We've got a scenario where we need to alter the url generated within the RTE content. We've found IContentResolver but that feels as though it's used during the request whereas we just want to alter the url on save.

Which interface do we need to implement/override to modify /{localLink:umb://document/...}?

In short there are two changes we need to make:

1. Enforce a custom domain name (there are reasons we can't use the hostnames)
2. Insert additional information into the URL