python - Trouble with django upload_to callable -

i'm working on uploading file dynamic path based on model instance. here sample code:

class test(models.model):     def _upload_to(instance, filename):         return '/'.join([instance.username.name, filename])      username = models.foreignkey(usermodel) #defined elsewhere     file = models.filefield(upload_to=_upload_to) 

and test it:

>>> t = test(file="myfile.txt") >>> t.save() 

but doesn't seem put in right path, still get:

>>> t.file.url /media/myfile.txt 

when should be

/media/someusername/myfile.txt 

what wrong in example?

your test isn't testing right thing. upload_to callable called when upload file, name implies, not when save model. need try actual upload: perhaps try through admin site.

when do, run problems because python think function instance method, because have defined inside class. you'll need take outside of class, or decorate @staticmethod.