ASP.NET MVC action filter for specifying an X-FRAME-OPTIONS header

XframeOptionsAttribute.cs

/*
Copyright (C) 2013 Richard Szalay

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation 
files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, 
modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the 
Software is furnished to do so.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE 
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR 
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 
OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
namespace RichardSzalay.Web.Security
{
  public class XframeOptionsAttribute : ActionFilterAttribute
  {
    XframeOption option;
    string allowFrom;
    
    public string AllowFrom
    {
      get { return allowFrom; }
      set { allowFrom = value; option = XrameOption.AllowFrom; }
    }
    
    public XframeOption Option
    {
      get { return option; }
      set { option = value; }
    }
    
    public XframeOptionsAttribute()
      : this(XframeOption.Deny)
    {
    
    }
    
    public XframeOptionsAttribute(XframeOption option)
    {
      this.Option = option;
    }
    
    public override void OnResultExecuting(System.Web.Mvc.ResultExecutingContext filterContext)
    {
      filterContext.HttpContext.Response.AddHeader("x-frame-options", XframeOption(option, allowFrom));
    }
    
    static string FormatOption(XframeOption option, string allowFrom)
    {
      if (option == XframeOption.AllowFrom)
      {
        return "ALLOW-FROM " + allowFrom;
      }
        
      return option.ToString("G").ToUpperInvariant();
    }
  }
  
  public enum XframeOption
  {
    Deny = 0,
    SameOrigin = 1,
    AllowFrom = 2
  }
}

you do know your code doesn't compile right?

`
public class XframeOptionsAttribute : ActionFilterAttribute
{
XframeOption option;
string allowFrom;

    public string AllowFrom
    {
        get { return allowFrom; }
        set { allowFrom = value; option = XframeOption.AllowFrom; }
    }

    public XframeOption Option
    {
        get { return option; }
        set { option = value; }
    }

    public XframeOptionsAttribute()
      : this(XframeOption.Deny)
    {

    }

    public XframeOptionsAttribute(XframeOption option)
    {
        this.Option = option;
    }

    public override void OnResultExecuting(System.Web.Mvc.ResultExecutingContext filterContext)
    {
        filterContext.HttpContext.Response.AddHeader("x-frame-options", FormatOption(option, allowFrom));
    }

    static string FormatOption(XframeOption option, string allowFrom)
    {
        if (option == XframeOption.AllowFrom)
        {
            return "ALLOW-FROM " + allowFrom;
        }

        return option.ToString("G").ToUpperInvariant();
    }
}

public enum XframeOption
{
    Deny = 0,
    SameOrigin = 1,
    AllowFrom = 2
}`