Fix imports of optional dependencies

tests/test_engines.py

@@ -5,8 +5,8 @@
 
 from PIL import Image
 
-from thumbnails.engines import (BaseThumbnailEngine, DummyEngine, PgmagickEngine, PillowEngine,
-                                WandEngine)
+from thumbnails.engines import DummyEngine, PgmagickEngine, PillowEngine, WandEngine
+from thumbnails.engines.base import BaseThumbnailEngine
 from thumbnails.errors import ThumbnailError
 from thumbnails.images import SourceFile, Thumbnail
 
@@ -17,8 +17,7 @@
 class EngineTestMixin(object):
 
     def setUp(self):
-        if self.ENGINE:
-            self.engine = self.ENGINE()
+        self.engine = self.ENGINE()
         self.filename = os.path.join(os.path.dirname(__file__), 'test_image.jpg')
         self.file = SourceFile(self.filename)
         self.url = SourceFile('http://puppies.lkng.me/400x600/')
@@ -36,15 +35,15 @@ def assertSize(self, thumbnail, width, height):
     def assertRawData(self, raw_data):
         self.assertEqual(hashlib.sha1(raw_data).hexdigest(), self.RAW_DATA_HASH)
 
-    @mock.patch('thumbnails.engines.BaseThumbnailEngine.create')
-    @mock.patch('thumbnails.engines.BaseThumbnailEngine.cleanup')
+    @mock.patch('thumbnails.engines.base.BaseThumbnailEngine.create')
+    @mock.patch('thumbnails.engines.base.BaseThumbnailEngine.cleanup')
     def test_get_thumbnail(self, mock_create, mock_cleanup):
         self.engine.get_thumbnail(self.file, '200', None, None)
         self.assertTrue(mock_create.called)
         self.assertTrue(mock_cleanup.called)
 
-    @mock.patch('thumbnails.engines.BaseThumbnailEngine.create', side_effect=ThumbnailError(''))
-    @mock.patch('thumbnails.engines.BaseThumbnailEngine.cleanup')
+    @mock.patch('thumbnails.engines.base.BaseThumbnailEngine.create', side_effect=ThumbnailError(''))
+    @mock.patch('thumbnails.engines.base.BaseThumbnailEngine.cleanup')
     def test_get_thumbnail_fail(self, mock_create, mock_cleanup):
         self.engine.get_thumbnail(self.file, '200', None, None)
         self.assertTrue(mock_create.called)

thumbnails/__init__.py

@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+
 from thumbnails.conf import settings
 from thumbnails.engines import DummyEngine
 from thumbnails.helpers import get_engine, generate_filename, get_cache_backend
@@ -29,6 +30,7 @@ def get_thumbnail(original, size, **options):
                    detected file type as well as the one specified in ``THUMBNAIL_FALLBACK_FORMAT``.
     :return: A Thumbnail object
     """
+
     engine = get_engine()
     cache = get_cache_backend()
     original = SourceFile(original)

thumbnails/engines/__init__.py

@@ -1,21 +1,5 @@
 # -*- coding: utf-8 -*-
-from thumbnails.engines.base import BaseThumbnailEngine  # noqa
 from thumbnails.engines.dummy import DummyEngine  # noqa
-
-
-try:
-    from thumbnails.engines.pillow_engine import PillowEngine  # noqa
-except ImportError:
-    PillowEngine = None
-
-
-try:
-    from thumbnails.engines.wand_engine import WandEngine  # noqa
-except ImportError:
-    WandEngine = None
-
-
-try:
-    from thumbnails.engines.pgmagick_engine import PgmagickEngine  # noqa
-except ImportError:
-    PgmagickEngine = None
+from thumbnails.engines.pillow_engine import PillowEngine  # noqa
+from thumbnails.engines.wand_engine import WandEngine  # noqa
+from thumbnails.engines.pgmagick_engine import PgmagickEngine  # noqa

thumbnails/engines/pgmagick_engine.py

@@ -1,8 +1,6 @@
 # -*- coding: utf-8 -*-
 from base64 import b64decode
 
-from pgmagick import Blob, Geometry, Image, ImageType
-
 from .base import BaseThumbnailEngine
 
 
@@ -11,15 +9,23 @@ class PgmagickEngine(BaseThumbnailEngine):
     Image backend for pgmagick, requires the pgmagick package.
     """
 
+    def __init__(self):
+        super(PgmagickEngine, self).__init__()
+        from pgmagick import Blob, Geometry, Image, ImageType
+        self._Blob = Blob
+        self._Geometry = Geometry
+        self._Image = Image
+        self._ImageType = ImageType
+
     def engine_load_image(self, original):
-        blob = Blob()
+        blob = self._Blob()
         blob.update(original.open().read())
-        return Image(blob)
+        return self._Image(blob)
 
     def engine_raw_data(self, image, options):
         image.magick(self.get_format(image, options))
         image.quality(options['quality'])
-        blob = Blob()
+        blob = self._Blob()
         image.write(blob)
         return b64decode(blob.base64())
 
@@ -28,14 +34,14 @@ def engine_image_size(self, image):
         return geometry.width(), geometry.height()
 
     def engine_scale(self, image, width, height):
-        geometry = Geometry(width, height)
+        geometry = self._Geometry(width, height)
         image.scale(geometry)
         return image
 
     def engine_crop(self, image, size, crop, options):
         x, y = crop
         width, height = size
-        geometry = Geometry(width, height, x, y)
+        geometry = self._Geometry(width, height, x, y)
         image.crop(geometry)
         return image
 
@@ -44,14 +50,13 @@ def engine_cleanup(self, original):
 
     def engine_colormode(self, image, colormode):
         if colormode == 'RGB':
-            image.type(ImageType.TrueColorMatteType)
+            image.type(self._ImageType.TrueColorMatteType)
         elif colormode == 'GRAY':
-            image.type(ImageType.GrayscaleMatteType)
+            image.type(self._ImageType.GrayscaleMatteType)
         return image
 
     def engine_get_format(self, image):
         _format = image.format()
-        # pgmagick in python 2.7 gives full length formats instead of abbrevations
         if _format == 'Joint Photographic Experts Group JFIF format':
             return 'JPEG'
         if _format == 'Portable Network Graphics':

thumbnails/engines/pillow_engine.py

@@ -1,5 +1,4 @@
 # -*- coding: utf-8 -*-
-from PIL import Image, ImageFile
 
 from thumbnails.compat import BytesIO
 from thumbnails.errors import ThumbnailError
@@ -12,16 +11,22 @@ class PillowEngine(BaseThumbnailEngine):
     Thumbnail engine for Pillow
     """
 
+    def __init__(self):
+        super(PillowEngine, self).__init__()
+        from PIL import Image, ImageFile
+        self._Image = Image
+        self._ImageFile = ImageFile
+
     def engine_load_image(self, original):
-        image = Image.open(BytesIO(original.open().read()))
+        image = self._Image.open(BytesIO(original.open().read()))
         try:
             image.load()
         except (IOError, OSError) as e:
             raise ThumbnailError('Could not load image', exception=e)
         return image
 
     def engine_raw_data(self, image, options):
-        ImageFile.MAXBLOCK = max(ImageFile.MAXBLOCK, int(image.size[0] * image.size[1]))
+        self._ImageFile.MAXBLOCK = max(self._ImageFile.MAXBLOCK, int(image.size[0] * image.size[1]))
         pillow_options = {
             'format': self.get_format(image, options),
             'quality': options['quality'],
@@ -34,7 +39,7 @@ def engine_image_size(self, image):
         return image.size
 
     def engine_scale(self, image, width, height):
-        return image.resize((width, height), resample=Image.ANTIALIAS)
+        return image.resize((width, height), resample=self._Image.ANTIALIAS)
 
     def engine_crop(self, image, size, crop, options):
         x, y = crop

thumbnails/engines/wand_engine.py

@@ -1,5 +1,4 @@
 # -*- coding: utf-8 -*-
-from wand.image import Image
 
 from .base import BaseThumbnailEngine
 
@@ -8,12 +7,16 @@ class WandEngine(BaseThumbnailEngine):
     """
     Image engine for wand.
     """
+    def __init__(self):
+        super(WandEngine, self).__init__()
+        from wand.image import Image
+        self._Image = Image
 
     def engine_image_size(self, image):
         return image.size
 
     def engine_load_image(self, original):
-        return Image(blob=original.open().read())
+        return self._Image(blob=original.open().read())
 
     def engine_scale(self, image, width, height):
         image.resize(width, height)