Using a C # regular expression to parse a domain name?

Question

I need to parse a domain name from a string. The string can change, and I need the exact domain.

Examples of lines:

http://somename.de/ www.somename.de/ somename.de/ somename.de/somesubdirectory www.somename.de/?pe=12 

I need it in the following format with the domain name, tld and www , if applicable:

 www.somename.de 

How to do it with C #?

Answer 1

i simple used

  Uri uri = new Uri("http://www.google.com/search?q=439489"); string url = uri.Host.ToString(); return url; 

because using this, you can be sure.

Answer 2

As an alternative to regex, you can let the System.Uri class System.Uri the string for you. You just need to make sure the string contains the schema.

 string uriString = "http://www.google.com/search"; if (!uriString.Contains(Uri.SchemeDelimiter)) { uriString = string.Concat(Uri.UriSchemeHttp, Uri.SchemeDelimiter, uriString); } string domain = new Uri(uriString).Host; 

This solution also filters out any port numbers and translates IPv6 addresses to its canonical form.

Answer 3

I checked the Regular Expression Library , and it looks like this might work for you:

 ^(([\w][\w\-\.]*)\.)?([\w][\w\-]+)(\.([\w][\w\.]*))?$ 

Answer 4

Try the following:

 ^(?:\w+://)?([^/?]*) 

this is a weak regular expression - it does not check the string, but assumes that it is already a URL, and receives the first word before the first slash, ignoring the protocol. To get a domain in the first captured group, for example:

 string url = "http://www.google.com/hello"; Match match = Regex.Match(url, @"^(?:\w+://)?([^/?]*)"); string domain = match.Groups[1].Value; 

As a bonus, is he also captured before the first ? so url google.com?hello=world will work as expected.