How do I get the site root URL?

I want to get the absolute root Url of an ASP.NET application dynamically. This needs to b开发者_如何学编程e 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.

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("~/")

You might try getting the raw URL and trimming off everything after the path forward slash. You could also incorporate ResolveUrl("~/").

public static string GetAppUrl()
{
    // This code is tested to work on all environments
    var oRequest = System.Web.HttpContext.Current.Request;
    return oRequest.Url.GetLeftPart(System.UriPartial.Authority)
        + System.Web.VirtualPathUtility.ToAbsolute("~/");

}

public static string GetFullRootUrl()
{   
    HttpRequest request = HttpContext.Current.Request;
    return request.Url.AbsoluteUri.Replace(request.Url.AbsolutePath, String.Empty);
}

I've solved this by adding a web.config setting in AppSettings ("SiteRootUrl"). Simple and effective, but yet another config setting to maintain.

 UrlHelper url = new UrlHelper(filterContext.RequestContext);
 string helpurl = url.Action("LogOn", "Account", new { area = "" },
                      url.RequestContext.HttpContext.Request.Url.Scheme);

Can get you the absolute url

@saluce had an excellent idea, but his code still requires an object reference and therefore can't run in some blocks of code. With the following, as long as you have a Current.Request the following will work:

With HttpContext.Current.Request
    Return .Url.GetLeftPart(UriPartial.Authority) + .ApplicationPath + If(.ApplicationPath = "/", Nothing, "/")
End With

This will work no matter the protocol, port, or root folder.

This has always worked for me

string root = Request.Url.AbsoluteUri.Replace(Request.Url.PathAndQuery, "");

Based off Uri's but stripping query strings and handling when it is a virtual directory off IIS:

private static string GetSiteRoot()
{
    string siteRoot = null;
    if (HttpContext.Current != null)
    {
        var request = HttpContext.Current.Request;
        siteRoot = request.Url.AbsoluteUri
                .Replace(request.Url.AbsolutePath, String.Empty)        // trim the current page off
                .Replace(request.Url.Query, string.Empty);              // trim the query string off

        if (request.Url.Segments.Length == 4)
        {
            // If hosted in a virtual directory, restore that segment
            siteRoot += "/" + request.Url.Segments[1];
        }

        if (!siteRoot.EndsWith("/"))
        {
            siteRoot += "/";
        }
    }

    return siteRoot;
}