You don't treat resolvers like RESTful endpoints. You check that the user has permission to access the object (edit: or other value) which the resolver returns. This has nothing to do with RPC and does not stop you using the "graph" part of GraphQL.

For the purposes of comparing a REST API, where permissions checking is done for every endpoint, to a GraphQL API, where permissions checking is done for any resolver which loads data, it is necessary to compare the number of permissions checks you would need across the two services. This does not mean resolvers are in any way equivalent to RESTful endpoints except for comparing how many times you'd need to write `ctx.can('read', photo);` across the two, and even then the numbers will almost certainly be different because the APIs will be different.

The problem is the 'graph' nature of the system; you can check the permission for the object that the resolver returns but that object might be linked to another object that you're not checking for. Because anything can just link to anything, you would have to recursively check the permissions of the entire graph.

This does not match my experience.

If the root query lets you query a user of type User, and the User object embeds an array photos of type [Photo], then there are two possibilities: either the resolver for user is loading the photos and letting the default resolver return them, in which case you know about it and can check permissions for them, or there's a resolver defined for photos, in which case you can check permissions in that second resolver.

Think about it. GraphQL won't go retrieve rows from your database without either a) you installing some other library to do the magic, in which case we should talk about that library instead, or b) you telling it to query your database, in which case you know what data you're querying in each resolver you write and can check that the user has permission to see it.