在powershell中「x」秒後停止函數

Question

我目前有一個腳本在指定的端口上偵聽。我希望此腳本在5秒後停止運行，無論連接與否。有沒有辦法可以做到這一點？某種延遲

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

如果你不打算跟客戶做任何事情，那麼你就必須接受他們，只需停止監聽：

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() 
} 

可以利用異步AcceptTcpClient方法（BeginAcceptTcpClient，EndAcceptTcpClient）如果你需要做一些與客戶端：

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() 
} 

另一種選擇是使用Pending方法對聽衆：

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() 
}