Perl

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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Perl

use chilkat();

$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.

$sftp = chilkat::CkSFtp->new();

#  Connect, authenticate, and initialize the SFTP subsystem.
$port = 22;
$success = $sftp->Connect("sftp.example.com",$port);
if ($success == 0) {
    print $sftp->lastErrorText() . "\r\n";
    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 == 0) {
    print $sftp->lastErrorText() . "\r\n";
    exit;
}

$success = $sftp->InitializeSftp();
if ($success == 0) {
    print $sftp->lastErrorText() . "\r\n";
    exit;
}

#  When followLinks is 1, a symbolic link is followed and the target's type is returned.
$followLinks = 1;
$result = $sftp->FileExists("subdir/report.pdf",$followLinks);

#  Interpret the return value.
if ($result == -1) {
    print $sftp->lastErrorText() . "\r\n";
    exit;
}

if ($result == 0) {
    print "The path does not exist." . "\r\n";
}

if ($result == 1) {
    print "A regular file exists." . "\r\n";
}

if ($result == 2) {
    print "A directory exists." . "\r\n";
}

#  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.

$sftp->Disconnect();