Cors Module for ASP.NET MVC

CorsModule.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

/// <summary>
///  Cross-Origin Request handler.
/// </summary>
public class CorsModule : IHttpModule
{
    public void Dispose()
    {
        // Nothing to dispose
    }

    public void Init(HttpApplication context)
    {
        context.BeginRequest += new EventHandler(Context_BeginRequest);
    }

    private void Context_BeginRequest(object sender, EventArgs e)
    {
        HttpApplication app = sender as HttpApplication;
        if (app.Request.Headers.AllKeys.Select(k => k.ToLower()).Contains("origin"))
        {
            // TODO - Do security checks
            app.Response.AddHeader("Access-Control-Allow-Origin", app.Request.Headers["Origin"]);            
        }
    }
}

web.config

....
<system.webServer>
    <validation validateIntegratedModeConfiguration="false" />
    <modules runAllManagedModulesForAllRequests="true">
      ....
      <add type="CorsModule" name="CorsModule" />
    </modules>