CODEWITHSUNDEEP
djangodjango-rest-framework
overlii
overlii

Reputation: 583

Django rest Framework, change filename of ImageField

I have an API endpoint with Django Rest Framework to upload an image.

class MyImageSerializer(serializers.ModelSerializer):
     image = serializers.ImageField(source='image')

I can upload images but they are saved with the filename that is sent from the client which can result to collisions. I would like instead to upload the file to my CDN with a timestamp filename.

Generating the filename is not the problem, just saving the image with it.

Any one knows how to do that? Thanks.

Upvotes: 4

Views: 3238

Answers (1)

AdelaN
AdelaN

Reputation: 3536

If your image is of type ImageField from django, then you don't really have to do anything, not even declare it in your serializer like you did. It's enough to add it in the fields attribute and django will handle collisions. This means django will add _index on each new file which might generate a collision, so if you upload a file named 'my_pic.jpg' 5 times, you will actually have files 'my_pic.jpg', 'my_pic_1.jpg', 'my_pic_2.jpg', 'my_pic_3.jpg', 'my_pic_4.jpg' on your server.

Now, this is done using django's implementation for FileSystemStorage (see here), but if you want it to append a timestamp to your filename, all you have to do is write a storage class where you overwrite the get_available_name(name) method. Example:

class MyFileSystemStorage(FileSystemStorage):
def get_available_name(self, name):
    ''' name is the current file name '''
    now = time.time()
    stamp = datetime.datetime.fromtimestamp(now).strftime('%Y-%m-%d-%H-%M-%S')
    return '{0}_{1}'.format(name, str(stamp))

And the image field in your model: 

image = models.ImageField(upload_to='your upload dir', storage= MyFileSystemStorage)

Important update

As of August 20, 2014 this is no longer an issue, since Django found a vulnerability related to this behaviour (thanks @mlissner for pointing it out) . Important excerpt :

We’ve remedied the issue by changing the algorithm for generating file names if a file with the uploaded name already exists. Storage.get_available_name() now appends an underscore plus a random 7 character alphanumeric string (e.g. "_x3a1gho"), rather than iterating through an underscore followed by a number (e.g. "_1", "_2", etc.).

Upvotes: 9

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