Tcl

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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Tcl


load ./chilkat.dll

set success 0

#  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.

set sftp [new_CkSFtp]

#  Step 1: Connect the SSH transport.  Port 22 is the usual port.
set port 22
set success [CkSFtp_Connect $sftp "sftp.example.com" $port]
if {$success == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    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.
set password "mySshPassword"

set success [CkSFtp_AuthenticatePw $sftp "mySshLogin" $password]
if {$success == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

#  Step 3: Open the SFTP subsystem.  This must be done after authentication and before any
#  file or directory operations.
set success [CkSFtp_InitializeSftp $sftp]
if {$success == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    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.
set homeDir [CkSFtp_realPath $sftp "." ""]
if {[CkSFtp_get_LastMethodSuccess $sftp] == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

puts "Home directory: $homeDir"

#  Canonicalize a relative path with "..", resolving it to an absolute path.
set resolved [CkSFtp_realPath $sftp "subdir/../otherdir" ""]
if {[CkSFtp_get_LastMethodSuccess $sftp] == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

puts "Resolved path: $resolved"

CkSFtp_Disconnect $sftp

delete_CkSFtp $sftp