使用 PowerShell 从 FTP 服务器删除文件

Question

我编写了一个 PowerShell 脚本来使用 FTP 将文件下载到我的本地计算机。

文件下载后，我想将其从 FTP 服务器中删除。我也写了这段代码。但不幸的是，它不起作用。

谁能帮我指出我的代码有什么问题？任何线索都会有所帮助...

这是我的代码

function Delete-File($Source,$Target,$UserName,$Password)
{

    $ftprequest = [System.Net.FtpWebRequest]::create($Source)
    $ftprequest.Credentials =  New-Object System.Net.NetworkCredential($UserName,$Password)

    if(Test-Path $Source)
    {
       "ABCDEF File exists on ftp server."
       $ftprequest.Method = [System.Net.WebRequestMethods+Ftp]::DeleteFile
       $ftprequest.GetResponse()

       "ABCDEF File deleted."
    }

}

function Get-FTPFile ($Source,$Target,$UserName,$Password)  
{  

    # Create a FTPWebRequest object to handle the connection to the ftp server  
    $ftprequest = [System.Net.FtpWebRequest]::create($Source)  

    # set the request's network credentials for an authenticated connection  
    $ftprequest.Credentials =  
    New-Object System.Net.NetworkCredential($username,$password)  
    if(Test-Path $targetpath)
    {
        "ABCDEF File exists"
    }
    else 
    { 
        "ABCDEF File downloaded"
         $ftprequest.Method = [System.Net.WebRequestMethods+Ftp]::DownloadFile  

         $ftprequest.UseBinary = $true  
         $ftprequest.KeepAlive = $false  
         Delete-File $sourceuri $targetpath $user $pass
    }

    # send the ftp request to the server  
    $ftpresponse = $ftprequest.GetResponse()  

    # get a download stream from the server response  
    $responsestream = $ftpresponse.GetResponseStream()  

    # create the target file on the local system and the download buffer  
    $targetfile = New-Object IO.FileStream ($Target,[IO.FileMode]::Create)  
    [byte[]]$readbuffer = New-Object byte[] 1024  

    # loop through the download stream and send the data to the target 
    file  
    do{  
          $readlength = $responsestream.Read($readbuffer,0,1024)  
          $targetfile.Write($readbuffer,0,$readlength)  
    }  
    while ($readlength -ne 0)  

    $targetfile.close()  
}  

$sourceuri = "ftp://ftpxyz.com/vit/ABCDEF.XML"  
$targetpath = "C:\Temp\M\NEWFOLDER\ABCDEF.XML"  
$user = "*******"  
$pass = "*******"  
Get-FTPFile $sourceuri $targetpath $user $pass 
Delete-File $sourceuri $targetpath $user $pass

每次我执行这个脚本，我得到的唯一语句

ABCDEF 文件已下载

或

ABCDEF 文件存在

我猜Delete-File 根本没有执行...任何类型的线索都会有所帮助。

Answer 1

您不能将Test-Path 与 FTP URL 一起使用。所以你删除文件的代码永远不会执行。

只需删除Test-Path 条件并尝试无条件删除文件。然后检查错误并根据需要处理“文件不存在”错误。

$ftprequest = [System.Net.FtpWebRequest]::create($Source)
$ftprequest.Credentials =  New-Object System.Net.NetworkCredential($UserName, $Password)

try
{
   $ftprequest.Method = [System.Net.WebRequestMethods+Ftp]::DeleteFile
   $ftprequest.GetResponse() | Out-Null

   Write-Host ("File {0} deleted." -f $Source)
}
catch
{
    if ($_.Exception.InnerException.Response.StatusCode -eq 550)
    {
        Write-Host ("File {0} does not exist." -f $Source)
    }
    else
    {
        Write-Host $_.Exception.Message
    }
}

---

虽然您只是在成功下载文件后才尝试删除该文件，但实际上该文件不太可能不存在。

所以你可以考虑放弃任何特定的错误处理。

Answer 2

我在本地运行了您的脚本进行尝试，发现了一些问题。我还重构了一些东西，只是为了让它更具可读性（至少在我看来:)）。

问题

• 第 13 行。$Source 参数有一个ftp://... 路径。 Test-Path 将始终在此处返回 $false，并且永远不会执行删除请求。
• 在Get-FTPFile 中，您没有引用函数的输入参数，而是在它之外定义的变量。我不知道这只是一个复制和粘贴错误还是故意的。在我看来，你应该使用你发送给函数的参数。至少在我下面的代码中的第 38、39 和 50 行。

代码

function Delete-File
{  
   param(
       [string]$Source,
       [string]$Target,
       [string]$UserName,
       [string]$Password
   ) 

   $ftprequest = [System.Net.FtpWebRequest]::create($Source)
   $ftprequest.Credentials =  New-Object System.Net.NetworkCredential($UserName,$Password)

   if(Test-Path $Source)
   {
      "ABCDEF File exists on ftp server."
      $ftprequest.Method = [System.Net.WebRequestMethods+Ftp]::DeleteFile
      $ftprequest.GetResponse()

      "ABCDEF File deleted."
   }

}

function Get-FTPFile
{  
   param(
       [string]$Source,
       [string]$Target,
       [string]$UserName,
       [string]$Password
   ) 

   # Create a FTPWebRequest object to handle the connection to the ftp server  
   $ftprequest = [System.Net.FtpWebRequest]::create($Source)  

   # set the request's network credentials for an authenticated connection  
   $ftprequest.Credentials =  
   New-Object System.Net.NetworkCredential($UserName,$Password)  
   if(Test-Path $Target)
   {
       "ABCDEF File exists"
   }
   else 
   { 
       "ABCDEF File downloaded"
        $ftprequest.Method = [System.Net.WebRequestMethods+Ftp]::DownloadFile  

        $ftprequest.UseBinary = $true  
        $ftprequest.KeepAlive = $false  
        Delete-File $Source $Target $UserName $Password
  }

  # send the ftp request to the server  
  $ftpresponse = $ftprequest.GetResponse()  

  # get a download stream from the server response  
  $responsestream = $ftpresponse.GetResponseStream()  

  # create the target file on the local system and the download buffer  
  $targetfile = New-Object IO.FileStream ($Target,[IO.FileMode]::Create)  
  [byte[]]$readbuffer = New-Object byte[] 1024  

  # loop through the download stream and send the data to the target 
  file  
  do{  
        $readlength = $responsestream.Read($readbuffer,0,1024)  
        $targetfile.Write($readbuffer,0,$readlength)  
  }  
  while ($readlength -ne 0)  

  $targetfile.close()  
}  

$sourceuri = "ftp://ftpxyz.com/vit/ABCDEF.XML"  
$targetpath = "C:\Temp\M\NEWFOLDER\ABCDEF.XML"  
$user = "*******"  
$pass = "*******"   
Get-FTPFile $sourceuri $targetpath $user $pass 
#Delete-File $sourceuri $targetpath $user $pass

还有现成的 PowerShell cmdlet 用于与 FTP/SFTP 通信，除非您需要，否则无需从头开始创建所有内容。

无论如何，作为参考，请查看例如

• https://www.powershellgallery.com/packages/PSFTP
• https://www.powershellgallery.com/packages/WinSCP