[Mulgara-general] Model-URI/URL Use-cases and Requirements and Proposal
David Wood
dwood at softwarememetics.com
Wed Oct 10 14:21:17 UTC 2007
On 20 Sep2007, at 22:41, Paul Gearon wrote:
> As far as I can tell we just need 2 things:
>
> 1) A way to reliably map from a URL to a server on a host.
> 2) A way to reliably map from a URL to a node ID on a host.
>
> The first point is required to allow the current paradigm, where a
> client library automatically makes connections to the server. I
> don't like this at all (particularly with federated queries) but I
> don't want to break what we already have. Discussing it with
> Andrae, we're expecting an initial attempt to use URLs that
> identify the host and service. Ultimately, we expect to have
> registry support.
>
> I fully expect some scenarios will result in the possibility of
> connecting to the wrong graph, due to an incorrect match while
> falling back through the different identification mechanisms.
> While undesirable, I believe it is mitigated because this mechanism
> will be deprecated. Also, if we introduce security again, then
> security domains will prevent unauthorized data from appearing.
> (There's also an argument to be made around the universality of RDF
> assertions, and the open world assumption - and while correct it's
> not really pragmatic). That all said, it should work 99% of the time.
>
> The second point will be done by mapping to a URI, which by
> definition is unique, and has a unique node ID. The form of this
> URI is what is keeping Andrae up at night. :-)
>
> Neither point proscribes how to treat the path of the URLs, nor
> whether or not fragments exist. So I'm OK with dropping fragments.
I'd like to be clear that in:
rmi://pneuma.netymon.com/rdfDatabase#addressBook
#addressBook is a URL fragment. Dropping that would be bad :)
Regards,
Dave
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