[OpenID] HTML markup for discovery in OpenId 2.0

[Jack]

Tony Locke wrote:
> Thanks for that Jack, I'll put the four separate <link> tags in to 
> support both versions.
> 
> I'm still not clear on why the server needs to be given on the 
> claimed id page. Can't the Relying Party just do discovery on the 
> OP-Local Identifier to find the OP Endpoint URL?

You're referring to the steps in discovery that result in an XRDS
document, I think. XRDS is not mandatory, in the sense that it is not a
requirement that you as an OpenID user should provide such a document
(RPs and OPs that support V2 MUST support Yadis/XRDS discovery, but they
cannot require that a given claimed_id should provide for it).

So in the absence of an XRDS document, the RP must fall back to HTML
discovery, which is what those link tags are for (HTML discovery means
nothing more than normalising the URL, and then extracting those tags
from the document at the resulting location).

http://openid.net/specs/openid-authentication-2_0-12.html#html_disco

-- 
Jack.