[FIXED] Making a custom Boolean field in Django REST Framework

Issue

I'm new to django rest framework.
The relevant part of my models looks something like this (simplified):

class Action(models.Model):
    type = models.CharField()
    bonus = models.IntegerField()

class User(models.Model):
    auth = models.OneToOneField(AuthUser)
    display_name = models.CharField()

class Comment(models.Model):
    contributor = models.ForeignKey(User)
    content = models.TextField()

class Activity(models.Model):
    user = models.ForeignKey(User)
    target_comment = models.ForeignKey(Comment)
    action = models.ForeignKey(Action)

I want one of my API endpoints to be able to return something like this:

{
    ...
    "comments":
    [
        {
            "id": 1,
            ...
            "curr_user_upvoted": true
        },
        ...
    ]
}

I know the query I need to execute in order to get the value for "curr_user_upvoted", but I don't know how to make it part of the API representation.
I know how to create custom relational fields, but it doesn't help since "curr_user_upvoted" is neither a field nor a relation.
Any idea?

Solution

You can create a SerializerMethodField to do this. This is just a method on the serializer class that returns the value you want.

The method name defaults to get_curr_user_upvoted - in other words it should be get_ followed by the field name, though you can pass an explicit method_name parameter to the field if you prefer.

Answered By - Matthew Daly