How to use matched ressources from keyMatch in policy model?

[DeppLearning]

I'm trying to implement a simplified RBAC model with groups on users and resources (REST). I have seen the tutorials for this use-case (https://casbin.org/docs/en/rbac) but I'm wondering if there is a simplified way to do this:

I want to have two groups of users, admins who can do anything with any resource, and simple users who can only access their own resources. I will switch to something more elaborate later, but am wondering if I can do this now, without needing to define (and update) resources and their owners.

Based on the keymatch2 example
(https://github.com/casbin/casbin/blob/master/examples/keymatch2_model.conf , https://github.com/casbin/casbin/blob/master/examples/keymatch2_policy.csv )

I would want to use the resource ids defined in the policy in matching rules in the model.

i.e. roughly like this
policy.csv

ptype	v1	v2	v3
p	sub	/users/:sub	GET

where :sub in v2 has to match sub in v1.

I'm aware of keyMatch3 and keyMatch4 but since I'm not passing the user id (sub) via URL I think they don't cover this use-case. Is there a simple way to do this without defining a fully fledged resource grouping layer that I'd have to update for each resource (i.e. each new user)

[0x8f701]

you can define a custom matched and pass

r. sub，r. obj as parameters

[hsluoyz]

I think you need to write a custom function like keyExtract() to extract :sub out of /users/:sub, then you can compare it with sub.

[DeppLearning]

Thanks @GopherJ and @hsluoyz, I'm using the rust version. Somehow thought I couldn't add custom functions there.

[hsluoyz]

@DeppLearning why can't add?

[nodece]

Let's ping @GopherJ. I'm not sure if supported the feature in casbin-rs.