Graphene: How to add a function before query execute?

Question

Is there a way to execute a function before all query?

When I add an annotation above Query class, It makes an error

AssertionError: Type <function Query at 0x104d1dd30> is not a valid ObjectType.


def my_func(f):
    @wraps(f)
    def my_func_wrap(*args, **kwargs):
        //do something
        return f(*args, **kwargs)

    return my_func_wrap

@my_func
class Query(graphene.ObjectType):
    node = relay.Node.Field()

    users = graphene.List(lambda: UserSchema)

    def resolve_users(self, info):
        //do something
        return User.query.all()


schema = graphene.Schema(query=Query)

If i add the annotation to every resolver, It works fine.

but I will add more than 20 resolvers and I don't think adding the annotation to every resolver is good idea.

Answer 1

Yes, you can. Just create a custom View class inheriting from GraphQLView and override dispatch method then use your own view class as graphql endpoint handler. Something like this:

    class CustomGraphQLView(GraphQLView):
        def dispatch(self, request, *args, **kwargs):
            // do something
            super(CustomGraphqlView, self).dispatch(request, *args, **kwargs)

If you want to manipulate the queryset itself, I suggest to use graphene-django-extras and override the list_resolver method on its query fields(DjangoFilterListField, DjangoFilterPaginateListField, ...) class and use your own custom class.

You can call super on override methods or copy the exact code from their source and edit them.