Hi Patrick,

DSpace has events for certain actions, but I don't believe there is anything that you can chain ahead of a download, that will allow you to alter the contents. I have built a cover-page generator for DSpace, that is custom code that on-the-fly generates an altered version of the PDF. This doesn't affect the Archival/stored version of the PDF, just the Disseminated/downloaded version of the PDF that the end user receives. The admin user gets the Archival version, when they're logged in.

The place where we altered the code to make this happen was in XMLUI's BitstreamReader, where we added some logic to determine if this object was eligible for watermarking (i.e. is PDF?, is enabled for this collection?, is user non-admin?).
You can read a wiki page about that at: https://github.com/osulibraries/DSpace/wiki/Citation-Cover-Page

For this feature to be considered more complete, it would be wise to also clean it up so that all bitstream-serving endpoints (JSPUI, XMLUI, OAI, REST, ...) also had the same logic.

________________
Peter Dietz
Longsight
www.longsight.com
peter@longsight.com
p: 740-599-5005 x809


On Sun, Aug 3, 2014 at 8:30 PM, Patrick Rynhart <P.Rynhart@massey.ac.nz> wrote:
We would like to add a watermark and/or annotations to PDFs that are
downloaded on the fly.  As an example, any paper that you download from
the Physics Archive (arxiv.org) has some annotations - e.g.:

http://arxiv.org/pdf/1407.8441.pdf

(In particular, note the download date and arXiv reference number
printed vertically in the left-hand margin.)

I'd like to be able to do this using ghostscript etc., but first DSpace
would need to support some kind of prehook when an asset is downloaded
on demand.  I had a look around the documentation but couldn't find
anything useful.

(Note: This is not a question about the preview thumbnails that are
displayed in DSpace - but the actual underlying asset served up by DSpace.)

With Thanks,

Patrick


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