Regular expression for URL

Question

I have written regex to validate URL which could be either like

• example.com

• www.example.com

• http://www.example.com

• https://www.example.com

All 4 are working

Now, if I am entering in a text like (www.example.com--thisisincorrect), it is allowing me to enter and save into db

The regex that I have used is:

http(s)?://([\w-]+\.)+[\w-]+(/[\w- ./?%&=]*)?

and

([\w-]+\.)+[\w-]+(/[\w- ./?%&=]*)?

Please help!

Answer 1

You don't need a regex for URLs, use System.Uri class for this. E.g. by using Uri.IsWellFormedUriString method for this:

bool isUri = Uri.IsWellFormedUriString(url, UriKind.RelativeOrAbsolute);

Answer 2

This works for me:

string pattern = @"^(ht|f)tp(s?)\:\/\/[0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*(:(0-9)*)*(\/?)([a-zA-Z0-9\-\.\?\,\'\/\\\+&%\$#_]*)?$";

Regex regex = new Regex(pattern, RegexOptions.Compiled | RegexOptions.IgnoreCase);

string url= txtAddressBar.Text.Trim();

if(regex.IsMatch(url)
{
  //do something
}