In Introduction to Web Services. Publish-Find-Bind Consuming Program Service Requestor Service Provider http transport SOAP message Service Registry UDDI.

In Introduction to Web Services

Publish-Find-Bind

ConsumingProgram

Service Requestor

ServiceProvider

http transport

SOAPmessage

Service Registry

UDDI

Discover services

SOAPmessagehttp transport

Publish services

WSDLdescribing

service

SOAP Message•Body - Payload

•Why header?

• Extensibility

• Control/meta Information

•Header is optional

•SOAP Intermediaries

<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope">

<env:Header>

...</env:Header>

<env:Body>

... </env:Body>

</env:Envelope>

SOAP ArchitectureService

implementationapplication levelClient application

code

Server skeleton

XML unmarshallerClient stub

XML marshaller

TCP/IP socket

remoting architecture level

wire protocol levelhttp protocol httpserver

httpclient

body

envelopeheader header

buyer

seller

seller

seller

messagebroker

RFQ

QuoteResponse

Award

Conversational Message Exchange

Conversational Message Exchange: A Request

<?xml version='1.0' ?>

<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope">

<env:Header> <r:RFQNum xmlns:r=“…” env:mustUnderstand=“true”>101</r:RFQNum><r:custNum env:mustUnderstand=“true”>17</r:custNum></env:Header>

<env:Body><r:RFQ xmlns:r=“http://bigco.example.org/RFQ”>

<r:manufacturer>SanDisk</r:<Manufacturer><r:productname>SecureDigital memory</r:productname><r:size>1GB</r:size><r:quantity>100</r:quantity>

</r:RFQ></env:Body>

</env:Envelope>

Conversational Message Exchange: A Response

<?xml version='1.0' ?>

<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope"> <env:Header>

<r:RFQNum xmlns:r=“http://bigco.example.org/RFQ”>env:mustUnderstand=“true”>101</m:RFQNum><r:vendorID env:mustUnderstand=“true”>2470</r:vendorID><r:bidNum env:mustUnderstand=“true”>1</r:bidNum><r:custNum env:mustUnderstand=“true”>17<r:custNum>

</env:Header>

<env:Body><r:quoteResponse xmlns:r=“http://bigco.example.org/RFQ”>

<r:manufacturer>KingMax</r:<Manufacturer><r:productName>SecureDigital memory</r:productname><r:size>1GB</r:size><r:speed>9000KB/s</r:speed><r:SKU>KM-SD1000</r:SKU><r:quantity>100</r:quantity>

</r:quoteResponse></env:Body>

</env:Envelope>

Conversational Message Exchange: Completion

<?xml version='1.0' ?>

<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope">

<env:Header> <r:vendorID env:mustUnderstand=“true”>2470</r:vendorID>

<r:bidNum env:mustUnderstand=“true”>1</r:bidNum>

<r:custNum env:mustUnderstand=“true”>17<r:custNum>

</env:Header><env:Body>

<r:Award xmlns:r=“http://bigco.example.org/RFQ”>

<r:SKU>KM-SD1000</r:SKU>

<r:quantity>50</r:quantity>

</r:Award>

</env:Body>

</env:Envelope>

SOAP Faults

• Place faults inside env:Body elements

• env:Fault Element:

• env:Node identifies node which generated fault• Absence indicates “ultimate recipient”

• env:Code • env:Value• env:Subcode

• env:Reason• env:Text

• env:Detail• Application specific

SOAP Fault Examples<env:Body>

<env:Fault> <env:Code>

<env:Value>env:Sender</env:Value> <env:Subcode>

<env:Value>rpc:BadArguments</env:Value></env:Subcode>

</env:Code> <env:Reason>

<env:Text xml:lang="en-US">Processing error</env:Text> <env:Text xml:lang="cs">Chyba zpracování</env:Text>

</env:Reason> <env:Detail>

<e:myFaultDetails xmlns:e=http://shippingservice.org/fault><e:message>Unknown destination</e:message> <e:errorcode>999</e:errorcode> </e:myFaultDetails>

</env:Detail> </env:Fault>

</env:Body>

SOAP Bindings• Transport of SOAP messages from one SOAP node to another

• Serialized representation of the message POST /Reservations HTTP/1.1Host: marketplace.example.orgContent-Type: application/soap+xml; charset="utf-8"Content-Length: nnnn<?xml version='1.0' ?><env:Envelope xmlns:env=”...”><env:Body>…

From: [email protected]: [email protected]: RFQ: Memory purchaseDate: Thursday, September 9 2004Message-Id: <[email protected]>Content-Type: application/soap+xml<?xml version='1.0' ?><env:Envelope xmlns:env=”...”><env:Body>…

WSDL: Introduction• Contract of a web service published by the provider• XML-based Service Description • W3C Candidate Recommendation

• Describe a Web Service?• Operations• Message Exchange Pattern• Messages• Protocol, Address

• WSDL Approach:• Abstract service description• Concrete network protocol and message format• Binding [Abstract -> Concrete]

WSDL: Specification<definitions

name="StockQuote" … >

<types>…</types>

<message>…</message>

<portType>

<operation>

…

</operation>

</portType>

<binding>…</binding>

<service>…</service>

</definitions>

types

message message message

operation

portType/interface

operation operation

binding

serviceport / endpoint

WSDL TypesData type definitions using some type system (such as XSD)

<types> <schema targetNamespace=“…“ xmlns="http://www.w3.org/....">

<complexType name=“StockIdentifier">      <sequence>        <element name=“Symbol“ type="xsd:string"/>        <element name=“StockMarket“

type="xsd:sting"/>      </sequence></complexType>

</schema></types>

External Schemas can be imported into the WSDL

<import namespace="http://example.com/stockquote/schemas" location=http://example.com/stockquote/stockquote.xsd />

WSDL PortType, Operation, Message

<portType name="StockPriceInterface">

<operation name=“GetStockPrice">

<input message="tns:GetStockPriceInput"/>

<output message="tns:GetStockPriceOutput"/>

</operation>

</portType>

<message name="GetStockPriceInput">

<part name=“stock" element=“xsd1:StockIdentifier"/>

<part name=“time" element="xsd:date"/>

</message>

<message name="GetStockPriceOutput">

<part name=“stock" element=“xsd1:StockIdentifier"/>

<part name=“value" element="xsd:float"/>

</message>

WSDL Binding• Maps the abstract service functionality to a specific network protocol and

message format

• Bindings defined for HTTP, SMTP etc..

<binding name="StockQuoteSOAPBinding" type="tns:StockQuotePortType">

<soap:binding style="document“ transport="http://schemas.xmlsoap.org/soap/http"/>

<operation name="GetStockPrice"><soap:operation soapAction="http://example.com/GetStockPrice"/>

<input><soap:body use="literal"/></input> <output><soap:body use="literal"/></output>

</operation>

</binding>

<service name="StockQuoteService">

<documentation>My first service</documentation>

<port name="StockQuotePort" binding="tns:StockQuoteSOAPBinding">

<soap:address location="http://example.com/stockquote"/>

</port>

</service>

WSDL Ports and Services

Port: A single endpoint defined as a combination of a binding and a network address.

Service: A collection of related endpoints.

WSDL Binding Example:One-way Over SMTP<message name="SubscribeToQuotes">

<part name=“subsBody" element="xsd1:SubscribeToQuotes"/>

<part name="subsHeader"element="xsd1:SubscriptionHeader"/>

</message>

<portType name="StockQuotePortType">

<operation name="SubscribeToQuotesOper"> <input message="tns:SubscribeToQuotes"/>

</operation>

</portType>

<binding name="StockQuoteSoap" type="tns:StockQuotePortType">

<soap:binding style="document" transport="http://example.com/smtp"/><operation name="SubscribeToQuotesOper">

<input message="tns:SubscribeToQuotes"> <soap:body parts=“subsBody" use="literal"/> <soap:header part="subsHeader" use="literal"/>

</input> </operation>

</binding>

<service name="StockQuoteService">

<port name="StockQuotePort" binding="tns:StockQuoteSoap"> <soap:address location="mailto:[email protected]"/>

</port>

</service>

UDDI

• Universal Description, Discovery and Integration

• businessEntity - Provider of service

• businessService - Collection of related services

• bindingTemplate - Information necessary to use

• tModel - “reusable concept” such as• Interface• Protocol used by web services• Category

• publisherAssertion - Relationship that business entity has with another businessEntity

• UUID (Universally Unique IDs) as Keys• businessKey, serviceKey, bindingKey , tModelKey

businessService

businessService

Interface tModelbindingTemplate

bindingTemplate

businessEntity

bindingTemplate

Interface tModel

Core UDDI Entities

tModels

• The “technical fingerprint”• tModel’s define unique identifiers for interfaces and interface

specifications• Once tModel is published service advertises compliance with the

spec represented by including the correct tModelKey

• Value sets• Categorization hierarchies• E.g. categoryBag and identifierBag have references to tModels with

the system of values

UDDI APIs• Inquiry

• Browse: find_xx• Drill-down: get_xx

• Invocation• Use browse and drilldown and get bindingTemplate• Invoke from bindingTemplate

• Publication• save_xx• delete_xx

• Subscription, Security, Custody Transfer, Replication

<find_business xmlns="urn:uddi-org:api_v3">

<findQualifiers><findQualifier>uddi:uddi.org:findqualifier:approximatematch</findQualifier>...

</findQualifiers>

<categoryBag><keyedReference keyValue="34.10.%“

tModelKey="uddi:uddi.org:ubr:categorization:unspsc"/></categoryBag>

</find_business>

Mapping WSDL to UDDI

The value proposition of SOA• Implement SOA for two major reasons.

• First is the ability to save development dollars through reuse of services.

• Second is the ability to change the IT infrastructure faster to adapt to changing needs of the business, or agility.

The vision: a true SOA Scenario•Describe the semantics of a client’s need

•Discover a provider of this need or compose multiple services dynamically

•Dynamically understand the protocol of messages to be exchanged with the provider

•Negotiate terms of use of a Service

•Move from one provider to another seamlessly

SOA Fabric Requirements

• Publish-Find-Bind paradigm++• Semantics (IOPE)• Context awareness• Trust models• Declarative and dynamic composition• Fabric services similar to “middleware services” of the

past• Transactions, naming etc. • Non repudiation• Metering and Billing (S-Commerce)• Differentiated service levels along with dynamic

provisioning of services

Whither WS?

• Many new standards are being formulated that extend WS with these capabilities• WSRF – for stateful interactions• WS Policy – Capabilities and constraint specification• C-WSDL – Context awareness • WS-Coordination – Orchestration• WS-Transactions – Transaction API

• Impact?• Certainly extend it’s usefulness• But …..