Base64EncodedImage field serializer including to_representation() method

fields.py

import six
import uuid
import base64

from django.conf import settings
from django.core.files import File
from django.core.files.base import ContentFile

from rest_framework import serializers

class Base64ImageField(serializers.ImageField):
    """
    A Django REST framework field for handling image-uploads through raw post data.
    It uses base64 for encoding and decoding the contents of the file.

    Heavily based on https://github.com/tomchristie/django-rest-framework/pull/1268

    Updated for Django REST Framework 3.
    """

    def to_representation(self, data):

        file_name = '{}/{}'.format(settings.MEDIA_ROOT, data.name)

        with open(file_name, "rb", buffering=0) as file:
            encoded_file = base64.b64encode(file.read()).decode("utf-8")

            file = {
                'encoded_file': encoded_file,
                'extension': 'jpg'
            }

            data = 'data:image/{extension};charset=utf-8;base64, {encoded_file}'.format(**file)

        return data

    def to_internal_value(self, data):
        # Check that the incoming data value is a base64 encoded string:
        if isinstance(data, six.string_types):
            # Check if the base64 string is in the prefixed "data:" format
            if 'data:' in data and ';base64,' in data:
                # Break out the header from the base64 content:
                header, data = data.split(';charset=utf-8;base64,')

                # Try to decode the file. Return validation error if it fails:
                try:
                    decoded_file = base64.b64decode(data)
                except TypeError:
                    self.fail('invalid_image')

                name = str(uuid.uuid4())

                file = {
                    'name': name,
                    'extension': self.get_file_extension(name, decoded_file)
                }

                complete_file_name = '{name}.{extension}'.format(**file)

                data = ContentFile(decoded_file, name=complete_file_name)

        return super(Base64ImageField, self).to_internal_value(data)

    def get_file_extension(self, filename, decoded_file):
        import imghdr

        extension = imghdr.what(filename, decoded_file)
        extension = "jpg" if extension == "jpeg" else extension

        return extension