How do I get Url.Action to use the right port number?

For everyone coming here who actually NEEDS an absolute path and are behind a load balanced system, here's what I came up with:

//http://stackoverflow.com/questions/126242/how-do-i-turn-a-relative-url-into-a-full-urlpublic static string AbsoluteAction(this UrlHelper url, string actionName, string controllerName, object routeValues = null){  Uri publicFacingUrl = GetPublicFacingUrl(url.RequestContext.HttpContext.Request, url.RequestContext.HttpContext.Request.ServerVariables);  string relAction = url.Action(actionName, controllerName, routeValues);  //this will always have a / in front of it.  var newPort = publicFacingUrl.Port == 80 || publicFacingUrl.Port == 443 ? "" : ":"+publicFacingUrl.Port.ToString();  return publicFacingUrl.Scheme + Uri.SchemeDelimiter + publicFacingUrl.Host + newPort + relAction;}

And then, from https://github.com/aarnott/dotnetopenid/blob/v3.4/src/DotNetOpenAuth/Messaging/HttpRequestInfo.cs via http://go4answers.webhost4life.com/Example/azure-messing-port-numbers-creates-28516.aspx

   /// <summary>    /// Gets the public facing URL for the given incoming HTTP request.    /// </summary>    /// <param name="request">The request.</param>    /// <param name="serverVariables">The server variables to consider part of the request.</param>    /// <returns>    /// The URI that the outside world used to create this request.    /// </returns>    /// <remarks>    /// Although the <paramref name="serverVariables"/> value can be obtained from    /// <see cref="HttpRequest.ServerVariables"/>, it's useful to be able to pass them    /// in so we can simulate injected values from our unit tests since the actual property    /// is a read-only kind of <see cref="NameValueCollection"/>.    /// </remarks>internal static Uri GetPublicFacingUrl(HttpRequestBase request, NameValueCollection serverVariables){  //Contract.Requires<ArgumentNullException>(request != null);  //Contract.Requires<ArgumentNullException>(serverVariables != null);  // Due to URL rewriting, cloud computing (i.e. Azure)  // and web farms, etc., we have to be VERY careful about what  // we consider the incoming URL.  We want to see the URL as it would  // appear on the public-facing side of the hosting web site.  // HttpRequest.Url gives us the internal URL in a cloud environment,  // So we use a variable that (at least from what I can tell) gives us  // the public URL:  if (serverVariables["HTTP_HOST"] != null)  {    //ErrorUtilities.VerifySupported(request.Url.Scheme == Uri.UriSchemeHttps || request.Url.Scheme == Uri.UriSchemeHttp, "Only HTTP and HTTPS are supported protocols.");    string scheme = serverVariables["HTTP_X_FORWARDED_PROTO"] ?? request.Url.Scheme;    Uri hostAndPort = new Uri(scheme + Uri.SchemeDelimiter + serverVariables["HTTP_HOST"]);    UriBuilder publicRequestUri = new UriBuilder(request.Url);    publicRequestUri.Scheme = scheme;    publicRequestUri.Host = hostAndPort.Host;    publicRequestUri.Port = hostAndPort.Port; // CC missing Uri.Port contract that's on UriBuilder.Port    return publicRequestUri.Uri;  }  // Failover to the method that works for non-web farm enviroments.  // We use Request.Url for the full path to the server, and modify it  // with Request.RawUrl to capture both the cookieless session "directory" if it exists  // and the original path in case URL rewriting is going on.  We don't want to be  // fooled by URL rewriting because we're comparing the actual URL with what's in  // the return_to parameter in some cases.  // Response.ApplyAppPathModifier(builder.Path) would have worked for the cookieless  // session, but not the URL rewriting problem.  return new Uri(request.Url, request.RawUrl);}

What happens if you just use Url.Action("Action", "Controller")? That should just generate a relative URL, which should work.

(Or perhaps a better question is: why aren't you using that overload?)

I found this worked for me...

var request = HttpContext.Request;string url = request.Url.Scheme + "://" +             request.UserHostAddress +  ":" +             request.Url.Port;