ITIS 1210 Introduction to Web-Based Information Systems Chapter 25 How.NET and Web Services Work How.NET and Web Services Work

Introduction  Normally, software must be installed on your computer for you to use it  This means  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  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