Review of Yadis section in XRI Resolution 2.0 WD11

[Johnny Bufu]

Hi Drummond,

On 30-May-07, at 10:45 PM, Drummond Reed wrote:
> To make this new section easy to review, we've put it on the XRI TC  
> wiki at:
>
> 	http://wiki.oasis-open.org/xri/XriCd02/XrdsDiscoveryFromHttpUris
>
> It's pretty short and sweet, mostly because XRDS documents and  
> their context
> and usage are defined elsewhere in the spec. So this section just  
> defines
> the URL-based discovery protocol, which is the meat of the Yadis  
> 1.0 spec.
> The wording has been restructured slightly to fit the OASIS spec  
> format,
> however the only normative change was to make the recommendation to  
> include
> the application/xrds+xml Accept header in the HEAD or GET request a  
> SHOULD
> instead of a MAY.

It looks really nice and clean to me :-) but I spotted two issues:

1) The final GET for the XRDS document MUST have the application/xrds 
+xml accept header in both 8.1 and 8.2:

> The requesting agent MUST then request the XRDS document using an  
> HTTP(S) GET with an Accept header specifying the content type  
> application/xrds+xml.

(I take it that the MUST applies to everything that follows in the  
sentence.)
This does not seem to be specified in Yadis.


2) Fallback from HEAD to GET:

8.1:
> If the response includes neither option above, discovery of an XRDS  
> document is not available for the target resource.

Yadis 6.2.8:
> If the response to an HTTP HEAD request does not contain a Yadis  
> Resource Descriptor URL, the Relying Party Agent MUST then issue an  
> HTTP GET request to the Yadis URL.

Fixing this in 8.1 may create an endless loop, since 8.1 is  
referenced from 8.2. So that portion in 8.2 would probably need to be  
revised as well.


Johnny