Be able to select a default receiving transport, different from the default sending transport.
This could allow to have a classic mail as receiver (larger storage, no messages deleted after 20 or 30 days), and a chatmail as sender (no rate or recipients sending limitations, lower latency).
Also, the pressure on chatmail operators is reduced because they could set up shorter message retention periods.
I noticed that when you send a message through a chatmail relay, it is also sent to your classic account transport, which also preserves your own messages to be synchronized beyond the chatmail deletion span.
Actual behavior
Default sending and receiving transports are the same.
You can already “hide” the relay (called “transport” internally), so you then have it, but it is not advertised and your contacts don’t send the messages back to it.
The problem here is that in the UI, unhiding the relay (internally set_transport_unpublished(..., false) and selecting it as the sending relay is the same action. So as soon as you select the relay for sending, it becomes published/unhidden.
What we can do without changing the UI much, is to allow long-press (looking at Delta Chat for Android UI now) on the currently selected sending relay, then in addition to “Edit relay” allow the “Hide Relay” option in the place where “Remove Relay” is normally shown. So you will end up with a sending but hidden relay by doing this.
There is a corner case of this making it possible to hide all your relays, but this is not different from using an old version of Delta Chat, when you advertise no relays in the key, the From address is used, so it will not break even if not handled explicitly.
But wait, for this usecase, what is the problem with just using both the classic email and chatmail as a receiver and using chatmail for sending? You send from chatmail so you don’t have ratelimit, you receive on classic email as well as chatmail so you get all messages even after 20 days.
Maybe I did not understand correctly how multi transport works.
If I set a chatmail as default relay and a contact sends me a message, is that message also sent to the classic mail transport?
If that’s the case, then you are right, my use case is already covered.
A second device which was offline for more than 20 days will fetch the message from the classic mail transport (not set as default).
Is this correct?
So an ideal setup would be a couple of chatmail transports (one of them as default) and a classic account to assure less frequently used devices don’t miss messages.
