W3C home > Mailing lists > Public > public-lod@w3.org > February 2010

Re: Recommendations for serving backlinks when having hash URIs?

From: Nathan <nathan@webr3.org>
Date: Wed, 10 Feb 2010 19:26:16 +0000
Message-ID: <4B730858.5050407@webr3.org>
To: Richard Cyganiak <richard@cyganiak.de>
CC: public-lod@w3.org
Richard Cyganiak wrote:
> Hi Nathan,
> 
> On 10 Feb 2010, at 17:26, Nathan wrote:
>> interested to here more opinions on the "*may* also just send a default
>> representation back to the client. That's because the Accept header is
>> just a statement of preference by the client" comment though; because
>> obviously if people did this for dereferenced URIs and just fired back a
>> generic html page regardless (or worse) then the whole linked data thing
>> would fall apart (surely)?
> 
> Well, let's turn this around and look at it from an RDF client's point
> of view. I send an Accept header asking for RDF/XML. But for 99% of the
> URIs out there, the server fires back HTML regardless.
> 
> Content negotiation is an *optional* feature of HTTP. Conformant clients
> and servers don't have to implement it. The vast majority of servers don't.
> 
>> I'd always taken the meaning of sentences in the http 1.1 rfc like:
>> "if the server cannot send a response which is acceptable according to
>> the combined Accept field value, then the server SHOULD send a 406 (not
>> acceptable) response."
>> http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1
>> to mean that's what you should do, not "you may do whatever you want"
> 
> It's what you *should* do, but not what you *must* do, hence conformant
> servers can elect not to do so, and conformant clients have to
> anticipate that behaviour.
> 
> Anyway, this describes *only* the case where it has already been
> established that the server has nothing that the client understands,
> hence no useful conversation can take place. This is not a particularly
> interesting case, and I'm not sure why you put so much weight on it.

nor I! :)

> From the client's POV, what's the difference between receiving a 406 (“I
> don't have a format that you understand”) and a 200 with a non-supported
> Content-Type (“Here, take a look at this thing in a format that you
> don't understand”)?
> 

Ambiguity? a 4xx is a clear definate answer which can't be miss-read,
and a 2xx indicates that you're giving back what the client asked for,
which you aren't. I pretty much equate it with asking for a pair of red
socks and getting a response of "certainly sir" followed by some Y-fronts.

regards!
Received on Wednesday, 10 February 2010 19:26:59 UTC

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