100% of the people interested in XRD's at the moment are from the identity community. I am not aware of any other community showing interest in XRD at the moment. What worries me is that people from the identity community are rooting for XRD's with 0 or 1 Subject, instead of requiring a Subject. <div>
<br></div><div>Also it would make sense to enforce the <Subject> on to the 1% who would not require it, rather than leave the rest of the 99% to their own interpretation of what you mean by 0 or 1 Subject. You have already seen on this thread talk about the first party (originator) not providing a Subject, and the 2nd or 3rd party having to insert the Subject if required by themselves.</div>
<div><br></div><div>After all the <Subject> of an XRD is the most important Element of an XRD. It is amazing that you don't see it that way, and are willing to leave it in an ambiguous state and subject to interpretation. If anything can be a recipe for incompatibility between future identity protocols, then this is it.</div>
<div><br></div><div>So if you are not going to do something about it then somebody else will have to add a new layer to XRD. <br><br><div class="gmail_quote">On Thu, Oct 22, 2009 at 12:12 PM, Drummond Reed <span dir="ltr"><<a href="mailto:drummond.reed@cordance.net">drummond.reed@cordance.net</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Santosh,<br><br>IMHO it's not worth all this worry about Subject being optional or not. If 99% of XRDs need Subject because some protocol that will use the XRD requires a Subject, then only 1% of XRDs will not have a Subject,<br>
<br>And those 1% will probably be for very clear edge cases uses of XRD for a specific job that doesn't care whether the XRD has a Subject.<br><br>All the XRI TC did was recognize that XRD would be useful in that last 1%.<br>
<br>Any protocol that uses XRD for discovery, such as OpenID, is free to specify that Subject is mandatory. If so, anyone who tries to use an XRD without a Subject for OpenID discovery will find it won't work, and will need to add the Subject.<br>
<br>Done (as is, I hope, this thread).<br><font color="#888888"><br>=Drummond<br><br></font><div class="gmail_quote"><div><div></div><div class="h5">On Wed, Oct 21, 2009 at 8:42 PM, Santosh Rajan <span dir="ltr"><<a href="mailto:santrajan@gmail.com" target="_blank">santrajan@gmail.com</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex"><div><div></div><div class="h5">So it is now clear to me that identity protocols cannot use the XRD specification "as is". There has to be a new "Identity Resource Descriptor" specification sitting in between XRD and all identity protocols that draw from XRD.<div>
<br></div><div>I will explain the problem with an hypothetical example. Lets say webfinger were to specify that the <Subject> of the XRD is not required. And a future OpenID spec mandates the use of <Subject>, because the OpenID folks felt that XRD with no Subject was a security risk. The future OpenID Spec will not be able to use the webfinger protocol (which according to current thinking it may want to).</div>
<div><br></div><div>In any case an "Identity Resource Descriptor", without a Subject to describe it, is entirely meaningless to me. So a new identity Layer for XRD is called for that mandates the use of <Subject> in all Identity Resource Descriptors. (IRD's).<div>
<div></div><div><br>
<br><div class="gmail_quote">On Thu, Oct 22, 2009 at 8:46 AM, John Bradley <span dir="ltr"><<a href="mailto:ve7jtb@ve7jtb.com" target="_blank">ve7jtb@ve7jtb.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">
<div style="word-wrap:break-word">I suppose if we were starting fresh we could have called it RDML.<br><div><br></div><div>I don't know that there is a meaningful distinction between a document format like OpenDocument and meta-markup language like SAML. Technically they are the same.</div>
<div><br></div><div>The XRI-TC will also be producing a XRI 3.0 spec that will use this updated XRD document specification.</div><div><br></div><div>Webfinger and others may also produce processing specifications for XRD or profiles of XRD.</div>
<div><br></div><div>XRD is NOT an identifier.</div><div><br></div><div>XRDS as currently used in openID discovery stands for eXtesable Resource Descriptor Sequence.</div><div><br></div><div>Yadis never made any use of the Sequence feature so we made it optional. </div>
<div><br></div><div>Hense the main document format spec is now called XRD and not XRDS.</div><div><br></div><div>I know people are planning on using it with a multitude of different identifiers including email addresses.</div>
<div><br></div><div>It is still XML and the document is a meta-data descriptor not an identifier.</div><div><br></div><div>John B.</div><div><div></div><div><div><br></div><div><div><div>On 2009-10-21, at 11:13 PM, Santosh Rajan wrote:</div>
<br><blockquote type="cite">In other words now you are saying that XRD is another markup language like HTML and SAML. In which case you should be calling it "XRML" for Extensible Resource Markup Language.<div><br>
</div><div>So what started as a "Descriptor" has morphed into a "Markup Language".</div>
<div><div><br></div><div>So this gives scope for someone else to write the "REAL" Extensible Resource Descriptor Specification on top of XRML.</div><div><br></div><div><br><div class="gmail_quote">On Thu, Oct 22, 2009 at 2:24 AM, John Bradley <span dir="ltr"><<a href="mailto:ve7jtb@ve7jtb.com" target="_blank">ve7jtb@ve7jtb.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">XRD is a XML document spec.<div><br>
<br>
On 2009-10-21, at 5:21 PM, John Kemp wrote:<br>
<br>
</div><div><blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
John Bradley wrote:<br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
It means that some protocol that is using XRD is defining the subject via some external mechanism.<br>
</blockquote>
<br>
So the XRD spec. is a template spec. meant to be simply incorporated by reference into other specs. I guess?<br>
<br>
</blockquote></div>
Like other XML specs eg SAML 2.0 it can be used multiple specifications that process XML documents.<br>
<br>
External specs can profile the XRD spec.<div><br>
<br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex"><blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
In the HTTP protocol case there may be an implicit subject based on the identifier that is being resolved.<br>
</blockquote>
<br>
As mentioned earlier, if the _subject_ of the XRD is identified (implicitly) by the same URI used to retrieve the XRD itself, then that seems rather circular.<br>
<br>
</blockquote></div>
The XML document describes a resource and provides links to associated resources.<br>
A HTML page doesn't need to explicitly say what URI it is retrieved from in its internal markup.<br>
<br>
Like with HTML sometimes the subject is defined by the transport or other external method.<br>
<br>
Thanks<br>
John B.<div><div></div><div><br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex"><blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
All normal http caching would apply in the http: case.<br>
</blockquote>
<br>
Sure, I'm not quibbling with caching...<br>
<br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
In the IMI/SAML case we have discussed pushing a XRD as a assertion/claim.<br>
In that case the subject may be the same as the saml:NameID in the containing saml:Assertion.<br>
It could perhaps be argued that putting a xrd:Subject and signature inside a signed saml:Asertion is un-neccicary.<br>
Suffice to say it is up to the protocol using XRD to decide what to make of a XRD without a xrd:Subject.<br>
</blockquote>
<br>
OK, I think I've understood ;)<br>
<br>
Cheers,<br>
<br>
- johnk<br>
<br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
John B.<br>
On 2009-10-21, at 3:09 PM, John Kemp wrote:<br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
John Bradley wrote:<br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
Yes a XRD can be used for identity. In that case it should be a signed XRD (with Subject)<br>
However a XRD can be used to describe any resource (URI).<br>
</blockquote>
<br>
What does it mean then (in XRD terms) if an XRD doesn't identify the resource it describes (ie. it doesn't have a subject)?<br>
<br>
- johnk<br>
</blockquote></blockquote>
<br>
</blockquote>
<br>
</div></div></blockquote></div><br><br clear="all"><br>-- <br><a href="http://hi.im/santosh" target="_blank">http://hi.im/santosh</a><br><br><br>
</div></div>
</blockquote></div><br></div></div></div></div></blockquote></div><br><br clear="all"><br></div></div>-- <br><a href="http://hi.im/santosh" target="_blank">http://hi.im/santosh</a><br><br><br>
</div>
<br></div></div><div class="im">_______________________________________________<br>
general mailing list<br>
<a href="mailto:general@lists.openid.net" target="_blank">general@lists.openid.net</a><br>
<a href="http://lists.openid.net/mailman/listinfo/openid-general" target="_blank">http://lists.openid.net/mailman/listinfo/openid-general</a><br>
<br></div></blockquote></div><br>
</blockquote></div><br><br clear="all"><br>-- <br><a href="http://hi.im/santosh">http://hi.im/santosh</a><br><br><br>
</div>