isFQDN static method

bool isFQDN(
  1. String value, {
  2. bool requireTld = true,
})

check if the string value is a fully qualified domain name (e.g. domain.com).

  • requireTld sets if TLD is required

Implementation

static bool isFQDN(String value, {bool requireTld = true}) {
  var parts = value.split('.');
  if (requireTld) {
    var tld = parts.removeLast();
    if (parts.isEmpty || !RegExp(r'^[a-z]{2,}$').hasMatch(tld)) {
      return false;
    }
  }

  for (var part in parts) {
    if (!RegExp(r'^[a-z\\u00a1-\\uffff0-9-]+$').hasMatch(part)) {
      return false;
    }
    if (part[0] == '-' || part[part.length - 1] == '-' || part.contains('---')) {
      return false;
    }
  }
  return true;
}