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  Integration Question: 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 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 Registry Service Registry Service Requestor Service 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 1 st /2 nd Tier Line 1 st /2 nd Tier Line 2 nd /3 rd Tier Line 2 nd /3 rd 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 Supplier 1 Supplier 1 Supplier 2 Supplier n Retailer A Retailer A Retailer B Retailer B Retailer n Retailer n Online 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

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