Re: last-modified date checks

[Roy Fielding <fi...@beach.w3.org>]

>A while back someone (I think it was Rob H) was talking about changing
>the code that handles if-modified-since to make it so that the date
>check was an exact match instead of seeing if the last modified date
>was before the IMS date.

I think that was an efficiency question -- check for an exact match
first, and only do the date-parsing comparison if the two differ.

>The reason I ask is that we're finding people with systems that are
>setting LM dates to whacky times such as April 1, 2010. That means the
>file stays in everybody's browser cache indefinitely. The browser
>people want us to change Netsite so it uses an exact match which seems
>okay to me but I wanted to see if you had problems with it.

Tell the browser people to fix their bugs first, before changing
the server.  I read the http-wg list first, so I've already answered
this question there today.

I do think it would be wise for a server to complain about bad
time data on the files it serves.  We know the server's date is
fairly accurate due to the network requirements, but the file
server may be in bizarro land.  The correct thing for it to do
is to inform the owners of the files to correct their dates,
but that is often an off-line operation.  I think it is reasonable
for the server to refuse to send a Last-Modified date if the date
is later than the time it is serving the file.

.......Roy

Re: last-modified date checks

[Rob McCool <ro...@netscape.com>]

/*
 * "Re: last-modified date checks " by Roy Fielding <fi...@beach.w3.org>
 *    written Tue, 15 Aug 1995 17:48:04 -0400
 * 
 * Tell the browser people to fix their bugs first, before changing
 * the server.  I read the http-wg list first, so I've already
 * answered this question there today.

Yeah, he kind of surprised me on that one.

 * I do think it would be wise for a server to complain about bad time
 * data on the files it serves.  

Complain to who, though? Log an error?

 * I think it is reasonable for the server to
 * refuse to send a Last-Modified date if the date is later than the
 * time it is serving the file.
 */

That sounds reasonable.

I happen to agree that having Netscape stop sending IMS for a forced
reload would be a good thing.

--Rob