Re: DATE-IF-MODIFIED
Ross Patterson (Ross_Patterson@ns.reston.vmd.sterling.com)
Mon, 8 Sep 97 11:31:38 EDT
jg@pa.dec.com (Jim Gettys) writes:
>"Note: An HTTP client should expect that If-Modified-Since headers sent
>for cache validation will be interpreted
"... by the origin server and all intervening proxy servers ..." or words
to that effect
> as
>'If-Modification-date-does-not-match-exactly'.
Let's not introduce the expectation of an "If-Modification-date-..."
header-field and associated semantics. Rephrasing that to read "... as
requesting an exact match between the supplied HTTP-date and the last
modification date and time of the resource ..." or something like it
would do the job.
> In other words, an HTTP client
>should preserve all of the accuracy in the Last-Modified date,
It's not just a date, so how about "HTTP-date" instead.
> rather than
>(perhaps) playing games based on the official semantics of If-Modified-Since."
Let's stop after "... in the Last-Modified date" and delete the remainder
of the sentence. That way we wind up with a normative statement, rather
than one that calls into question the motivation of the change or limits
the interpretation of its scope.
To summarize the above, here's my suggested replacement:
"Note: An HTTP client should expect that If-Modified-Since headers
sent for cache validation will be interpreted by the origin server
and all intervening proxy servers as requesting an exact match
between the supplied HTTP-date and the last modification date and
time of the resource. In other words, an HTTP client should preserve
all of the accuracy in the Last-Modified HTTP-date."
Ross Patterson
Sterling Software, Inc.
VM Software Division