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Re: HTTP HEAD requests for Last-Modified info

From: Patrick McManus <mcmanus@nysernet.org>
Date: Wed, 19 Jun 1996 08:41:15 -0400 (EDT)
Message-Id: <199606191241.IAA02239@pat.nyser.net>
To: steve@wco.com (Stephen Zagerman)
Cc: www-talk@w3.org
In a previous episode...Stephen Zagerman said:
-> Awhile ago, I posted a question re: HTTP requests to obtain Last-Modified
-> info for web pages. I got answers that indicated the way to get header info
-> for a theoretical "www.site.com/page.html" would be to open a connection to
-> www.site.com and issue the following request:
-> HEAD /page.html HTTP/1.0 <CRLF><CRLF>
-> This is good in that it does elicit a set of info, but it's bad in that it
-> does not ALWAYS return Last-Modified info... which is what I really need.
-> Does anyone know if there is something additional I need to add to the
-> request to ALWAYS get the Last-Modified info? I've read the spec, but am
-> not clear on what I need to do.

Last-Modified is an Entity Header.. here's what http/1.0 has to say
about entity headers:

Entity-Header fields define optional metainformation about the
Entity-Body or, if no body is present, about the resource identified
by the request.

In short they are optional.. if the server doesn't supply them you
pretty much have to assume last-modified = currentdate.

Received on Wednesday, 19 June 1996 08:41:23 UTC

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