Django Graphql 中间件解码令牌

Question

In my project I used Django and GraphQl for building API. User will be authenticated by API Gateway in AWS , and send a JWT token , with uuid username body, included in the request headers to the backend.

I need to decode that token and get an username value, that will be next used in the resolvers. I have planned to use something similar as G object in Flask or something similar using Rack Djangos middleware but I'm struggling how to do it in Django.

Do you have any idea or hint?

Answer 1

Here's the result which I implemented:

The middleware checks the jwt token before resolver call, based on decoded username it create a User instance, that is assigned in info.context.user parameter. The info.context will be visible in resolver.

So basically in resolver you can check a User instance as:

user = info.context.user
if isinstance(user, User):
    # do something

middleware.py

class AuthorizationGraphQLMiddleware:
    """Middleware add User object for each GraphQL resolver info.context"""
    def resolve(self, next, root, info, **kwargs):
        username = None
        auth_header = info.context.META.get('HTTP_AUTHORIZATION')

        if auth_header:
            username = decode_token(auth_header)['username']

        if username is not None:
            info.context.user = User(username)
        else:
            info.context.user = AnonymousUser()

        return next(root, info, **kwargs)

entities.py

@dataclass
class User:
    name: str

utils.py

class TokenValidationError(GraphQLError):
    pass

def decode_token(token):
    try:
        return jwt.decode(token.replace('Bearer ', ''), verify=False)
    except (jwt.DecodeError, AttributeError):
        raise TokenValidationError('Invalid token.')

settings.py

GRAPHENE = {
    'MIDDLEWARE': ('api.graphql.middleware.AuthorizationGraphQLMiddleware',)
}