Ticket #8817: 8817_2.diff

django/core/files/images.py

@@ -28 +28 @@
     """Returns the (width, height) of an image, given an open file or a path."""
     from PIL import ImageFile as PILImageFile
     p = PILImageFile.Parser()
-    if hasattr(file_or_path, 'read'):
+    local_file = True
+    # If we have a file name, prefer to open a new file to avoid modifying the
+    # state of the file object we were given.
+    if hasattr(file_or_path, 'name'):
+        # If this is a FileField, use custom storage backend to re-open file
+        if hasattr(file_or_path, 'storage'):
+            file = file_or_path.storage.open(file_or_path.name, 'rb')
+        else:
+            file = open(file_or_path.name, 'rb')
+    elif hasattr(file_or_path, 'read'):
         file = file_or_path
+        local_file = False
+        if file.tell() != 0:
+            file.seek(0)
     else:
         file = open(file_or_path, 'rb')
     while 1:
@@ -38 +50 @@
             break
         p.feed(data)
         if p.image:
+            if local_file:
+                file.close()
+            else:
+                file.seek(0)
             return p.image.size
+    if local_file:
+        file.close()
+    else:
+        file.seek(0)
     return None

tests/regressiontests/file_storage/models.py

@@ -84 +84 @@
 >>> hasattr(p3.mugshot, '_file')
 False
 
+# Bug #8817: ImageField.width and ImageField.height should not leave the file open
+>>> _ = p3.mugshot.width
+>>> hasattr(p3.mugshot, '_file')
+False
+
+>>> _ = p3.mugshot.height
+>>> hasattr(p3.mugshot, '_file')
+False
+
+# get_image_dimensions is used to populate the width/height fields
+# and should not fail if the file position is not 0
+# or leave the position at the end of the file
+>>> from django.core.files.images import get_image_dimensions
+>>> f = ContentFile(image_data)
+>>> f.seek(1)
+>>> get_image_dimensions(f)
+(16, 16)
+>>> f.tell()
+0
+
 >>> shutil.rmtree(temp_storage_dir)
 """}