isURL static method

bool isURL(String? str, { List<String?> protocols = const ['http', 'https', 'ftp'], bool requireTld = true, bool requireProtocol = false, bool allowUnderscore = false, List<String> hostWhitelist = const [], List<String> hostBlacklist = const [], })

Implementation

static bool isURL(String? str,
    {List<String?> protocols = const ['http', 'https', 'ftp'],
    bool requireTld = true,
    bool requireProtocol = false,
    bool allowUnderscore = false,
    List<String> hostWhitelist = const [],
    List<String> hostBlacklist = const []}) {
  if (str == null || str.isEmpty || str.length > 2083 || str.startsWith('mailto:')) {
    return false;
  }
  int port;
  String? protocol, auth, user;
  String host, hostname, portStr, path, query, hash;

  // check protocol
  var split = str.split('://');
  if (split.length > 1) {
    protocol = shift(split);
    if (!protocols.contains(protocol)) {
      return false;
    }
  } else if (requireProtocol == true) {
    return false;
  }
  str = split.join('://');

  // check hash
  split = str.split('#');
  str = shift(split);
  hash = split.join('#');
  if (hash.isNotEmpty && RegExp(r'\s').hasMatch(hash)) {
    return false;
  }

  // check query params
  split = str!.split('?');
  str = shift(split);
  query = split.join('?');
  if (query.isNotEmpty && RegExp(r'\s').hasMatch(query)) {
    return false;
  }

  // check path
  split = str!.split('/');
  str = shift(split);
  path = split.join('/');
  if (path.isNotEmpty && RegExp(r'\s').hasMatch(path)) {
    return false;
  }

  // check auth type urls
  split = str!.split('@');
  if (split.length > 1) {
    auth = shift(split);
    if (auth?.contains(':') ?? false) {
      user = shift(auth!.split(':'))!;
      if (!RegExp(r'^\S+$').hasMatch(user)) {
        return false;
      }
      if (!RegExp(r'^\S*$').hasMatch(user)) {
        return false;
      }
    }
  }

  // check hostname
  hostname = split.join('@');
  split = hostname.split(':');
  host = shift(split)!;
  if (split.isNotEmpty) {
    portStr = split.join(':');
    try {
      port = int.parse(portStr, radix: 10);
    } catch (e) {
      return false;
    }
    if (!RegExp(r'^\d+$').hasMatch(portStr) || port <= 0 || port > 65535) {
      return false;
    }
  }

  if (!BasicIPValidator.isIP(host, null) &&
      !isFullDomainName(host, requireTld: requireTld, allowUnderscores: allowUnderscore) &&
      host != 'localhost') {
    return false;
  }

  if (hostWhitelist.isNotEmpty && !hostWhitelist.contains(host)) {
    return false;
  }

  if (hostBlacklist.isNotEmpty && hostBlacklist.contains(host)) {
    return false;
  }

  return true;
}