upload: Replace exif_rotate with Pillow exif_transpose.

Fixes #18599.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

zerver/lib/upload.py

@@ -25,7 +25,7 @@ from django.http import HttpRequest
 from django.urls import reverse
 from django.utils.translation import gettext as _
 from jinja2.utils import Markup as mark_safe
-from PIL import ExifTags, Image, ImageOps
+from PIL import Image, ImageOps
 from PIL.GifImagePlugin import GifImageFile
 from PIL.Image import DecompressionBombError
 
@@ -103,33 +103,10 @@ class BadImageError(JsonableError):
     code = ErrorCode.BAD_IMAGE
 
 
-name_to_tag_num = {name: num for num, name in ExifTags.TAGS.items()}
-
-# https://stackoverflow.com/a/6218425
-def exif_rotate(image: Image) -> Image:
-    if not hasattr(image, "_getexif"):
-        return image
-    exif_data = image._getexif()
-    if exif_data is None:
-        return image
-
-    exif_dict = dict(exif_data.items())
-    orientation = exif_dict.get(name_to_tag_num["Orientation"])
-
-    if orientation == 3:
-        return image.rotate(180, expand=True)
-    elif orientation == 6:
-        return image.rotate(270, expand=True)
-    elif orientation == 8:
-        return image.rotate(90, expand=True)
-
-    return image
-
-
 def resize_avatar(image_data: bytes, size: int = DEFAULT_AVATAR_SIZE) -> bytes:
     try:
         im = Image.open(io.BytesIO(image_data))
-        im = exif_rotate(im)
+        im = ImageOps.exif_transpose(im)
         im = ImageOps.fit(im, (size, size), Image.ANTIALIAS)
     except OSError:
         raise BadImageError(_("Could not decode image; did you upload an image file?"))
@@ -145,7 +122,7 @@ def resize_avatar(image_data: bytes, size: int = DEFAULT_AVATAR_SIZE) -> bytes:
 def resize_logo(image_data: bytes) -> bytes:
     try:
         im = Image.open(io.BytesIO(image_data))
-        im = exif_rotate(im)
+        im = ImageOps.exif_transpose(im)
         im.thumbnail((8 * DEFAULT_AVATAR_SIZE, DEFAULT_AVATAR_SIZE), Image.ANTIALIAS)
     except OSError:
         raise BadImageError(_("Could not decode image; did you upload an image file?"))
@@ -202,7 +179,7 @@ def resize_emoji(image_data: bytes, size: int = DEFAULT_EMOJI_SIZE) -> bytes:
             )
             return resize_gif(im, size) if should_resize else image_data
         else:
-            im = exif_rotate(im)
+            im = ImageOps.exif_transpose(im)
             im = ImageOps.fit(im, (size, size), Image.ANTIALIAS)
             out = io.BytesIO()
             im.save(out, format=image_format)

zerver/tests/test_upload.py

@@ -51,7 +51,6 @@ from zerver.lib.upload import (
     ZulipUploadBackend,
     delete_export_tarball,
     delete_message_image,
-    exif_rotate,
     resize_avatar,
     resize_emoji,
     sanitize_name,
@@ -2153,38 +2152,6 @@ class UploadSpaceTests(UploadSerializeMixin, ZulipTestCase):
         self.assert_length(data2, self.realm.currently_used_upload_space_bytes())
 
 
-class ExifRotateTests(ZulipTestCase):
-    def test_image_do_not_rotate(self) -> None:
-        # Image does not have _getexif method.
-        with get_test_image_file("img.png") as f, Image.open(f) as img:
-            result = exif_rotate(img)
-            self.assertEqual(result, img)
-
-        # Image with no exif data.
-        with get_test_image_file("img_no_exif.jpg") as f, Image.open(f) as img:
-            result = exif_rotate(img)
-            self.assertEqual(result, img)
-
-        # Orientation of the image is 1.
-        with get_test_image_file("img.jpg") as f, Image.open(f) as img:
-            result = exif_rotate(img)
-            self.assertEqual(result, img)
-
-    def test_image_rotate(self) -> None:
-        with mock.patch("PIL.Image.Image.rotate") as rotate:
-            with get_test_image_file("img_orientation_3.jpg") as f, Image.open(f) as img:
-                exif_rotate(img)
-                rotate.assert_called_with(180, expand=True)
-
-            with get_test_image_file("img_orientation_6.jpg") as f, Image.open(f) as img:
-                exif_rotate(img)
-                rotate.assert_called_with(270, expand=True)
-
-            with get_test_image_file("img_orientation_8.jpg") as f, Image.open(f) as img:
-                exif_rotate(img)
-                rotate.assert_called_with(90, expand=True)
-
-
 class DecompressionBombTests(ZulipTestCase):
     def setUp(self) -> None:
         super().setUp()