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Re: i19 Bodies on GET (and other) requests

From: Mark Nottingham <mnot@mnot.net>
Date: Wed, 17 Jan 2007 13:09:56 +1100
Message-Id: <AAF03150-000D-418C-88F1-613CAA815B3D@mnot.net>
Cc: "ietf-http-wg@w3.org Group" <ietf-http-wg@w3.org>
To: Roy T. Fielding <fielding@gbiv.com>


On 2007/01/17, at 10:20 AM, Roy T. Fielding wrote:

>
> On Jan 16, 2007, at 2:49 PM, Mark Nottingham wrote:
>> My reading is that this would be cacheable, and that the cache key  
>> would be just the URI. In particular, the last sentence of the  
>> quoted spec text above helps clarify this, although it's talking  
>> about servers, not necessarily caches.
>
> Don't get the terminology messed up.  Caches are storage things that
> could be on either clients or servers.  Servers are components that
> happen to be playing the role of sending a response at this moment.
> As such, the only thing it should talk about is servers -- whether
> or not a cache exists in the server is irrelevant.

That's what I meant by "it's talking about servers, not necessarily  
caches."

>> Does that make sense? I'd feel a bit better if the language were  
>> massaged to include not just servers, but caches as well. E.g.,
>>
>> "A server SHOULD read and forward a message-body on any request.  
>> If the request method does not include defined semantics for an  
>> entity-body, or if the request method is unrecognised, then the  
>> message-body SHOULD be ignored by servers and caches when handling  
>> the request."
>
> I disagree with both sentences.  The first one is just wrong -- it
> contradicts both the rules for message parsing (fails to account for
> HEAD requests) and lumps all servers into the category of proxies
> and gateways.

2616 already says "A server SHOULD read and forward a message-body on  
any request; if the request method does not include defined semantics  
for an entity-body, then the message-body SHOULD be ignored when  
handling the request." so it seems that this problem already exists.

> In the second sentence, caches do not "handle the request",
> ever.  The cache is part of the server and subject to its  
> requirements.
>
> When a request message contains both a message-body of non-zero
> length and a method that does not define any semantics for that
> request message-body, then an origin server SHOULD either ignore
> the message-body or respond with an appropriate error message
> (e.g., 413).  A proxy or gateway, when presented the same request,
> SHOULD either forward the request inbound with the message-body or
> ignore the message-body when determining a response.

Are you saying that a cache on such a proxy or gateway SHOULD NOT  
return a fresh response from cache, but instead forward the request,  
if a GET request has a message-body?

--
Mark Nottingham     http://www.mnot.net/
Received on Wednesday, 17 January 2007 02:09:48 GMT

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