Allow for overriding image upload path

CHANGELOG.txt

@@ -12,6 +12,7 @@ Changelog
  * Added `Page` methods `can_exist_under`, `can_create_at`, `can_move_to` for customising page type business rules
  * `wagtailadmin.utils.send_mail` now passes extra keyword arguments to Django's `send_mail` function (Matthew Downey)
  * `page_unpublish` signal is now fired for each page that was unpublished by a call to `PageQuerySet.unpublish()`
+ * Add `get_upload_to` method to `AbstractImage`, to allow overriding the default image upload path (Ben Emery)
  * Fix: HTTP cache purge now works again on Python 2 (Mitchel Cabuloy)
  * Fix: Locked pages can no longer be unpublished (Alex Bridge)
  * Fix: Site records now implement `get_by_natural_key`

docs/releases/1.3.rst

@@ -22,6 +22,7 @@ Minor features
  * Added ``Page`` methods ``can_exist_under``, ``can_create_at``, ``can_move_to`` for customising page type business rules
  * ``wagtailadmin.utils.send_mail`` now passes extra keyword arguments to Django's ``send_mail`` function (Matthew Downey)
  * ``page_unpublish`` signal is now fired for each page that was unpublished by a call to ``PageQuerySet.unpublish()``
+ * Add `get_upload_to` method to `AbstractImage`, to allow overriding the default image upload path (Ben Emery)
 
 
 Bug fixes

wagtail/tests/testapp/migrations/0019_customimagefilepath.py

@@ -0,0 +1,42 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+from django.conf import settings
+import taggit.managers
+import wagtail.wagtailadmin.taggable
+import wagtail.wagtailimages.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('taggit', '0001_initial'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('tests', '0018_singletonpage'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='CustomImageFilePath',
+            fields=[
+                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
+                ('title', models.CharField(max_length=255, verbose_name='Title')),
+                ('file', models.ImageField(height_field='height', upload_to=wagtail.wagtailimages.models.get_upload_to, width_field='width', verbose_name='File')),
+                ('width', models.IntegerField(verbose_name='Width', editable=False)),
+                ('height', models.IntegerField(verbose_name='Height', editable=False)),
+                ('created_at', models.DateTimeField(db_index=True, auto_now_add=True, verbose_name='Created at')),
+                ('focal_point_x', models.PositiveIntegerField(null=True, blank=True)),
+                ('focal_point_y', models.PositiveIntegerField(null=True, blank=True)),
+                ('focal_point_width', models.PositiveIntegerField(null=True, blank=True)),
+                ('focal_point_height', models.PositiveIntegerField(null=True, blank=True)),
+                ('tags', taggit.managers.TaggableManager(to='taggit.Tag', through='taggit.TaggedItem', blank=True, help_text=None, verbose_name='Tags')),
+                ('uploaded_by_user', models.ForeignKey(blank=True, editable=False, to=settings.AUTH_USER_MODEL, null=True, verbose_name='Uploaded by user')),
+                ('file_size', models.PositiveIntegerField(null=True, editable=False)),
+            ],
+            options={
+                'abstract': False,
+            },
+            bases=(models.Model, wagtail.wagtailadmin.taggable.TagSearchable),
+        ),
+    ]

wagtail/tests/testapp/models.py

@@ -1,5 +1,8 @@
 from __future__ import unicode_literals
 
+import hashlib
+import os
+
 from django.db import models
 from django.core.paginator import Paginator, EmptyPage, PageNotAnInteger
 from django.utils.encoding import python_2_unicode_compatible
@@ -461,7 +464,6 @@ class StreamModel(models.Model):
         ('image', ImageChooserBlock()),
     ])
 
-
 class StreamPage(Page):
     body = StreamField([
         ('text', CharBlock()),
@@ -536,3 +538,34 @@ class GenericSnippetPage(Page):
     snippet_content_type = models.ForeignKey(ContentType, on_delete=models.SET_NULL, null=True)
     snippet_object_id = models.PositiveIntegerField(null=True)
     snippet_content_object = GenericForeignKey('snippet_content_type', 'snippet_object_id')
+
+
+class CustomImageFilePath(AbstractImage):
+    def get_upload_to(self, filename):
+        """Create a path that's file-system friendly.
+
+        By hashing the file's contents we guarantee an equal distribution
+        of files within our root directories. This also gives us a
+        better chance of uploading images with the same filename, but
+        different contents - this isn't guaranteed as we're only using
+        the first three characters of the checksum.
+        """
+        original_filepath = super(CustomImageFilePath, self).get_upload_to(filename)
+        folder_name, filename = original_filepath.split(os.path.sep)
+
+        # Ensure that we consume the entire file, we can't guarantee that
+        # the stream has not be partially (or entirely) consumed by
+        # another process
+        original_position = self.file.tell()
+        self.file.seek(0)
+        hash256 = hashlib.sha256()
+
+        while True:
+            data = self.file.read(256)
+            if not data:
+                break
+            hash256.update(data)
+        checksum = hash256.hexdigest()
+
+        self.file.seek(original_position)
+        return os.path.join(folder_name, checksum[:3], filename)

wagtail/wagtailimages/models.py

@@ -48,19 +48,9 @@ class ImageQuerySet(SearchableQuerySetMixin, models.QuerySet):
 
 
 def get_upload_to(instance, filename):
-    folder_name = 'original_images'
-    filename = instance.file.field.storage.get_valid_name(filename)
+    # Dumb proxy to instance method.
+    return instance.get_upload_to(filename)
 
-    # do a unidecode in the filename and then
-    # replace non-ascii characters in filename with _ , to sidestep issues with filesystem encoding
-    filename = "".join((i if ord(i) < 128 else '_') for i in unidecode(filename))
-
-    # Truncate filename so it fits in the 100 character limit
-    # https://code.djangoproject.com/ticket/9893
-    while len(os.path.join(folder_name, filename)) >= 95:
-        prefix, dot, extension = filename.rpartition('.')
-        filename = prefix[:-1] + dot + extension
-    return os.path.join(folder_name, filename)
 
 
 @python_2_unicode_compatible
@@ -106,6 +96,21 @@ class AbstractImage(models.Model, TagSearchable):
 
         return self.file_size
 
+    def get_upload_to(self, filename):
+        folder_name = 'original_images'
+        filename = self.file.field.storage.get_valid_name(filename)
+
+        # do a unidecode in the filename and then
+        # replace non-ascii characters in filename with _ , to sidestep issues with filesystem encoding
+        filename = "".join((i if ord(i) < 128 else '_') for i in unidecode(filename))
+
+        # Truncate filename so it fits in the 100 character limit
+        # https://code.djangoproject.com/ticket/9893
+        while len(os.path.join(folder_name, filename)) >= 95:
+            prefix, dot, extension = filename.rpartition('.')
+            filename = prefix[:-1] + dot + extension
+        return os.path.join(folder_name, filename)
+
     def get_usage(self):
         return get_object_usage(self)
 

wagtail/wagtailimages/tests/tests.py

@@ -7,7 +7,7 @@ from django.core.urlresolvers import reverse
 
 from taggit.forms import TagField, TagWidget
 
-from wagtail.tests.testapp.models import CustomImage
+from wagtail.tests.testapp.models import CustomImage, CustomImageFilePath
 from wagtail.tests.utils import WagtailTestUtils
 from wagtail.wagtailimages.utils import generate_signature, verify_signature
 from wagtail.wagtailimages.rect import Rect, Vector
@@ -374,3 +374,21 @@ class TestRenditionFilenames(TestCase):
         rendition = image.get_rendition('fill-100x100')
 
         self.assertEqual(rendition.file.name, 'images/test_rf3.15ee4958.fill-100x100.png')
+
+
+class TestDifferentUpload(TestCase):
+    def test_upload_path(self):
+        image = CustomImageFilePath.objects.create(
+            title="Test image",
+            file=get_test_image_file(),
+        )
+
+        second_image = CustomImageFilePath.objects.create(
+            title="Test Image",
+            file=get_test_image_file(colour='black'),
+
+        )
+
+        # The files should be uploaded based on it's content, not just
+        # it's filename
+        self.assertFalse(image.file.url == second_image.file.url)

wagtail/wagtailimages/tests/utils.py

@@ -9,8 +9,8 @@ from wagtail.wagtailimages.models import get_image_model
 Image = get_image_model()
 
 
-def get_test_image_file(filename='test.png'):
+def get_test_image_file(filename='test.png', colour='white', size=(640, 480)):
     f = BytesIO()
-    image = PIL.Image.new('RGB', (640, 480), 'white')
+    image = PIL.Image.new('RGB', size, colour)
     image.save(f, 'PNG')
     return ImageFile(f, name=filename)