Subject: #1336 Expires field semantics

From: Harald Alvestrand <[email-masked]>
Date: Thu, 27 Jul 2006 01:50:35 -0700

> | 3.2.4. Expires
 > |
 > | The Expires header field specifies a date and time when
 > | the article is deemed to be no longer relevant and could
 > | usefully be removed ("expired").
 >
 > How about a note that this is used both to reduce and to
 > extend the "regular" expiration period and that the local
 > effects are implementation/configuration-specific?

Suggested change, indicating that the field is the desire of the poster:

   The Expires header field specifies a date and time when the poster deems
   the article to be no longer relevant and could usefully be removed
   ("expired").

  The way in which this interacts with local retention policy on servers is
  a local matter.

Comments?

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From: Russ Allbery <[email-masked]>
Date: Thu, 27 Jul 2006 11:02:52 -0700

> Comments?

I prefer the original, although wouldn't mind the addition of the "poster"
bit.  I think the second sentence could be added to everything in the
standard; I don't think there's much point.

-- 
Russ Allbery ([email-masked])             <http://www.eyrie.org/~eagle/>

---

From: "Charles Lindsey" <[email-masked]>
Date: Sun, 30 Jul 2006 18:51:44 GMT

>  The way in which this interacts with local retention policy on servers is

No, I don't think that is what Ralph was after. What a server is expected
to do when it receives an Expires header is quite clear according to
USEPRO. The only choice the server admin has is whether or not to do it
(news servers are usually configurable both to set the normal expiry
time, and in addition to indicate whether (and by how much) an Expires
header can change it.

If you wanted to say that, then a sentence like "It is a matter of local
policy whether, and by how much, this header is allowed to modify the
normal expiry time".

I think Ralph's first point would be covered by somerthing like the
following NOTE, which appeared in our earlier "article" series of drafts:

        NOTE: This header is suitable for specifying both unusually
        short and unusually long expiry times; there is little point in
        using it in other circumstances.

I wanted that to be retained in USEFOR, but the WG thought otherwise.
Naturally, I would be happy to see it restored. Alternatively, it could go
in USEAGE. The point is that its use for extending the storage of FAQs
until the next issue appears is well known. Not so well known is its use
in articles like "I have two spare tickets for the cup final on Friday".
Keeping such an article beyond Friday would be pointless, so an Expires
header for Friday would be a kindness.

-- 
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Tel44 161 436 6131 Fax: +44 161 436 6133   Web: http://www.cs.man.ac.uk/~chl
Email: [email-masked]      Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K.
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