Generated: Wed 2013-03-13 10:33 CET
Source file: /media/Envs/Envs/filer-gallery/lib/python2.7/site-packages/easy_thumbnails/files.py
Stats: 0 executed, 283 missed, 11 excluded, 292 ignored
from django.core.files.base import File, ContentFile
from django.core.files.storage import get_storage_class, default_storage, \
Storage
from django.db.models.fields.files import ImageFieldFile, FieldFile
import os
from django.utils.safestring import mark_safe
from django.utils.html import escape
from django.utils.http import urlquote
from easy_thumbnails import engine, exceptions, models, utils, signals
from easy_thumbnails.alias import aliases
from easy_thumbnails.conf import settings
def get_thumbnailer(obj, relative_name=None):
"""
Get a :class:`Thumbnailer` for a source file.
The ``obj`` argument is usually either one of the following:
* ``FieldFile`` instance (i.e. a model instance file/image field
property).
* A string, which will be used as the relative name (the source will be
set to the default storage).
* ``Storage`` instance - the ``relative_name`` argument must also be
provided.
Or it could be:
* A file-like instance - the ``relative_name`` argument must also be
provided.
In this case, the thumbnailer won't use or create a cached reference
to the thumbnail (i.e. a new thumbnail will be created for every
:meth:`Thumbnailer.get_thumbnail` call).
If ``obj`` is a ``Thumbnailer`` instance, it will just be returned. If it's
an object with an ``easy_thumbnails_thumbnailer`` then the attribute is
simply returned under the assumption it is a Thumbnailer instance)
"""
if hasattr(obj, 'easy_thumbnails_thumbnailer'):
return obj.easy_thumbnails_thumbnailer
if isinstance(obj, Thumbnailer):
return obj
elif isinstance(obj, FieldFile):
if not relative_name:
relative_name = obj.name
return ThumbnailerFieldFile(obj.instance, obj.field, relative_name)
source_storage = None
if isinstance(obj, basestring):
relative_name = obj
obj = None
if not relative_name:
raise ValueError("If object is not a FieldFile or Thumbnailer "
"instance, the relative name must be provided")
if isinstance(obj, File):
obj = obj.file
if isinstance(obj, Storage) or obj == default_storage:
source_storage = obj
obj = None
return Thumbnailer(file=obj, name=relative_name,
source_storage=source_storage, remote_source=obj is not None)
def save_thumbnail(thumbnail_file, storage):
"""
Save a thumbnailed file, returning the saved relative file name.
"""
filename = thumbnail_file.name
if storage.exists(filename):
try:
storage.delete(filename)
except:
pass
return storage.save(filename, thumbnail_file)
def generate_all_aliases(fieldfile, include_global):
"""
Generate all of a file's aliases.
:param fieldfile: A ``FieldFile`` instance.
:param include_global: A boolean which determines whether to generate
thumbnails for project-wide aliases in addition to field, model, and
app specific aliases.
"""
all_options = aliases.all(fieldfile, include_global=include_global)
if all_options:
thumbnailer = get_thumbnailer(fieldfile)
for options in all_options.values():
thumbnailer.get_thumbnail(options)
class FakeField(object):
name = 'fake'
def __init__(self, storage=None):
self.storage = storage or default_storage
def generate_filename(self, instance, name, *args, **kwargs):
return name
class FakeInstance(object):
def save(self, *args, **kwargs):
pass
class ThumbnailFile(ImageFieldFile):
"""
A thumbnailed file.
This can be used just like a Django model instance's property for a file
field (i.e. an ``ImageFieldFile`` object).
"""
def __init__(self, name, file=None, storage=None, thumbnail_options=None,
*args, **kwargs):
fake_field = FakeField(storage=storage)
super(ThumbnailFile, self).__init__(FakeInstance(), fake_field, name,
*args, **kwargs)
del self.field
if file:
self.file = file
self.thumbnail_options = thumbnail_options
def _get_image(self):
"""
Get a PIL Image instance of this file.
The image is cached to avoid the file needing to be read again if the
function is called again.
"""
if not hasattr(self, '_image_cache'):
from easy_thumbnails.source_generators import pil_image
self.image = pil_image(self)
return self._image_cache
def _set_image(self, image):
"""
Set the image for this file.
This also caches the dimensions of the image.
"""
if image:
self._image_cache = image
self._dimensions_cache = image.size
else:
if hasattr(self, '_image_cache'):
del self._cached_image
if hasattr(self, '_dimensions_cache'):
del self._dimensions_cache
image = property(_get_image, _set_image)
def tag(self, alt='', use_size=None, **attrs):
"""
Return a standard XHTML ``<img ... />`` tag for this field.
:param alt: The ``alt=""`` text for the tag. Defaults to ``''``.
:param use_size: Whether to get the size of the thumbnail image for use in
the tag attributes. If ``None`` (default), it will be ``True`` or
``False`` depending on whether the file storage is local or not.
All other keyword parameters are added as (properly escaped) extra
attributes to the `img` tag.
"""
if use_size is None:
try:
self.storage.path(self.name)
use_size = True
except NotImplementedError:
use_size = False
attrs['alt'] = alt
attrs['src'] = self.url
if use_size:
attrs.update(dict(width=self.width, height=self.height))
attrs = ' '.join(['%s="%s"' % (key, escape(value))
for key, value in sorted(attrs.items())])
return mark_safe('<img %s />' % attrs)
def _get_file(self):
self._require_file()
if not hasattr(self, '_file') or self._file is None:
self._file = self.storage.open(self.name, 'rb')
return self._file
def _set_file(self, value):
if value is not None and not isinstance(value, File):
value = File(value)
self._file = value
self._committed = False
def _del_file(self):
del self._file
file = property(_get_file, _set_file, _del_file)
def _get_url(self):
"""
Return the full url of this file.
.. note:: storages should already be quoting the urls, but Django's
built in ``FileSystemStorage`` doesn't.
``ThumbnailFieldFile`` works around a common case of the file
containing a ``#``, which shouldn't ever be used for a url.
"""
url = super(ThumbnailFile, self).url
if '#' in url:
url = urlquote(url)
return url
url = property(_get_url)
def open(self, mode=None, *args, **kwargs):
if self.closed and self.name:
mode = mode or getattr(self, 'mode', None) or 'rb'
self.file = self.storage.open(self.name, mode)
else:
return super(ThumbnailFile, self).open(mode, *args, **kwargs)
class Thumbnailer(File):
"""
A file-like object which provides some methods to generate thumbnail
images.
You can subclass this object and override the following properties to
change the defaults (pulled from the default settings):
* source_generators
* thumbnail_processors
"""
source_generators = None
thumbnail_processors = None
def __init__(self, file=None, name=None, source_storage=None,
thumbnail_storage=None, remote_source=False, generate=True, *args,
**kwargs):
super(Thumbnailer, self).__init__(file, name, *args, **kwargs)
self.source_storage = source_storage or default_storage
if not thumbnail_storage:
thumbnail_storage = get_storage_class(
settings.THUMBNAIL_DEFAULT_STORAGE)()
self.thumbnail_storage = thumbnail_storage
self.remote_source = remote_source
self.alias_target = None
self.generate = generate
# Set default properties. For backwards compatibilty, check to see
# if the attribute exists already (it could be set as a class property
# on a subclass) before getting it from settings.
for default in ('basedir', 'subdir', 'prefix', 'quality', 'extension',
'preserve_extensions', 'transparency_extension',
'check_cache_miss'):
attr_name = 'thumbnail_%s' % default
if getattr(self, attr_name, None) is None:
value = getattr(settings, attr_name.upper())
setattr(self, attr_name, value)
def __getitem__(self, alias):
"""
Retrieve a thumbnail matching the alias options (or raise a
``KeyError`` if no such alias exists).
"""
options = aliases.get(alias, target=self.alias_target)
if not options:
raise KeyError(alias)
return self.get_thumbnail(options)
def generate_source_image(self, thumbnail_options):
return engine.generate_source_image(self, thumbnail_options,
self.source_generators)
def generate_thumbnail(self, thumbnail_options):
"""
Return an unsaved ``ThumbnailFile`` containing a thumbnail image.
The thumbnail image is generated using the ``thumbnail_options``
dictionary.
"""
image = self.generate_source_image(thumbnail_options)
if image is None:
raise exceptions.InvalidImageFormatError(
"The source file does not appear to be an image")
thumbnail_image = engine.process_image(image, thumbnail_options,
self.thumbnail_processors)
quality = thumbnail_options.get('quality', self.thumbnail_quality)
filename = self.get_thumbnail_name(thumbnail_options,
transparent=utils.is_transparent(thumbnail_image))
data = engine.save_image(thumbnail_image, filename=filename,
quality=quality).read()
thumbnail = ThumbnailFile(filename, file=ContentFile(data),
storage=self.thumbnail_storage,
thumbnail_options=thumbnail_options)
thumbnail.image = thumbnail_image
thumbnail._committed = False
return thumbnail
def get_thumbnail_name(self, thumbnail_options, transparent=False):
"""
Return a thumbnail filename for the given ``thumbnail_options``
dictionary and ``source_name`` (which defaults to the File's ``name``
if not provided).
"""
path, source_filename = os.path.split(self.name)
source_extension = os.path.splitext(source_filename)[1][1:]
filename = '%s%s' % (self.thumbnail_prefix, source_filename)
if self.thumbnail_preserve_extensions == True or \
(self.thumbnail_preserve_extensions and \
source_extension.lower() in self.thumbnail_preserve_extensions):
extension = source_extension
elif transparent:
extension = self.thumbnail_transparency_extension
else:
extension = self.thumbnail_extension
extension = extension or 'jpg'
thumbnail_options = thumbnail_options.copy()
size = tuple(thumbnail_options.pop('size'))
quality = thumbnail_options.pop('quality', self.thumbnail_quality)
initial_opts = ['%sx%s' % size, 'q%s' % quality]
opts = thumbnail_options.items()
opts.sort() # Sort the options so the file name is consistent.
opts = ['%s' % (v is not True and '%s-%s' % (k, v) or k)
for k, v in opts if v]
all_opts = '_'.join(initial_opts + opts)
data = {'opts': all_opts}
basedir = self.thumbnail_basedir % data
subdir = self.thumbnail_subdir % data
filename_parts = [filename]
if ('%(opts)s' in self.thumbnail_basedir or
'%(opts)s' in self.thumbnail_subdir):
if extension != source_extension:
filename_parts.append(extension)
else:
filename_parts += [all_opts, extension]
filename = '.'.join(filename_parts)
return os.path.join(basedir, path, subdir, filename)
def get_thumbnail(self, thumbnail_options, save=True, generate=None):
"""
Return a ``ThumbnailFile`` containing a thumbnail.
If a matching thumbnail already exists, it will simply be returned.
By default (unless the ``Thumbnailer`` was instanciated with
``generate=False``), thumbnails that don't exist are generated.
Otherwise ``None`` is returned.
Force the generation behaviour by setting the ``generate`` param to
either ``True`` or ``False`` as required.
The new thumbnail image is generated using the ``thumbnail_options``
dictionary. If the ``save`` argument is ``True`` (default), the
generated thumbnail will be saved too.
"""
opaque_name = self.get_thumbnail_name(thumbnail_options,
transparent=False)
transparent_name = self.get_thumbnail_name(thumbnail_options,
transparent=True)
if opaque_name == transparent_name:
names = (opaque_name,)
else:
names = (opaque_name, transparent_name)
for filename in names:
if self.thumbnail_exists(filename):
return ThumbnailFile(name=filename,
storage=self.thumbnail_storage,
thumbnail_options=thumbnail_options)
if generate is None:
generate = self.generate
if not generate:
signals.thumbnail_missed.send(sender=self,
options=thumbnail_options)
return
thumbnail = self.generate_thumbnail(thumbnail_options)
if save:
save_thumbnail(thumbnail, self.thumbnail_storage)
signals.thumbnail_created.send(sender=thumbnail)
# Ensure the right thumbnail name is used based on the transparency
# of the image.
filename = (utils.is_transparent(thumbnail.image) and
transparent_name or opaque_name)
self.get_thumbnail_cache(filename, create=True, update=True)
return thumbnail
def thumbnail_exists(self, thumbnail_name):
"""
Calculate whether the thumbnail already exists and that the source is
not newer than the thumbnail.
If both the source and thumbnail file storages are local, their
file modification times are used. Otherwise the database cached
modification times are used.
"""
if self.remote_source:
return False
# Try to use the local file modification times first.
source_modtime = self.get_source_modtime()
thumbnail_modtime = self.get_thumbnail_modtime(thumbnail_name)
# The thumbnail modification time will be 0 if there was an OSError,
# in which case it will still be used (but always return False).
if source_modtime and thumbnail_modtime is not None:
return thumbnail_modtime and source_modtime <= thumbnail_modtime
# Fall back to using the database cached modification times.
source = self.get_source_cache()
if not source:
return False
thumbnail = self.get_thumbnail_cache(thumbnail_name)
return thumbnail and source.modified <= thumbnail.modified
def get_source_cache(self, create=False, update=False):
if self.remote_source:
return None
modtime = self.get_source_modtime()
update_modified = modtime and utils.fromtimestamp(modtime)
if update:
update_modified = update_modified or utils.now()
return models.Source.objects.get_file(
create=create, update_modified=update_modified,
storage=self.source_storage, name=self.name,
check_cache_miss=self.thumbnail_check_cache_miss)
def get_thumbnail_cache(self, thumbnail_name, create=False, update=False):
if self.remote_source:
return None
modtime = self.get_thumbnail_modtime(thumbnail_name)
update_modified = modtime and utils.fromtimestamp(modtime)
if update:
update_modified = update_modified or utils.now()
source = self.get_source_cache(create=True)
return models.Thumbnail.objects.get_file(
create=create, update_modified=update_modified,
storage=self.thumbnail_storage, source=source, name=thumbnail_name,
check_cache_miss=self.thumbnail_check_cache_miss)
def get_source_modtime(self):
try:
path = self.source_storage.path(self.name)
return os.path.getmtime(path)
except OSError:
return 0
except NotImplementedError:
return None
def get_thumbnail_modtime(self, thumbnail_name):
try:
path = self.thumbnail_storage.path(thumbnail_name)
return os.path.getmtime(path)
except OSError:
return 0
except NotImplementedError:
return None
def open(self, mode=None):
if self.closed:
mode = mode or getattr(self, 'mode', None) or 'rb'
self.file = self.source_storage.open(self.name, mode)
else:
self.seek(0)
# open() doesn't alter the file's contents, but it does reset the pointer.
open.alters_data = True
class ThumbnailerFieldFile(FieldFile, Thumbnailer):
"""
A field file which provides some methods for generating (and returning)
thumbnail images.
"""
def __init__(self, *args, **kwargs):
super(ThumbnailerFieldFile, self).__init__(*args, **kwargs)
self.source_storage = self.field.storage
thumbnail_storage = getattr(self.field, 'thumbnail_storage', None)
if thumbnail_storage:
self.thumbnail_storage = thumbnail_storage
self.alias_target = self
def save(self, name, content, *args, **kwargs):
"""
Save the file, also saving a reference to the thumbnail cache Source
model.
"""
super(ThumbnailerFieldFile, self).save(name, content, *args, **kwargs)
self.get_source_cache(create=True, update=True)
def delete(self, *args, **kwargs):
"""
Delete the image, along with any generated thumbnails.
"""
source_cache = self.get_source_cache()
# First, delete any related thumbnails.
self.delete_thumbnails(source_cache)
# Next, delete the source image.
super(ThumbnailerFieldFile, self).delete(*args, **kwargs)
# Finally, delete the source cache entry.
if source_cache:
source_cache.delete()
delete.alters_data = True
def delete_thumbnails(self, source_cache=None):
"""
Delete any thumbnails generated from the source image.
:arg source_cache: An optional argument only used for optimisation
where the source cache instance is already known.
:returns: The number of files deleted.
"""
source_cache = self.get_source_cache()
deleted = 0
if source_cache:
thumbnail_storage_hash = utils.get_storage_hash(
self.thumbnail_storage)
for thumbnail_cache in source_cache.thumbnails.all():
# Only attempt to delete the file if it was stored using the
# same storage as is currently used.
if thumbnail_cache.storage_hash == thumbnail_storage_hash:
self.thumbnail_storage.delete(thumbnail_cache.name)
# Delete the cache thumbnail instance too.
thumbnail_cache.delete()
deleted += 1
return deleted
delete_thumbnails.alters_data = True
def get_thumbnails(self, *args, **kwargs):
"""
Return an iterator which returns ThumbnailFile instances.
"""
# First, delete any related thumbnails.
source_cache = self.get_source_cache()
if source_cache:
thumbnail_storage_hash = utils.get_storage_hash(
self.thumbnail_storage)
for thumbnail_cache in source_cache.thumbnails.all():
# Only iterate files which are stored using the current
# thumbnail storage.
if thumbnail_cache.storage_hash == thumbnail_storage_hash:
yield ThumbnailFile(name=thumbnail_cache.name,
storage=self.thumbnail_storage)
class ThumbnailerImageFieldFile(ImageFieldFile, ThumbnailerFieldFile):
"""
A field file which provides some methods for generating (and returning)
thumbnail images.
"""
def save(self, name, content, *args, **kwargs):
"""
Save the image.
The image will be resized down using a ``ThumbnailField`` if
``resize_source`` (a dictionary of thumbnail options) is provided by
the field.
"""
options = getattr(self.field, 'resize_source', None)
if options:
if not 'quality' in options:
options['quality'] = self.thumbnail_quality
content = Thumbnailer(content, name).generate_thumbnail(options)
super(ThumbnailerImageFieldFile, self).save(name, content, *args,
**kwargs)