def __init__(self, name, file=None, storage=None, thumbnail_options=None,
*args, **kwargs):
fake_field = FakeField(storage=storage)
super().__init__(FakeInstance(), fake_field, name, *args, **kwargs)
del self.field
if file:
self.file = file
if thumbnail_options is None:
thumbnail_options = ThumbnailOptions()
elif not isinstance(thumbnail_options, ThumbnailOptions):
thumbnail_options = ThumbnailOptions(thumbnail_options)
self.thumbnail_options = thumbnail_options
def generate_source_image(source_file,
processor_options,
generators=None,
fail_silently=True):
"""
Processes a source ``File`` through a series of source generators, stopping
once a generator returns an image.
The return value is this image instance or ``None`` if no generators
return an image.
If the source file cannot be opened, it will be set to ``None`` and still
passed to the generators.
"""
processor_options = ThumbnailOptions(processor_options)
# Keep record of whether the source file was originally closed. Not all
# file-like objects provide this attribute, so just fall back to False.
was_closed = getattr(source_file, 'closed', False)
if generators is None:
generators = [
utils.dynamic_import(name)
for name in settings.THUMBNAIL_SOURCE_GENERATORS
]
exceptions = []
try:
for generator in generators:
source = source_file
# First try to open the file.
try:
source.open()
except Exception:
# If that failed, maybe the file-like object doesn't support
# reopening so just try seeking back to the start of the file.
try:
source.seek(0)
except Exception:
source = None
try:
image = generator(source, **processor_options)
except Exception as e:
if not fail_silently:
if len(generators) == 1:
raise
exceptions.append(e)
image = None
if image:
return image
finally:
# Attempt to close the file if it was closed originally (but fail
# silently).
if was_closed:
try:
source_file.close()
except Exception:
pass
if exceptions and not fail_silently:
raise NoSourceGenerator(*exceptions)
def get_options(self, thumbnail_options, **kwargs):
"""
Get the thumbnail options that includes the default options for this
thumbnailer (and the project-wide default options).
"""
if isinstance(thumbnail_options, ThumbnailOptions):
return thumbnail_options
args = []
if thumbnail_options is not None:
args.append(thumbnail_options)
opts = ThumbnailOptions(*args, **kwargs)
if 'quality' not in thumbnail_options:
opts['quality'] = self.thumbnail_quality
return opts
def process_image(source, processor_options, processors=None):
"""
Process a source PIL image through a series of image processors, returning
the (potentially) altered image.
"""
processor_options = ThumbnailOptions(processor_options)
if processors is None:
processors = [
utils.dynamic_import(name)
for name in settings.THUMBNAIL_PROCESSORS]
image = source
for processor in processors:
image = processor(image, **processor_options)
return image
def test_thumbnail_missed_signal(self):
def signal_handler(sender, **kwargs):
sender.missed_signal = kwargs.get('options')
signals.thumbnail_missed.connect(signal_handler)
try:
# Standard generation doesn't trigger signal.
self.thumbnailer.get_thumbnail({'size': (100, 100)})
self.assertFalse(hasattr(self.thumbnailer, 'missed_signal'))
# Retrieval doesn't trigger signal.
self.thumbnailer.get_thumbnail({'size': (100, 100)},
generate=False)
self.assertFalse(hasattr(self.thumbnailer, 'missed_signal'))
# A thumbnail miss does trigger it.
options = {'size': (10, 20)}
thumb = self.thumbnailer.get_thumbnail(options, generate=False)
self.assertEqual(thumb, None)
self.assertEqual(self.thumbnailer.missed_signal,
ThumbnailOptions(options))
finally:
signals.thumbnail_created.disconnect(signal_handler)
def test_thumbnailfile_options(self):
opts = {'size': (50, 50), 'crop': True, 'upscale': True}
thumb = self.thumbnailer.get_thumbnail(opts)
self.assertEqual(thumb.thumbnail_options, ThumbnailOptions(opts))
