Tcl

Check if a Remote File or Directory Exists

Demonstrates the Chilkat SFtp.FileExists method, which checks a remote path and returns an integer describing what is there. The first argument is the remote path and the second (followLinks) selects whether a symbolic link is followed to its target. The return value is -1 on error, 0 if nothing exists, 1 for a file, 2 for a directory, 3 for a symbolic link, and higher values for special entry types.

Background: This returns more than a yes/no because "does it exist" usually comes with "and is it the kind of thing I expect" — a job that means to write a file should notice if a directory already occupies the path. The followLinks flag decides whether a symbolic link is reported as a link (3, only when not following) or transparently resolved to its target's type. Always handle the -1 case: it means the check itself failed, which is different from the path not existing.

Chilkat Tcl Downloads

Download Chilkat for Tcl

Tcl


load ./chilkat.dll

set success 0

#  Demonstrates the SFtp.FileExists method, which checks a remote path and returns an integer
#  describing what is there.  The 1st argument is the remote path and the 2nd (followLinks)
#  selects whether a symbolic link is followed to its target.

set sftp [new_CkSFtp]

#  Connect, authenticate, and initialize the SFTP subsystem.
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
}

set success [CkSFtp_InitializeSftp $sftp]
if {$success == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

#  When followLinks is 1, a symbolic link is followed and the target's type is returned.
set followLinks 1
set result [CkSFtp_FileExists $sftp "subdir/report.pdf" $followLinks]

#  Interpret the return value.
if {$result == -1} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

if {$result == 0} then {
    puts "The path does not exist."
}

if {$result == 1} then {
    puts "A regular file exists."
}

if {$result == 2} then {
    puts "A directory exists."
}

#  Other possible values: 3 = symbolic link (only when followLinks is 0), 4 = special
#  entry, 5 = unknown, 6 = socket, 7 = character device, 8 = block device, 9 = FIFO.

CkSFtp_Disconnect $sftp

delete_CkSFtp $sftp