Scott Reynen wrote:
> On Feb 20, 2007, at 6:56 PM, John Panzer wrote:
>
>> Scott Reynen wrote:
>> ...
>
> Here's the purpose of UID from vCard:
>
>> To specify a value that represents a globally
unique
>> identifier corresponding to the individual or
resource associated
>> with the vCard.
>
>
> So if two hCards have the same UID, they must refer to
the same
> person, because otherwise it wouldn't be globally
unique. And I
> think that solves the problem Thom described above,
unless I'm
> missing why it needs to be specific to OpenID.
Nope, it solves it. OpenID URLs are just one example.
> ...
>
>> I'm thinking here of cases where the target may be
an OpenID, but
>> not necessarily provide an hCard.
>
>
> UIDs do not need to point to hCards. Nor do they need
to be
> OpenIDs. They can do both, but the only requirement is
that they be
> globally unique and correspond to the subject of the
hCard. And that
> minimal requirement seems to be just enough to solve
this problem
> without worrying about what, if anything, is on the
other end of the
> UID.
>
Thanks. (The thread in the archives was somewhat twisty;
the summary is
helpful.) So, rel="url uid" it is.
I think this solves the problem of how to match one hCard up
with
another using a convenient unique key well above the 80%
level.
One minor point: URLs are unique but not truly persistent.
Due to URL
reuse,when trawling through archives you can't assume that
UID1 == UID2
means person 1 == person 2 unless both UIDs were minted at
the same
time. I'd probably solve this heuristically if ever
necessary, but: Is
it worth an implementor's warning somewhere?
Interestingly, the vcard people seemingly dealt with this
issue, because
they edited [1] "persistent, globally unique
identifier" prior to the
final RFC draft.
-John Panzer
[1] http://www.imc.or
g/pdi/vcard-21.txt
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