Remove trailing slash in URLs with ASP.NET MVC routing

gistfile1.cs

    // Put this in Global.asax.cs

    protected void Application_BeginRequest(object sender, EventArgs e)
    {
        // Do Not Allow URL to end in trailing slash
        string url = HttpContext.Current.Request.Url.AbsolutePath;
        if (string.IsNullOrEmpty(url)) return;

        string lastChar = url[url.Length-1].ToString();
        if (lastChar == "/" || lastChar == "\\")
        {
            url = url.Substring(0, url.Length - 1);
            Response.Clear();
            Response.Status = "301 Moved Permanently";
            Response.AddHeader("Location", url);
            Response.End();
        }
    }

MVC has a general issue with this if your webapplication is rooted at the URI authority. So:
http://www.google.com/
will become
httP://www.google.com

MVC will not attempt to run any default routes if this is the case. The modern browsers I've tested do append a trailing slash if missing from a URL authority. It appears to be because of HTTP/1.1 requirements:
http://stackoverflow.com/questions/11325425/remove-trailing-slash-in-asp-net-mvc-4-route-to-application-root

https://gist.github.com/AniAko/3f955b5ad9a71f17635e

Wouldn't url.ToLower().TrimEnd('/', '\\') be more clear of what you are trying to achieve ?

Try this:
var uri = Context.Request.Url.ToString();
if (UriHasRedundantSlashes(uri))
{
var correctUri = RemoveRedundantSlashes(uri);
Response.RedirectPermanent(correctUri);
}
}

private string RemoveRedundantSlashes(string uri)
{
    const string http = "http://";
    const string https = "https://";
    string prefix = string.Empty;

    if (uri.Contains(http))
    {
        uri = uri.Replace(http, string.Empty);
        prefix = http;
    }
    else if (uri.Contains(https))
    {
        uri = uri.Replace(https, string.Empty);
        prefix = https;
    }

    while (uri.Contains("//"))
    {
        uri = uri.Replace("//", "/");
    }

    if (!string.IsNullOrEmpty(prefix))
    {
        return prefix + uri;
    }
    return uri;
}

private bool UriHasRedundantSlashes(string uri)
{
    const string http = "http://";
    const string https = "https://";

    if (uri.Contains(http))
    {
        uri = uri.Replace(http, string.Empty);
    }
    else if (uri.Contains(https))
    {
        uri = uri.Replace(https, string.Empty);
    }
    return uri.Contains("//");
}

See: https://pro-papers.com/