Hello Steve! 1. Agreed on the FinderModule. I was planning this to work with the existing XACML machinery, so it really boils down to surfacing the attribute where appropriate. In general (and this applies to a certain extent to my thought on #2 as well), I'm disinclined to wedge the data into RELS-EXT, as it will tend to be a very granular literal value and I have some performance concerns there for my triplestore.
As far as locating the date in the Policies: I'm concerned that this would lead to a proliferation of policies, whereas an appropriate attribute would allow me to define a single policy (is current date after object's specified date). When I'm wearing my repository manager hat, fewer policies to worry about is vastly preferred. 2. I share some of the concerns you mention about the way data modelling plays with the use of dc:identifier here, but since my use case is ultimately just trying to guarantee that I only ingest resources once, it shouldn't violate the uniqueness of the identifier to the object. I am a bit more concerned with an explosion in the number of literal triples in the triplestore. Like you, I had been thinking that pushing the data into the database backing object search may be the way to go. thanks for your thoughts! - Ben On 10/29/10, Steve Bayliss <stephen.bayl...@acuityunlimited.net> wrote: > Hello Ben > > 1. A ResourceAttribueFinderModule sounds like the way to go here -- how do > you envisage the policies looking to make use of this? Also it might be > worth looking at some of the FeSL code -- not sure if you are intending this > as part of FeSL or the existing Fedora XACML functionality (or both), but I > believe there is a configurable Resource Index attribute finder module in > FeSL which could possibly be used (I have to go away and dig a bit to be > sure). In any case something generic and re-usable would be useful, eg a > generic XML datastream + Xpath specification of a resource property that > could be picked up by a ResourceAttributeFinderModule; and a generic > RDF-based similar ResourceAttribueFinderModule. > > An alternative thought - rather than having an embargo date as an object > property, it could be part of the policy specification, with application of > that policy to a set of objects that have the same embargo date. Depends on > the detail of your use case I guess, but there's a question to explore as to > whether it is a property of the resource itself or it belongs as part of a > policy specification for the object. And the granularity to which you wish > to go in specifying resouce policies vs generic policies. > > 2. I think a content hash is a useful object identifier to be published in > general. Although it's not guaranteed globally unique (but there again nor > is a UUID in the extreme), I think it is sufficiently unique (sorry, > oxymoronic I know) to be worth exposing as an identifier, rather than an > attribute, of a resource. On that basis would it make sense to expose it as > dc:identifier? You'd get both inclusion in basic search and the resource > index for nothing. It might be worth exploring if there are any URI schemes > for md5, sha-1, sha-2 etc. I have seen urn:md5:xxxx used in practice but I > don't believe that's actually a registered urn > namespace(http://www.iana.org/assignments/urn-namespaces/urn-namespaces.xml) > . And it would appear as a literal rather than a URI in the resource index. > > There is an issue here of compound vs atomistic content models if you want > to publish the hash as an identifier for more than one datastream in an > object using dc:identifier (though RELS-INT does provide a vehicle for this > if you wanted to go down the resource index route). > > A thought - if a content hash was felt to be a sufficiently useful > identifier, maybe inclusion in the core SQL database and RI of checksums > should be a core feature? > > Regards > Steve > > > > >> -----Original Message----- >> From: Benjamin Armintor [mailto:armin...@gmail.com] >> Sent: 28 October 2010 16:38 >> To: fedora-commons-users@lists.sourceforge.net >> Subject: [fcrepo-user] Some library use-case solicitations >> >> >> Hello, >> >> I'm sketching out some potential Fedora customizations, but would >> like to canvas the user community for solutions to a couple of >> library-oriented needs first. >> >> 1. Embargo dates and XACML: We'd like to be able to indicate a date >> property on an object before which actions are denied to >> non-administrative users. My proposal would involve a >> ResourceAttributeFinderModule that provides an object property that >> can be compared to the existing current date functions in XACML. Are >> there any other solutions out there? >> >> 2. Searching objects or datastreams by content hash: This could be >> spun off into an external search (like gsearch), but has anyone >> experimented with Fedora search customizations to push md5 hash values >> into the object search database? I'd rather avoid using the >> triplestore both to minimize the size of the graph and to avoid >> reproducing the hash value twice in an object. >> >> regards, >> Ben Armintor >> >> -------------------------------------------------------------- >> ---------------- >> Nokia and AT&T present the 2010 Calling All Innovators-North >> America contest >> Create new apps & games for the Nokia N8 for consumers in >> U.S. and Canada >> $10 million total in prizes - $4M cash, 500 devices, nearly >> $6M in marketing >> Develop with Nokia Qt SDK, Web Runtime, or Java and Publish >> to Ovi Store >> http://p.sf.net/sfu/nokia-dev2dev >> _______________________________________________ >> Fedora-commons-users mailing list >> Fedora-commons-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/fedora-commons-users >> > > > ------------------------------------------------------------------------------ > Nokia and AT&T present the 2010 Calling All Innovators-North America contest > Create new apps & games for the Nokia N8 for consumers in U.S. and Canada > $10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing > Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store > http://p.sf.net/sfu/nokia-dev2dev > _______________________________________________ > Fedora-commons-users mailing list > Fedora-commons-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/fedora-commons-users > ------------------------------------------------------------------------------ Nokia and AT&T present the 2010 Calling All Innovators-North America contest Create new apps & games for the Nokia N8 for consumers in U.S. and Canada $10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store http://p.sf.net/sfu/nokia-dev2dev _______________________________________________ Fedora-commons-users mailing list Fedora-commons-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/fedora-commons-users
