Do not leak open files after generation

imagekit/specs/__init__.py

@@ -143,23 +143,26 @@ class ImageSpec(BaseImageSpec):
             raise MissingSource("The spec '%s' has no source file associated"
                                 " with it." % self)
 
-        file_opened_locally = False
         # TODO: Move into a generator base class
         # TODO: Factor out a generate_image function so you can create a generator and only override the PIL.Image creating part. (The tricky part is how to deal with original_format since generator base class won't have one.)
+
+        closed = self.source.closed
+        if closed:
+            # Django file object should know how to reopen itself if it was closed
+            # https://code.djangoproject.com/ticket/13750
+            self.source.open()
+
         try:
             img = open_image(self.source)
-        except ValueError:
-
-            # Re-open the file -- https://code.djangoproject.com/ticket/13750
-            self.source.open()
-            file_opened_locally = True
-            img = open_image(self.source)
-
-        new_image =  process_image(img, processors=self.processors,
-                                   format=self.format, autoconvert=self.autoconvert,
-                                   options=self.options)
-        if file_opened_locally:
-            self.source.close()
+            new_image = process_image(img,
+                                      processors=self.processors,
+                                      format=self.format,
+                                      autoconvert=self.autoconvert,
+                                      options=self.options)
+        finally:
+            if closed:
+                # We need to close the file if it was opened by us
+                self.source.close()
         return new_image
 
 

tests/test_closing_fieldfiles.py

@@ -0,0 +1,25 @@
+from nose.tools import assert_false, assert_true
+
+from .models import Thumbnail
+from .utils import create_photo
+
+
+def test_do_not_leak_open_files():
+    instance = create_photo('leak-test.jpg')
+    source_file = instance.original_image
+    # Ensure the FieldFile is closed before generation
+    source_file.close()
+    image_generator = Thumbnail(source=source_file)
+    image_generator.generate()
+    assert_true(source_file.closed)
+
+
+def test_do_not_close_open_files_after_generate():
+    instance = create_photo('do-not-close-test.jpg')
+    source_file = instance.original_image
+    # Ensure the FieldFile is opened before generation
+    source_file.open()
+    image_generator = Thumbnail(source=source_file)
+    image_generator.generate()
+    assert_false(source_file.closed)
+    source_file.close()