Authenticate a Webservice using SOAP Header

SOAP Header :

SOAP Header is an optional part of a SOAP message that contain 

Application specific information related to the SOAP message.

It normally contains information like Authentication information,

Transaction Semantics, Routing information, etc.

Let me explain how to make use of SOAP Header for Authenticating

Webservice.

Below is the sample Code :

Service1.asmx.cs (C# Code) :

using System;

using System.Collections.Generic;

using System.Web;

using System.Web.Services;

using System.Web.Services.Protocols;

namespace WebService1

{

    /// <summary>

    /// Summary description for Service1

    /// </summary>

    [WebService(Namespace = "http://tempuri.org/")]

    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]

    [System.ComponentModel.ToolboxItem(false)]

    // To allow this Web Service to be called from script, using ASP.NET AJAX,

         uncomment the following line. 

    // [System.Web.Script.Services.ScriptService]

    public class Service1 : System.Web.Services.WebService

    {

        public AuthHeader Authentication;

        [SoapHeader("Authentication", Required = true)]

        [WebMethod]

        public string Concatenate(string a,string b)

        {

            if (Authentication.Username == "KM123" && Authentication.Password == "q@s#d$a^")

                return a + "," + b;

            else

                return "Error : Authentication failed";

        }

    }

    public class AuthHeader : SoapHeader

    {

        public string Username;

        public string Password;

    }

}

I will explain the above code. For using SOAP Header class, we have to

include the namespace, System.Web.Services.Protocols;

Concatenate is the sample Webservice method which gives concatenated

string as the output. In the following post I have explained how to create a

Webservice :

http://aspdotnetandmssqlserver.blogspot.com/2016/08/create-sample-webservice-in-c.html

In order to add Authentication to a webservice method we have to create

a class derived from a SOAPHeader class as follows :

public class AuthHeader : SoapHeader

{

        public string Username;

        public string Password;

 }

In this example I have included the class within the namespace WebService1

itself . It can be created as a separate class file also.

Above the Concatenate function, first an object of the AuthHeader class

is created as :

 public AuthHeader Authentication;

And then specify SOAPHeader attribute above the Webservice method as :

   [SoapHeader("Authentication", Required = true)]

Inside the webmethod we can validate the credentials as follows:

 public string Concatenate(string a,string b)

  {

       if (Authentication.Username == "KM123" && Authentication.Password == "q@s#d$a^")

            return a + "," + b;

       else

            return "Error : Authentication failed";

  }