Web Service Example

Any application can have a Web Service component.

Web Services can be created regardless of programming language.

A Web Service Example

In the following example we will use ASP.NET to create a simple Web Service that converts the temperature from Fahrenheit to Celsius, and vice versa:

<%@ WebService Language="VBScript" Class="TempConvert" %>

Imports System
Imports System.Web.Services

Public Class TempConvert :Inherits WebService

<WebMethod()> Public Function FahrenheitToCelsius
(ByVal Fahrenheit As String) As String
  dim fahr
  fahr=trim(replace(Fahrenheit,",","."))
  if fahr="" or IsNumeric(fahr)=false then return "Error"
  return ((((fahr) - 32) / 9) * 5) 
end function

<WebMethod()> Public Function CelsiusToFahrenheit
(ByVal Celsius As String) As String
  dim cel
  cel=trim(replace(Celsius,",","."))
  if cel="" or IsNumeric(cel)=false then return "Error"
  return ((((cel) * 9) / 5) + 32)
end function

end class

This document is saved as an .asmx file. This is the ASP.NET file extension for XML Web Services.

Example Explained

Note: To run this example, you will need a .NET server.

The first line in the example states that this is a Web Service, written in VBScript, and has the class name "TempConvert":

<%@ WebService Language="VBScript" Class="TempConvert" %>

The next lines import the namespace "System.Web.Services" from the .NET framework:

Imports System
Imports System.Web.Services

The next line defines that the "TempConvert" class is a WebService class type:

Public Class TempConvert :Inherits WebService

The next steps are basic VB programming. This application has two functions. One to convert from Fahrenheit to Celsius, and one to convert from Celsius to Fahrenheit.

The only difference from a normal application is that this function is defined as a "WebMethod()".

Use "WebMethod()" to convert the functions in your application into web services:

<WebMethod()> Public Function FahrenheitToCelsius
(ByVal Fahrenheit As String) As String
  dim fahr
  fahr=trim(replace(Fahrenheit,",","."))
  if fahr="" or IsNumeric(fahr)=false then return "Error"
  return ((((fahr) - 32) / 9) * 5) 
end function

<WebMethod()> Public Function CelsiusToFahrenheit
(ByVal Celsius As String) As String
  dim cel
  cel=trim(replace(Celsius,",","."))
  if cel="" or IsNumeric(cel)=false then return "Error"
  return ((((cel) * 9) / 5) + 32)
end function

Then, end the class:

end class

Publish the .asmx file on a server with .NET support, and you will have your first working Web Service.

Look at our example Web Service

ASP.NET Automates the Process

With ASP.NET, you do not have to write your own WSDL and SOAP documents.

If you look closer at our example Web Service, you will see that ASP.NET has automatically created a WSDL and SOAP request.