I have an abstract model class UploadItem for handling uploaded files. I want each subclass to be able to define the upload_to path. For this, i pass a callback to the constructor of FileField.
This is an example:
class UploadItem(models.Model):
file = models.FileField(upload_to=UploadItem.get_directory)
class Meta:
abstract = True
# I want videos to be storred in 'videos/' directory
class Video(UploadItem):
def get_directory(self, instance, filename):
return 'videos/'
But this doesn't work, i am getting this error:
file = models.FileField(upload_to=UploadItem.get_directory)
NameError: name 'UploadItem' is not defined
The error is natural given that at the time of evaluating
file = models.FileField(upload_to=UploadItem.get_directory)
the UploadItem
class is not yet defined. You can do the following to make it work:
def get_directory():
pass
class UploadItem(models.Model):
file = models.FileField(upload_to=get_directory)
class Meta:
abstract = True
This won't solve all your problems though. Adding (or overriding) a method get_directory
in the Video
class will not change the upload_to
property of the file
attribute of the model.
Update
The documentation says that the upload_to
can be a callable.
This may also be a callable, such as a function, which will be called to obtain the upload path, including the filename. This callable must be able to accept two arguments, and return a Unix-style path (with forward slashes) to be passed along to the storage system.
Given this we can write a custom call back function like this:
categories_and_paths = { 'video': 'videos/', 'photo': 'photos/' } # etc.
def get_directory(instance, filename):
category = instance.category
return categories_and_paths.get(category, '')
Instance
here will be the instance of the respective model. For this to work each model instance should have a category field. We can add one in the body of the model.
class Video(UploadItem):
category = 'video'