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Re: [Handle-info] Handle as PID :Was: Please help me understand the value of Handle

You may find it useful to look at the 'raw' version of the handle that Sean is using in his examples, to see what is going on there.

If you address the hdl.handle.net proxy with no arguments at all, i.e.,

http://hdl.handle.net/

you'll see a query page in which you can type or paste a handle and check a box that says

Don't Redirect to URLs

This will show you a formatted version of the handle record. For Sean's examples, just use the handle without the parameters -- 200/0

The parameters, e.g., type=urn, are for the proxy, and aren't part of the handle record. Having the proxy select handle values of a certain type is just one possible use of types -- other client applications could, and have been, built that also key off the various types.

The most common use of non-URL types is probably internal to the handle system - the core handle client will begin any resolution by either examining a cache or contacting the global root to find where to go to resolve any handle. It gets this by resolving the prefix. All handle prefixes, e.g., the 200 in 200/0 are held in the global root as handles of the form 0.NA/someprefix, e.g., 0.NA/200. If you follow that handle using the technique described above you'll find a type called HS_SERV. This is the type for the handle service responsible for all handles starting with 200. The value of that type is generally another handle and if you resolve that handle you'll find one or more type/value pairs for HS_SITE, which is a binary data structure containing the specifics of IPs, ports, hashing schemes, etc., that the client uses to get the end resolution of the handle. 200 may be a confusing prefix to use, since its homed in the root service, but you should be able to follow that pattern for any handle.

Larry


On Mar 29, 2007, at 4:25 AM, Sean Reilly wrote:


On Mar 28, 2007, at 2:42 PM, Konstantin Rekk wrote:
Is there any working demonstration for a use case including general
type/value pairs? May be using the proxy (or extending it) by providing
get-attributes within request
A theoretical example: providing urn and not url, something like
http://hdl.handle.net?type=urn -> gives a urn-redirect (if browser
supports it) -
one thinkable application (don't know if that makes sense) of this could
be to store handles for resources which are provided by external
repositories and which
are using urns;
instead of urn one could also use ppn (production numbers) for the
library catalog entry, so handle system would provide a two directional
link between digital object and catalog entry ...

Hi Konstantin,

Some of the parameters that can be passed to the proxy are described here:
http://www.handle.net/proxy.html

There are also additional parameters that the proxy understands, some of which are supported and some are not (meaning they could go away or how they work could change).

One parameter that I think is supported is "type," as in your example. So you can tell the proxy to resolve handle values that have a type that is provided in the URL. For example, if you want to resolve the handle 200/0 and redirect to the value with the type of "URL.A" then you can do:
http://hdl.handle.net/200/0?type=URL.A

You can also give it the type URN:
  http://hdl.handle.net/200/0?type=URN

but the proxy currently doesn't understand that URN is a redirect- able type so it just displays the value instead of sending an HTTP redirect. The proxy will currently send an HTTP redirect for values with type URL or that start with "URL."

I think this list is a good place to post and discuss additional features that you'd like to see, in case the feature described above don't cover your needs.

Thanks,
Sean



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