Populate Django request.FILES from base64 encoded file in request.POST

to_file.py

import base64
import io
import sys
from django.core.files.uploadedfile import InMemoryUploadedFile
from django.core.exceptions import SuspiciousOperation


# WARNING: quick and dirty, should be used for reference only.

def to_file(file_from_POST):
    """base64 encoded file to Django InMemoryUploadedFile that can be placed into request.FILES.""""
    # 'data:image/png;base64,<base64 encoded string>'
    try:
        idx = file_from_POST[:50].find(',')  # comma should be pretty early on

        if not idx or not file_from_POST.startswith('data:image/'):
            raise Exception()

        base64file = file_from_POST[idx+1:]
        attributes = file_from_POST[:idx]
        content_type = attributes[len('data:'):attributes.find(';')]
    except Exception as e:
        raise SuspiciousOperation("Invalid picture")

    f = io.BytesIO(base64.b64decode(base64file))
    image = InMemoryUploadedFile(f,
       field_name='picture',
       name='picture',  # use UUIDv4 or something
       content_type=content_type,
       size=sys.getsizeof(f),
       charset=None)
    return image
  
  
def some_view(request):
    f = request.POST.get('picture', None)
        if f:
            request.FILES['picture'] = to_file(f)
    ....