> However, it doesn't always seem to be the case that the "persistent URLs" that were coined by one repository are kept live by the next repository (or an adjunct piece of software). The effect is that all the legacy links break when the old service is switched off.
> Does anyone have any experience of this? What do platform developers need to do to make the smooth transition of legacy URLs "really simple" as opposed to "technically possible"?
Sure, I've seen it happen. There are several potential barriers here:
- The initial repository isn't using any kind of indirection mechanism
(handles, PURLs, ARKs, pick your poison), such that the software's URL
construction and the repo's domain name are the only address an item
has. Moving to new software without breaking URLs means a
URL-rewriting strategy at minimum. Changing domains, likewise -- and
the repo had better hang onto the old domain in order to continue
forwarding it; if its registration lapses, that's the end. About all I
can think of to make this easier is an effort to figure out
mod_rewrite rules for common software transitions, and even this is
dubious; moving to Fedora means the software no longer mandates the
form of URLs.
- The initial repository doesn't mint indirect URLs for aspects of the
system that turn out to need them. DSpace and bitstreams leaps to
mind; most DSpace devs will tell you that this is Working As Designed,
but I as a working repository manager will tell you that it is Broken
because like it or not, many people do prefer to link directly to
bitstreams.
- There's no easy way to mass-repoint indirect URLs. Frankly, the
handle system is black magic to me. I don't know how to do this. I
certainly should (as I have a migration in the offing myself). Better
documentation and perhaps a lightweight tool or two (that works off
something simple like a CSV file) for the major indirection systems
would assuredly help.
- The system (old or new) supports multiple URLs for the same object.
This can be done in Fedora. It obviously multiplies redirection
problems.
I'm probably missing some scenarios, but these are the ones that come to mind.
Dorothea
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Dorothea Salo [log in to unmask]
Research Services Librarian AIM: mindsatuw
University of Wisconsin
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(608) 262-5493
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