- From: Ben Soares <Ben.Soares@ed.ac.uk>
- Date: Mon, 19 Apr 2004 14:56:42 +0100
- To: "NJ Rogers, Learning and Research Technology" <Nikki.Rogers@bristol.ac.uk>
- Cc: Alex Khokhlov <alex@lib.msu.ru>, "'Alan Kent'" <ajk@mds.rmit.edu.au>, www-zig@w3.org
Hello all, Nikki's description of Xgrain project/GetRef service is accurate, though let me expand a little as I'm one of the developers. The focus of GetRef is on Abstracting & Indexing databases available to the UK HE/FE (mainly HE), though of course the technology could be deployed elsewhere. GetRef provides a brokering service with (currently) a web interface and a Z39.50 target. Searches on these get distributed concurrently across the list of configured end-resources (which the end-user is authorised to use, since most of the resources require an institutional subscription). We intend to create an SRW/U service on top of this too. Only a few access-points are searchable, but this is perhaps the nature of cross-searching large numbers of resources. Incidentally, the modular nature of construction means that the end-resources do not need to be Z39.50 targets themselves, though that seems to be the most popular means of m2m searching. We are currently developing screen-scraping (ugh!) capabilities where necessary. The authentication/authorisation issues are no minor part either! The returned records are normalised into something hopefully still useful. Having a focus on A&I dbs is a help here. As for client notification, this isn't available in the Z30.50 target, though we may look into it in future. I hadn't realised that there was a prescribed way of doing this in Z39.50 and have been reading this thread with interest. We were thinking more along the lines of adding additional functionality to an SRW service (on the appropriate hooks) to allow "query-monitoring" and perhaps linking this to Z39.50 queries too (so you could make a query with a simple zclient, and monitor its progress using SOAP queries...?). We've been working with SPP to make the Z39.50 server more useful in terms of its cross-search functionality (must resume this!). I would quite like to see us also create some kind of unbuffered event-driven SOAP response which could provide a single query with a single response with realtime information, though I suppose the client would have to be threaded to make good use of that, and it probably wouldn't allow for retrieval of records before the whole search had finished. Our web interface allows result components to be reported as they happen, and for searches to be put in the background whilst existing records are viewed, though this is just using internal communication. Unfortunately there are no plans to make the Xgrain/GetRef code open source :( See <http://edina.ac.uk/getref/> for more details! Ben On Mon, 19 April, 2004 13:07, NJ Rogers, Learning and Research Technology wrote: > Hi > > >> My curiosity was a little different - I was wondering how to expose > >> a Z39.50 interface instead of a web interface. That is, develop a > >> server that allowed Z39.50 clients to access it where the server > >> forwarded requests on to all the remote servers, did the query > >> translations, record normalization, etc. > > Just for information - some projects here in the UK (HE/FE) that are > probably relevant to your discussion: > > 1) The EDINA GetRef service > http://edina.ac.uk/getref/ > (was previously the Xgrain project - > http://edina.ed.ac.uk/projects/joinup/xgrain/) > This represents a broker service - to remote Z39.50 and other services. > > 2) The Subject Portals Project > http://www.portal.ac.uk/spp/ > > I am a developer on 2). We have developed a xsearch portlet for 2), the > functionality of which will ultimately be abstracted. Hence it will > represent a cross-searching client in essence, capable of concurrently > searching Z39.50 (and other types of) targets. In developing this > xsearch portlet we have also targeted 1) as a means of including > additional multiple targets via a broker. There have been lots of issues > along the way, these will get documented as project outputs and I believe > the source code will be made freely available (not sure which license > yet!) at the project end. The project (2) will conclude August of this > year. > > Nikki > -- Ben Soares tel: +44 (0)131-651 1238 EDINA, Edinburgh University Data Library fax: +44 (0)131-650 3308 Main Library Building, George Square email: ben.soares@ed.ac.uk Edinburgh EH8 9LJ, Scotland, UK www: http://edina.ac.uk/ "Hmmm, that makes no sense to me... But then you are very small, perhaps you're right." -- Treebeard
Received on Monday, 19 April 2004 09:57:42 UTC