How to use custom serializers fields in my HyeprlinkedModelSerializer

Question

I need to store bitmap representation of an image in my code, so I did this in my model

logo = models.BinaryField(blank=True, null=True)

now Django-rest doesn't have a serializer field for BinaryField. If I create my own serializer field for this, how would I be able to use it in my code ? For example, if I create something like

class MyBinaryField(serializers.Field):
    def to_representation(self, obj):
        return base64.b64decode(obj)
    def to_internal_value(self, data):
        return base64.encodestring(data)

How can I plug this mapping of models.BinaryField and MyBinaryField in my serializer. I know there is a default serializer_field_mapping map available and I can override it, but I want to use existing serializer_field_mapping as well. How can I insert my new entry into existing serializer_field_mapping or declare new values in current map ?

Answer 1

Just make a copy of serializer_field_mapping from the base class of your serializer and update it with new "model field - serializer" field pair. For example if you use ModelSerializer subclass then:

from rest_framework import serializers
class MySerializer(serializers.ModelSerializer):
    serializer_field_mapping = (
        serializers.ModelSerializer.serializer_field_mapping.copy()
    )
    serializer_field_mapping[models.BinaryField] = MyBinaryField