//// <summary>

/// 防盗链Filter.

/// </summary>

public class AntiOutSiteLinkAttribute : ActionFilterAttribute, IActionFilter

{

    public AntiOutSiteLinkAttribute(FileType fileType)

    {

        this.FileType = fileType;

    }

    //// <summary>

    /// 请求的文件类型.(文件或图片)

    /// </summary>

    public FileType FileType { get; set; }

    #region IActionFilter 成员

    void IActionFilter.OnActionExecuting(ActionExecutingContext filterContext)

    {

        HttpContextBase httpContext = filterContext.HttpContext;

        if (null != httpContext.Request.UrlReferrer)

        {

            string serverDomain = httpContext.Request.Url.Host;

            string refDomain = httpContext.Request.UrlReferrer.Host;

            if (GetRootDomain(refDomain).Equals(GetRootDomain(serverDomain), StringComparison.OrdinalIgnoreCase))

            {

                return;//如果根域名相同就返回

            }

        }

        ContentResult cr = new ContentResult();

        if (FileType == FileType.Image)

        {

            cr.ContentType = "image/jpeg";

            FileInfo fi = new FileInfo(httpContext.Server.MapPath("~/Content/images/outsitelink.jpg"));

            if (fi.Exists)

            {

                httpContext.Response.WriteFile(fi.FullName);

            }

            else

            {

                Bitmap bmp = new Bitmap(, );

                Graphics g = Graphics.FromImage(bmp);

                g.FillRectangle(Brushes.White, , , , );

                g.DrawString("请不要盗链", new Font("Arial", ), Brushes.Red, new PointF(, ));

                bmp.Save(httpContext.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Gif);

            }

        }

        else

        {

            cr.ContentType = "text/html";

            cr.Content = string.Format("请不要盗链。返回<a href='{0}'>{1}</a>", Utils.AbsoluteWebRoot, BlogSettings.Instance.Name);

        }

        //将当前的上下文的ActionResult设置为我们的cr(ContentResult)

        filterContext.Result = cr;

    }

    #endregion

    //// <summary>

    /// 获取网站的根域名

    /// </summary>

    /// <param name="domain">网站的域名，不带"Http://"</param>

    /// <returns></returns>

    private string GetRootDomain(string domain)

    {

        if (string.IsNullOrEmpty(domain))

        {

            throw new ArgumentNullException("参数'domain'不能为空");

        }

        string[] arr = domain.Split(new[] { '.' }, StringSplitOptions.RemoveEmptyEntries);

        if (arr.Length <= )

        {

            return domain;

        }

        else

        {

            return arr[arr.Length - ] + "." + arr[arr.Length - ];

        }

    }

}

public enum FileType

{

    File = ,

    Image

}

public class FilesController : BaseController

 {

     [AntiOutSiteLink(FileType.Image)]

     public ActionResult Image(string file)

     {

         return Content("Image From 4mvc");

     } 

     [AntiOutSiteLink(FileType.File)]

     public ActionResult File(string file)

     {

         return Content("File From 4mvc");

     }

 }