ITIS 1210ITIS 1210Introduction to Web-Based Introduction to Web-Based

Information SystemsInformation Systems

Chapter 25Chapter 25

How .NET and Web Services WorkHow .NET and Web Services Work

IntroductionIntroduction

Normally, software must be installed on Normally, software must be installed on your computer for you to use ityour computer for you to use it

This meansThis means You have a acquire (buy) a copyYou have a acquire (buy) a copy Install itInstall it Learn to use itLearn to use it Keep it updated (with newer versions)Keep it updated (with newer versions)

Can be expensive & frustratingCan be expensive & frustrating

IntroductionIntroduction

Also means your OS has to be compatible Also means your OS has to be compatible with the softwarewith the software

For most of us this means buying the For most of us this means buying the latest version of Windowslatest version of Windows With whatever problems it hasWith whatever problems it has Converting older versions of our softwareConverting older versions of our software Learning to use new Windows featuresLearning to use new Windows features

IntroductionIntroduction

Web servicesWeb services Allows programs to be run remotely via the Allows programs to be run remotely via the

InternetInternet Can be delivered automatically to your Can be delivered automatically to your

desktopdesktop

These technologies are extremely These technologies are extremely versatileversatile

Can be used for a wide variety of Can be used for a wide variety of purposespurposes

IntroductionIntroduction

For example:For example: Deliver news & weather directly to your Deliver news & weather directly to your

desktopdesktop Deliver stock informationDeliver stock information Maintain communications between business Maintain communications between business

partners so they canpartners so they can Exchange informationExchange information Buy & sell goodsBuy & sell goods Provide other servicesProvide other services

IntroductionIntroduction

Basically these are modular software Basically these are modular software components contained within specific components contained within specific Internet communication protocolsInternet communication protocols

Revolutionary because they eliminate Revolutionary because they eliminate need for an OS to run softwareneed for an OS to run software The protocols act as a substitute OS to permit The protocols act as a substitute OS to permit

these services to run within your browserthese services to run within your browser

IntroductionIntroduction

““Web services” is a misused termWeb services” is a misused term Technically, only those services which use Technically, only those services which use

a specific set of protocols and a specific set of protocols and technologies are actually Web servicestechnologies are actually Web services

These includeThese include XML – Extensible Markup LanguageXML – Extensible Markup Language

Describes the service and its dataDescribes the service and its data

SOAP – Simple Object Access ProtocolSOAP – Simple Object Access Protocol Web services communication standardWeb services communication standard

IntroductionIntroduction

These also includeThese also include WSDL - Web Services Description LanguageWSDL - Web Services Description Language UDDI – Universal Description, Discovery and UDDI – Universal Description, Discovery and

IntegrationIntegration

The Web service itself is software written The Web service itself is software written in Javain Java

Can run on any browser that has Java Can run on any browser that has Java capabilitiescapabilities I.e., almost all of themI.e., almost all of them

Understanding .NET and Web ServicesUnderstanding .NET and Web Services

Step 1 – writing the applicationStep 1 – writing the application Written in JavaWritten in Java For .NET can use Visual Studio .NETFor .NET can use Visual Studio .NET

Supports a variety of languagesSupports a variety of languages C#, J#, Visual Basic, C++C#, J#, Visual Basic, C++

Completed applications are posted to an Completed applications are posted to an application serverapplication server

WSDL (Web Services Description WSDL (Web Services Description Language)Language) Used to create a description of the serviceUsed to create a description of the service

Understanding .NET and Web ServicesUnderstanding .NET and Web Services

Description includesDescription includes What kind of service it isWhat kind of service it is Keywords associated with the serviceKeywords associated with the service What business is hosting itWhat business is hosting it How to run itHow to run it Location (the application server where it runs)Location (the application server where it runs)

WSDL is an XML syntax for defining Web WSDL is an XML syntax for defining Web servicesservices Includes all information necessary for Includes all information necessary for

someone to find and run the servicesomeone to find and run the service

Understanding .NET and Web ServicesUnderstanding .NET and Web Services

Using the SOAP communications protocolUsing the SOAP communications protocol The descriptor is published to a Service The descriptor is published to a Service

RegistryRegistry

The Registry uses UDDIThe Registry uses UDDI A group of specificationsA group of specifications Lets companies publish information about Lets companies publish information about

themselves and their Web servicesthemselves and their Web services Also lets users search that information to find Also lets users search that information to find

a Web service they want to usea Web service they want to use

Understanding .NET and Web ServicesUnderstanding .NET and Web Services

Using SOAP, users – Service Requestors Using SOAP, users – Service Requestors – search the Registry– search the Registry

The Service Descriptor tells the userThe Service Descriptor tells the user Where to find the Web service andWhere to find the Web service and How to run itHow to run it

Based on this information the user “binds” Based on this information the user “binds” to the service and runs itto the service and runs it