Perl

Get Received SSH Text into a StringBuilder

Demonstrates the Chilkat Ssh.GetReceivedSb method, which decodes a channel's receive buffer and appends the text to a StringBuilder. The arguments are the channel number, the charset, and the StringBuilder. The receive buffer is cleared afterward.

Background: Because this appends rather than replaces, it is the natural choice for accumulating output across repeated reads — call it in a loop and the StringBuilder grows into the complete transcript. It also avoids creating a new string on every retrieval, which matters when a command produces a large amount of text.

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use strict;
use warnings;
use Chilkat2;

# Demonstrates the Ssh.GetReceivedSb method, which decodes the channel's receive buffer and
# appends the text to a StringBuilder.  The 1st argument is the channel number, the 2nd is the
# charset, and the 3rd is the StringBuilder.  The receive buffer is cleared afterward.

my $ssh = Chilkat2::Ssh->new;

my $sshPort = 22;
my $success = $ssh->Connect('ssh.example.com', $sshPort);
if (!$success) {
    print $ssh->LastErrorText, "\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.
my $password = 'mySshPassword';

$success = $ssh->AuthenticatePw('mySshLogin', $password);
if (!$success) {
    print $ssh->LastErrorText, "\n";
    exit;
}

my $channelNum = $ssh->OpenSessionChannel();
if ($channelNum < 0) {
    print $ssh->LastErrorText, "\n";
    exit;
}

$success = $ssh->SendReqExec($channelNum, 'ls -l /tmp');
if (!$success) {
    print $ssh->LastErrorText, "\n";
    exit;
}

# IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
# it, this call waits forever if the server never sends channel close.
$ssh->ReadTimeoutMs(15000);

$success = $ssh->ChannelReceiveToClose($channelNum);
if (!$success) {
    print $ssh->LastErrorText, "\n";
    exit;
}

# Append the received text to a StringBuilder.  Existing content is preserved.
my $sb = Chilkat2::StringBuilder->new;
$success = $ssh->GetReceivedSb($channelNum, 'utf-8', $sb);
if (!$success) {
    print $ssh->LastErrorText, "\n";
    exit;
}

print 'Characters received: ', $sb->Length, "\n";
my $output = $sb->GetAsString();
print $output, "\n";

$ssh->Disconnect();