[FIXED] Django: getting the value of a serializer's field within the serializer itself

Issue

In my Django serializer, I have a validate() method.

In it, I want to access the value of one of the serializer's fields. How would I do this?

I'm using Python 3.10.2 and Django 3.2.23.

Previous answers here have suggested using self.initial_data.get("field_name")) but that doesn't work for my version of Django (message: AttributeError: 'MySerializer' object has no attribute 'initial_data').

class MySerializer:
    models = models.MyModel

    class Meta:
        fields = "my_field"

    def validate(self, data):
        # Want to get the value of my_field here

Many thanks in advance for any assistance.

Solution

The solution was to add data into the associated Django view's context - in my case, an id - and populate it when the serializer is defined.

View:

def put(self, request, *args, **kwargs):
    serializer = MySerializer(
        instance=instance,
        data=request.data,
        context={"user_id": self.request.user.id},
    )

Serializer:

def validate(self, data):
    context = getattr(self, "context", None)

    if context is None:
        return data

    user_id = context.get("user_id")
    obj = MyEntity.objects.get(user_id=user_id)

This also works for nested serializers: the context value automatically gets supplied for each.

Answered By - GarlicBread