Check file existence on FTP server in PowerShell

Question

I want to check if some file exists on FTP server. I wrote code with Test-Path but it's not working. Then I wrote code to get FTP server file size, but it's not working either.

My code

function File-size()
{
   Param ([int]$size)
   if($size -gt 1TB) {[string]::Format("{0:0.00} TB ",$size /1TB)}
   elseif($size -gt 1GB) {[string]::Format("{0:0.00} GB ",$size/1GB)}
   elseif($size -gt 1MB) {[string]::Format("{0:0.00} MB ",$size/1MB)}
   elseif($size -gt 1KB) {[string]::Format("{0:0.00} KB ",$size/1KB)}
   elseif($size -gt 0) {[string]::Format("{0:0.00} B ",$size)}
   else                {""}
}

$urlDest = "ftp://ftpxyz.com/folder/ABCDEF.XML"
$sourcefilesize = Get-Content($urlDest)
$size = File-size($sourcefilesize.length)
Write-Host($size)

This code is not working.

ERROR

Get-Content : Cannot find drive. A drive with the name 'ftp' does not exist.At C:\documents\upload-file.ps1:67 char:19 + $sourcefilesize = Get-Item($urlDest) + ~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : ObjectNotFound: (ftp:String) [Get-Content], DriveNotFoundException + FullyQualifiedErrorId : DriveNotFound,Microsoft.PowerShell.Commands.GetContentCommand

Any idea how to solve this error? Is there any way I can check some exists into FTP server? Any clue regarding this will be helpful.

Answer 1

You cannot use Test-Path nor Get-Content with FTP URL.

You have to use FTP client, like WebRequest (FtpWebRequest).

Though it does not have any explicit method to check file existence. You need to abuse a request like GetFileSize or GetDateTimestamp.

$url = "ftp://ftp.example.com/remote/path/file.txt"

$request = [Net.WebRequest]::Create($url)
$request.Credentials = New-Object System.Net.NetworkCredential("username", "password");
$request.Method = [System.Net.WebRequestMethods+Ftp]::GetFileSize

try
{
    $request.GetResponse() | Out-Null
    Write-Host "Exists"
}
catch
{
    $response = $_.Exception.InnerException.Response;
    if ($response.StatusCode -eq [System.Net.FtpStatusCode]::ActionNotTakenFileUnavailable)
    {
        Write-Host "Does not exist"
    }
    else
    {
        Write-Host ("Error: " + $_.Exception.Message)
    }
}

The code is based on C# code from How to check if file exists on FTP before FtpWebRequest.

---

If you want a more straightforward code, use some 3rd party FTP library.

For example with WinSCP .NET assembly, you can use its Session.FileExists method:

Add-Type -Path "WinSCPnet.dll"

$sessionOptions = New-Object WinSCP.SessionOptions -Property @{
    Protocol = [WinSCP.Protocol]::Ftp
    HostName = "ftp.example.com"
    UserName = "username"
    Password = "password"
}

$session = New-Object WinSCP.Session
$session.Open($sessionOptions)

if ($session.FileExists("/remote/path/file.txt"))
{
    Write-Host "Exists"
}
else
{
    Write-Host "Does not exist"
}

(I'm the author of WinSCP)