asp.net - How do I get the site root URL?

Question

I want to get the absolute root Url of an ASP.NET application dynamically. This needs to be the full root url to the application in the form: http(s)://hostname(:port)/

I have been using this static method:

public static string GetSiteRootUrl()
{
    string protocol;

    if (HttpContext.Current.Request.IsSecureConnection)
        protocol = "https";
    else
        protocol = "http";

    StringBuilder uri = new StringBuilder(protocol + "://");

    string hostname = HttpContext.Current.Request.Url.Host;

    uri.Append(hostname);

    int port = HttpContext.Current.Request.Url.Port;

    if (port != 80 && port != 443)
    {
        uri.Append(":");
        uri.Append(port.ToString());
    }

    return uri.ToString();
}

BUT, what if I don't have HttpContext.Current in scope? I have encountered this situation in a CacheItemRemovedCallback.

Answer 1

For WebForms, this code will return the absolute path of the application root, regardless of how nested the application may be:

HttpContext.Current.Request.Url.GetLeftPart(UriPartial.Authority) + ResolveUrl("~/")

The first part of the above returns the scheme and domain name of the application (http://localhost) without a trailing slash. The ResolveUrl code returns a relative path to the application root (/MyApplicationRoot/). By combining them together, you get the absolute path of the web forms application.

Using MVC:

HttpContext.Current.Request.Url.GetLeftPart(UriPartial.Authority) + Url.Content("~/")

or, if you are trying to use it directly in a Razor view:

@HttpContext.Current.Request.Url.GetLeftPart(UriPartial.Authority)@Url.Content("~/")