Circularity and Asynchrony

[Tim Bray <Tim.Bray@xxxxxxx>]

After re-subscribing, I see in the archive that John Panzer pointed out 
a couple of tough corner cases where multipart might do it and separate 
uploads might not.

I'm not 100% convinced that the circular-reference case is common 
enough to be worth designing around; it's certainly not something you 
see every day and it feels to me like it's on the other side of the 
80/20 point.  And, I note that none of the existing protocols help you 
with this problem.

As for the Asynch-gateway problem, that's tough.  First of all, does 
this manifest to the caller as truly async, or just potentially-slow 
RPC?   I.e. assuming I don't know the URI where the posting ended until 
the operation completed:  If this is a truly async operation (inject 
the posting request now, at some point later poll for a message telling 
you where it ended up) then the existing protocol proposals aren't 
really going to work at all.  Note that I'm not saying this is a bad 
idea, because async architectures are generally more scalable.  But 
once again, I'm not convinced it's on this side of the 80/20 split.

I would note that *if* the publishing protocol lets you select your own 
URIs, then those cases are more tractable.  I suspect that would be a 
popular feature anyhow.

 -Tim