Django FileField with upload_to determined at runtime
I'm trying to set up my uploads so that if user joe uploads a file it goes to MEDIA_ROOT/joe as opposed to having everyone's files go to MEDIA_ROOT. The problem is I don't know how to define this in the model. Here is how it currently looks:
class Content(models.Model):
name = models.CharField(max_length=200)
user = models.ForeignKey(User)
file = models.FileField(upload_to='.')
So what I want is instead of '.' as the upload_to, have it be the user's name.
I understand that as of Django 1.0 you can define your own function to handle the upload_to but that function has no idea of who the user will be either so I'm a bit lost.
Thanks for the help!
Solution 1:
You've probably read the documentation, so here's an easy example to make it make sense:
def content_file_name(instance, filename):
return '/'.join(['content', instance.user.username, filename])
class Content(models.Model):
name = models.CharField(max_length=200)
user = models.ForeignKey(User)
file = models.FileField(upload_to=content_file_name)
As you can see, you don't even need to use the filename given - you could override that in your upload_to callable too if you liked.
Solution 2:
This really helped. For a bit more brevity's sake, decided to use lambda in my case:
file = models.FileField(
upload_to=lambda instance, filename: '/'.join(['mymodel', str(instance.pk), filename]),
)
Solution 3:
A note on using the 'instance' object's pk value. According to the documentation:
In most cases, this object will not have been saved to the database yet, so if it uses the default AutoField, it might not yet have a value for its primary key field.
Therefore the validity of using pk depends on how your particular model is defined.
Solution 4:
If you have problems with migrations you probably should be using @deconstructible
decorator.
import datetime
import os
import unicodedata
from django.core.files.storage import default_storage
from django.utils.deconstruct import deconstructible
from django.utils.encoding import force_text, force_str
@deconstructible
class UploadToPath(object):
def __init__(self, upload_to):
self.upload_to = upload_to
def __call__(self, instance, filename):
return self.generate_filename(filename)
def get_directory_name(self):
return os.path.normpath(force_text(datetime.datetime.now().strftime(force_str(self.upload_to))))
def get_filename(self, filename):
filename = default_storage.get_valid_name(os.path.basename(filename))
filename = force_text(filename)
filename = unicodedata.normalize('NFKD', filename).encode('ascii', 'ignore').decode('ascii')
return os.path.normpath(filename)
def generate_filename(self, filename):
return os.path.join(self.get_directory_name(), self.get_filename(filename))
Usage:
class MyModel(models.Model):
file = models.FileField(upload_to=UploadToPath('files/%Y/%m/%d'), max_length=255)