def delete_file_if_needed(instance, filefield_name):
"""Delete file from database only if needed.
When editing and the filefield is a new file,
deletes the previous file (if any) from the database.
Call this function immediately BEFORE saving the instance.
"""
if instance.pk:
model_class = type(instance)
# Check if there is a file for the instance in the database
if model_class.objects.filter(pk=instance.pk).exclude(
**{
'%s__isnull' % filefield_name: True
}).exclude(**{
'%s__exact' % filefield_name: ''
}).exists():
old_file = getattr(
model_class.objects.only(filefield_name).get(pk=instance.pk),
filefield_name)
else:
old_file = None
# If there is a file, delete it if needed
if old_file:
# When editing and NOT changing the file,
# old_file.name == getattr(instance, filefield_name)
# returns True. In this case, the file must NOT be deleted.
# If the file IS being changed, the comparison returns False.
# In this case, the old file MUST be deleted.
if (old_file.name == getattr(instance, filefield_name)) is False:
DatabaseFileStorage().delete(old_file.name)
class GalleryEntry(models.Model):
title = models.CharField(max_length=255)
title_slug = models.CharField(max_length=255, null=True)
section = models.ForeignKey(GallerySection,
on_delete=models.DO_NOTHING,
related_name='entries')
content = models.TextField(help_text="markdown-formatted text")
image = models.ImageField(
# this looks wonky, but it seems like it's the way it's supposed to be. Each of these slash delimited fields
# specifies the name of the field in CMSPicture which stores that information. Uploading 'whatever.jpg' yields
# the file name 'capweb.CMSPicture/bytes/filename/mimetype/whatever.jpg'... the fields are not replaced with
# their values
upload_to='capweb.CMSPicture/bytes/filename/mimetype',
storage=DatabaseFileStorage(),
blank=True,
null=True)
page_link = models.CharField(max_length=255, blank=True, null=True)
repo_link = models.CharField(max_length=255, blank=True, null=True)
order = models.IntegerField(default=10)
featured = models.BooleanField(default=True, null=False)
def save(self, *args, generate_slug=True, **kwargs):
if not self.title_slug or generate_slug:
self.title_slug = slugify(self.title)
return super().save(*args, **kwargs)
else:
return super().save(*args, **kwargs)
def __str__(self):
return self.title
def delete_file(instance, filefield_name):
"""Delete the file (if any) from the database.
Call this function immediately AFTER deleting the instance.
"""
file_instance = getattr(instance, filefield_name)
if file_instance:
DatabaseFileStorage().delete(file_instance.name)
# django
from wsgiref.util import FileWrapper
from django.http import HttpResponse, HttpResponseBadRequest
from django.utils.translation import ugettext as _
# project
from db_file_storage.storage import DatabaseFileStorage
storage = DatabaseFileStorage()
def get_file(request, add_attachment_headers):
name = request.GET.get('name')
try:
_file = storage.open(name)
except Exception:
return HttpResponseBadRequest(_('Invalid request'))
response = HttpResponse(FileWrapper(_file), content_type=_file.mimetype)
if add_attachment_headers:
response['Content-Disposition'] = \
'attachment; filename=%(name)s' % {'name': _file.filename}
return response
def _get_unique_filename(self, model_cls, filename_field, filename):
return DatabaseFileStorage._get_unique_filename(self, model_cls, filename_field, normpath(filename))
def _get_storage_attributes(self, name):
return DatabaseFileStorage._get_storage_attributes(self, normpath(name))
def database_storage():
"""Returns storage backend used by `FileProxy.file` to store files in the database."""
return DatabaseFileStorage()
class Migration(migrations.Migration):
initial = True
dependencies = []
operations = [
migrations.CreateModel(
name='CMSPicture',
fields=[
('id',
models.AutoField(auto_created=True,
primary_key=True,
serialize=False,
verbose_name='ID')),
('bytes', models.TextField()),
('filename', models.CharField(max_length=255)),
('mimetype', models.CharField(max_length=50)),
],
),
migrations.CreateModel(
name='GallerySection',
fields=[
('id',
models.AutoField(auto_created=True,
primary_key=True,
serialize=False,
verbose_name='ID')),
('title', models.CharField(max_length=255)),
('order', models.IntegerField(default=10)),
],
),
migrations.CreateModel(
name='GalleryEntry',
fields=[
('id',
models.AutoField(auto_created=True,
primary_key=True,
serialize=False,
verbose_name='ID')),
('section',
models.ForeignKey(
on_delete=django.db.models.deletion.DO_NOTHING,
related_name='entries',
to='capweb.GallerySection')),
('title', models.CharField(max_length=255)),
('content', models.TextField()),
('page_link',
models.CharField(blank=True, max_length=255, null=True)),
('repo_link',
models.CharField(blank=True, max_length=255, null=True)),
('order', models.IntegerField(default=10)),
('image',
models.ImageField(
blank=True,
null=True,
storage=DatabaseFileStorage(),
upload_to='capweb.CMSPicture/bytes/filename/mimetype')),
],
),
]