Ruby

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.

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Ruby

require 'chilkat'

success = false

#  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.

sftp = Chilkat::CkSFtp.new()

#  Connect, authenticate, and initialize the SFTP subsystem.
port = 22
success = sftp.Connect("sftp.example.com",port)
if (success == false)
    print sftp.lastErrorText() + "\n";
    exit
end

#  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 == false)
    print sftp.lastErrorText() + "\n";
    exit
end

success = sftp.InitializeSftp()
if (success == false)
    print sftp.lastErrorText() + "\n";
    exit
end

#  When followLinks is true, a symbolic link is followed and the target's type is returned.
followLinks = true
result = sftp.FileExists("subdir/report.pdf",followLinks)

#  Interpret the return value.
if (result == -1)
    print sftp.lastErrorText() + "\n";
    exit
end

if (result == 0)
    print "The path does not exist." + "\n";
end

if (result == 1)
    print "A regular file exists." + "\n";
end

if (result == 2)
    print "A directory exists." + "\n";
end

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

sftp.Disconnect()