SignalR CORS error

Question

I get the following error when attempting to invoke server side method from a javascript client via SignalR:

XMLHttpRequest cannot load http://localhost:49679/signalr/send?transport=serverSentEvents&clientProtoc…XWYPNm9Av7oD1DiEodZenKiQdpQFWUqDJ9vD0UgrYc%2FjZs21i3&connectionData=%5B%5D. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:63342' is therefore not allowed access. The response had HTTP status code 500.

I am building a simple prototype and this is what I have in my Startup.cs class in my Web server:

using Microsoft.AspNet.SignalR;
using Microsoft.Owin;
using Microsoft.Owin.Cors;
using Owin;

[assembly: OwinStartupAttribute(typeof(WebRTCSignalServer.Web.Startup))]
namespace WebRTCSignalServer.Web
{
    public partial class Startup
    {
        public void Configuration(IAppBuilder app)
        {
           //app.UseCors(CorsOptions.AllowAll);

            //Add SignalR
            app.Map("/signalr", map =>
            {
               map.UseCors(CorsOptions.AllowAll);

               // configure signalR
               HubConfiguration hubConfiguration = new HubConfiguration()
               {
                  EnableJavaScriptProxies = false,
                  EnableDetailedErrors = true
               };

               //GlobalHost.HubPipeline.AddModule(new ErrorHandlingPipelineModule());

               // Run the SignalR pipeline. We're not using MapSignalR
               // since this branch already runs under the "/signalr"
               // path.
               map.RunSignalR(hubConfiguration);
            });

            ConfigureAuth(app);
        }
    }
}

This is the javascript signalr client code:

var connection = $.hubConnection('http://localhost:49679/signalr', { useDefaultPath: false });
console.log(connection);

connection.stateChanged(function () {
    console.log('stateChanged.... state=' + connection.state);
});

connection.connectionSlow(function () {
    console.log('connectionSlow.... state=' + connection.state);
});

connection.reconnecting(function () {
    console.log('reconnecting.... state=' + connection.state);
});

connection.reconnected(function () {
    console.log('reconnected.... state=' + connection.state);
});

connection.disconnected(function () {
    console.log('disconnected.... state=' + connection.state);
});

connection.error(function (error) {
    console.log('error.... state=' + connection.state);
});

var webRTCSignalServerHub = connection.createHubProxy('webrtcsignalserver');

console.log(webRTCSignalServerHub);

connection.start().done(function(){
    webRTCSignalServerHub.invoke('register', 'wkst0314');
});

Can someone explain why this is happening and how to fix it please? I followed this example in the SignalR docs to enable CORS but it is not working for me. Not sure if it is important but I am trying this in Chrome: http://www.asp.net/signalr/overview/guide-to-the-api/hubs-api-guide-javascript-client#crossdomain

Thanks in advance for the help.

user1870738 user1870738 · Accepted Answer · 2015-01-04T05:00:24

I was able to figure this out. The name of the signalR Hub that I was using was incorrect and this is why that error was occurring. After correcting the hub name things were working as expected.

SignalR CORS error

1 Answers