django1/django/db/models/fields/files.py

236 lines
8.9 KiB
Python

import datetime
import os
from django.conf import settings
from django.db.models.fields import Field
from django.core.files.base import File, ContentFile
from django.core.files.storage import default_storage
from django.core.files.images import ImageFile, get_image_dimensions
from django.core.files.uploadedfile import UploadedFile
from django.utils.functional import curry
from django.db.models import signals
from django.utils.encoding import force_unicode, smart_str
from django.utils.translation import ugettext_lazy, ugettext as _
from django import forms
from django.db.models.loading import cache
class FieldFile(File):
def __init__(self, instance, field, name):
self.instance = instance
self.field = field
self.storage = field.storage
self._name = name or u''
self._closed = False
def __eq__(self, other):
# Older code may be expecting FileField values to be simple strings.
# By overriding the == operator, it can remain backwards compatibility.
if hasattr(other, 'name'):
return self.name == other.name
return self.name == other
# The standard File contains most of the necessary properties, but
# FieldFiles can be instantiated without a name, so that needs to
# be checked for here.
def _require_file(self):
if not self:
raise ValueError("The '%s' attribute has no file associated with it." % self.field.name)
def _get_file(self):
self._require_file()
if not hasattr(self, '_file'):
self._file = self.storage.open(self.name, 'rb')
return self._file
file = property(_get_file)
def _get_path(self):
self._require_file()
return self.storage.path(self.name)
path = property(_get_path)
def _get_url(self):
self._require_file()
return self.storage.url(self.name)
url = property(_get_url)
def _get_size(self):
self._require_file()
return self.storage.size(self.name)
size = property(_get_size)
def open(self, mode='rb'):
self._require_file()
return super(FieldFile, self).open(mode)
# open() doesn't alter the file's contents, but it does reset the pointer
open.alters_data = True
# In addition to the standard File API, FieldFiles have extra methods
# to further manipulate the underlying file, as well as update the
# associated model instance.
def save(self, name, content, save=True):
name = self.field.generate_filename(self.instance, name)
self._name = self.storage.save(name, content)
setattr(self.instance, self.field.name, self.name)
# Update the filesize cache
self._size = len(content)
# Save the object because it has changed, unless save is False
if save:
self.instance.save()
save.alters_data = True
def delete(self, save=True):
# Only close the file if it's already open, which we know by the
# presence of self._file
if hasattr(self, '_file'):
self.close()
del self._file
self.storage.delete(self.name)
self._name = None
setattr(self.instance, self.field.name, self.name)
# Delete the filesize cache
if hasattr(self, '_size'):
del self._size
if save:
self.instance.save()
delete.alters_data = True
def __getstate__(self):
# FieldFile needs access to its associated model field and an instance
# it's attached to in order to work properly, but the only necessary
# data to be pickled is the file's name itself. Everything else will
# be restored later, by FileDescriptor below.
return {'_name': self.name, '_closed': False}
class FileDescriptor(object):
def __init__(self, field):
self.field = field
def __get__(self, instance=None, owner=None):
if instance is None:
raise AttributeError, "%s can only be accessed from %s instances." % (self.field.name(self.owner.__name__))
file = instance.__dict__[self.field.name]
if not isinstance(file, FieldFile):
# Create a new instance of FieldFile, based on a given file name
instance.__dict__[self.field.name] = self.field.attr_class(instance, self.field, file)
elif not hasattr(file, 'field'):
# The FieldFile was pickled, so some attributes need to be reset.
file.instance = instance
file.field = self.field
file.storage = self.field.storage
return instance.__dict__[self.field.name]
def __set__(self, instance, value):
instance.__dict__[self.field.name] = value
class FileField(Field):
attr_class = FieldFile
def __init__(self, verbose_name=None, name=None, upload_to='', storage=None, **kwargs):
for arg in ('primary_key', 'unique'):
if arg in kwargs:
raise TypeError("'%s' is not a valid argument for %s." % (arg, self.__class__))
self.storage = storage or default_storage
self.upload_to = upload_to
if callable(upload_to):
self.generate_filename = upload_to
kwargs['max_length'] = kwargs.get('max_length', 100)
super(FileField, self).__init__(verbose_name, name, **kwargs)
def get_internal_type(self):
return "FileField"
def get_db_prep_lookup(self, lookup_type, value):
if hasattr(value, 'name'):
value = value.name
return super(FileField, self).get_db_prep_lookup(lookup_type, value)
def get_db_prep_value(self, value):
"Returns field's value prepared for saving into a database."
# Need to convert File objects provided via a form to unicode for database insertion
if value is None:
return None
return unicode(value)
def contribute_to_class(self, cls, name):
super(FileField, self).contribute_to_class(cls, name)
setattr(cls, self.name, FileDescriptor(self))
signals.post_delete.connect(self.delete_file, sender=cls)
def delete_file(self, instance, sender, **kwargs):
file = getattr(instance, self.attname)
# If no other object of this type references the file,
# and it's not the default value for future objects,
# delete it from the backend.
if file and file.name != self.default and \
not sender._default_manager.filter(**{self.name: file.name}):
file.delete(save=False)
elif file:
# Otherwise, just close the file, so it doesn't tie up resources.
file.close()
def get_directory_name(self):
return os.path.normpath(force_unicode(datetime.datetime.now().strftime(smart_str(self.upload_to))))
def get_filename(self, filename):
return os.path.normpath(self.storage.get_valid_name(os.path.basename(filename)))
def generate_filename(self, instance, filename):
return os.path.join(self.get_directory_name(), self.get_filename(filename))
def save_form_data(self, instance, data):
if data and isinstance(data, UploadedFile):
getattr(instance, self.name).save(data.name, data, save=False)
def formfield(self, **kwargs):
defaults = {'form_class': forms.FileField}
# If a file has been provided previously, then the form doesn't require
# that a new file is provided this time.
# The code to mark the form field as not required is used by
# form_for_instance, but can probably be removed once form_for_instance
# is gone. ModelForm uses a different method to check for an existing file.
if 'initial' in kwargs:
defaults['required'] = False
defaults.update(kwargs)
return super(FileField, self).formfield(**defaults)
class ImageFieldFile(ImageFile, FieldFile):
def save(self, name, content, save=True):
# Repopulate the image dimension cache.
self._dimensions_cache = get_image_dimensions(content)
# Update width/height fields, if needed
if self.field.width_field:
setattr(self.instance, self.field.width_field, self.width)
if self.field.height_field:
setattr(self.instance, self.field.height_field, self.height)
super(ImageFieldFile, self).save(name, content, save)
def delete(self, save=True):
# Clear the image dimensions cache
if hasattr(self, '_dimensions_cache'):
del self._dimensions_cache
super(ImageFieldFile, self).delete(save)
class ImageField(FileField):
attr_class = ImageFieldFile
def __init__(self, verbose_name=None, name=None, width_field=None, height_field=None, **kwargs):
self.width_field, self.height_field = width_field, height_field
FileField.__init__(self, verbose_name, name, **kwargs)
def formfield(self, **kwargs):
defaults = {'form_class': forms.ImageField}
defaults.update(kwargs)
return super(ImageField, self).formfield(**defaults)