Enforce unique upload file names using django?

Question

What's the best way to rename photos with a unique filename on the server as they are uploaded, using django? I want to make sure each name is used only once. Are there any pinax apps that can do this, perhaps with GUID?

Answer 1

Use uuid. To tie that into your model see Django documentation for FileField upload_to.

For example in your models.py define the following function:

import uuid
import os

def get_file_path(instance, filename):
    ext = filename.split('.')[-1]
    filename = "%s.%s" % (uuid.uuid4(), ext)
    return os.path.join('uploads/logos', filename)

Then, when defining your FileField/ImageField, specify get_file_path as the upload_to value.

file = models.FileField(upload_to=get_file_path,
                        null=True,
                        blank=True,
                        verbose_name=_(u'Contact list'))

Answer 2

A better way could be using a common class in your helpers.py. This way you could reuse the random file generator across your apps.

In your helpers.py:

import os
import uuid
from django.utils.deconstruct import deconstructible


@deconstructible
class RandomFileName(object):
    def __init__(self, path):
        self.path = os.path.join(path, "%s%s")

    def __call__(self, _, filename):
        # @note It's up to the validators to check if it's the correct file type in name or if one even exist.
        extension = os.path.splitext(filename)[1]
        return self.path % (uuid.uuid4(), extension)

And then in your model just import the helper class:

from mymodule.helpers import RandomFileName 

And then use it:

logo = models.ImageField(upload_to=RandomFileName('logos'))

Ref: https://coderwall.com/p/hfgoiw/give-imagefield-uploads-a-unique-name-to-avoid-file-overwrites

Answer 3

Prior to Django 1.6.6, 1.5.9, and 1.4.14, the get_avaialable_name function would automatically give files a unique name by adding an underscore. So, for example, if you save one file "test.jpg" and then another file, "test.jpg" to your server, the first will be called test.jpg, and the second will be called test_1.jpg.

Alas, that turns out to be a vector for DDOSing a machine, by sending it thousands of zero-byte files to store, each one checking thousands of previous files to see what its name should be.

As you'll see in the docs, the new system appends seven random digits after the underscore to fix this problem.

Answer 4

As of the writing of this answer it seems like you no longer need to do anything special to make this happen. If you set up a FileField with a static upload_to property, the Django storage system will automatically manage naming so that if a duplicate filename is uploaded, Django will randomly generate a new unique filename for the duplicate.

Works on Django 1.10.

Answer 5

How about concatenating the filename with the date / time the photo was uploaded and then using hashlib to create a message digest? That should give you unique filenames.

Alternatively you could re-use a neat little snippet which creates unique filenames and then use the full path to that file as the input to your hash call. That gives you unique constant length strings which you can map to your files.