 -0500
Subject: [PATCH 1/2] Add support for using Django's caching mechanism

---
 easy_thumbnails/conf.py   |  8 ++++++
 easy_thumbnails/models.py | 52 +++++++++++++++++++++++++++++----------
 2 files changed, 47 insertions(+), 13 deletions(-)

diff --git a/easy_thumbnails/conf.py b/easy_thumbnails/conf.py
index 9b61dfa8..7f801a9b 100644
--- a/easy_thumbnails/conf.py
+++ b/easy_thumbnails/conf.py
@@ -325,6 +325,14 @@ class Settings(AppSettings):
     still works as a fall back.
     """
 
+    THUMBNAIL_CACHE = None
+    """
+    Use Django's caching system to cache sources and thumbnails
+
+    Setting this to ``None`` will disable caching.  To enable it, set
+    this to the name of the Django cache you would like to use.
+    """
+
     THUMBNAIL_WIDGET_OPTIONS = {'size': (80, 80)}
     """
     Default options for the
diff --git a/easy_thumbnails/models.py b/easy_thumbnails/models.py
index 4c0d261e..86665437 100644
--- a/easy_thumbnails/models.py
+++ b/easy_thumbnails/models.py
@@ -6,6 +6,15 @@
 from easy_thumbnails import utils, signal_handlers
 from easy_thumbnails.conf import settings
 
+if settings.THUMBNAIL_CACHE:
+    try:
+        from django.core.cache import caches
+    except ImportError:
+        from django.core.exceptions import ImproperlyConfigured
+        raise ImproperlyConfigured(
+                'You are trying to use the cache on a version of Django '
+                'that does not support caching')
+
 
 class FileManager(models.Manager):
 
@@ -13,6 +22,9 @@ def get_file(self, storage, name, create=False, update_modified=None,
                  check_cache_miss=False, **kwargs):
         kwargs.update(dict(storage_hash=utils.get_storage_hash(storage),
                            name=name))
+        if settings.THUMBNAIL_CACHE:
+            cache = caches[settings.THUMBNAIL_CACHE]
+            cache_key = self._get_cache_key(kwargs)
         if create:
             if update_modified:
                 defaults = kwargs.setdefault('defaults', {})
@@ -21,28 +33,39 @@ def get_file(self, storage, name, create=False, update_modified=None,
         else:
             created = False
             kwargs.pop('defaults', None)
-            try:
-                manager = self._get_thumbnail_manager()
-                obj = manager.get(**kwargs)
-            except self.model.DoesNotExist:
-
-                if check_cache_miss and storage.exists(name):
-                    # File already in storage, update cache. Using
-                    # get_or_create again in case this was updated while
-                    # storage.exists was running.
-                    obj, created = self.get_or_create(**kwargs)
-                else:
-                    return
+            obj = None
+            if settings.THUMBNAIL_CACHE:
+                obj = cache.get(cache_key)
+            if obj is None:
+                try:
+                    manager = self._get_thumbnail_manager()
+                    obj = manager.get(**kwargs)
+                except self.model.DoesNotExist:
+
+                    if check_cache_miss and storage.exists(name):
+                        # File already in storage, update cache. Using
+                        # get_or_create again in case this was updated while
+                        # storage.exists was running.
+                        obj, created = self.get_or_create(**kwargs)
+                    else:
+                        return
 
         if update_modified and not created:
             if obj.modified != update_modified:
-                self.filter(pk=obj.pk).update(modified=update_modified)
+                obj.modified = update_modified
+                obj.save()
+
+        if settings.THUMBNAIL_CACHE:
+            cache.set(cache_key, obj, None)
 
         return obj
 
     def _get_thumbnail_manager(self):
         return self
 
+    def _get_cache_key(self, kwargs):
+        return 'et:source:{storage_hash}:{name}'.format(**kwargs)
+
 
 class ThumbnailManager(FileManager):
 
@@ -51,6 +74,9 @@ def _get_thumbnail_manager(self):
             return self.select_related("dimensions")
         return self
 
+    def _get_cache_key(self, kwargs):
+        return 'et:thumbnail:{storage_hash}:{name}:{source_id}'.format(**kwargs)
+
 
 class File(models.Model):
     storage_hash = models.CharField(max_length=40, db_index=True)

From 1554df48813ca2111095f4643294c92d8351dda1 Mon Sep 17 00:00:00 2001
From: Mitchell Kotler <mitch@mitchellkotler.net>
Date: Sat, 19 Nov 2016 12:51:16 -0500
Subject: [PATCH 2/2] set source id for cache key correctly

---
 easy_thumbnails/models.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/easy_thumbnails/models.py b/easy_thumbnails/models.py
index 86665437..1fb4f5cf 100644
--- a/easy_thumbnails/models.py
+++ b/easy_thumbnails/models.py
@@ -75,6 +75,7 @@ def _get_thumbnail_manager(self):
         return self
 
     def _get_cache_key(self, kwargs):
+        kwargs['source_id'] = kwargs['source'].pk
         return 'et:thumbnail:{storage_hash}:{name}:{source_id}'.format(**kwargs)