powershell - 有没有办法在powershell中使用WebClient对象来监控下载进度？

Question

我正在使用这样的简单行下载文件:

$webclient = New-Object -TypeName System.Net.WebClient
$webclient.DownloadFile("https://www.example.com/file", "C:/Local/Path/file")

问题是我想在使用弹出窗口或使用 shell 中的进度条下载时向用户显示一条消息。是否可以制作一个下载完成时消失的弹出框，或者监控下载进度的进度条？

Answer 1

要显示下载文件的进度条，请查看 Jason Niver 的博客文章:
Downloading files from the internet in Power Shell (with progress)
基本上，您可以创建一个仍使用 Web 客户端功能但包括捕获状态的方法的函数。然后，您可以使用
写入进度 Power shell 功能。

function DownloadFile($url, $targetFile)

{

   $uri = New-Object "System.Uri" "$url"

   $request = [System.Net.HttpWebRequest]::Create($uri)

   $request.set_Timeout(15000) #15 second timeout

   $response = $request.GetResponse()

   $totalLength = [System.Math]::Floor($response.get_ContentLength()/1024)

   $responseStream = $response.GetResponseStream()

   $targetStream = New-Object -TypeName System.IO.FileStream -ArgumentList $targetFile, Create

   $buffer = new-object byte[] 10KB

   $count = $responseStream.Read($buffer,0,$buffer.length)

   $downloadedBytes = $count

   while ($count -gt 0)

   {

       $targetStream.Write($buffer, 0, $count)

       $count = $responseStream.Read($buffer,0,$buffer.length)

       $downloadedBytes = $downloadedBytes + $count

       Write-Progress -activity "Downloading file '$($url.split('/') | Select -Last 1)'" -status "Downloaded ($([System.Math]::Floor($downloadedBytes/1024))K of $($totalLength)K): " -PercentComplete ((([System.Math]::Floor($downloadedBytes/1024)) / $totalLength)  * 100)

   }

   Write-Progress -activity "Finished downloading file '$($url.split('/') | Select -Last 1)'"

   $targetStream.Flush()

   $targetStream.Close()

   $targetStream.Dispose()

   $responseStream.Dispose()

}

然后你只需调用函数:

downloadFile "http://example.com/largefile.zip" "c:\temp\largefile.zip"

此外，这里还有一些来自 docs.microsoft 的用于 powshell 7 的其他写入进度示例。
Write-Progress