Re: [core] [Anima] date-and-time and "created-on" field in constrained-voucher

[Carsten Bormann <[e-mail]>]

> So your proposal is for the sender to check every single string it sends to the receiver to
> see if some complex 20 byte string can be changed to an 8 byte integer instead?

In an actual implementation, these 20 byte strings never exist.

How a sender finds out that the 4-byte integer is enough is not specified.
The answer is probably: because the data were in platform time format, and we just don’t do a strftime but a memmove(..htonl(..)).

> This seems rather CPU-intensive and not very useful for YANG Push.

The way you describe it definitely is.  
But the specification would not stop you from doing do this, just your implementation common sense.

> I doubt constrained devices have enough CPU for this, or that they need to send
> lots of date-and-time data nodes to justify it.

So far we have:

— date-time and friends (as POSIX time integer): CBOR tag 1
— IP addresses and friends (as binary): CBOR tag 52 and 54

Fortunately, “type binary” is an actual base type, so here we already have actual schema support and therefore support in YANG-CBOR as is.

> The date-and-time typedef for a string is not special in YANG in any way.
> Just another derived type defined in a YANG module.

Indeed, this is the reason why it is hard to do this properly (i.e., deterministically in a way that it is guaranteed that every generator gets the choice right) without additional language support.

Grüße, Carsten