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Re: Issue: HTTP transcoding [ was: What is W3C's position on RFC 3205? ]

From: Christopher Ferris <chris.ferris@sun.com>
Date: Thu, 11 Apr 2002 19:17:22 -0400
Message-ID: <3CB61982.6040107@sun.com>
To: Mark Nottingham <mnot@mnot.net>
CC: xml-dist-app@w3.org, LMM@acm.org
Mark,

Interesting observation. Seems to me though that the no-transform
directive if applied with SOAP header blocks targetted at an role
other than the ultimate recipient URI might present an unreconcilable
conflict with an intermediary SOAP node that was acting in the
role specified by that URI such that it could not perform its
obligations w/r/t the SOAP process model.

Just a thought,

Chris

Mark Nottingham wrote:

> Has the WG considered whether to give advice about/dictate handling of 
> the 'no-transform' cache-control directive, as well as the '214 
> Transformation applied' warning-value in the HTTP binding? It may be 
> prudent to do so.
> 
> 
> Begin forwarded message:
> 
>> From: "Larry Masinter" <LMM@acm.org>
>> Date: Thu Apr 11, 2002  11:51:15  AM US/Pacific
>> To: "'Michael Brennan'" <Michael_Brennan@Allegis.com>, <www-tag@w3.org>
>> Cc: "Keith Moore" <moore@cs.utk.edu>
>> Subject: RE: [HTTPSubstrate-16] What is W3C's position on RFC 3205?
>> Reply-To: <LMM@acm.org>
>>
>>> I have also run afoul of faulty HTTP client stacks that don't respect 
>>> HTTP
>>> semantics in my programming -- including the HTTP client included in the
>>> W3C-sponsored Jigsaw project. Last time I checked (admittedly over a 
>>> year
>>> ago), it included code that would intercept HTTP error status codes from
>>> proxy servers, and return to the client an HTTP status code of 200 and a
>>> generic HTML message with a generic error message (while blocking the
>>> message body from the server).
>>
>>
>> I question your use of "faulty"...
>>
>>> Trying to steer standards around such abuses is not a promising path
>>> forward, in my opinion. The TAG and/or IETF really should issue a best
>>> practices document admonishing such behavior and exhorting implentors to
>>> respect HTTP semantics.
>>
>>
>> Well, for better or worse, RFC 2616 reflects, in several places,
>> an acknowledgement that there are translating proxies that do
>> a wide variety of content transformations of results. For example,
>> there would be no need for a "no-transform" directive if it weren't
>> for that acknowledgement (RFC 2616 section 14.9.5).
>>
>> I'm not sure where to get "HTTP semantics" from, except from the
>> document that defines HTTP. There may be some difficulties with
>> having intermediaries transform data without warning, but the
>> design of HTTP for web browsing allowed for these kinds of modifications.
>>
>> The HTTP specification distinguishes semantically transparent
>> caches from other kinds of intermediaries, but it doesn't declare
>> non-transparent intermediaries to be an "abuse". The introduction
>> in Section 13 of RFC 2616 is very explicit about the conditions
>> in which transparency may be relaxed, in the section starting:
>>
>> "The HTTP/1.1 protocol allows origin servers, caches,
>>  and clients to explicitly reduce transparency when necessary."
>>
>> Since this is the actual definition of HTTP, you could say,
>> on the contrary, that it is an "abuse" of HTTP to design
>> protocols in general (and the XML Protocol binding to HTTP in
>> particular) in a way that ignores this possibility or assumes
>> that it doesn't happen.
>>
>> Larry
>> -- 
>> http://larry.masinter.net
>>
>>
>>
>>
>>
>>
> -- 
> Mark Nottingham
> http://www.mnot.net/
> 
> 
Received on Thursday, 11 April 2002 19:18:29 GMT

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