List-Unsubscribe-Post support

Your software
My Mautic version is: 4.4.11
My PHP version is: php8.0
My Database type and version is: tidb

Your problem
My problem is:

(I missed [$300 bounty] Add support for rfc 8058 (One-Click unsubscribe) · Issue #12880 · mautic/mautic · GitHub when i posted this)

its not so much a problem as a question on how to configure.
I would like to implement the List-Unsubscribe-Post (RFC 8058) AKA one click unsubscribe.

I looked at control unsubscribe header send by regevbr · Pull Request #7688 · mautic/mautic · GitHub (which sought to make List-Unsubscribe optional), thinking I would then globally add these two headers and implement an out of band post mech. E.g. i would add something w/ contactfield expansion.

the default as-is is to put List-Unsubscribe: https://myurl/email/unsubscribe/idhash

this in turn brings up a form i have created.

To implement the List-Unsubscribe-Post on this, i would need to make this APi endpoint deal w/ POST a bit differently.

Currently its a form post, and, in the body,

  1. mauticform[formId]:
  2. mauticform[return]: https://myurl/email/unsubscribe/idHash
  3. mauticform[formName]: addtodonotcontact
  4. mauticform[messenger]: 1

so i can’t see how to make the List-Unsubscribe-Post work, i won’t know the formId/formName/idhash in the headers.

Has anybody implemented this yet? Any pointers to where/how?