[ZOOM] Web Services binding (Was: Responses to Qns)

Robert Sanderson azaroth at liverpool.ac.uk
Wed Jul 17 14:26:42 CEST 2002


For people not interested in SRW/SRU or just don't have a clue what we're 
talking about, I apologise and feel free to ignore this message :)

> > It probably depends on your level of internal abstraction... I tend
> > top think of an abstract framework for talking about Z39.50-like IR
> > operations which happens to be expressed in OO-like concepts.
> Quite.
> Here's how I see it working.  "Creating a connection" in the putative
> WS binding is essentially a matter of asking the server for an opaque
> cookie to act as a connection handle.  That's your "object": you
> submit that along with other parameters to do a search, and what you
> get back includes another opaque cookie which is the "object"
> representing the result set.  It might look like this:

Can we wait for SRW v1.0 before making any decisions on this sort of 
thing?  It really is a vastly vastly improved spec on the draft and I 
think that it would be much preferable to have one web service definition 
rather than multiple.

> The meta-questions that springs to mind here is: to what extent are we
> reinventing SRU?  How close is what we're proposing to the SRU
> proposal?  If the answer is "pretty damned close" then should we (A)
> abandon work, or (B) carefully massage our parameter names and
> defaults so that they closely resemble SRU, then kidnap SRU and
> rebrand it as "the web-services binding for ZOOM"?

A couple of things that got decided were that SRW and SRU are not the same 
protocol with different bindings. SRW is SOAP based and doesn't cater to 
the idiosyncracies of the URL restrictions any more.  There's also TWO 
forms of CQL now, an XML encoded version and a plain text version. Ditto 
for the sort spec.  

So you know what?  If you wanted to add in a third type 1 query in PQN, 
it's not that hard to do as the query parameter can already accept CQL 
string or XCQL xml.


Obligatory Disclaimer:
   A lot of my hand here is being played from politics, not from technical 
merit.  It would be a much easier sell if there was a simple, existing 
object oriented interface for both Z39.50 and an approved web service in 
one box.  Technical Merit would say to forget it as we have Z which is far 
better than web services anyway.  SRW looks like the one to go with as 
it uses enough of the Z39.50 architecture and models to be useful and 
easily interoperable while also having enough buzzwords to impress people 
who aren't impressed by BER and ASN.1


Rob

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      ,'/:.          Rob Sanderson (azaroth at liverpool.ac.uk)
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