/// <summary>
/// Gets the regular expression to validate a password.
/// </summary>
/// <param name="userName">Name of the user. This name must not occur in the password.</param>
/// <param name="p">The password policy check parameters.</param>
/// <returns>A regular expression string that can be used in .NET and Javascript.</returns>
/// <exception cref="System.ArgumentOutOfRangeException">
/// Cannot enforce \"MinNumberOfSymbols\" when \"SelectedSymbols\" is
/// empty.
/// </exception>
public static string GetRegularExpression(string userName, PasswordPolicyConfiguration p)
{
if (p.MinNumberOfSymbols != null && string.IsNullOrEmpty(p.SelectedSymbols))
{
throw new ArgumentOutOfRangeException(null, "Cannot enforce \"MinNumberOfSymbols\" when \"SelectedSymbols\" is empty.");
}
var sb = new StringBuilder("^");
if (p.MaxNumberOfAllowedRepetitions.GetValueOrDefault() > 0)
{
sb.Append($"(?=^(?:(.)(?!(?:.*\\1){{{p.MaxNumberOfAllowedRepetitions},}}))+$)");
}
p.SelectedSymbols = p.SelectedSymbols ?? "";
IEnumerable <KeyValuePair <string, int?> > lookaheadInfo = new Dictionary <string, int?>
{
{ "A-Z\\u00C0-\\u00DE", p.MinNumberOfUpperCaseChars }, /* Javascript does not support Unicode character classes */
{ "a-z\\u00DF-\\u00FF", p.MinNumberOfLowerCaseChars },
{ "0-9", p.MinNumberOfDigits },
{ RegexEscape(p.SelectedSymbols), p.MinNumberOfSymbols }
}.Where(x => x.Value.HasValue);
foreach (KeyValuePair <string, int?> kvp in lookaheadInfo)
{
sb.Append($"(?=(?:.*[{kvp.Key})]){{{kvp.Value},}})");
}
if (!string.IsNullOrEmpty(userName))
{
sb.Append($"(?!.*{RegexEscape(userName)})");
}
string matchCharClass = !string.IsNullOrEmpty(p.DisallowedChars) ? $"[^{RegexEscape(p.DisallowedChars)}]" : ".";
sb.Append($"{matchCharClass}{{{p.MinPasswordLength},}}$");
return(sb.ToString());
}
/// <summary>
/// Gets the regular expression to validate a password.
/// </summary>
/// <param name="p">The password policy check parameters.</param>
/// <returns></returns>
/// <exception cref="System.ArgumentOutOfRangeException">
/// Cannot enforce \"MinNumberOfSymbols\" when \"SelectedSymbols\" is
/// empty.
/// </exception>
public static string GetRegularExpression(PasswordPolicyConfiguration p)
{
return(GetRegularExpression(null, p));
}
