Perl

Multiple SendReqExec on the Same Connection

Demonstrates running a series of commands on one SSH connection using SendReqExec. Each exec request requires its own logical channel — this is not a separate SSH connection, just a new session channel on the existing one.

Background: An SSH session channel is single-use for an exec request: once the command runs and the server closes the channel, that channel cannot be reused. Opening a fresh channel per command is cheap, since the expensive work — the TCP connection, key exchange, and authentication — is done once and shared. This is why running ten commands over one connection is far faster than connecting ten times.

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Perl

use chilkat();

$success = 0;

#  This example requires the Chilkat API to have been previously unlocked.
#  See Global Unlock Sample for sample code.

#  Demonstrates running a series of commands on one SSH connection using SendReqExec.  Each exec
#  request requires its own logical channel.  This is not a new SSH connection -- it is simply a
#  new session channel on the existing one.

$ssh = chilkat::CkSsh->new();

$hostname = "ssh.example.com";
$port = 22;
$success = $ssh->Connect($hostname,$port);
if ($success == 0) {
    print $ssh->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 = $ssh->AuthenticatePw("mySshLogin",$password);
if ($success == 0) {
    print $ssh->lastErrorText() . "\r\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->put_ReadTimeoutMs(15000);

#  ---- 1st command, on its own session channel ----
$channelNum = $ssh->OpenSessionChannel();
if ($channelNum < 0) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

$success = $ssh->SendReqExec($channelNum,"ls -al");
if ($success == 0) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

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

$cmdOutput = $ssh->getReceivedText($channelNum,"utf-8");
if ($ssh->get_LastMethodSuccess() == 0) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

print $cmdOutput . "\r\n";
print "----" . "\r\n";

#  ---- 2nd command, on a NEW session channel over the same connection ----
$channelNum = $ssh->OpenSessionChannel();
if ($channelNum < 0) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

$success = $ssh->SendReqExec($channelNum,"nslookup chilkatsoft.com");
if ($success == 0) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

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

$cmdOutput = $ssh->getReceivedText($channelNum,"utf-8");
if ($ssh->get_LastMethodSuccess() == 0) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

print $cmdOutput . "\r\n";

$ssh->Disconnect();