Ports / 端口检测

checkPort() returns a full PortCheckResult for one port; isPortOpen() is the plain boolean convenience; scanPorts() runs many ports concurrently with bounded in-flight connections.

checkPort() 返回单个端口的完整 PortCheckResult；isPortOpen() 是便捷的布尔版； scanPorts() 以有界并发批量扫描多个端口。

Single port / 单端口

// Boolean convenience / 便捷布尔版
final open = await NetworkDiagnostic.isPortOpen(
  host: 'example.com',
  port: 443,
  timeout: const Duration(seconds: 3),
);
print(open ? 'HTTPS reachable' : 'HTTPS unreachable');
 
// Full result with RTT and error message / 含 RTT 与错误信息的完整结果
final result = await NetworkDiagnostic.checkPort(host: 'example.com', port: 443);
print('open=${result.isOpen} rtt=${result.responseTimeMs} ms '
      'err=${result.errorMessage}');

Bulk scan / 批量扫描

final scan = await NetworkDiagnostic.scanPorts(
  host: 'example.com',
  ports: const <int>[22, 80, 443, 8080, 8443],
  concurrency: 8,
);
 
for (final r in scan) {
  print('${r.host}:${r.port} '
        '${r.isOpen ? "open" : "closed"} '
        '${r.responseTimeMs.toStringAsFixed(1)} ms '
        '${r.errorMessage ?? ""}');
}

checkPort() returns a PortCheckResult (with isOpen, responseTimeMs and errorMessage); use isPortOpen() for a plain boolean. When you need the round-trip time or the failure reason for a single port, call checkPort() directly or pass a one-element list to scanPorts(): scanPorts(host: 'example.com', ports: [443]).first. checkPort() 返回 PortCheckResult（含 isOpen、responseTimeMs、 errorMessage）；单端口布尔诉求请用 isPortOpen()。需要 RTT 或失败原因时可直接 调用 checkPort()，或给 scanPorts(..., ports: [443]) 取单条结果。