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Re: Clarification of the term "deflate"

From: Mark Nottingham <mnot@mnot.net>
Date: Mon, 20 Aug 2007 13:40:27 +1000
Message-Id: <D9689CC0-11FF-4402-A400-16520F5B1697@mnot.net>
Cc: <ietf-http-wg@w3.org>
To: <paul.marquess@ntlworld.com>

http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i73

On 07/08/2007, at 11:20 PM, Paul Marquess wrote:

>
> Below is the definition of "deflate" from RFC 2616, section 3.5  
> "Content
> Codings"
>
>   deflate
>     The "zlib" format defined in RFC 1950 [31] in combination with
>     the "deflate" compression mechanism described in RFC 1951 [29].
>
> There is ambiguity in that definition because of the inconsistent  
> use of the
> term "deflate". This has resulted in a long standing confusion  
> about how to
> implement "deflate" encoding.
>
> There was a time a few years back when most of the high profile  
> browser and
> some http server implementations incorrectly implemented http  
> "deflate"
> encoding using RFC 1951 without the RFC 1950 wrapper. Admittedly  
> most, if
> not all, of the incorrect implementations have now been fixed, but  
> the fix
> applied recognises the reality that there are incorrect  
> implementations of
> "deflate" out in the wild. All browsers now seem to be able to cope  
> with
> "deflate" in both its RFC1950 or RFC1951 incarnations.
>
> So I suggest there are two issues that need to be addressed
>
> 1. The definition of "deflate" needs to be rewritten to remove the
> ambiguity.
>
> 2. Document the reality that there are incorrect implementations, and
> recommend that anyone writing a "deflate" decoder should cope with  
> both
> forms.
>
> cheers
> Paul
>
>


--
Mark Nottingham     http://www.mnot.net/
Received on Monday, 20 August 2007 03:40:45 GMT

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