Preserve EXIF orientation data for profile images.

When creating profile images from an uploaded file, ensure that EXIF
orientation information is preserved, so profile images appear
right-side-up.

https://openedx.atlassian.net/browse/MA-1559

openedx/core/djangoapps/profile_images/exceptions.py

+"""
+Exceptions related to the handling of profile images.
+"""
+
+
+class ImageValidationError(Exception):
+    """
+    Exception to use when the system rejects a user-supplied source image.
+    """
+    @property
+    def user_message(self):
+        """
+        Translate the developer-facing exception message for API clients.
+        """
+        return self.message

openedx/core/djangoapps/profile_images/images.py

@@ -3,13 +3,16 @@ Image file manipulation functions related to profile images.
 """
 from cStringIO import StringIO
 from collections import namedtuple
+from contextlib import closing
 
 from django.conf import settings
 from django.core.files.base import ContentFile
 from django.utils.translation import ugettext as _
+import piexif
 from PIL import Image
 
 from openedx.core.djangoapps.user_api.accounts.image_helpers import get_profile_image_storage
+from .exceptions import ImageValidationError
 
 
 ImageType = namedtuple('ImageType', ('extensions', 'mimetypes', 'magic'))
@@ -33,42 +36,47 @@ IMAGE_TYPES = {
 }
 
 
-def user_friendly_size(size):
+def create_profile_images(image_file, profile_image_names):
     """
-    Convert size in bytes to user friendly size.
+    Generates a set of image files based on image_file and stores them
+    according to the sizes and filenames specified in `profile_image_names`.
 
     Arguments:
-        size (int): size in bytes
+
+        image_file (file):
+            The uploaded image file to be cropped and scaled to use as a
+            profile image.  The image is cropped to the largest possible square,
+            and centered on this image.
+
+        profile_image_names (dict):
+            A dictionary that maps image sizes to file names.  The image size
+            is an integer representing one side of the equilateral image to be
+            created.
 
     Returns:
-        user friendly size
+
+        None
     """
-    units = [_('bytes'), _('KB'), _('MB')]
-    i = 0
-    while size >= 1024:
-        size /= 1024
-        i += 1
-    return u'{} {}'.format(size, units[i])
+    storage = get_profile_image_storage()
 
+    original = Image.open(image_file)
+    image = _set_color_mode_to_rgb(original)
+    image = _crop_image_to_square(image)
 
-def get_valid_file_types():
-    """
-    Return comma separated string of valid file types.
-    """
-    return ', '.join([', '.join(IMAGE_TYPES[ft].extensions) for ft in IMAGE_TYPES.keys()])
+    for size, name in profile_image_names.items():
+        scaled = _scale_image(image, size)
+        exif = _get_corrected_exif(scaled, original)
+        with closing(_create_image_file(scaled, exif)) as scaled_image_file:
+            storage.save(name, scaled_image_file)
 
 
-class ImageValidationError(Exception):
+def remove_profile_images(profile_image_names):
     """
-    Exception to use when the system rejects a user-supplied source image.
+    Physically remove the image files specified in `profile_image_names`
     """
-    @property
-    def user_message(self):
-        """
-        Translate the developer-facing exception message for API clients.
-        """
-        # pylint: disable=translation-of-non-string
-        return _(self.message)
+    storage = get_profile_image_storage()
+    for name in profile_image_names.values():
+        storage.delete(name)
 
 
 def validate_uploaded_image(uploaded_file):
@@ -86,14 +94,14 @@ def validate_uploaded_image(uploaded_file):
         file_upload_too_large = _(
             u'The file must be smaller than {image_max_size} in size.'
         ).format(
-            image_max_size=user_friendly_size(settings.PROFILE_IMAGE_MAX_BYTES)
+            image_max_size=_user_friendly_size(settings.PROFILE_IMAGE_MAX_BYTES)
         )
         raise ImageValidationError(file_upload_too_large)
     elif uploaded_file.size < settings.PROFILE_IMAGE_MIN_BYTES:
         file_upload_too_small = _(
             u'The file must be at least {image_min_size} in size.'
         ).format(
-            image_min_size=user_friendly_size(settings.PROFILE_IMAGE_MIN_BYTES)
+            image_min_size=_user_friendly_size(settings.PROFILE_IMAGE_MIN_BYTES)
         )
         raise ImageValidationError(file_upload_too_small)
 
@@ -103,7 +111,7 @@ def validate_uploaded_image(uploaded_file):
     if not filetype:
         file_upload_bad_type = _(
             u'The file must be one of the following types: {valid_file_types}.'
-        ).format(valid_file_types=get_valid_file_types())
+        ).format(valid_file_types=_get_valid_file_types())
         raise ImageValidationError(file_upload_bad_type)
     filetype = filetype[0]
 
@@ -127,51 +135,106 @@ def validate_uploaded_image(uploaded_file):
     uploaded_file.seek(0)
 
 
-def _get_scaled_image_file(image_obj, size):
+def _crop_image_to_square(image):
+    """
+    Given a PIL.Image object, return a copy cropped to a square around the
+    center point with each side set to the size of the smaller dimension.
+    """
+    width, height = image.size
+    if width != height:
+        side = width if width < height else height
+        left = (width - side) // 2
+        top = (height - side) // 2
+        right = (width + side) // 2
+        bottom = (height + side) // 2
+        image = image.crop((left, top, right, bottom))
+    return image
+
+
+def _set_color_mode_to_rgb(image):
+    """
+    Given a PIL.Image object, return a copy with the color mode set to RGB.
     """
-    Given a PIL.Image object, get a resized copy using `size` (square) and
-    return a file-like object containing the data saved as a JPEG.
+    return image.convert('RGB')
 
-    Note that the file object returned is a django ContentFile which holds
-    data in memory (not on disk).
+
+def _scale_image(image, side_length):
+    """
+    Given a PIL.Image object, get a resized copy with each side being
+    `side_length` pixels long.  The scaled image will always be square.
+    """
+    return image.resize((side_length, side_length), Image.ANTIALIAS)
+
+
+def _create_image_file(image, exif):
+    """
+    Given a PIL.Image object, create and return a file-like object containing
+    the data saved as a JPEG.
+
+    Note that the file object returned is a django ContentFile which holds data
+    in memory (not on disk).
     """
-    if image_obj.mode != "RGB":
-        image_obj = image_obj.convert("RGB")
-    scaled = image_obj.resize((size, size), Image.ANTIALIAS)
     string_io = StringIO()
-    scaled.save(string_io, format='JPEG')
+
+    # The if/else dance below is required, because PIL raises an exception if
+    # you pass None as the value of the exif kwarg.
+    if exif is None:
+        image.save(string_io, format='JPEG')
+    else:
+        image.save(string_io, format='JPEG', exif=exif)
+
     image_file = ContentFile(string_io.getvalue())
     return image_file
 
 
-def create_profile_images(image_file, profile_image_names):
+def _get_corrected_exif(image, original):
     """
-    Generates a set of image files based on image_file and
-    stores them according to the sizes and filenames specified
-    in `profile_image_names`.
+    If the original image contains exif data, use that data to
+    preserve image orientation in the new image.
     """
-    image_obj = Image.open(image_file)
+    if 'exif' in original.info:
+        image_exif = image.info.get('exif', piexif.dump({}))
+        original_exif = original.info['exif']
+        image_exif = _update_exif_orientation(image_exif, _get_exif_orientation(original_exif))
+        return image_exif
 
-    # first center-crop the image if needed (but no scaling yet).
-    width, height = image_obj.size
-    if width != height:
-        side = width if width < height else height
-        image_obj = image_obj.crop(((width - side) / 2, (height - side) / 2, (width + side) / 2, (height + side) / 2))
 
-    storage = get_profile_image_storage()
-    for size, name in profile_image_names.items():
-        scaled_image_file = _get_scaled_image_file(image_obj, size)
-        # Store the file.
-        try:
-            storage.save(name, scaled_image_file)
-        finally:
-            scaled_image_file.close()
+def _update_exif_orientation(exif, orientation):
+    """
+    Given an exif value and an integer value 1-8, reflecting a valid value for
+    the exif orientation, return a new exif with the orientation set.
+    """
+    exif_dict = piexif.load(exif)
+    exif_dict['0th'][piexif.ImageIFD.Orientation] = orientation
+    return piexif.dump(exif_dict)
 
 
-def remove_profile_images(profile_image_names):
+def _get_exif_orientation(exif):
+    """Return the orientation value for the given Image object"""
+    exif_dict = piexif.load(exif)
+    return exif_dict['0th'].get(piexif.ImageIFD.Orientation)
+
+
+def _get_valid_file_types():
     """
-    Physically remove the image files specified in `profile_image_names`
+    Return comma separated string of valid file types.
     """
-    storage = get_profile_image_storage()
-    for name in profile_image_names.values():
-        storage.delete(name)
+    return ', '.join([', '.join(IMAGE_TYPES[ft].extensions) for ft in IMAGE_TYPES.keys()])
+
+
+def _user_friendly_size(size):
+    """
+    Convert size in bytes to user friendly size.
+
+    Arguments:
+        size (int): size in bytes
+
+    Returns:
+        user friendly size
+    """
+    units = [_('bytes'), _('KB'), _('MB')]
+    i = 0
+    while size >= 1024 and i < len(units):
+        size /= 1024
+        i += 1
+    return u'{} {}'.format(size, units[i])

openedx/core/djangoapps/profile_images/tests/helpers.py

@@ -7,10 +7,11 @@ from tempfile import NamedTemporaryFile
 
 from django.core.files.uploadedfile import UploadedFile
 from PIL import Image
+import piexif
 
 
 @contextmanager
-def make_image_file(dimensions=(320, 240), extension=".jpeg", force_size=None):
+def make_image_file(dimensions=(320, 240), extension=".jpeg", force_size=None, orientation=None):
     """
     Yields a named temporary file created with the specified image type and
     options.
@@ -24,7 +25,11 @@ def make_image_file(dimensions=(320, 240), extension=".jpeg", force_size=None):
     image = Image.new('RGB', dimensions, "green")
     image_file = NamedTemporaryFile(suffix=extension)
     try:
-        image.save(image_file)
+        if orientation and orientation in xrange(1, 9):
+            exif_bytes = piexif.dump({'0th': {piexif.ImageIFD.Orientation: orientation}})
+            image.save(image_file, exif=exif_bytes)
+        else:
+            image.save(image_file)
         if force_size is not None:
             image_file.seek(0, os.SEEK_END)
             bytes_to_pad = force_size - image_file.tell()

openedx/core/djangoapps/profile_images/tests/test_images.py

@@ -15,12 +15,13 @@ import ddt
 import mock
 from PIL import Image
 
+from ..exceptions import ImageValidationError
 from ..images import (
     create_profile_images,
-    ImageValidationError,
     remove_profile_images,
     validate_uploaded_image,
-    get_valid_file_types,
+    _get_exif_orientation,
+    _get_valid_file_types,
 )
 from .helpers import make_image_file, make_uploaded_file
 
@@ -33,7 +34,7 @@ class TestValidateUploadedImage(TestCase):
     """
     FILE_UPLOAD_BAD_TYPE = (
         u'The file must be one of the following types: {valid_file_types}.'.format(
-            valid_file_types=get_valid_file_types()
+            valid_file_types=_get_valid_file_types()
         )
     )
 
@@ -146,24 +147,54 @@ class TestGenerateProfileImages(TestCase):
             100: "hundred.jpg",
             1000: "thousand.jpg",
         }
-        mock_storage = mock.Mock()
         with make_uploaded_file(dimensions=dimensions, extension=extension, content_type=content_type) as uploaded_file:
-            with mock.patch(
-                "openedx.core.djangoapps.profile_images.images.get_profile_image_storage",
-                return_value=mock_storage,
-            ):
-                create_profile_images(uploaded_file, requested_sizes)
-                names_and_files = [v[0] for v in mock_storage.save.call_args_list]
-                actual_sizes = {}
-                for name, file_ in names_and_files:
-                    # get the size of the image file and ensure it's square jpeg
-                    with closing(Image.open(file_)) as image_obj:
-                        width, height = image_obj.size
-                        self.assertEqual(width, height)
-                        self.assertEqual(image_obj.format, 'JPEG')
-                        actual_sizes[width] = name
-                self.assertEqual(requested_sizes, actual_sizes)
-                mock_storage.save.reset_mock()
+            names_and_files = self._create_mocked_profile_images(uploaded_file, requested_sizes)
+            actual_sizes = {}
+            self.assertEqual(len(names_and_files), 3)
+            for name, file_ in names_and_files:
+                # get the size of the image file and ensure it's square jpeg
+                with closing(Image.open(file_)) as image_obj:
+                    width, height = image_obj.size
+                    self.assertEqual(width, height)
+                    self.assertEqual(image_obj.format, 'JPEG')
+                    actual_sizes[width] = name
+            self.assertEqual(requested_sizes, actual_sizes)
+
+    def test_jpeg_with_exif_orientation(self):
+        requested_images = {10: "ten.jpg"}
+        rotate_90_clockwise = 8  # Value used in EXIF Orientation field.
+        with make_image_file(orientation=rotate_90_clockwise, extension='.jpg') as imfile:
+            names_and_files = self._create_mocked_profile_images(imfile, requested_images)
+        self.assertEqual(len(names_and_files), 1)
+        for file_ in [nf[1] for nf in names_and_files]:
+            with closing(Image.open(file_)) as image_obj:
+                self.assertEqual(image_obj.format, 'JPEG')
+                self.assertIn('exif', image_obj.info)
+                self.assertEqual(_get_exif_orientation(image_obj.info['exif']), rotate_90_clockwise)
+
+    def test_jpeg_without_exif_orientation(self):
+        requested_images = {10: "ten.jpg"}
+        with make_image_file(extension='.jpg') as imfile:
+            names_and_files = self._create_mocked_profile_images(imfile, requested_images)
+        self.assertEqual(len(names_and_files), 1)
+        for file_ in [nf[1] for nf in names_and_files]:
+            with closing(Image.open(file_)) as image_obj:
+                self.assertEqual(image_obj.format, 'JPEG')
+                self.assertNotIn('exif', image_obj.info)
+
+    def _create_mocked_profile_images(self, image_file, requested_images):
+        """
+        Create image files with mocked-out storage.  Return a list of tuples
+        consisting of the name and content of the file.
+        """
+        mock_storage = mock.Mock()
+        with mock.patch(
+            "openedx.core.djangoapps.profile_images.images.get_profile_image_storage",
+            return_value=mock_storage,
+        ):
+            create_profile_images(image_file, requested_images)
+        names_and_files = [v[0] for v in mock_storage.save.call_args_list]
+        return names_and_files
 
 
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Profile Image API is only supported in LMS')

openedx/core/djangoapps/profile_images/views.py

@@ -22,8 +22,9 @@ from openedx.core.lib.api.parsers import TypedFileUploadParser
 from openedx.core.lib.api.permissions import IsUserInUrl, IsUserInUrlOrStaff
 from openedx.core.lib.api.view_utils import DeveloperErrorViewMixin
 from openedx.core.djangoapps.user_api.accounts.image_helpers import get_profile_image_names, set_has_profile_image
+from .exceptions import ImageValidationError
 from .images import (
-    IMAGE_TYPES, validate_uploaded_image, create_profile_images, remove_profile_images, ImageValidationError
+    IMAGE_TYPES, validate_uploaded_image, create_profile_images, remove_profile_images
 )
 
 log = logging.getLogger(__name__)

requirements/edx/base.txt

@@ -54,6 +54,7 @@ nose-xunitmp==0.3.2
 oauthlib==0.7.2
 paramiko==1.9.0
 path.py==7.2
+piexif==1.0.2
 Pillow==2.7.0
 polib==1.0.3
 pycrypto>=2.6