PowerShell，运行外部进程时流处理输出和错误

Question

我正在使用 PowerShell 脚本来执行控制台应用程序，并尝试从那里重定向标准输出和标准错误。我使用的代码如下:

$ProcessInfo = New-Object System.Diagnostics.ProcessStartInfo 
$ProcessInfo.FileName = "myExe.exe"
$ProcessInfo.Arguments = "bla bla bla"
$ProcessInfo.RedirectStandardError = $true 
$ProcessInfo.RedirectStandardOutput = $true 
$ProcessInfo.UseShellExecute = $false 
$Process = New-Object System.Diagnostics.Process 
$Process.StartInfo = $ProcessInfo 

$Process.Start() | Out-Null 
$output = $Process.StandardOutput.ReadToEnd() 
$errors = $Process.StandardError.ReadToEnd()
$Process.WaitForExit() 
$output 
$errors 

return $Process.ExitCode

到目前为止一切顺利，如果我有错误，我可以看到它被重定向到我的 PowerShell 控制台，如果我有输出，它也会被重定向。问题是这个过程需要 10 分钟，而在此期间我们不知道发生了什么。

在 PowerShell 中，有什么方法可以在进程运行时流式传输输出和错误的内容吗？在纯.NET中我们可以订阅Process类的事件，我可以在PowerShell中做同样的事情吗？

Answer 1

Is there any way in PowerShell I can stream the content of the Output and the Error while the process is running? In pure .NET we can subscribe to events of the Process class, can I do the same in PowerShell?

当然可以!您需要的是 Object Events :

An object event is a .Net object that not only has the usual Properties and Methods in the object, but also has another member called Event, which you can register a subscription on using Register-ObjectEvent

这里是来自 PowerShell forums 的示例，稍加修改。它将异步地从 ping 命令输出数据( at least from the script point of view ):

# Setup stdin\stdout redirection
$StartInfo = New-Object System.Diagnostics.ProcessStartInfo -Property @{
                FileName = 'ping.exe'
                Arguments = '-t 127.0.0.1'
                UseShellExecute = $false
                RedirectStandardOutput = $true
                RedirectStandardError = $true
            }

# Create new process
$Process = New-Object System.Diagnostics.Process

# Assign previously created StartInfo properties
$Process.StartInfo = $StartInfo

# Register Object Events for stdin\stdout reading
$OutEvent = Register-ObjectEvent -Action {
    Write-Host $Event.SourceEventArgs.Data
} -InputObject $Process -EventName OutputDataReceived

$ErrEvent = Register-ObjectEvent -Action {
    Write-Host $Event.SourceEventArgs.Data
} -InputObject $Process -EventName ErrorDataReceived

# Start process
[void]$Process.Start()

# Begin reading stdin\stdout
$Process.BeginOutputReadLine()
$Process.BeginErrorReadLine()

# Do something else while events are firing
do
{
    Write-Host 'Still alive!' -ForegroundColor Green
    Start-Sleep -Seconds 1
}
while (!$Process.HasExited)

# Unregister events
$OutEvent.Name, $ErrEvent.Name |
    ForEach-Object {Unregister-Event -SourceIdentifier $_}