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ACTION-722: Check why HTTP RFC states comments MAY be removed from a VIA header.

From: Francois Daoust <fd@w3.org>
Date: Mon, 14 Apr 2008 18:07:02 +0200
Message-ID: <48038126.9090601@w3.org>
To: public-bpwg-ct <public-bpwg-ct@w3.org>


Per ACTION-722, I was to check why the HTTP RFC says that comments in a 
Via header may be removed by a Proxy that receives such a header.

The reason is: size.

As the Via header normally grows a bit each time a request/response goes 
through a proxy, this is to make sure that a given web agent (server, 
other proxy, or client) that would run with limited memory may get rid 
of the "useless" bits.

In practice, such memory constraints don't really exist and most proxies 
only append a string to the received Via header, and keep the comments 
intact (this is more the result of casual talks and browsing than of a 
precise and complete investigation though, so I may wrong).

Conclusion: I don't see any problem noting in our Guidelines that we do 
recommend comments be kept, noting that someone may remove the comments. 
If we consider the comments added by the CT-proxy to be mandatory, then 
using comments (even if we knew they would always be kept) is probably 
not the way we should do that anyway.
Received on Monday, 14 April 2008 16:07:37 UTC

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