Re: feature negotiation?

On Tue, Feb 12, 2002 at 09:05:19PM -0600, Karl Fogel wrote:
>...
> This specific instance isn't what's important; the general question is
> still valid: Will we someday be in a situation where we want to add a
> feature that is not compatible with older clients (or servers), and
> where merely discovering the incompatibility may be difficult if
> feature negotiation isn't available?

Nope.

1) The server would only use a new capability when the client advertises
   that it can accept it.

2) The client would attempt to use a new capability, but deal with servers
   that don't respond to that attempt.

Example:

1) the server does not send svndiff unless it sees the right header
2) the client sends the header, but is fine with a fulltext being returned

> I'm not saying the answer is definitely "yes". Perhaps Apache+DAV
> give us so much flexibility that we'll always be able to improvise a
> case-specific negotiation for any given incompatible change.

We'll always be fine. This isn't something to worry about it.

>...
> Is there an extensible DAVvy way to do this already? Would we have to
> design our own sub-protocol?

It varies based on the situation, but yes. And: no(*).

Cheers,
-g

(*) it could be argued that our custom reports are sub-protocols. at some
point in the future, we'll probably still have them, but have fallbacks to
generic HTTP/WebDAV/DeltaV functionality.

-- 
Greg Stein, http://www.lyra.org/
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