Web Services

Web Services:
A Web Service is programmable application logic accessible using standard Internet protocols. They are made up of XML and are accessible through HTTP and SOAP (Simple Object Access Protocol). A special XML format named Web services Description Language (WSDL) defines the Web service.
(Or)
An application hosted on a Web server that provides information and services to other network applications using the HTTP and XML protocols.
Interoperability has Highest Priority:
When all major platforms could access the Web using Web browsers, different platforms could interact. For these platforms to work together, Web applications were developed.
Web-applications are simple applications run on the web. These are built around the Web browser standards and can mostly be used by any browser on any platform.
Web service consumer:
An application that uses Internet protocols to access the information and functionality made available by a Web service provider.
What are Web Services:
Web services are application components
Web services communicate using open protocols
Web services are self-contained and self-describing
Web services can be discovered using UDDI
Web services can be used by other applications
XML is the basis for Web services
Web Services take Web-applications to the Next Level:
Using Web services, your application can publish its function or message to the rest of the world.
Web services use XML to code and to decode data, and SOAP to transport it (using open protocols).
With Web services, your accounting department's Win 2k server's billing system can connect with your IT supplier's UNIX server.
The basic Web services platform is XML + HTTP:
The HTTP protocol is the most used Internet protocol.
XML provides a language which can be used between different platforms and programming languages and still express complex messages and functions.
Web Services have Two Types of Uses:
a) Reusable application components:
There are things applications needs very often. So why make these over and over again?
Web services can offer applications components like currency conversion, weather reports, or even language translation as services.
Ideally, there will be only one type of each application component, and anyone can use it in their application.
b) Connect existing software:
Web services help to solve the interoperability problem by giving different applications a way to link their data.
With Web services you can exchange data between different applications and different platforms.
Web services platform elements:
SOAP (Simple Object Access Protocol)
UDDI (Universal Description, Discovery and Integration)
WSDL (Web Services Description Language)
What is SOAP?
SOAP is a simple XML-based protocol to let applications exchange information over HTTP.
Or simpler: SOAP is a protocol for accessing a Web Service.
SOAP stands for Simple Object Access Protocol
SOAP is a communication protocol
SOAP is a format for sending messages
SOAP is designed to communicate via Internet
SOAP is platform independent
SOAP is language independent
SOAP is based on XML
SOAP is simple and extensible
SOAP allows you to get around firewalls
SOAP is a W3C standard
What is WSDL?
WSDL is an XML-based language for describing Web services and how to access them.
WSDL stands for Web Services Description Language
WSDL is based on XML
WSDL is used to describe Web services
WSDL is also used to locate Web services
WSDL is a W3C standard
What is UDDI?
UDDI is a directory service where businesses can register and search for Web services.
UDDI stands for Universal Description, Discovery and Integration
UDDI is a directory for storing information about web services
UDDI is a directory of web service interfaces described by WSDL
UDDI communicates via SOAP
UDDI is built into the Microsoft .NET platform
Some other Important Q`s
1. Which method do you use to redirect the user to another page without performing a round trip to the client?
server. transfer
2 What is the transport protocol you use to call a Web service SOAP
http
3. True or False: A Web service can only be written in .NET
false
4. What does WSDL stand for?
WebService description language. It is used to generate for proxy (server object)
5. What property do you have to set to tell the grid which page to go to when using the Pager object?
Page Index.
6.What is the transport protocol you use to call a Web service?
SOAP (Simple Object Access Protocol) is the preferred protocol.
7.Where on the Internet would you look for Web services?
http://www.uddi.org
8.True or False: To test a Web service you must create a Windows application or Web application to consume this service?
False, the web service comes with a test page and it provides HTTP-GET method to test.