Django model with FileField -- dynamic 'upload_to' argument

Question

I am using the model with FileField to deal with file uploading. Now the files can be uploaded successfully. However, there is one more small improvement I want to make, which is to create folder for the user with the username.

Here is the code I've tried

class UserFiles(models.Model):
    user = models.OneToOneField(User)
    file = models.FileField(upload_to='files/users/user.username/%Y_%m_%d/')

this would give the folder of 'user.username' instead of 'John'(one example of username)

I have also tried other ways like files/users/%user.username/%Y_%m_%d/ ,but it would not give the folder with the user name. Not sure how the syntax should be or whether this is possible.

Can you give some suggestions on this? Thank you very much for your help and explanation.

Angelicaangelico

#1191197 solution found in this link – Angelicaangelico

Answer 1

Instead of a string try passing a function:

def generate_filename(self, filename):
    url = "files/users/%s/%s" % (self.user.username, filename)
    return url

class UserFiles(models.Model):
    user = models.OneToOneField(User)
    file = models.FileField(upload_to=generate_filename)

Banjermasin

hi, thank you very much for your answer, the first solution works fine. The second one, the username of the user object,i.e. user.username can not be recognized. – Angelicaangelico

try changging str(user.username) for str(user), You're welcome! :D – Banjermasin

that would give <django.db.models.fields.related.OneToOneField> as the name of the folder – Angelicaangelico

Well that it's returning OneToOneField instance, so I think you have to choose the first option. – Banjermasin

It's a generally a Bad Idea to name functions using reserved words like file because you effectively overwrite the builtin function and introduce unpredictable behaviour. A better choice here might have been generate_filename(). – Pepperandsalt

and what do i pass from my views in .save call?? – Joselyn

@Joselyn You only have to save the object, the function gets executed before saving by its own :D – Banjermasin

where is generate_filename getting the self and filename arguments? and why doesn't it need () at the end in the kwargs? – Fruitcake

@shenk a bit late, but here is the answer: before saving the object, django executes the function you passed as an argument to the FielField like this generate_filename(userfiles_instance, name_of_the_original_file). Regarding the parenthesis, as you need more than 1 value to the string in order to format it you have to provide an iterable, and by using parenthesis you build a tuple which is an iterable – Banjermasin