[Dspace-general] creating web presentations using dspace content

[Tansley, Robert]

I think the DIDL plug in does just contain references (URLs) for
bitstreams below a certain size, so it should help.  I believe you can
configure (or easily modify the code) so that all bitstreams are
included by reference.  Hopefully, the DIDL plug-in will be part of the
core DSpace code before too long.  

Another possibility is to use METS -- a project I'm involved in will be
exposing METS via OAI-PMH; also intended to be part of the core code
base (but optional in both cases, of course).  This will include
references to bitstreams.  Both METS and DIDL contain the structural
metadata you need.  Your app can just obtain the METS or DIDL, construct
whatever page is required, embedding the relevant URLs to DSpace
bitstreams which the user's browser can retrieve transparently (assuming
public read access).

Of course this is just part of the problem.  The real problem is that
the structural metadata you need has to be in DSpace in the first place!
There's currently no place for that 'understood' by DSpace.  So you have
a few options:

- Put METS or DIDL with the relevant information as a bitstream in
DSpace alongside the bitstreams in an item.  Then your app would need to
know which bitstream is the METS/DIDL (as opposed to the content).
Plus, you'd need a convenient way of creating that METS/DIDL in the
first place.

- Use some heuristic method, and modify the METS/DIDL code to react
accordingly.  E.g. if you named the pages 'page01.tiff', 'page01.tiff'
etc. your customised METS/DIDL code could order the pages appropriately.

- Modify the DSpace database/code to have this structural info (e.g.
page ordering) and contribute the code back to the DSpace code base!
Probably the most work but if you have resources to do it, it would
benefit many other people.

Hope this helps,

 Robert Tansley / Digital Media Systems Programme / HP Labs
  http://www.hpl.hp.com/personal/Robert_Tansley/

> -----Original Message-----
> From: dspace-general-bounces at mit.edu 
> [mailto:dspace-general-bounces at mit.edu] On Behalf Of Don Gourley
> Sent: 05 May 2005 08:36
> To: dspace-general at mit.edu
> Subject: Re: [Dspace-general] creating web presentations 
> using dspace content
> 
> Thanks for the pointers to the DIDL plug-in and pluggable package
> exporter proposal.  The concept of the structural metadata as a
> manifest in a named bitstream is exactly what I'm thinking of,
> but I don't think my viewer application wants to get a package
> that contains the metadata with the content bitstreams.  It would
> be simpler and more efficient to include URLs for the bitstreams
> in the structural metadata so the viewer can create pages using
> <img> tag that refers to the bitstream that represents the current
> page.  Would that still be considered a DIP?
> 
> > Is the item likely to be small enough that packaging wouldn't insert
> > too long a delay, or would you need to package fragments of 
> the item?
> 
> In my case, an item might be 30 or 40 JPGs, each representing a
> page of the document.  Only one page is needed at a time, and it
> isn't really needed by the viewer app, but by the user's browser.
> So it doesn't make sense to me to pass even fragments of content
> through the viewer app.
> 
> -Don
> 
> 
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