Find application root URL without using ~ - asp.net

Question

I need to construct the URL of a page in a String, to send it an email (as part of an email verification system). If i use the ~ symbol to denote the app root, it is taken literally.
The app will be deployed on a server on three different sites (on different ports) and each site can be accessed via 2 different URLs (one for LAn and one for internet).
So hardcoding the URL is out of question. I want to construct the url to verify.aspx in my application
Please help

Answer 1

You need this:
HttpContext.Current.Request.ApplicationPath
It's equivalent to "~" in a URL.
http://msdn.microsoft.com/en-us/library/system.web.httprequest.applicationpath.aspx

Answer 2

Unfortunately none of the methods listed generated the full url starting from http://---.
So i had to extract these from request.url. Something like this
Uri url=HttpContext.Current.Request.Url;
StringBuilder urlString = new StringBuilder();
urlString.Append(url.Scheme);
urlString.Append("://");
urlString.Append(url.Authority);
urlString.Append("/MyDesiredPath");
Can someone spot any potential problems with this?

Answer 3

Try:
HttpRequest req = HttpContext.Current.Request;
string url = req.Url.GetComponents(UriComponents.SchemeAndServer, UriFormat.SafeUnescaped)
+ ((req.ApplicationPath.Length > 1) ? req.ApplicationPath : "");

Answer 4

You need to put the URL as part of your web application's configuration. The web application does not know how it can be reached from the outside world.
E.g. consider a scenario where there's multiple proxies and load balancers in front of your web server... how would the web server know anything but its own IP?
So, you need to configure each instance of your web application by adding the base URL e.g. as an app setting in its web.config.

Answer 5

You can use HttpRequest.RawURL (docs here)property and base your URL on that, but if you are behind any kind of redirection, the RawURL may not reflect the actual URL of your application.

Answer 6

I ended up with this. I take the request url, and use the position of Request.ApplicationRoot to discover the left part of the uri. Should work with applications hosted in a virtual directory "/example" or in the root "/".
private string GetFullUrl(string relativeUrl)
{
if (string.IsNullOrWhiteSpace(relativeUrl))
throw new ArgumentNullException("relativeUrl");
if (!relativeUrl.StartsWith("/"))
throw new ArgumentException("url should start with /", "relativeUrl");
string current = Request.Url.ToString();
string applicationPath = Request.ApplicationPath;
int applicationPathIndex = current.IndexOf(applicationPath, 10, StringComparison.InvariantCultureIgnoreCase);
// should not be possible
if (applicationPathIndex == -1) throw new InvalidOperationException("Unable to derive root path");
string basePath = current.Substring(0, applicationPathIndex);
string fullRoot = string.Concat(
basePath,
(applicationPath == "/") ? string.Empty : applicationPath,
relativeUrl);
return fullRoot;
}

Answer 7

This has always worked for me:
string root = Request.Url.AbsoluteUri.Replace(Request.Url.PathAndQuery, "");