[Opensim-dev] Global identifiers

Sun Aug 29 22:33:14 UTC 2010

mmm... the argument that tacking an identifier onto the end of a URL
smacks of premature optimization to me. it should be possible for any
reasonable client to cache the relationship between a display name and
a URL. in fact, HTTP has some mechanisms to help you with that. so you
wouldn't have to query the agent service EVERY time you need the name.

at linden i developed a pathological dislike of the secondlife:/// URI
scheme (more on that later), and making the path of URLs "important"
sort of smacks of that old URI scheme. i understand why you might want
to stuff names and other information into URLs, but IMHO, the benefits
you get from one less query is minimal compared to loss of
flexibility.

for instance... the reason the VWRAP CALM message exists is because
jhurliman and i sorta figured out it would be a PITA to support
multiple revisions of the secondlife:/// URI handling code. john was
doing some cool stuff with OAuth and OpenID to allow peeps to log into
a grid via the web. the last part of john's auth process was to
redirect you to a secondlife:/// URI.

the idea here was that if the second life viewer was installed, then
it would register itself as a helper app for that URI scheme and "do
the right thing" of rezzing you at a certain location on the main
grid.

but

the problem here was that the secondlife:/// URI handling code in the
viewer would ONLY rez you on linden's main grid. we would have had to
modify the viewer to handle the addition of a 'loginurl' term. it was
technically doable, but i was worried about maintaining the URI scheme
as the defacto way of altering the viewer's startup behavior. i was
kinda worried that anyone who wanted to experiment with new features
for the SL viewer would have to perform surgery on the secondlife:///
URI handling code (and might become durty with respect to the GPL in
the process.)

so john and i put our heads together and came up with the CALM idea.
from a technical perspective it seemed a bit easier to take everything
that was buried in the secondlife:/// URI and turn it into a LLSD map.
since we already had LLSD map parsing code, it was pretty
straightforward to use. it also allowed us to remove the processing of
startup messages from the GPL'd source, which had been problematic for
some people.

so why am i hijacking this thread to tell you about the history of a
VWRAP component? mostly as a parable about making things as flexible
as possible. had the secondlife:/// URI scheme (and it's
implementation in the viewer) not been inflexible, we would never have
had to take the time to build the CALM scheme.

starting with designs that enhance flexibility will payoff in the future.

though seriously, it's not going to be the end of the world if you do
this "wrong."

-cheers
-meadhbh
--
meadhbh hamrick * it's pronounced "maeve"
@OhMeadhbh * http://meadhbh.org/ * OhMeadhbh at gmail.com

On Sun, Aug 29, 2010 at 2:51 PM, Steven Westcot <tsudico at gmail.com> wrote:
> Hello,
> I've been reading the mailing list for a while, but haven't really had much
> input.  I'd like to give my own opinion on the current matter though.  I
> like Melanie's format:
> http://www.avination.net/user/44626b40-13d6-4817-b61b-de5df7b5e7e8/Melanie+Milland
> I think having the avatar name added to the URI would definitely help give
> attribution and prevent unnecessary polling.  For a hypergrid avatar, IMs
> and Friends would only need the UUID.  Objects are a different matter
> though. If the object has left one grid and traveled to another, the only
> way a human readable name can be discerned would either be to poll the
> original grid's agent service each time the creator's name was needed or to
> cache the data in the URI itself.  Having the data exist in the URI would
> help prevent issues if the original grid was temporarily
> or permanently unavailable.
> The only issue I see with including the extra information is if a grid
> doesn't conform to the standard first + last naming, but has their own
> identity format.  In cases such as those, the grid's agent/identity service
> should be able to create a URI that does give proper attribution(perhaps by
> using existing escaped characters)
> Steve W.
>
>>
>> Message: 2
>> Date: Sun, 29 Aug 2010 14:50:08 -0400
>> From: Mike Dickson <mike.dickson at hp.com>
>> To: "opensim-dev at lists.berlios.de" <opensim-dev at lists.berlios.de>
>> Subject: Re: [Opensim-dev] Global identifiers
>> Message-ID: <1283107808.13484.104.camel at mdickson-linux>
>> Content-Type: text/plain; charset="UTF-8"
>>
>> Sigh
>>
>> The name has absolutely zero value for any sort of attribution.  I can
>> have the same name someplace else (or on the same grid if the grid owner
>> allows it an uses some other identifier or mechanism for
>> authentication). Only UUID is valid to identify a specific agent.  Also,
>> what if I don't want just anyone to know the full names of my users.  Or
>> if I use a slightly different mechanism to describe a user (email
>> addresses for instance).
>>
>> The core developers have said over and over again that OpenSim is a
>> framework.  That being the case the semantics of "names" can vary across
>> grids and how could you ever depend on anything like that to do
>> "attribution".  Only the Agent service for a grid should be able to
>> resolve agent id's down to more specific information.  In that way it
>> can also provide whatever access controls on that information the grid
>> owner prefers in order to enforce that grid's TOS.
>>
>> Mike
>
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