Web Services based e-Commerce System

Sandy Liu

Jodrey School of Computer Science

Acadia University

July, 2002

Existing Problems

Most existing e-commerce systems have common problems in:

Flexibility Information Sharing IntegrationQuestion: How to build a highly flexible,

integratable and maintainable application?

Proposed Solution

A Web Services based e-commerce system: Flexible System Architecture Well-defined Software Components Multiple Information/Data Access Channels

A practical strategy to improve the overall efficiency of existing systems at a low cost.

What is Web Services

It is a platform and implementation independent software component that can be:

Described using a service description language

Published to a registry of services

Discovered through a standard mechanism at runtime or design time

Composed with other services Examples: credit card processing, shipment tracking…

What is Web Services

Application Code

Application Code

Application Client

Application Client

Web Services

Platform, Language & Location specific communication

Platform, Language & Location agnostic communication

• Web Services are intended to be used by other programs or applications, not by a human user.

• It acts as an abstraction layer, separating the platform and programming-language specific details from how the application code is invoked.

Service-Oriented Architecture

Service RegistryService Registry

Service Requestor

Service Requestor

ServiceProviderService

Provider

Find

Bind

Publish

Web Services Stack

Network

Transport

Packaging

Description

Publishing / Discovery UDDI/ebXML registries

WSDL/WSCL

SOAP/XML Protocol

HTTP/SMTP/FTP/Jabber

TCP/IP

Enabling Technologies and Standards

HTTP XML and XML Schema (XSD) SOAP (Simple Object Access Protocol) WSDL (Web Services Description

Language) UDDI (Universal Description, Discovery and

Integration)

HTTP

The most pervasive communication protocol used in the Internet world.

A feature of HTTP is the typing and negotiation of data representation, which allows systems to be built independent of the data being transferred.

XML & XML Schema (XSD)

XML Schema or XSD (XML Schema Definition) lays the mechanism for defining the vocabulary and structure of XML documents:

XSD is defined using an XML format XSD has a data typing mechanism

XSD uses namespace

SOAP

SOAP – Simple Object Access Protocol Industry’s best effort to date to standardize

on the infrastructure technology for cross-platform XML distributed computing

Use HTTP to transfer data (by default) Based on XML-RPC, everything is encoded

in XML format

SOAP Message Structure

Envelope (Mandatory)

Header (Optional)

Body (Mandatory)

WSDL

WSDL- Web Service Description Language Formally, it’s an XML format for describing network

services as a set of end points operating on messages containing either document-oriented or procedure-oriented information

Informally, it’s a document that provides the access information for the service consumer, such as the method signature (input/output parameters, and so forth); the protocol to be used (IIOP, SOAP, and so on); the network address (URL); and the data format (encoding schemes).

UDDI

Universal Description, Discovery and Integration a platform-independent, open framework for

describing services, discovering businesses, and integrating business services using the Internet

Enables businesses to describe their services and business processes and their preferred methods for conducting business.

Offers both a web-based user interface and a set of APIs for program access.

Web Services and e-Commerce

The magic glue for B2B integration Enterprise-wide application integration

The 3-tier Architecture

Enhydra Application: IBuildPC.com

1st/2nd

Tier Line1st/2nd

Tier Line2nd/3rd

Tier Line 2nd/3rd

Tier Line

Enhydra Framework

Architecting Web Services

3rd Party Programs or Applications

(Service Requestors)

Human Users

Challenge

Putting the puzzles together: SOAP container Application Server Web Server Database Server

IBuildPC.com

IBuildPC.com

IBuildPC.com

Supplier 1

Supplier 1

Supplier 2Supplier 2

Supplier nSupplier n

Retailer A

Retailer A

Retailer B

Retailer B

Retailer n

Retailer n

Online ShoppersOnline Shoppers

IBuildPC.com

In the Service-Oriented-Architecture, it is a Service Provider towards its downstream

customers a Service Requestor towards its suppliers,

credit card verification service provider, SMTP service provider, etc.

The Client System

Used by a retailer of IBuildPC.com Built with Visual Basic Requests the web services provided by

IBuildPC.com (built with Java) Demo…

Conclusion

Modularized, portable, and highly integratable system

Great deployment flexibility Low entrance cost

But it is not a cure-all solution for everyone – yet to mature at its current state

Questions