在powershell中“x”秒后停止函数

Question

我目前有一个脚本在指定的端口上侦听。我希望此脚本在5秒后停止运行，无论连接与否。有没有办法可以做到这一点？某种延迟

function listen-port ($port) { 
    $endpoint = new-object System.Net.IPEndPoint ([ipaddress]::any,$port) 
    $listener = new-object System.Net.Sockets.TcpListener $endpoint 
    $listener.start() 
    $listener.AcceptTcpClient() # will block here until connection 
    $listener.stop() 
    } 
listen-port 25 

Answer 1

如果你不打算跟客户做任何事情，那么你就必须接受他们，只需停止监听：

function listen-port ($port) { 
$endpoint = new-object System.Net.IPEndPoint ([ipaddress]::any,$port) 
$listener = new-object System.Net.Sockets.TcpListener $endpoint 
$listener.start() 
Start-Sleep -s 5 
$listener.stop() 
} 

可以利用异步AcceptTcpClient方法（BeginAcceptTcpClient，EndAcceptTcpClient）如果你需要做一些与客户端：

function listen-port ($port) { 
$endpoint = new-object System.Net.IPEndPoint ([ipaddress]::any,$port) 
$listener = new-object System.Net.Sockets.TcpListener $endpoint 
$listener.start() 
$ar = $listener.BeginAcceptTcpClient($null,$null) # will not block here until connection 

if ($ar.AsyncWaitHandle.WaitOne([timespan]'0:0:5') -eq $false) 
{ 
Write-Host "no connection within 5 seconds" 
} 
else 
{ 
Write-Host "connection within 5 seconds" 
$client = $listener.EndAcceptTcpClient($ar) 
} 

$listener.stop() 
} 

另一种选择是使用Pending方法对听众：

function listen-port ($port) { 
$endpoint = new-object System.Net.IPEndPoint ([ipaddress]::any,$port) 
$listener = new-object System.Net.Sockets.TcpListener $endpoint 
$listener.start() 
Start-Sleep -s 5 

if ($listener.Pending() -eq $false) 
{ 
Write-Host "nobody connected" 
} 
else 
{ 
Write-Host "somebody connected" 
$client = $listener.AcceptTcpClient() 
} 

$listener.stop() 
}