Perl sFTP : how to check remote file doesnt exist - perl

Question

I am 1 day old to Perl, was going through API doc here, have few basic questions
$sftp = Net::SFTP::Foreign->new($host, autodie => 1);
my $ls = $sftp->ls("/bar");
# dies as: "Couldn't open remote dir '/bar': No such file"
Question
with autodie will the connection be auto closed ?
we see in above example how to use folder , similar syntax also works for file ?
Or something like this makes more sense ??
my $sftp = Net::SFTP::Foreign->new($host, autodie => 1);
$sftp->find("/sdfjkalshfl", # nonexistent directory
on_error => sub { print "foo!\n";sftp->disconnect();exit; });
I was trying to run following code on my windows machine
use Net::SFTP::Foreign;
my $host = "demo.wftpserver.com";
my $sftp = Net::SFTP::Foreign->new($host ,ssh_cmd => 'plink',autodie => 1);
my $ls = $sftp->ls("/bar");
But i get error
'plink' is not recognized as an internal or external command ,
however when i run plink from windows command line it works fine !!

Answer 1

with autodie will the connection be auto closed ?
Yes. When the program ends, everything is destroyed and connections are closed. That is also the case when the $sftp variable goes out of scope. Modules like this usually implement a DESTROY sub. Those are invoked when the object (which is just a reference in Perl) goes out of scope. There can be some cleanup in that sub. Another example that has that is DBI, and of course lexical filehandles (like $fh from a open call).
we see in above example how to use folder , similar syntax also works for file ?
No. The docs say ls is for a directory:
Fetches a listing of the remote directory $remote. If $remote is not given, the current remote working directory is listed.
But you can just do ls for the directory that the file you want is in, and use the wanted option.
my $ls = $sftp->ls( '/home/foo', wanted => qr/^filename.txt$/ );
Though with the autodie that should die, so if you don't want it to actually die here, you should wrap it in a Try::Tiny call or an eval.
use Try::Tiny
# ...
my $ls = try {
return $sftp->ls( '/home/foo', wanted => qr/^filename.txt$/ );
} catch {
return; # will return undef
};
say 'Found file "filename.txt" on remote server' if $ls;
As to plink being not found, probably the Windows PATH is different from what your Perl sees.