Remote scripting - Calling a WebService with JavaScript and C#

Calling a WebService with JavaScript. Security included by using a local asmx with the function of proxy, and not revealing the webservice URI in the JavaScript.

Introduction

I have been using webservices for the past two years, but whenever I use a function, I have to post back all my pages. Using remote scripting we can call our webservices from the client, using JavaScript, and there is no need to post back all the page content, just an instruction. We send the line, catch the result and show it. We need not do a post back, the operation is processed behind, blind to the user, and fast as a "line go-line comes".

<script language="JavaScript">
init(){
 service.useService("http://localhost/CursoAspNetWebService/Service1.asmx?WSDL",_
                                                                     "Service1"); 
}
function tst(){ 
   iCallID = service.Service1.callService("Suma",ip1.value,ip2.value); 
}
function onmyresult(){ 
   service.innerHTML= "Resultado : " + event.result.value; 
} 
</script>
<body onLoad="init();">
  <button onclick="javascript:tst()" ID="Button1">Call Add Web Method</button>
  <div id="service" style="BEHAVIOR:url(webservice.htc)" onresult="onmyresult();">
  </div>
</body>

The source code includes the webservice.htc, the HTML component that is used.

The HTML

We need to create an interface using just HTML controls, because we don't want to send the page to the server. We need just a text, and a button with a function:

onclick="doSuma(texta.value,textb.value)

and the section where we want to display the result, like a <Div>.

id="service" style="BEHAVIOR: url(webservice.htc)"

The Init script

We need to put init() in the load of HTML, and the function doSuma(...) is called by clicking the button:

function init() { 
    service.useService("proxy.asmx?WSDL","proxy"); 
}
function doSuma(y, x){ 
    oSPAN.innerText = y + " + " + x + " = "; 
    iCallID = service.proxy.callService(myResults, "Adicion", y,x); 
}

The iCallID is a var that is unused later, but the result comes with the call from it. We need to fill parameters to:

Call a function to manage the result.
Call the public function.
Send the values to process, from the 3^rd to the necessary values needed.

The MyResult JavaScript function

function myResults(result){ 
    if(result.error){ 
        var xfaultcode = result.errorDetail.code; 
        var xfaultstring = result.errorDetail.string; 
        var xfaultsoap = result.errorDetail.raw; 
        oSPAN.innerText = xfaultcode + " " + xfaultstring + " " + xfaultsoap;
    }
    else{ 
        oSPAN.innerText += result.value; 
    } 
} //the end of function

The local proxy

The local proxy has the goal of giving security to the application. We have seen in JavaScript that a URI points to localhost. If we don't use the proxy in localhost we need to give the full URI of the webservice, and we give other users the door wide open. In this case, we can apply security by forms level protection in ASP.NET

The proxy just has an instance of the real web service and a single call of a function:

using System;
using System.Web;
using System.Web.Services;

namespace RemoteScriptingDemo1
{
 public class proxy : System.Web.Services.WebService
 {
  public proxy()
  {
   InitializeComponent();
  }

  private IContainer components = null;
    
  private void InitializeComponent()
  {
  }

  protected override void Dispose( bool disposing )
  {
   if(disposing && components != null)
   {
    components.Dispose();
   }
   base.Dispose(disposing);  
  }
  

  [WebMethod]
  public decimal Adicion(decimal x, decimal y)
  {
   WSDemo.Service1 ws = new RemoteScriptingDemo1.WSDemo.Service1();
   return ws.suma(x,y);
  }
 }
}

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

About the Author

Marcelo Lujan [El Bebe.Net ]

Founder
Cimar Solutions

Mexico

Member

Ing. F. Marcelo Lujan alias El Bebe Dot Net. Hola, yo desarrollo de forma independiente en C#. ASP.NET y Win32 Diseño Macromedia etc. con mas de 10 años de experiencia en informática y soporte a sistemas, así como desarrollo de software y nuevos productos.

Espero que ayude la informacion que pongo a su disposicion.
I Hope this information that i upload to codeproject helps you.
Atte: Marcelo Lujan

Article Top