Fix #206 -- Overwrite variations by defaults

We now overwrite files by default when a new files gets uploaded.
This fixes an issue, where someone might upload a file with the
same name twice the first initial variations get not replaced
with a version of the newer file.
It happens in the least IO consuming way. The rendervariations
management command still behaves as before where variations are
not replaced by default.

stdimage/models.py

@@ -48,24 +48,25 @@ def is_smaller(img, variation):
         return img.size[0] > variation['width'] \
             or img.size[1] > variation['height']
 
-    def render_variations(self, replace=False):
+    def render_variations(self, replace=True):
         """Render all image variations and saves them to the storage."""
         for _, variation in self.field.variations.items():
             self.render_variation(self.name, variation, replace, self.storage)
 
     @classmethod
-    def render_variation(cls, file_name, variation, replace=False,
+    def render_variation(cls, file_name, variation, replace=True,
                          storage=default_storage):
         """Render an image variation and saves it to the storage."""
         variation_name = cls.get_variation_name(file_name, variation['name'])
-        if storage.exists(variation_name):
-            if replace:
-                storage.delete(variation_name)
-                logger.info('File "%s" already exists and has been replaced.',
-                            variation_name)
-            else:
-                logger.info('File "%s" already exists.', variation_name)
-                return variation_name
+        file_overwrite = getattr(storage, 'file_overwrite', False)
+        if not replace and storage.exists(variation_name):
+            logger.info('File "%s" already exists.', variation_name)
+            return variation_name
+        elif replace and not file_overwrite and storage.exists(variation_name):
+            logger.warning(
+                'File "%s" already exists and will be overwritten.', variation_name
+            )
+            storage.delete(variation_name)
 
         ImageFile.LOAD_TRUNCATED_IMAGES = True
         with storage.open(file_name) as f:

tests/test_commands.py

@@ -57,7 +57,7 @@ def test_no_replace(self, image_upload_file):
         file_path = obj.image.thumbnail.path
         assert os.path.exists(file_path)
         before = os.path.getmtime(file_path)
-        time.sleep(1)
+        time.sleep(0.1)
         call_command(
             'rendervariations',
             'tests.ThumbnailModel.image',
@@ -71,7 +71,7 @@ def test_replace(self, image_upload_file):
         file_path = obj.image.thumbnail.path
         assert os.path.exists(file_path)
         before = os.path.getmtime(file_path)
-        time.sleep(1)
+        time.sleep(0.1)
         call_command(
             'rendervariations',
             'tests.ThumbnailModel.image',
@@ -87,7 +87,7 @@ def test_ignore_missing(self, image_upload_file):
         assert os.path.exists(file_path)
         os.remove(file_path)
         assert not os.path.exists(file_path)
-        time.sleep(1)
+        time.sleep(0.1)
         call_command(
             'rendervariations',
             'tests.ThumbnailModel.image',
@@ -101,7 +101,7 @@ def test_short_ignore_missing(self, image_upload_file):
         assert os.path.exists(file_path)
         os.remove(file_path)
         assert not os.path.exists(file_path)
-        time.sleep(1)
+        time.sleep(0.1)
         call_command(
             'rendervariations',
             'tests.ThumbnailModel.image',
@@ -115,7 +115,7 @@ def test_no_ignore_missing(self, image_upload_file):
         assert os.path.exists(file_path)
         os.remove(file_path)
         assert not os.path.exists(file_path)
-        time.sleep(1)
+        time.sleep(0.1)
         with pytest.raises(CommandError):
             call_command(
                 'rendervariations',

tests/test_models.py

@@ -1,5 +1,6 @@
 import io
 import os
+import time
 
 import pytest
 from django.conf import settings
@@ -210,6 +211,19 @@ def test_render_variations_callback(self, db):
         file_path = obj.image.thumbnail.path
         assert os.path.exists(file_path)
 
+    def test_render_variations_overwrite(self, db, image_upload_file):
+        obj = ThumbnailModel.objects.create(image=image_upload_file)
+        file_path = obj.image.thumbnail.path
+        before = os.path.getmtime(file_path)
+        time.sleep(0.1)
+        os.remove(obj.image.path)
+        assert os.path.exists(file_path)
+        obj.image = image_upload_file
+        obj.save()
+        assert file_path == obj.image.thumbnail.path
+        after = os.path.getmtime(file_path)
+        assert before != after, obj.image.path
+
 
 class TestValidators(TestStdImage):
     def test_max_size_validator(self, admin_client):