PowerShell System.Net.WebClient never closes ftp connection - powershell

Question

I'm trying to use PowerShell to upload a (long) list of queued files, using System.Net.WebClient and the UploadFile function. This works fine, but after a file us uploaded, the ftp-connection never closes, either when the WebClient object instance goes out of scope or even after the script has finished. The function looks as follows:
function Upload-File() {
Param (
[string] $user,
[string] $password,
[string] $srceFileName,
[string] $destFileName
)
# Set up FTP-client
$client = New-Object System.Net.WebClient
$client.Credentials = New-Object System.Net.NetworkCredential($user, $password)
$client.UploadFile($destFileName, ".\$srceFileName")
$client.Dispose()
}
All the information I can find states that the connection should close automatically when $client goes out of scope but this is clearly not happening.
Any idea on how to force the connection to close?
(This is part of a legacy system and for now I am stuck with ftp, so switching to another protocol is not an option.)

Answer 1

For anyone else running into this problem, the solution is to use FtpWebRequest instead of WebClient and to set KeepAlive = $false. The function below will upload and then terminate the connection immediately afterwards.
function Upload-File() {
Param (
[string] $user,
[string] $password,
[string] $srceFileName,
[string] $destFileName
)
$request = [Net.WebRequest]::Create($destFileName)
$request.KeepAlive = $false
$request.Credentials =
New-Object System.Net.NetworkCredential($user, $password)
$request.Method = [System.Net.WebRequestMethods+Ftp]::UploadFile
$fileStream = [System.IO.File]::OpenRead(".\$srceFileName")
$ftpStream = $request.GetRequestStream()
$fileStream.CopyTo($ftpStream)
$ftpStream.Dispose()
$fileStream.Dispose()
}
This post pointed me in the right direction.