[cosmo-dev] options to fix security hole

[Jeffrey Harris]

Hi Randy,

> I'm having doubts about making the server + security fixes fully 
> backwards compatible with existing clients.  I'm mainly talking about 
> silently failing when  updating read-only items.  I don't like the idea 
> that the client thinks something succeeded, when it really didn't.  

To be clear, I'd been hoping we could send a non-fatal warning to the 
client, so recent Desktop clients could handle this case gracefully.  As 
I think about it, I don't know of a mechanism in Morse Code to provide 
non-fatal warnings; maybe we could use custom HTTP headers in the response?

But I think it's problematic for the server to fail when old desktop 
clients do normal sharing activities like sharing an item in two 
collections.  It seems like this would happen frequently in a 
fail-without-read-write-ticket world, but maybe I'm not understanding 
why this wouldn't happen often?

It occurs to me that we should probably add some future proofing to the 
desktop error system, so future desktop clients can display arbitrary 
error messages from the server.  Right now errors get logged and users 
don't get much feedback about why things fail (unless they think to 
mouseover the sync-failure icon).  It'd be nice if after a server 
upgrade we could have the server provide arbitrary messages to display 
as a pop-up in the client.

Sincerely,
Jeffrey