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Re: HTTP/1.1 ISSUE: TRAILER_FIELDS - Proposed Resolution

From: Jeffrey Mogul <mogul@pa.dec.com>
Date: Thu, 20 Nov 97 10:54:40 PST
Message-Id: <9711201854.AA07681@acetes.pa.dec.com>
To: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Regarding
>Is there any reason we can't change
>
>  An HTTP/1.1 sender MAY include a Trailer header field in a message using
>  chunked transfer-coding with a non-empty trailer. Doing so allows the
>  recipient to know which header fields to expect in the trailer.
>
>to
>
>  An HTTP/1.1 sender SHOULD include a Trailer header field in a message using
>  chunked transfer-coding with a non-empty trailer. Doing so allows the
>  recipient to know which header fields to expect in the trailer.
>
>? Is this because of already installed implementations?

Henrik wrote:

    Yes, we can't upgrade that requirement.

Why not?  Increasing the requirement level could have the effect
of converting some deployed implementations from "unconditionally
compliant" to "conditionally compliant" ... but ONLY if they
already send trailers (which means, in this case, only if they
send Content-MD5 in the chunk trailer, since until now nothing
else was allowed) and ONLY if they are otherwise unconditionally
compliant with the rest of the spec.

Since we haven't actually finished writing the HTTP/1.1 spec,
it's hard to believe that there are any deployed implementations
that could be unconditionally compliant with the final result.

Converting this to SHOULD will make things much simpler, I think.

-Jeff
Received on Thursday, 20 November 1997 10:59:00 EST

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