Re: comments on draft-ietf-http-ext-mandatory-00.txt

From: Henrik Frystyk Nielsen (frystyk@w3.org)
Date: Sat, Apr 11 1998


Message-Id: <3.0.5.32.19980411173233.0089ec90@localhost>
Date: Sat, 11 Apr 1998 17:32:33 +0900
To: Dave Kristol <dmk@bell-labs.com>
From: Henrik Frystyk Nielsen <frystyk@w3.org>
Cc: ietf-http-ext@w3.org
Subject: Re: comments on draft-ietf-http-ext-mandatory-00.txt

At 10:13 04/08/98 -0400, Dave Kristol wrote:

>Given what I said above, I don't think it's the '-' that prevents
>reserving the whole extension space.  Rather it's the 2*DIGIT part.  You
>would have to reserve 00, 01, 02, ..., 99 to hog the space.  (Maybe I
>should have listed this point under "nits". :-)

Without the "-" (or any other non-numeric character) you can potentially
hog the space by reserving 00, 01, 02, ..., 99. With the "-", it is not
possible to hog the space because "99-" doesn't include "999-" and so forth.

>> Wrt 1) the idea is that if an extension is no longer then it would not be
>> available and return 410 (Gone) if trying to resolve it. On the other hand
>> the extension may at that time be ubiquitous and doesn't have to be
>> resolved as everybody knows what it is. I don't think we have to deal with
>> this here.
>
>I don't think 410 (Gone) is an appropriate status code in this context. 
>510 (Not extended) seems more appropriate.

There is a difference between trying to resolve an extension and to apply
an extension. When resolving a resource, it simply acts as any other
resource and if it is gone then 410 is the appropriate status code.

Note that two parties may still use an extension if they both know what it
means and don't have to resolve it - even after it is "gone". This is why I
don't think it makes sense to make the distinction while applying the
application.

>> For 2) I would suggest that we use Harald's notion of reasonable amount of
>> time as 50 years.
>>
>> Do you agree?
>
>I think there are two sub-problems, for a given pair of client/server
>hosts.
>a) How long should a program that knows it previously used an extension
>assume it can continue to use the extension?

If an application knows what an extension means it can continue to use it
forever if that is its policy. If an extension tries to resolve an
extension then the information returned (for example 410 Gone) would
determine whether it should try again or forget about the extension.

I will make a note trying to sum up this discussion and add it to section 8
Publishing an Extension.

Henrik
--
Henrik Frystyk Nielsen,
World Wide Web Consortium
http://www.w3.org/People/Frystyk