[OpenID] host-meta and "acct:"

[John Kemp]

On Nov 5, 2009, at 3:30 PM, Manger, James H wrote:

> Hi Santosh,
>
> > You are assuming the meta-data "is not a resource".
>
> No I am not.
>
> > I think meta-data is also a "Resource".
>
> I agree, the jim.footy.xrd  file has its own URI so it is a resource  
> — but that is irrelevant to <Subject>.

<Subject> identified by a URI, is itself a resource. An XRD document  
ABOUT the subject has another URI, which identifies an "XRD resource".

>
> The XRD <Subject> element “provides the identifier of the resource  
> described by this XRD” [XRD v1.0 WD9, §2.1.1.].
> jim.footy.xrd does not describe itself, it describes hundreds of  
> other *.html pages I wrote about football. It makes no sense for  
> <Subject> to hold the URI of the XRD file itself in this situation.

Right, it seems self-referential and circular.

>
>
> If you have an OpenID identifier that isn’t used for anything else  
> (eg its not your blog or home page), then (in some potential future  
> OpenID v3) a GET on that OpenID identifier could return a XRD with  
> its own URI in the <Subject>.

The URI in the Subject is the SAME URI as that for the XRD document  
which provides "metadata" about that subject?

> It would be metadata about itself.

Unless you used HTTP content-negotiation (and I'd consider that an  
abuse) or the HTTP 303 redirect mechanism to distinguish between a  
"non-information resource" from an "information resource" where the  
subject was a "non-information resource" (which would mean you  
essentially had two URIs anyway) I don't see how this would work.

I think I prefer the existing host metadata proposal better (even if  
I'd prefer, even more, XRD to allow a non-URI Subject rather than  
having Subject be optional and thus require additional semantic  
extension by those using the XRD spec.)

> It could point to an OP directly, eliminating the extra round-trip  
> of going from a resource to its metadata since they are one and the  
> same in this case. [Mind you, I’m not sure you gain much over  
> serving an HTML page with OpenID v1 or v2 <link>s to the OP.]


- johnk

>
>
> James Manger
>
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