Why can't I access my WCF web service with Javascript?

Question

I'm new at AJAX and I'm trying to access a WCF web service the following way:

$(function () {
    $('#formNew').submit(function () {
        var datos = {
            "Nombre": $('#nombre').val(),
            "ApellidoP": $('#appP').val(),
            "ApellidoM": $('#appM').val(),
            "UserName": $('#username').val(),
            "Password": $('#password').val(),
        };
        var args = "Data=" + JSON.stringify(datos);
        var url = 'http://127.0.0.1:81/SismosService.svc/usuario/new?' + args;
        alert(url);
        $.ajax({
            type: 'GET',
            url: url,
            success: function (data) {
                alert("Exito " + JSON.stringify(data));
            },
            error: function (data) {
                alert("Error " + JSON.stringify(data));
            }
        });
    });
});

When I fill the form and click the submit button, I get the following error on Firebug:

N

S_ERROR_NOT_AVAILABLE: prompt aborted by user
[Break On This Error]   

throw Components.Exception("prompt aborted by user", Cr.NS_ERROR_NOT_AVAILABLE)

My web service is defined as follows:

    [WebGet(UriTemplate = "/usuario/new?Data={data}",
    RequestFormat = WebMessageFormat.Json,
    ResponseFormat = WebMessageFormat.Json,
    BodyStyle = WebMessageBodyStyle.Bare)]
    ResponseObject<Usuarios> NewUsuario(string data);

What am I doing wrong? Is it the way I'm sending the parameters? Is is the way I'm trying to access the web service? Thanks for any help.

Answer 1

The JSON.stringify(data) use is to convert a javascript object to json representation.

I think that in the success\\error functions you need to go the other way:

 success: function (data) {
                            alert("Exito " + JSON.parse(data));
                          },
 error:   function (data) {
                            alert("Error " + JSON.parse(data));
                          }

(when using JSON.parse, JSON.stringify - make sure you included the json2.min.js in your project)

Answer 2

I normally use the following configuration to enable ajax calls to my WCF services:

1) First I create a JSON endpoint behaviour in Web.config and associate my service to it:

<system.serviceModel>
  <behaviors>
    <endpointBehaviors>
      <behavior name="WebHttpJson">
        <webHttp defaultBodyStyle="Wrapped"
                 defaultOutgoingResponseFormat="Json" />
      </behavior>
    </endpointBehaviors>
  </behaviors>
  <services>
    <service name="MyApp.LoginService">
      <endpoint address=""
                behaviorConfiguration="WebHttpJson"
                binding="webHttpBinding"
                contract="MyApp.LoginService" />
    </service>
  </services>
</system.serviceModel>

2) Then I can simply define my WCF service like this:

[ServiceContract]
public class LoginService
{
    [OperationContract]
    public void SignIn(string email, string pswd)
    {
        // Check credentials and create session cookie
    }
}

3) And finally make jQuery ajax calls like showed below:

$.ajax({
    contentType: 'application/json; charset=utf-8',
    url: serviceUrl + '/SignIn',
    type: 'POST',
    data: JSON.stringify({
        email: 'john.doe@abc.com', 
        pswd: 'qwerty'
    }),
    success: function () { alert('success!'); },
    error: function () { alert('error!'); }
});