Remove subdomains from URI

Question

I want to remove subdomain names from a URI.

Example: I want to return 'baseurl.com' from the Uri "subdomain.sub2.baseurl.com".

Is there a way of doing this using URI class or is Regex the only solution?

Thank you.

Answer 1

This should get it done:

var tlds = new List<string>()
{
    //the second- and third-level TLDs you expect go here, set to null if working with single-level TLDs only
    "co.uk"
};

Uri request = new Uri("http://subdomain.domain.co.uk");
string host = request.Host;
string hostWithoutPrefix = null;

if (tlds != null)
{
    foreach (var tld in tlds)
    {
        Regex regex = new Regex($"(?<=\\.|)\\w+\\.{tld}$");
        Match match = regex.Match(host);


        if (match.Success)
            hostWithoutPrefix = match.Groups[0].Value;
    }
}

//second/third levels not provided or not found -- try single-level
if (string.IsNullOrWhiteSpace(hostWithoutPrefix))
{
    Regex regex = new Regex("(?<=\\.|)\\w+\\.\\w+$");
    Match match = regex.Match(host);


    if (match.Success)
        hostWithoutPrefix = match.Groups[0].Value;
}