DRF field to handle base64 encoded string as attachment. Automatically transform it to binary file.

fields.py

import cStringIO
import six
import uuid
from base64 import decodestring
from mimetypes import guess_type, guess_extension
from django.core.files.uploadedfile import SimpleUploadedFile


class Base64CharField(serializers.CharField):
    """
    This field will accept image/file attachment as base64 image 
    encoded and transform it to binary file.
    """
    def _base64_to_binary(self, data):
        """
        Convert given base64 encoded file.
        """
        # Remove noise: data:image/jpeg;base64, from base64 encoded file.
        b64encoded_file = raw.split(',')[1] if len(raw.split(',')) > 1 else ''
        file_type, _ = guess_type(raw)
        extension = guess_extension(file_type)
        image_output = cStringIO.StringIO()
        image_output.write(decodestring(b64encoded_file))
        image_output.seek(0)
        filename = '{name}{ext}'.format(name=uuid.uuid4().hex, ext=extension)
        return SimpleUploadedFile(filename, image_output.read(), content_type=file_type)

    def to_representation(self, value):
        return value.url

    def to_internal_value(self, data):
        if not isinstance(data, six.string_types):
            msg = 'Incorrect type. Expected a string, but got %s'
            raise serializers.ValidationError(msg % type(data).__name__)

        if not ('data:' in data and ';base64,' in data):
            msg = 'Invalid base64 format'
            raise serializers.ValidationError(msg)
        return self._base64_to_binary(data)