Referencing relation on "grandparent" (or more distantly related) objects

[torstenbm]

Hi!

The part of the docs, Referencing Relations On Related Objects, do a great job of describing how to reference relations on related objects, but what if two objects are related only through a third object (or even further away)?

Imagine the following case:

We have three objects: drive, folder and doc. A user can be a member of a drive, and a drive can have a folder and a folder can have a doc.

type drive
  relations
    define member as self

type folder
  relations
    define parent_drive as self

type doc
  relations
    define parent_folder as self

Now if we want to create a relation read_folder such that only members of the parent drive of a folder have it, we would as the docs describe modify the folder type to something like this:

type folder
  relations
    define parent_drive as self
    define read_folder as member from parent_drive

How do I go about defining a relation read_doc on the doc type in a way that only members of the "grandparent" drive (the drive of the folder of the doc) have it? Something along the lines of

type doc
  relations
    define parent_folder as self
    define read_doc as member from parent_drive from parent_folder

but that gives me a syntax error.

In other words: given the tuples

(torsten, member, drive:123)
(drive:123, parent_drive, folder:123)
(folder:123, parent_folder, doc:123)

To define the relation read_folder on the folder type such that the query check(torsten, read_folder, folder:123) resolves to true is easy.

How do I define the relation read_doc on the doc type such that the query check(torsten, read_doc, doc:123) resolves to true?

[torstenbm]

Is something like this considered best practices for these cases?

type drive
  relations
    define member as self

type folder
  relations
    define parent_drive as self
    define is_member_of_parent_drive as member from parent_drive
    define read_drive as is_member_of_parent_drive

type doc
  relations
    define parent_folder as self
    define is_member_of_parent_drive_of_parent_folder as is_member_of_parent_drive from parent_folder
    define read_doc as is_member_of_parent_drive_of_parent_folder

[rhamzeh]

Hi @torstenbm! Yes, you are correct.

The DSL does not support referencing from more distantly related objects, so the solution is exactly what you did here: bringing those relations closer.

You can see an example of this in entitlements (Playground/Documentation).

[torstenbm]

Thank you for your answer @rhamzeh! Is it just the DSL that's not supporting more distantly related objects or is it the config language itself? I.e. is it possible to reference more distantly related objects by nesting "tupleToUserset" attributes with JSON?