<div class="gmail_quote">On Tue, Jun 9, 2009 at 7:00 PM, Santosh Rajan <span dir="ltr"><<a href="mailto:santrajan@gmail.com">santrajan@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
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We need to remember that XRD only addreses discovery for URL identifiers.</blockquote><div><br>This is not really true. The XRD document schema only demands that an identifier be a URI, both for the XRD document's "subject" (i.e., the canonical-id) and the XRD document's "alias" (i.e., other synonymn Identifiers).<br>
<br>"<a href="mailto:david@google.com">david@google.com</a>" is really the following URI: "mailto:<a href="mailto:david@google.com">david@google.com</a>", and would work just fine in XRD.<br><br> </div>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> XRD<br>
does not address email like identifiers. XRD actually has two properties.<br>
1) generic format for resource descriptor documents (XRD documents)<br>
2) protocol for obtaining XRD documents from HTTP(S) URIs.<br>
For email identifiers we are using only property (1) which is by and large<br>
defined, except for the signature part.<br>
<div><div></div><div class="h5"></div></div></blockquote><div><br>Actually, XRD relies on a "well known location" to begin the Discovery process. That is the subject of a different spec called "Host Meta" (<a href="http://tools.ietf.org/html/draft-nottingham-site-meta-01">http://tools.ietf.org/html/draft-nottingham-site-meta-01</a>). FYI, Eran has a great blog post on all of this here: <a href="http://www.hueniverse.com/hueniverse/2009/03/the-discovery-protocol-stack.html">http://www.hueniverse.com/hueniverse/2009/03/the-discovery-protocol-stack.html</a><br>
<br>All that to say: as long as OpenID defines how to locate the "host-meta" file for a particular Identifier (like an email address), then that Identifier can work just fine with XRD, and we can then use that identifier (e.g., an email address) in the OpenID flow (some other parts of the spec would need to be adjusted for this to actually work, but you get the idea).<br>
<br>We (the OpenID community) just need to define how this is going to happen (thus, the 2.1 Discovery WG).<br></div></div>