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Re: Entity Tags

From: Paul Hethmon <phethmon@utk.edu>
Date: Mon, 12 Aug 1996 14:01:48 EST
Message-Id: <199607121401.5125364.7@hops.ag.utk.edu>
To: Gavin Button <gavinb@imaging.co.uk>, "'www-talk@w3.org'" <www-talk@w3.org>
Addressed to: Gavin Button <gavinb@imaging.co.uk>
              "'www-talk@w3.org'" <www-talk@w3.org>

** Reply to note from Gavin Button <gavinb@imaging.co.uk> Mon, 12 Aug 1996 17:02:01 +-100 
> I am in the process of designing an HTTP 1.1 server which  provides  
>  JPEG Images when a GET method with a certain URL is received, but am unsure  
> about the use of entity tags.  Should an entity of this type respond with an ETag  
> field ? In turn, should I support If-Match/If-None-Match? If so ,How? 
Yes. If you're going to supply an Etag then you need to support 
If-Match and If-None-Match. There's no need for an Etag unless you 
do since the client request must use those headers to make 
conditional requests. 
Just match on the Etag when a request comes in. The Etag is an 
opaque identifier to the sender, so you may use any unique id 
for the image. 
Just remember to allow for *both* If-Match and If-None-Match 
headers in the same request. It's also possible, although stupid,  
that you may receive the same Etag in both headers by a  
confused client/proxy. 

Paul Hethmon 
Computerman -- Agricultural Policy Analysis Center 
NeoLogic FTP & Mail Servers 
Knoxville Warp User's Group: http://apacweb.ag.utk.edu/os2 
Received on Monday, 12 August 1996 14:01:49 UTC

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