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

Re: Recommendations for serving backlinks when having hash URIs?

From: Richard Cyganiak <richard@cyganiak.de>
Date: Wed, 10 Feb 2010 19:09:46 +0000
Cc: public-lod@w3.org
Message-Id: <CE8820CE-68B7-4332-A8E9-847333D02029@cyganiak.de>
To: nathan@webr3.org
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. 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”)?


> ps: last sentence may sound a bit like a personal attack, but it's  
> not,
> unsure how else to word it! :)
> Many Regards,
> Nathan
Received on Wednesday, 10 February 2010 19:10:22 UTC

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