class UriUtility { static bool isURL(String url) { // Validate if the URL string is empty, or contains spaces or invalid characters if (url.isEmpty || RegExp(r'[\s<>]').hasMatch(url)) { print('URL is either empty or contains spaces/invalid characters.'); return false; } // Check for 'mailto:' at the start of the URL if (url.startsWith('mailto:')) { print('URL starts with "mailto:".'); return false; } // Try to parse the URL, return false if parsing fails Uri? uri; try { uri = Uri.parse(url); } catch (e) { print('URL parsing failed: $e'); return false; } // Validate the URL has a scheme (protocol) and host if (uri.scheme.isEmpty || uri.host.isEmpty) { print('URL is missing a scheme (protocol) or host.'); return false; } // Check if the URI has user info, which is not a common case for a valid HTTP/HTTPS URL if (uri.hasAuthority && uri.userInfo.contains(':') && uri.userInfo.split(':').length > 2) { print('URL contains invalid user info.'); return false; } // Validate the port number if exists if (uri.hasPort && (uri.port <= 0 || uri.port > 65535)) { print('URL contains an invalid port number.'); return false; } print('URL is valid.'); return true; } }