Transcript Chapter 25 - Personal Web Pages

ITIS 1210
Introduction to Web-Based
Information Systems
Chapter 25
How .NET and Web Services Work
Introduction
 Normally, software must be installed on
your computer for you to use it
 This means
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You have a acquire (buy) a copy
Install it
Learn to use it
Keep it updated (with newer versions)
 Can be expensive & frustrating
Introduction
 Also means your OS has to be compatible
with the software
 For most of us this means buying the
latest version of Windows
 With whatever problems it has
 Converting older versions of our software
 Learning to use new Windows features
Introduction
 Web services
 Allows programs to be run remotely via the
Internet
 Can be delivered automatically to your
desktop
 These technologies are extremely
versatile
 Can be used for a wide variety of
purposes
Introduction
 For example:
 Deliver news & weather directly to your
desktop
 Deliver stock information
 Maintain communications between business
partners so they can
 Exchange information
 Buy & sell goods
 Provide other services
Introduction
 Basically these are modular software
components contained within specific
Internet communication protocols
 Revolutionary because they eliminate
need for an OS to run software
 The protocols act as a substitute OS to permit
these services to run within your browser
Introduction
 “Web services” is a misused term
 Technically, only those services which use
a specific set of protocols and
technologies are actually Web services
 These include
 XML – Extensible Markup Language
 Describes the service and its data
 SOAP – Simple Object Access Protocol
 Web services communication standard
Introduction
 These also include
 WSDL - Web Services Description Language
 UDDI – Universal Description, Discovery and
Integration
 The Web service itself is software written
in Java
 Can run on any browser that has Java
capabilities
 I.e., almost all of them
Understanding .NET and Web Services
 Step 1 – writing the application
 Written in Java
 For .NET can use Visual Studio .NET
 Supports a variety of languages
 C#, J#, Visual Basic, C++
 Completed applications are posted to an
application server
 WSDL (Web Services Description
Language)
 Used to create a description of the service
Understanding .NET and Web Services
 Description includes
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What kind of service it is
Keywords associated with the service
What business is hosting it
How to run it
Location (the application server where it runs)
 WSDL is an XML syntax for defining Web
services
 Includes all information necessary for
someone to find and run the service
Understanding .NET and Web Services
 Using the SOAP communications protocol
 The descriptor is published to a Service
Registry
 The Registry uses UDDI
 A group of specifications
 Lets companies publish information about
themselves and their Web services
 Also lets users search that information to find
a Web service they want to use
Understanding .NET and Web Services
 Using SOAP, users – Service Requestors
– search the Registry
 The Service Descriptor tells the user
 Where to find the Web service and
 How to run it
 Based on this information the user “binds”
to the service and runs it