ez3950 SOAP & Z39.50 ZIG December 2000 at LC Poul Henrik Jørgensen, DBC

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC2 Background & Objectives Z39.50 Difficult to understand and debug – Use human-readable encoding Technology seems obscure to implementors – Adopt emerging XML standards Ignored by mainstream development tools – Use widespread XML tools Object Oriented development paradigma – Specify Object RPC API

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC3 Communication Models Message-passing with optional queuing – E.g. ISO ILL (almost) – Applications must handle asynchronous messages from concurrent external processes Request/Response – E.g. Z39.50 (almost) – Client initiates request and waits for matching response from remote process – Resembles Remote Procedure Calls (RPC)

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC4 RPC Standards – SUN RPC, e.g. Network File System NFS – DCE RPC, e.g. Windows NT – HTTP Object RPC Standards – CORBA Internet Inter-Orb Protocol, IIOP – MS Distributed COM, DCOM

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC5 Object RPC Elements Request Object Id Interface Id Method Id Extension Headers Parameter Data Response Status code Extension Headers Parameter Data

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC6 SOAP Overview HTTP supports most of the same functions as IIOP and DCOM (framing, connection management, object references) XLM is well suited to represent to represent parameter data (cf. NDR and SOAP = HTTP (transport) + XML (parameter encoding)

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC7 SOAP Elements HTTP Header – Request URI: SOAP ClassId and ObjectId – SOAPAction: InterfaceId and Method SOAP Envelope (XML Structure) – Header (Optional protocol data) – Body RPC Parameters Error Reports

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC8 SOAP HTTP Request POST /ZServ/Danbib HTTP/1.1 Host: zoap.dbc.dk Content-Type: text/xml; charset="utf-8" Content-Length: 1234 SOAPAction: ="urn:ez3950:api" <soap:Envelope...request parameters..

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC9 SOAP HTTP Response 200 OK Content-Type: text/xml Content-Length: 123 <Envelope...response data & error reports...

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC10 eZ3950: Z39.50 over SOAP Specification of e-Z39.50 API Complete Z39.50 Protocol over SOAP ASN.1 encoded by XER General IR API (GIR:API) features Asyncronous Services excluded – triggerResourceControlRequest – segmentRequest

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC11 eZ3950 Methods Init search present deleteResultSet accessControl resourceControl resourceReport scan sort extendedServices close

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC12 <SOAP:Envelope xmlns:SOAP=" xmlns:xsi=" xmlns:xsd=" SOAP:encodingStyle=" version-1 version-2 search present scan <ez:preferredMessageSiz xsi:type="xsd:int"> OCLC z39.50 API <ez:implementationVersion xsi:type="xsd:string">3.0 eZ3950 Init Request

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC13 <SOAP-ENV:Envelope xmlns:SOAP-ENV=" xmlns:xsi=" xmlns:xsd=" <ns1:initResponse xmlns:ns1="urn:ez3950:api" SOAP-ENV:encodingStyle=" "JAFER" <exceptionalRecordSize xsi:type="xsd:int"> <preferredMessageSize xsi:type="xsd:int">16384 <implementationVersion xsi:type="xsd:string">"JAFER" true search present eZ3950 Init Response

eZ3950 / Dec. 2000Poul Henrik Jørgensen, DBC14 Benefits of eZ3950 Supports entire Z90.50 protocol XER standard with tools to encode ASN.1 Readable XML encoding of Z39.50 Object RPC model of Z39.50 services Platform independent API for e-Z39.50 Tools from major vendors Acceptance among developers and executives