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

Answer 1

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
}

Answer 2

This is to support both http, https as optional and validate blank space is not included in url.

this.isValidURL = function (url) {

    if (!url) return false;

    const expression = /^(?:http(s)?:\/\/)?[\w.-]+(?:\.[\w\.-]+)+[\w\-\._~:/?#[\]@!\$&'\(\)\*\+,;=.]+$/gm;

    return url.match(new RegExp(expression));
}

Answer 3

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 4

Best Regex:

private bool IsUrlValid(string url)
{

    string pattern = @"^(http|https|ftp|)\://|[a-zA-Z0-9\-\.]+\.[a-zA-Z](:[a-zA-Z0-9]*)?/?([a-zA-Z0-9\-\._\?\,\'/\\\+&%\$#\=~])*[^\.\,\)\(\s]$";
    Regex reg = new Regex(pattern, RegexOptions.Compiled | RegexOptions.IgnoreCase);
    return reg.IsMatch(url);
}