multiple URI elements per Service in XRDs

Josh Hoyt josh at
Fri Jan 20 15:30:03 UTC 2006

Drummond and Johannes,

On 1/19/06, Drummond Reed <drummond.reed at> wrote:
> 1) Those proposed processing rules for XRD subelements (specifically
> XRD/Service and XRD/Service/URI) are the general rules suggested and
> followed by the XRI resolution spec. Another spec/protocol that uses XRDS
> can set it own rules. For example, YADIS could say that all but the first
> XRD/Service/URI child element will be ignored.

I think that someone using XRDS had better have a pretty good reason
to diverge from the XRI resolution spec. If using the same rules makes
technical sense, then it seems like a pure loss to require two
different interpretations of the same document.

> 3) ...UNLESS they need the second key reason the XRI TC decided to allow
> more than one XRD/Service/URI element: they want to expose a service via
> more than one protocol (classic example: http and https.)

This rule definitely applies! Using HTTPS is the only way to be sure
that there is not a man-in-the middle for OpenID, but HTTPS is not
required or desired for the common case. For OpenID, I hope that
services will allow either protocol.


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