Ronny Haryanto wrote:
>
> On 30-Mar-2000, [EMAIL PROTECTED] wrote:
> > However, since the date--as it is believed by the
> > origin--is important for evaluating cached responses, origin servers
> > MUST include a Date header field in all responses.
>
> Ah, itu HTTP/1.0 ya? pantes kelewat.. setelah membaca alasannya kenapa
> diharuskan, saya cek lagi di HTTP/1.1 begini:
anda yang baca HTTP/1.0 kan? di HTTP/1.0 should, tapi
di HTTP/1.1 jadi MUST. ini dari RFC 1945 (HTTP/1.0):
>>>
10.6 Date
The Date general-header field represents the date and time at which
the message was originated, having the same semantics as orig-date in
RFC 822. The field value is an HTTP-date, as described in Section
3.3.
Date = "Date" ":" HTTP-date
An example is
Date: Tue, 15 Nov 1994 08:12:31 GMT
If a message is received via direct connection with the user agent
(in the case of requests) or the origin server (in the case of
responses), then the date can be assumed to be the current date at
the receiving end. However, since the date--as it is believed by the
origin--is important for evaluating cached responses, origin servers
should always include a Date header. Clients should only send a Date
header field in messages that include an entity body, as in the case
of the POST request, and even then it is optional. A received message
which does not have a Date header field should be assigned one by the
recipient if the message will be cached by that recipient or
gatewayed via a protocol which requires a Date.
<<<
>
> 13.2.3 Age Calculations
>
> [...]
>
> Also note that HTTP/1.1 requires origin servers to send a Date header
> with every response, giving the time at which the response was
> generated. We use the term "date_value" to denote the value of the
> Date header, in a form appropriate for arithmetic operations.
>
> Mereka (yahoo) sih ngasih header "Client-Date" tapi itu tidak termasuk
> HTTP/1.1. Mungkin alasannya supaya cachenya langsung expired?
di mana ya? saya ngga liat ini. tapi ini kalo ngga salah
header Client-Date ditambahkan oleh beberapa proxy untuk
memberikan date dari client-nya ke server. kalo untuk expire
saya rasa ngga manfaatin header itu, itu bisa pake cara
standar: Expires satu tahun ke belakang, Pragma: no-cache
dan Cache-Control: no-cache/private. (coba liat response
untuk salah satu halaman yahoo berikut (all in one line):
http://edit.members.yahoo.com/config/edit_my_interests?
.src=ytc&.done=http%3a//members.yahoo.com/interests/
setelah saya liat2 beberapa halaman yahoo, saya semakin
yakin bahwa itu tujuannya semata2 untuk ngirit bandwidth.
sebab hanya halaman lapis atas yang di-streamline banget:
- 302 Moved Temporarily -> 302 RD
- header2 HTTP minim sekali
- link2 di halaman depan direktori pake inisial satu
huruf
- dan, tentu, disain halaman yahoo amat konservatif,
minim grafik
page depan yahoo itu mestinya di-hit puluhan-ratusan
juta kali per hari.
--
regards,
[EMAIL PROTECTED]
(huruf kecil bukan berarti tidak hormat...)
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