PHP ActiveX

Release an SSH Channel's Local Resources

Demonstrates the Chilkat Ssh.ChannelRelease method, which releases Chilkat's retained local resources for a channel after all output and exit information has been retrieved. The only argument is the channel number.

Background: Chilkat retains a channel's buffered output and exit information after the channel closes, so you can still read a command's final output. That retention costs memory, and a long-running program that opens many channels should release each one when finished with it. Note this is not a channel-closing method — it sends neither EOF nor CLOSE. Retrieve everything you need first, because releasing discards it.

Chilkat PHP ActiveX Downloads

Download Chilkat for PHP ActiveX

PHP ActiveX

<?php

$success = 0;

//  Demonstrates the Ssh.ChannelRelease method, which releases Chilkat's retained local resources
//  for a channel after all output and exit information has been retrieved.  The only argument is
//  the channel number.

$ssh = new COM("Chilkat.Ssh");

$sshPort = 22;
$success = $ssh->Connect('ssh.example.com',$sshPort);
if ($success == 0) {
    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.
$password = 'mySshPassword';

$success = $ssh->AuthenticatePw('mySshLogin',$password);
if ($success == 0) {
    print $ssh->LastErrorText . "\n";
    exit;
}

//  Open a session channel.  A negative return value indicates failure.
$channelNum = $ssh->OpenSessionChannel();
if ($channelNum < 0) {
    print $ssh->LastErrorText . "\n";
    exit;
}

$success = $ssh->SendReqExec($channelNum,'uname -a');
if ($success == 0) {
    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;

//  Retrieve everything of interest before releasing the channel.
$success = $ssh->ChannelReceiveToClose($channelNum);
if ($success == 0) {
    print $ssh->LastErrorText . "\n";
    exit;
}

$output = $ssh->getReceivedText($channelNum,'utf-8');
if ($ssh->LastMethodSuccess == 0) {
    print $ssh->LastErrorText . "\n";
    exit;
}

print $output . "\n";

//  Release the retained local resources.  This does not send EOF or CLOSE.
$ssh->ChannelRelease($channelNum);

$ssh->Disconnect();

?>