Extensions and permissions

Permissions run before resolver extensions and the resolver itself.

from fastql import BasePermission, Field, FieldExtension, Query


class IsAuthenticated(BasePermission):
    message = "Authentication required"

    def has_permission(self, source, info, **kwargs) -> bool:
        return info.context.user_id is not None


class TraceField(FieldExtension):
    async def resolve(self, next_, source, info, **kwargs):
        info.context.trace.append(info.field_name)
        return await next_(source, info, **kwargs)


@Query
class QueryRoot:
    @Field(
        permission_classes=[IsAuthenticated],
        extensions=[TraceField()],
    )
    def private_profile(self) -> Profile:
        return load_profile()

BasePermission.has_permission may be synchronous or asynchronous. Return a false value to produce a field error using the permission’s message. Extensions wrap the next stage in declared order and may inspect or transform its result. Keep authorization rules explicit and narrow. Context establishes identity; permissions decide whether the active field operation is allowed.

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Extensions and permissions