On Fri, Aug 6, 2010 at 7:50 AM, Paul Trevithick
<ptrevithick@xxxxxxxxx> wrote:
Drummond, you're right about the urn's not being shorten-able. But they shouldn't have been urns in the first place. That was another error in the XDI example that I should have called out separately (I'll updated the wiki page now (
http://wiki.eclipse.org/Higgins_PDS_Access#UDIs_not_URNs)).
1) UDIs not URNs
EntityIDs are supposed to be resource UDIs not URNs. So after we correct that error in our XDI then the entityIDs will look like this:
=
mydex.org@alice/$context$xdi+home+and+family//=alice
Where
- =mydex is the name of the PDS operator
- @alice is the community name assigned to alice by Mydex
This is not correct. @alice is a global organization i-name. This should be *alice.
- $context indicates that we're looking for a "context" service endpoint in the LDDR/XRD
- $xdi indicates that this entityID can be accessed over XDI
- +home+and+family is the id of the context
It's been so long since I've worked with UDIs and UDI resolution that I can't answer this. Markus will have to. However service endpoint selection is no longer part of XRD (as opposed to XRDS), so I think there's going to be an issue here one way or another.
- =alice is the entityID within +home+and+family
Yes, that's fine.
Which as an XRI 3.0 in URI form would be:
Yes, modulo the points I made above.
or for external non-correlation purposes...
http://xri.net/=mydex@!F83.62B1.44F.2813/$context$xdi+home+and+family//=!2C75.AC49.21D3.1207
Agreed.
Where
- !F83.62B1.44F.2813 is an i-number (randomly generated per-RP pseudonym) that is associated with =mydex@alice
Agreed.
BTW, Mike and I a few weeks ago discussed the performance load on our active client to maintain a local cache of the resolutions of these UDIs. The active client will attempt resolution on every UDI and then cache the results of the resolution (by associating the resolved URI (or nil) with the UDI). It must maintain this cache else it will be attempting resolution every time it touches one of these UDIs.
Agreed.
2) Namespace contractions of UDI in XDI
With the correct form of the UDIs in the XDI per #1 above we see lots of UDIs with the same prefix:
and in fact multiple entityIDs (UDIs) in the home&family context that share this longer prefix:
Thus, if XDI added the ability to say:
Then we would have:
a:=alice
...or something similarly short and sweet.
Yes, I understand.
=Drummond
On Aug 6, 2010, at 1:16 AM, Drummond Reed wrote:
*It would be nice if XDI had a convention for URI shortening based on a default namespace. That if relative entityIDs were used (e.g. "#245") we wouldn't have to have these long entityIDs like this one used below: "urn:efa25e71-5b6f-4844-b139-4ed26dd1c3e5".
Interestingly, the example you use - of a URN - is not an address that can benefit from namespacing. All URNs are globally unique.
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