Ash FrameworkAF
Ash Framework•3mo ago•
6 replies
matt_savvy

Referencing action argument in policy

Hey all. I have a create action where the argument is an instance of my Maps.Map struct, like so
create :add_to_map do
  accept [:name]

  argument :map, :struct,
    allow_nil?: false,
    constraints: [instance_of: Maps.Map]

  ...
end

Maps.Map has a belongs_to relationship with a User. I'm trying to set up a policy so that only the owner of the map can use the create action above.

I can get this to work by using matches, but it feels like there's a more built-in way I should be able to do this.
   policy action_type(:create) do
      access_type :strict

      authorize_if matches("lorem ipsum", fn actor, context ->
                     context.changeset.arguments.map.user_id == actor.id
                   end)

    end


I've tried context_equals like so but this doesn't work
      authorize_if context_equals([:arguments, :map, :user_id], expr(^actor(:id)))


I know I can also write a SimpleCheck module that defines the same logic above, but this feels like something there would be a built in way to handle.

Thanks
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