How Does a Web Service Work?

Web Development
#1

A web service enables communication among various applications by using open standards such as HTML, XML, WSDL, and SOAP. A web service takes the help of −

  • XML to tag the data
  • SOAP to transfer a message
  • WSDL to describe the availability of service.

You can build a Java-based web service on Solaris that is accessible from your Visual Basic program that runs on Windows.

You can also use C# to build new web services on Windows that can be invoked from your web application that is based on JavaServer Pages (JSP) and runs on Linux.

Example

Consider a simple account-management and order processing system. The accounting personnel use a client application built with Visual Basic or JSP to create new accounts and enter new customer orders.

The processing logic for this system is written in Java and resides on a Solaris machine, which also interacts with a database to store information.

The steps to perform this operation are as follows −

  • The client program bundles the account registration information into a SOAP message.
  • This SOAP message is sent to the web service as the body of an HTTP POST request.
  • The web service unpacks the SOAP request and converts it into a command that the application can understand.
  • The application processes the information as required and responds with a new unique account number for that customer.
  • Next, the web service packages the response into another SOAP message, which it sends back to the client program in response to its HTTP request.
  • The client program unpacks the SOAP message to obtain the results of the account registration process.