ez3950 SOAP

1
ez3950SOAP Z39.50

• ZIG December 2000 at LC
• Poul Henrik Jørgensen, DBC
• mailtophj_at_dbc.dk

2
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

3
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)

4
RPC Standards

• 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

5
Object RPC Elements

• Request
• Object Id
• Interface Id
• Method Id
• Extension Headers
• Parameter Data

• Response
• Status code
• Extension Headers
• Parameter Data

6
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)

7
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

8
SOAP HTTP Request

• POST /ZServ/Danbib HTTP/1.1
• Host zoap.dbc.dk
• Content-Type text/xml charset"utf-8"
• Content-Length 1234
• SOAPAction "urnez3950api"
• ltsoapEnvelope
• ...request parameters..
• lt/soapEnvelopegt

9
SOAP HTTP Response

• 200 OK
• Content-Type text/xml
• Content-Length 123
• ltEnvelope
• ...response data error reports...
• lt/Envelopegt

10
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 (GIRAPI) features
• Asyncronous Services excluded
• triggerResourceControlRequest
• segmentRequest

11
eZ3950 Methods

• Init
• search
• present
• deleteResultSet
• accessControl
• resourceControl

• resourceReport
• scan
• sort
• extendedServices
• close

12
eZ3950 Init Request

• ltSOAPEnvelope xmlnsSOAP"http//schemas.xmlsoap.
  org/soap/envelope/"
• xmlnsxsi"http//www.w3.org/1999/X
  MLSchema-instance"
• xmlnsxsd"http//www.w3.org/1999/X
  MLSchema"
• SOAPencodingStyle"http//schemas.
  xmlsoap.org/soap/encoding/"gt
• ltSOAPBodygt
• ltezinit xmlnsez"urnez3950api"
  version"1.0"gt
• ltezprotocolVersion xsitype"xsdstring"gt
• version-1 version-2lt/ezprotocolVersio
  ngt
• ltezoptions xsitype"xsdstring"gtsearch
  present scanlt/ezoptionsgt
• ltezpreferredMessageSiz
• xsitype"xsdint"gt16384lt/ezpreferred
  MessageSizegt
• ltezexceptionalRecordSize
  xsitype"xsdint"gt500000lt/ezexceptionalRecordSiz
  egt
• ltezimplementationId xsitype"xsdstring"gt1
  995lt/ezimplementationIdgt
• ltezimplementationName xsitype"xsdstring"
  gt
• OCLC z39.50 APIlt/ezimplementationNamegt
  
• ltezimplementationVersion
• xsitype"xsdstring"gt3.0lt/ezimplement
  ationVersiongt
• lt/ezinitgt
• lt/SOAPBodygt

13
eZ3950 Init Response

• ltSOAP-ENVEnvelope
• xmlnsSOAP-ENV"http//schemas.xmlsoap.org/soap
  /envelope/"
• xmlnsxsi"http//www.w3.org/1999/XMLSchema-ins
  tance"
• xmlnsxsd"http//www.w3.org/1999/XMLSchema"gt
• ltSOAP-ENVBodygt
• ltns1initResponse xmlnsns1"urnez3950api"
• SOAP-ENVencodingStyle"http//schemas.xmlso
  ap.org/soap/encoding/"gt
• ltreturn xsitype"ns1parm"gt
• ltimplementationId xsitype"xsdstring"gt"J
  AFER"lt/implementationIdgt
• ltidAuthentication xsitype"ns1idAuthenti
  cation" xsinull"true"/gt
• ltexceptionalRecordSize
• xsitype"xsdint"gt500000lt/exceptionalRe
  cordSizegt
• ltpreferredMessageSize
• xsitype"xsdint"gt16384lt/preferredMessa
  geSizegt
• ltimplementationVersion
• xsitype"xsdstring"gt"JAFER"lt/implemen
  tationVersiongt
• ltresult xsitype"xsdboolean"gttruelt/resul
  tgt
• ltoptions xsitype"xsdstring"gtsearch
  presentlt/optionsgt
• lt/returngt

14
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