Date:Wed, 9 Jan 2002 15:53:32 -0000
Reply-To:"Z39.50 Next-Generation Initiative" <[log in to unmask]>
Sender:"Z39.50 Next-Generation Initiative" <[log in to unmask]>
From:Matthew Dovey <[log in to unmask]>
Subject:Re: test server SRU
Comments:To: "Z39.50 Next-Generation Initiative" <[log in to unmask]>
Content-Type:text/plain; charset="us-ascii"
I'm not convinced that the WSDL description per se cannot be left
defining the contact of the record body to be defined externally and
hence returned in the example given.
The problem is that this makes it trickier to use standard SOAP toolkits
which would build the source code from the WSDL.
Matthew
> -----Original Message-----
> From: LeVan,Ralph [mailto:[log in to unmask]]
> Sent: 09 January 2002 15:40
> To: [log in to unmask]
> Subject: Re: test server SRU
>
> I second Alan's comment about the SOAP wrapper for an SRU response.
It is
> completely inappropriate. The response should have been a
> ZNG:searchRetrieveResponse. The SOAP wrappers only happen in SRW.
>
> I definitely want a single WSDL description for the entire service.
> (Though, each of us will have our own tailored version with local
address
> information and we will have a separate one for each database.) It's
not
> clear to me why we would have to embed the schema into the WSDL, but
doing
> so would be bad.
>
> Ralph
>
> > -----Original Message-----
> > From: Alan Kent [mailto:[log in to unmask]]
> > Sent: Tuesday, January 08, 2002 5:55 PM
> > To: [log in to unmask]
> > Subject: Re: test server SRU
> >
> >
> > On Tue, Jan 08, 2002 at 02:36:26PM -0500, Larry E. Dixson wrote:
> > > Theo,
> > > I wanted to report that I was able to successfully retrieve and
> > > display records from your test server.
> > >
> > > For example:
> > >
> > http://redbelly.bk.nl/cgi-zoek/srw.pl?query=vrml&recordSchema=
> > dc_record&collection=DUTC
> > > retrieved the following:
> > >
> > > <SOAP-ENV:Envelope xmlns:zng="urn:z3950:zng_prototype1"
xmlns:SOAP-
> > > ENV="http://schemas.xmlsoap.org/soap/envelope/" SOAP-
> > > ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
> > > <SOAP-ENV:Body>
> > > <zng:searchRetrieveResponse>
> > > <zng:resultSetReference>
> > > <zng:resultSetName>200218.108.kqf</zng:resultSetName>
> > > </zng:resultSetReference>
> > > <zng:totalHits>1</zng:totalHits>
> > > <zng:query>vrml</zng:query>
> > > <zng:setLimit>3000</zng:setLimit>
> > > <zng:records>
> > > <zng:record>
> > > <zng:recordNumber>0</zng:recordNumber>
> > > <zng:recordId>DUTC:4612</zng:recordId>
> > > <zng:schema>dc_record</zng:schema>
> > > <zng:recordData>
> > > <rdf:Description
> > xmlns:dc="http://purl.org/dc/elements/1.1/"
> > >
> > xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns">
> > > <dc:creator>Margulies, Stephen</dc:creator>
> > > <dc:creator>Bauman, Johanna</dc:creator>
> > > <dc:title>The power of woe, the power of life
> > : Images of
> > > women in prints from the Renaissance to the
> > > present</dc:title>
> > > <dc:date>1999</dc:date>
> > > </rdf:Description>
> > > </zng:recordData>
> > > </zng:record>
> > > </zng:records>
> > > <zng:status>
> > > <zng:statusCode>0</zng:statusCode>
> > > </zng:status>
> > > </zng:searchRetrieveResponse>
> > > </SOAP-ENV:Body>
> > > </SOAP-ENV:Envelope>
> >
> > First its great to see people having a go at implementing things. So
I
> > am not trying to criticise - just work out issues as we go along.
> >
> > But I am a little confused - mainly about goals. I don't have any
> > immediate plans for SRU (that is, the URL version). But the above
> > response packet seems to be a mix of SOAP and other things.
> >
> > For example, I believe with *SOAP* (and SRW) that the most robust
> > approach for recordData is going to be as a string (I may be wrong).
> > As such, all the tags would need to be released with < etc inside
> > the <zng:recordData> element. One reason was that SOAP does not
> > permit all of XML - for example processing instructions are
> > not permitted in SOAP, so to allow all valid XML records inside
SOAP,
> > using string is the safest way to go.
> >
> > The thing with SOAP is that if you use a toolkit, the fact that
> > SOAP uses XML to encode packets is irrelevant. No-one looks at
> > SOAP packets. SOAP has lots of weird decoding rules that mean
> > you would never want to apply an XSLT style sheet to a SOAP packet.
> > Also, only a subset of the SOAP toolkits support document/literal
> > encoding (which is the closest thing to the packet above).
> > So its not an ideal choice in terms of implementations.
> > So I recommend putting XML in SOAP as a string and let the
application
> > parse the string as XML.
> >
> > But for SRU it is clearly very useful to return records as XML.
> > So I think its probably wrong to put SOAP-ENV:Body and
> > SOAP-ENV:Envelope
> > wrappers around the whole packet.
> >
> > Maybe what should be done is to define XML schemas for the data
> > structures, where the schema is reused between WSDL (for SOAP)
> > and SRU (the URL scheme). But its important to realise that in
> > SOAP a WSDL schema *does not* define the wire representation of
> > XML in SOAP packets (confusing, possibly stupid, but true). It
> > defines an abstract data structure that SOAP then defines its
> > own encoding rules for (unless you use document/literal encoding).
> >
> >
> > I have previously put forward the opinion that using strings for
> > record data is the best approach with SOAP.
> >
> > However, there is the alternative of document/literal encoding.
> > One alternative approach that has some attractiveness is to say
> > - use document/literal encoding for record data
> > - require that all record data in SRW/SRU have an XML schema defined
> > - don't allow record data to contain processing instructions
> >
> > I guess put another way, do people want to be able to insert
arbitary
> > XML documents in as record data to be returned, or is it acceptable
> > to say with SRW/U that record data must have an XML schema defined
> > and PI's are not supported.
> >
> > Oh, there is another ramification by the way - do we want a single
> > WSDL file (for SRW/SOAP anyway) that represents SRW? If so, then
> > record XML schemas cannot go in there - because you will have a
> > different WSDL file per record XML schema. So there will be no
> > standard file. If you make recordData a string, then you can have
> > a single standard WSDL file for SRW.
> >
> > I personally still lean towards a single SRW WSDL file, possible
> > only by using string for record data (unless someone can show
> > me how!).
> > In that case, maybe SRU should be based on use of XML schemas and
> > not WSDL files. I thought SRU was for people without SOAP toolkits
> > around (just a HTTP client), so you want nice clean XML coming back,
> > not complex SOAP packets.
> >
> > Alan
> >
