EXIF fixes (linked to #142).

CHANGELOG.txt

@@ -4,11 +4,15 @@ Changelog
 3.4 (unreleased)
 ----------------
 
+Upgrade notes:
+- The EXIF property of an Image is now a method instead.
+
 - Dropped support for Django 1.7.
 - Fixed a few minor issues with the unit tests.
 - Adding a watermark was crashing (fix suggested by hambro).
 - Added/updated translations: Danish, Slovak (contributed by Rasmus Klett, saboter).
 - Fixed Django 1.9 Deprecation warnings (contributed by jlemaes).
+- Processing of EXIF data was broken (and very broken in Python 3) - updated library and bug fixes.
 
 
 3.3.2 (2015-07-20)

photologue/admin.py

@@ -151,6 +151,7 @@ class PhotoAdmin(admin.ModelAdmin):
     search_fields = ['title', 'slug', 'caption']
     list_per_page = 10
     prepopulated_fields = {'slug': ('title',)}
+    readonly_fields = ('date_taken',)
     form = PhotoAdminForm
     if MULTISITE:
         filter_horizontal = ['sites']
@@ -192,10 +193,10 @@ def remove_photos_from_current_site(modeladmin, request, queryset):
     def get_urls(self):
         urls = super(PhotoAdmin, self).get_urls()
         custom_urls = [
-                               url(r'^upload_zip/$',
-                                   self.admin_site.admin_view(self.upload_zip),
-                                   name='photologue_upload_zip')
-                               ]
+            url(r'^upload_zip/$',
+                self.admin_site.admin_view(self.upload_zip),
+                name='photologue_upload_zip')
+        ]
         return custom_urls + urls
 
     def upload_zip(self, request):

photologue/models.py

@@ -5,6 +5,7 @@
 import logging
 from io import BytesIO
 from importlib import import_module
+import exifread
 
 from django.utils.timezone import now
 from django.db import models
@@ -42,7 +43,6 @@
 
 from sortedm2m.fields import SortedManyToManyField
 
-from .utils import EXIF
 from .utils.reflection import add_reflection
 from .utils.watermark import apply_watermark
 from .managers import GalleryQuerySet, PhotoQuerySet
@@ -259,7 +259,7 @@ class ImageModel(models.Model):
     date_taken = models.DateTimeField(_('date taken'),
                                       null=True,
                                       blank=True,
-                                      editable=False)
+                                      help_text=_('Date image was taken; is obtained from the image EXIF data.'))
     view_count = models.PositiveIntegerField(_('view count'),
                                              default=0,
                                              editable=False)
@@ -277,21 +277,16 @@ class ImageModel(models.Model):
     class Meta:
         abstract = True
 
-    @property
-    def EXIF(self):
+    def EXIF(self, file=None):
         try:
-            f = self.image.storage.open(self.image.name, 'rb')
-            tags = EXIF.process_file(f)
-            f.close()
+            if file:
+                tags = exifread.process_file(file)
+            else:
+                with self.image.storage.open(self.image.name, 'rb') as file:
+                    tags = exifread.process_file(file, details=False)
             return tags
         except:
-            try:
-                f = self.image.storage.open(self.image.name, 'rb')
-                tags = EXIF.process_file(f, details=False)
-                f.close()
-                return tags
-            except:
-                return {}
+            return {}
 
     def admin_thumbnail(self):
         func = getattr(self, 'get_admin_thumbnail_url', None)
@@ -429,10 +424,10 @@ def create_size(self, photosize):
         if im.size != photosize.size and photosize.size != (0, 0):
             im = self.resize_image(im, photosize)
         # Rotate if found & necessary
-        if 'Image Orientation' in self.EXIF and \
-                self.EXIF.get('Image Orientation').values[0] in IMAGE_EXIF_ORIENTATION_MAP:
+        if 'Image Orientation' in self.EXIF() and \
+                self.EXIF().get('Image Orientation').values[0] in IMAGE_EXIF_ORIENTATION_MAP:
             im = im.transpose(
-                IMAGE_EXIF_ORIENTATION_MAP[self.EXIF.get('Image Orientation').values[0]])
+                IMAGE_EXIF_ORIENTATION_MAP[self.EXIF().get('Image Orientation').values[0]])
         # Apply watermark if found
         if photosize.watermark is not None:
             im = photosize.watermark.post_process(im)
@@ -480,21 +475,22 @@ def __init__(self, *args, **kwargs):
         self._old_image = self.image
 
     def save(self, *args, **kwargs):
-        if self.date_taken is None:
+        image_has_changed = False
+        if self._get_pk_val() and (self._old_image != self.image):
+            image_has_changed = True
+            self.clear_cache()
+        if self.date_taken is None or image_has_changed:
+            # Attempt to get the date the photo was taken from the EXIF data.
             try:
-                exif_date = self.EXIF.get('EXIF DateTimeOriginal', None)
+                exif_date = self.EXIF(self.image.file).get('EXIF DateTimeOriginal', None)
                 if exif_date is not None:
                     d, t = str.split(exif_date.values)
                     year, month, day = d.split(':')
                     hour, minute, second = t.split(':')
                     self.date_taken = datetime(int(year), int(month), int(day),
                                                int(hour), int(minute), int(second))
             except:
-                pass
-        if self.date_taken is None:
-            self.date_taken = now()
-        if self._get_pk_val() and (self._old_image != self.image):
-            self.clear_cache()
+                logger.error('Failed to read EXIF DateTimeOriginal', exc_info=True)
         super(ImageModel, self).save(*args, **kwargs)
         self.pre_cache()