[Dspace-general] [Dspace-tech] DSpace Bistream

[Robert Tansley]

On 05/07/07, James Rutherford <james.rutherford at hp.com> wrote:
> On Wed, Jul 04, 2007 at 01:13:38PM +0200, Ina Smith wrote:
> > My question relates to the preservation of the bitstream URL: In stead
> > of linking from another database (e.g. our library catalogue) to the
> > Item URL, we would like to link directly to the Bitstream URL. Is
> > there any guarantee that the Bitstream URL will also stay persistent
> > if we decide to export our items to another server one day? We also
> > use the CNRI Handle System.
>
> The short answer is "no". Bitstreams don't get handles, so if you move
> your DSpace having directly referenced a Bitstream URL, that link will
> either break, or you will have to maintain it yourself (which is a bad
> road to go down). Until this is fixed (and I should point out that not
> everyone thinks it's a problem) you shouldn't use Bitstream URLs
> anywhere unless you're prepared to deal with it when the time comes.

Software systems do not persist or guarantee URLs or identifiers,
people do.  This use case is precisely the one that led to DSpace
bitstream URLs being in the current form they are -- a form that is
easy to persist, but does not require the overhead of minting and
resolving huge numbers of Handles.

So it depends what you mean by 'export ... to another server'.  If
you're just thinking about having DSpace run on beefier hardware,
although the 'preferred' bitstream direct access URL may change in the
future, certainly the existing /bitstream/* URLs will always be
supported by DSpace as redirects, so provided the new server can get
the same DNS name you will be able to persist the bitstream URLs.

If you're thinking about running other software, provided you still
have control of the DNS space, it shouldn't be too hard to keep (e.g.)
dspace.up.ac.za/bitstream/123/456/1/foo.pdf pointing at the right
place.  At least, it wouldn't be any harder to do this than to update
a huge number of Handle records to point at the right (new) place.

If you think that the DNS name may change, you would have to look into
Handles or another ID scheme resilient to DNS name changes of the
actual server.

Rob