eCommerce Technology 20-751 Lecture 14: Web Services

20-751 ECOMMERCE TECHNOLOGY

SUMMER 2002

COPYRIGHT © 2002 MICHAEL I. SHAMOS

eCommerce Technology20-751

Lecture 14:Web Services


SUMMER 2002


Machine-to-Machine M2M Commerce

• There are more machines than people• Machines are always becoming more functional

(Moore’s law)• Intelligent agents exist• More commerce will be occur between machines

than between people• Commerce machines must discover each other and

be able to do business (common language)


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Human Web v. Transactional Web

• They’re the same hardware, different software• WWW was designed to be accessed by humans

– browsers• Protocols needed to allow machines to access

information• Need to run software resident on other systems and

networks

B2B Much More Complicated Than B2C

B2CB2C ChooseVendorChooseVendor

Select& OrderSelect

& OrderProcess

CreditCard

Process CreditCard

ShipShip

B2BB2B Review CatalogsReview

CatalogsIdentify

SpecificationsIdentify

SpecificationsSend RFP

Send RFP

Select VendorSelect Vendor

ApproveP.O.

ApproveP.O.

Set Up CreditSet Up Credit

Define Requirements

Define Requirements

Review VendorsReview Vendors

Fill Out P.O.

Fill Out P.O.

Send P.O. to VendorSend P.O. to Vendor

Letter of Credit / Terms

Letter of Credit / Terms

Prepare Fulfillment

Prepare Fulfillment

Generate P.O. Receipt

Generate P.O. Receipt

Check Availability

Check Availability

Send OrderSend Order

InspectionsInspections Receive Order

Receive Order

Prepare InvoicePrepare Invoice

Send InvoiceSend

Invoice

Receive Invoice / Prepare PaymentReceive Invoice / Prepare Payment

Arrange ShippingArrange Shipping Tariffs /

CustomsTariffs /

CustomsPost

PaymentPost

PaymentSend

CheckSend

Check

SOURCE: METALSITE


SUMMER 2002


Web Services

• Self-contained, self-describing applications• Created using familiar programming languages (Java)• Published, located and invoked over the Web using Web

service interface standards• By machines• Function may be very simple or very complicated• Examples:

– a foreign currency converter– stock quotations, analysis– product recommender agent– freight forwarder


SUMMER 2002


Example: Shopping Cart Checkout

ShoppingCart

TaxCalculation

ShippingCalculation

DiscountCalculation

Services may reside somewhere else, provided by someone else


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Web Services Example

BUYERSERVICE

SELLERSERVICE

OUT IN

IN OUT

1ORDER

3GOODS

CreditValidation

Service

2VALIDATE

A Buyer Service is ordering goods from a Seller Service.

The Seller Service may need to use other web services to accept and process the order

SOURCE: HEATHER KREGER, IBM


SUMMER 2002


CreditValidationService

InventoryManagement

Service

CustomerAccounting

Service

IN OUT

BuyerService

SellerService

Private Flow

Public Flow

PublicCredit Service Step 1 Step 2 Step 3

Public v. Private Workflows



SUMMER 2002


Six Properties of a Web Service

• IBM definition:

– self-contained

– self-describing

– modular applications

– published

– located

– invoked across the web

object-oriented

WSDLWEB SERVICESDESCRIPTION LANGUAGE

UDDI UNIVERSAL DESCRIPTIONDISCOVERY AND INFORMATION

SOAP or XML-RPC

SIMPLE OBJECTACCESS PROTOCOL

XML REMOTEPROCEDURE CALL

SOURCE: OBJECTIVE SOLUTIONS


SUMMER 2002


UDDI Summary

UDDI Business Registry

3. UBR assigns a unique identifier to each service and business registration

Marketplaces, search engines, and business apps query the registry to discover services at other companies

4.

Service TypeRegistrations

Companies, standards bodies, and programmers populate the registry with descriptions of different types of services

1.

BusinessRegistrationsBusinesses

populate the registry withdescriptions of the services they support

2.

Business uses this data to facilitate easier integration with each other over the Web

5.

SOURCE: UDDI.ORG

WebServices Client

ClientFunction

Stub

Publishing and Using Web Services

UDDI Registry

White

Yellow

Green

WSDL Descriptions

WebService

WebServer

BusinessFunction

ApplicationServer

Find

ServiceDescription

(WSDL)

Publish

WSDL

Bind +Business Methods

Web Service Provider


Web Services In Action

WebService

Consumer Web

ServiceProvider

UDDI

http://myservice.com/service

XML/SOAP body

Let’s talk (SOAP)

http://myservice.com?wsdl

Service descriptions

How do we talk? (WSDL)

http://www.uddi.org

Link to WSDL document

Find a web service provider (UDDI)

SOURCE: SIMON HUTSON, KPMG


SUMMER 2002


Simple Web Services Workflow

BUYERSERVICE

SELLERSERVICE

OUT IN

IN OUT

ORDER

GOODS

A Buyer Service is ordering goods from a Seller Service.

The Seller Service interface is defined using WSDL.

Buyer Service invokes the “order” method on the seller service using SOAP and the WSDL definition for the seller service.

The Buyer Service knows what to expect in the SOAP reply message. This is defined in the Seller Service WSDL.



SUMMER 2002


Architectural Overview

• Web service is a standards-based façade• Wrapper for accessing non-standardized applications

List

en

erXML Request

XML Response

Web Server

mid

dle

ware

BusinessService

WebService


HTTP

HTTP

• Web services are invoked by sending text files over HTTP


SUMMER 2002


Invoking a Web Service

• Client queries a UDDI registry node• Server returns a list of records matching request• Client identifies a specific service of interest• Server “binds” client to the service so client can invoke the

methods of the service

Clientapplication

Web

server

UDDIregistrynode

SOAPprocessor

UDDI registryservice

UDDIdatabase

SOAP request

SOAP response


MACHINEMACHINE


SUMMER 2002


Simple Object Access Protocol (SOAP)

• SOAP demo• UDDI demo• Amazon search• Google search• Digital signature demo• xmethods.com

http://www.soapclient.com/soapclient.com/soaptest.html

http://www.soapclient.com/uddiadv.html

http://www.soapclient.com/AmazonSearch.html

http://www.soapclient.com/googleSearch.html

http://www.soapclient.com/SoapSecurity.html

http://www.xmethods.com/

http://www.xmethods.com/

Types: xSchema definition of data

Port Types

Service

Port

Binding

Operations

Messages

Types

<types><schema

targetNamespace="http://example.com/stockquote.xsd"xmlns="http://www.w3.org/2000/10/XMLSchema"><element name="TradePriceRequest">

<complexType><element name="tickerSymbol" type="string"/>

</complexType></element><element name="TradePrice">

<complexType><element name="price" type="float"/>

</complexType></element>

</schema></types>

SOURCE: FRANK ROBINSON. SILVERSTREAM

Messages: Collections of Types

Port Types

Service

Port

Binding

Operations

Messages

Types

<message name="GetLastTradePriceInput"><part name="body" element="xsd1:TradePriceRequest"/>

</message>

<message name="GetLastTradePriceOutput"><part name="body" element="xsd1:TradePrice"/>

</message>


Operations: Available Methods

Port Types

Service

Port

Binding

Operations

Messages

Types

<operation name="GetLastTradePrice"><soap:operation

soapAction="http://example.com/GetLastTradePrice"/><input>

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

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

</operation>


Port Types: XML Method I/O

Port Types

Service

Port

Binding

Operations

Messages

Types

<portType name="StockQuotePortType"><operation name="GetLastTradePrice">

<input message="tns:GetLastTradePriceInput"/><output message="tns:GetLastTradePriceOutput"/>

</operation></portType>

Maps Operations to Messages


Binding: Maps Protocols to Methods

Port Types

Service

Port

Binding

Operations

Messages

Types

<binding name="StockQuoteSoapBinding“type="tns:StockQuotePortType"><soap:binding style="document“

transport="http://schemas.xmlsoap.org/soap/http"/><operation name="GetLastTradePrice">

<soap:operation soapAction="http://example.com/GetLastTradePrice"/><input>

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

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

</operation></binding>


Port: Maps URLs to Methods

Port Types

Service

Port

Binding

Operations

Messages

Types

<port name="StockQuotePort" binding="tns:StockQuoteBinding"><soap:address location="http://example.com/stockquote"/>

</port>


Service: Packages Ports & Bindings

Port Types

Service

Port

Binding

Operations

Messages

Types

<service name="StockQuoteService"><documentation>My first service</documentation><port name="StockQuotePort"

binding="tns:StockQuoteBinding"><soap:address

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

</service>



SUMMER 2002


Web Service Definition Language (WSDL)

• A WSDL file contains details in XML about provider (server) services

• For each service, WSDL describes the set of allowed operations

• For each operation, WSDL describes the formats of messages exchanged between the requesting consumer (client) and the provider (server)– to request the service; and– to interpret the results (output) of the service

SOURCE: ELIOT CHRISTIAN, USGS


SUMMER 2002


WSDL Contains Details About Services



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WSDL Contains Details About Operations



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WSDL Contains Details About Messages



SUMMER 2002


SOAP Mechanisms

• Request and Response messages– request invokes a method on a remote object– response returns the result of the method execution

• Messages wrapped in a SOAP envelope– SOAP envelope is an XML grammar– Message grammar is different from envelope

SOAP EnvelopeSOAP Envelope(SOAP grammar) (SOAP grammar)

Application Application MessageMessage(Application-Specific (Application-Specific grammar) grammar)

SOURCE: JEZ WAIN, BULL


SUMMER 2002


POST /weather HTTP/1.1Host: www.meteo.frContent-Type: text/xmlContent-Length: <nnn>SOAPAction: http://www.meteo.fr/meteo#getWeather

<SOAP:Envelope xmlns:SOAP="urn:schemas-xmlsoap-org:soap.v1.1">

<SOAP:Body><m:getWeather xmlns:m=”meteo.xsd">

<location>Grenoble</location></m:getWeather>

</SOAP:BODY></SOAP:Envelope>

Standard

http HeaderSOAP header

Extensions

Xml

Payload

SOAP Request



SUMMER 2002


SOAP – Writing a Servicepackage meteo;public class MeteoServer { public MeteoServer() { private HashMap weathermap = new HashMap; weathermap.put(“Grenoble”, “sunny and warm”); weathermap.put(“London”, “cold and wet”); } public String getWeather(String location) { String weather; if ((weather = (String)weathermap.get(location))!= null) { return new String(“the weather in “ + location + “ is “ + weather + “ as usual”); } else { return new String(“Can’t find “ + location + “ on the map”); }}}



SUMMER 2002


Example: Notification Service

MessageSender

SubscriberList

publishMessage

NotificationService

APIs: publishMessage() subscribe() unsubscribe() …

MessageSubscriber

Service

subscribeunsubscribe

receiveMessage

Topic Subscriber Reference

WS\A\B <wsdlURL>#<port>

WS\C\D <wsdlURL>#<port>

… …

SOURCE: IDC

…Service

Example: Utility Services

BusinessService

ServiceRequestor

IdentityHandler

IdentityService

IdentityServlet

DigSigSOAPMessage

ContractHandler

ContractService Message

LoggingServiceCheck

UsageContract

All PublishedMessages

CommonData

Service

Create,Update,QueryData

Store IdentityKeyIn MessageContext

…ServiceXXX

Service

MeteringService

RecordMeter Event

MeteringRequestHandler

MeteringResponseHandler

NotificationService

AccountingService

Get MeterEvents

DriveDemo

DigSigHandler

Provisioning Service UIGenerate

Report

IdentityCheck

RegisterSubscribe

Provisioning Service UI

SOURCE: IDC


SUMMER 2002


Web Services Vision• Applications become process flow & event management• Processes are just sets of object method invocations• Object can:

– Exist anywhere

– Be owned by anyone

– Be developed anyhow

– Execute on any platform

• Applications use methods as needed– Discover them through UDDI

– Negotiate their use dynamically

– Bind to & execute them in real timeSOURCE: IDC


SUMMER 2002


Timeline for Web Services Adoption

Within thefirewall

Simplif

ied applicatio

n inte

gratio

n

Incre

ased develo

per pro

ductivity

Simplif

ied busin

ess partn

er connectiv

ity

Richer applic

ation fu

nctionalit

y

Subscriptio

n-based serv

ices

Casual/ad-h

oc use o

f serv

ices

New busin

ess models p

ossible

Pervasive u

se in n

on-traditi

onal devices

Comm

oditiza

tion o

f softw

are

Containedexternalusers

2002 2004

Fully dynamic search & use2006 2008

SOURCE: IDC


SUMMER 2002


QA&

eCommerce Technology 20-751 Lecture 14: Web Services

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