Improvements to thumbnails code for using remote media storage

docs/settings.rst

@@ -716,7 +716,7 @@ Default: ``('ACCOUNTS_APPROVAL_REQUIRED', 'ACCOUNTS_VERIFICATION_REQUIRED', 'ADM
 ``THUMBNAILS_DIR_NAME``
 -----------------------
 
-Directory name to store thumbnails in, that will be created relative to the original image's directory.
+Directory name to store thumbnails in, that will be created relative to the original image's directory, or to MEDIA_ROOT if an absolute path.
 
 Default: ``'.thumbnails'``
 

mezzanine/core/defaults.py

@@ -518,7 +518,8 @@
 register_setting(
     name="THUMBNAILS_DIR_NAME",
     description=_("Directory name to store thumbnails in, that will be "
-        "created relative to the original image's directory."),
+        "created relative to the original image's directory, or to "
+        "MEDIA_ROOT if an absolute path."),
     editable=False,
     default=".thumbnails",
 )

mezzanine/core/templatetags/mezzanine_tags.py

@@ -1,8 +1,15 @@
 from __future__ import absolute_import, division, unicode_literals
-from future.builtins import int, open, str
+
+import sys
+
+from django.core.files.uploadedfile import InMemoryUploadedFile
+from future.builtins import int, str
 
 from hashlib import md5
 import os
+
+from six import BytesIO
+
 try:
     from urllib.parse import quote, unquote
 except ImportError:
@@ -13,7 +20,6 @@
 from django.contrib.auth import REDIRECT_FIELD_NAME
 from django.contrib.sites.models import Site
 from django.core.exceptions import ObjectDoesNotExist
-from django.core.files import File
 from django.core.files.storage import default_storage
 from django.urls import reverse, resolve, NoReverseMatch
 from django.db.models import Model
@@ -312,24 +318,29 @@ def thumbnail(image_url, width, height, upscale=True, quality=95, left=.5,
     # image, which is something we do in filebrowser when a new image
     # is written, allowing us to purge any previously generated
     # thumbnails that may match a new image name.
-    thumb_dir = os.path.join(settings.MEDIA_ROOT, image_dir,
-                             settings.THUMBNAILS_DIR_NAME, image_name)
-    if not os.path.exists(thumb_dir):
-        try:
-            os.makedirs(thumb_dir)
-        except OSError:
-            pass
+    if os.path.isabs(settings.THUMBNAILS_DIR_NAME):
+        thumb_dir = os.path.join(settings.MEDIA_ROOT,
+                                 settings.THUMBNAILS_DIR_NAME,
+                                 image_dir, image_name)
+        thumb_url = ("%s/%s/%s/%s" % (settings.THUMBNAILS_DIR_NAME,
+                                  os.path.dirname(image_url),
+                                  quote(image_name.encode("utf-8")),
+                                  quote(thumb_name.encode("utf-8")))
+                     ).lstrip('/')
+    else:
+        thumb_dir = os.path.join(settings.MEDIA_ROOT, image_dir,
+                                 settings.THUMBNAILS_DIR_NAME, image_name)
+        thumb_url = "%s/%s/%s" % (settings.THUMBNAILS_DIR_NAME,
+                                  quote(image_name.encode("utf-8")),
+                                  quote(thumb_name.encode("utf-8")))
+        image_url_path = os.path.dirname(image_url)
+        if image_url_path:
+            thumb_url = "%s/%s" % (image_url_path, thumb_url)
 
     thumb_path = os.path.join(thumb_dir, thumb_name)
-    thumb_url = "%s/%s/%s" % (settings.THUMBNAILS_DIR_NAME,
-                              quote(image_name.encode("utf-8")),
-                              quote(thumb_name.encode("utf-8")))
-    image_url_path = os.path.dirname(image_url)
-    if image_url_path:
-        thumb_url = "%s/%s" % (image_url_path, thumb_url)
 
     try:
-        thumb_exists = os.path.exists(thumb_path)
+        thumb_exists = default_storage.exists(thumb_url)
     except UnicodeEncodeError:
         # The image that was saved to a filesystem with utf-8 support,
         # but somehow the locale has changed and the filesystem does not
@@ -422,18 +433,19 @@ def thumbnail(image_url, width, height, upscale=True, quality=95, left=.5,
     to_pos = (left, top)
     try:
         image = ImageOps.fit(image, to_size, Image.ANTIALIAS, 0, to_pos)
-        image = image.save(thumb_path, filetype, quality=quality, **image_info)
-        # Push a remote copy of the thumbnail if MEDIA_URL is
-        # absolute.
-        if "://" in settings.MEDIA_URL:
-            with open(thumb_path, "rb") as f:
-                default_storage.save(unquote(thumb_url), File(f))
+        thumb_io = BytesIO()
+        image.save(thumb_io, filetype, quality=quality, **image_info)
+        thumb_file = InMemoryUploadedFile(
+            thumb_io, None, 'foo.jpg', 'image/jpg',
+            sys.getsizeof(thumb_io), None
+        )
+        default_storage.save(unquote(thumb_url), thumb_file)
     except Exception:
         # If an error occurred, a corrupted image may have been saved,
         # so remove it, otherwise the check for it existing will just
         # return the corrupted image next time it's requested.
         try:
-            os.remove(thumb_path)
+            default_storage.delete(thumb_path)
         except Exception:
             pass
         return image_url