PowerShell

Resolve an Absolute Remote Path with SFTP RealPath

Demonstrates the Chilkat SFtp.RealPath method, which asks the server to canonicalize a path and returns the resulting absolute remote path. The first argument is the original path and the second is an optional compose path (SFTP v5 or later); pass an empty string when no composition is needed.

Background: The server — not the client — owns the remote filesystem's layout, so path canonicalization must happen on the server. RealPath resolves ., .., and symbolic links into a single absolute path, which is the reliable way to learn the session's home directory (canonicalize .) or to turn a relative path into an absolute one before storing or displaying it. On SFTP v5 and later, the compose path can additionally join or override the original.

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Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

#  Demonstrates the SFtp.RealPath method, which asks the server to canonicalize a path and
#  returns the resulting absolute remote path.  The 1st argument is the original path and the
#  2nd is an optional compose path (SFTP v5+), which may be an empty string.

$sftp = New-Object Chilkat.SFtp

#  Step 1: Connect the SSH transport.  Port 22 is the usual port.
$port = 22
$success = $sftp.Connect("sftp.example.com",$port)
if ($success -eq $false) {
    $($sftp.LastErrorText)
    exit
}

#  Normally you would not hard-code the password in source.  You should instead obtain it
#  from an interactive prompt, environment variable, or a secrets vault.
$password = "mySshPassword"

$success = $sftp.AuthenticatePw("mySshLogin",$password)
if ($success -eq $false) {
    $($sftp.LastErrorText)
    exit
}

#  Step 3: Open the SFTP subsystem.  This must be done after authentication and before any
#  file or directory operations.
$success = $sftp.InitializeSftp()
if ($success -eq $false) {
    $($sftp.LastErrorText)
    exit
}

#  Resolve "." to the absolute path of the session's default (home) directory.  No compose path
#  is needed, so the 2nd argument is an empty string.
$homeDir = $sftp.RealPath(".","")
if ($sftp.LastMethodSuccess -eq $false) {
    $($sftp.LastErrorText)
    exit
}

$("Home directory: " + $homeDir)

#  Canonicalize a relative path with "..", resolving it to an absolute path.
$resolved = $sftp.RealPath("subdir/../otherdir","")
if ($sftp.LastMethodSuccess -eq $false) {
    $($sftp.LastErrorText)
    exit
}

$("Resolved path: " + $resolved)

$sftp.Disconnect()