.Net Framework

Information Integration on the WebSpring 2003

February 3, 2003

Wrapper &AgentRunner

Information Integration –Wrapper View

Web

Wrapper &AgentRunnerWeb

Wrapper &AgentRunnerWeb Web

Apache Tomcat

Web Service

Information Integration – Web Services View

Web Service

Web ServiceWeb

Web Server

Glue code

What’s the Difference?

• Web services– Standard protocols, WSDL, SOAP…– “Easy” integration using commercial tools– Restricted to web sites that are web services– Less than 0.01% of web is in web service format

• Wrappers– Can support more web sites compared to web services– Integration using academic tools may be little harder

compared to commercial tools for web services– No standard protocols

Overview

• Web services• Web services protocols• Develop web services• Consume web services

What We Are Not Going to Cover About .Net

• We don’t expect you to become experts at C# or VB.NET

What We Are Going to Cover About .Net

• Develop Web Services• Consume Web Services• Build simple applications with C#, VS.NET

Web Services Defined

• Definition– According to IBM “web services are self-

contained, modular applications that can be described, published, located, and invoked over a network, generally, the world wide web”

– According to Microsoft “a web service is programmable application logic, accessible using standard internet protocols”

Web Services: Major Protocols

• XML• SOAP• WSDL• UDDI

Developing .Net Framework Web Service

Hands on LabCreate Hello World Web ServiceDevelop a simple web service that

sends a message Hello World.

Creating Hello World Web Service

When VS.NET comes up click on new project to beginTip: VS.NET can make machine run really slow, be patient

Creating Hello World Web Service (Cont’d)

Pick Visual C# projects and select ASP.NET Web ServiceTip: Remember the location of your web service, also make sure IIS

is running on the machine.

Creating Hello World Web Service (Cont’d)

You will see the standard VS.NET IDE, click on switch to code view to see the code behind the web service

Creating Hello World Web Service (Cont’d)

Uncomment the four lines that have code for Hello World method.

Developing .Net Framework Web Service

Hands on LabCreate Hello World Web ServiceLet’s See Web Service in Action

Hello World Web Service

• What just happened?– VS.NET created test page for hello world– VS.NET also created WSDL for hello world– VS.NET also enabled hello world to ‘talk’

SOAP, WSDL and XML over HTTP• Why do we care about WSDL?

– WSDL can be used by programs like VS.NET or users to integrate our web service with their apps or web services

Web Services

• Building blocks for building applications that integrate information

Geocoded Restaurant List

with Ratings

Name, Address, Lat, Long, Rating

RatingsRatingGeocoded

Restaurant ListName, Address, Lat, Long

Restaurant List Name, Address

City, State

GeocodeLat, Long

Address

Integrating Web Services Using Visual Studio.Net

Hands on LabCalculator Example

Develop a windows application that accepts two numbers and an

operation and calls appropriate web service to provide the result

Integrating Web Services Using Visual Studio.Net

Hands on LabCalculator Example

Let’s See the Application in Action

Conclusion

• Issues– Web services coverage– Web services discovery– Object identification– Web service content description

• Solutions– Web services discovery

• Directory services, e.g. UDDI– Web service content description

• Resource description framework(RDF), semantic web ??– Object identification

• Active learning techniques ??

Conclusion (Cont’d)

• More information on .Net framework– http://msdn.microsoft.com/library/ click on .Net

development– http://www.gotdotnet.com

• Questions, comments?