Adding claims to DRF simple JWT payload

Question

Using djangorestframework_simplejwt library, when POST to a custom view

#urls.py
path('api/token/', MyTokenObtainPairView.as_view(), name='token_obtain'),

#views.py
class MyTokenObtainPairView(TokenObtainPairView):
    serializer_class = MyTokenObtainPairSerializer

I'm able to get a the following access token

eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzUxMiJ9.eyJ0b2tlbl90eXBlIjoiYWNjZXNzIiwiZXhwIjoxNTkwOTEwNjg0LCJqdGkiOiI3M2MxYmZkOWNmMGY0ZjI3OTY4MGY0ZjhlYjA1NDQ5NyIsInVzZXJfaWQiOjExfQ.5vs0LmNGseU6rtq3vuQyApupxhQM3FBAoKAq8MUukIBOOYfDAV9guuCVEYDoGgK6rdPSIq2mvcSxkILG8OH5LQ

By going to https://jwt.io/ I can see the payload is currently

{
  "token_type": "access",
  "exp": 1590910684,
  "jti": "73c1bfd9cf0f4f279680f4f8eb054497",
  "user_id": 11
}

So, we can see that the second part of the token is the payload - containing the claims.

I've explored how to add more information to the Response body and now would like to know how to customize the Payload data by adding iat claim, username and today's date.

Answer 1

As you already created a subclass for the desired view (MyTokenObtainPairView) and a subclass for its corresponding serializer (MyTokenObtainPairSerializer), add the following to the serializer

class MyTokenObtainPairSerializer(TokenObtainPairSerializer):

    ...

    @classmethod
    def get_token(cls, user):
        token = super().get_token(user)

        # Add custom claims
        token['iat'] = datetime.datetime.now()
        token['user'] = user.username
        token['date'] = str(datetime.date.today())

        return token

Then, when you POST to that same location, you'll get an access token like this

eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzUxMiJ9.eyJ0b2tlbl90eXBlIjoiYWNjZXNzIiwiZXhwIjoxNTkwOTE0MTk4LCJqdGkiOiJhZDZmNzZhZjFmOGU0ZWJlOGI2Y2Y5YjQ4MGQzZjY2MiIsInVzZXJfaWQiOjExLCJpYXQiOjE1OTA5MTc0OTgsInVzZXIiOiJ0aWFnbyIsImRhdGUiOiIyMDIwLTA1LTMxIn0.-5U9P-WWmhlOenzCvc6b7_71Tz17LyNxe_DOMwwqH4RqrNsilVukEcZWFRGupLHRZjIvPya2QJGpiju9ujzQuw

Using JWT you can see the Payload changing accordingly

{
  "token_type": "access",
  "exp": 1590914198,
  "jti": "ad6f76af1f8e4ebe8b6cf9b480d3f662",
  "user_id": 11,
  "iat": 1590917498,
  "user": "tiago",
  "date": "2020-05-31"
}