fyi.opensocial.requestJoin

Ask to join a group, optionally redeeming an invitation. An invite the group has sent the caller, neither taken back nor past its expiresAt, admits them at once, whatever the group's join policy, with the group's default roles; one named that is not such an invite is refused. Unnamed, a waiting invite is redeemed all the same. No role required; authenticated as the requester.