PHP Extension

Check Whether an SSH Channel is Open

Demonstrates the Chilkat Ssh.ChannelIsOpen method, which reports whether a channel number identifies a channel Chilkat currently considers open for application I/O. The only argument is the channel number. This example checks the channel before and after sending CLOSE.

Background: Because one SSH connection can carry many channels with independent lifetimes, code that manages several needs a way to ask whether a given one is still usable. This returns false for invalid or nonexistent channel numbers, after a local Disconnect, once remote closure is processed, and immediately after ChannelSendClose — which marks the channel locally closed without waiting for the remote side.

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PHP Extension

<?php

include("chilkat.php");

$success = false;

//  Demonstrates the Ssh.ChannelIsOpen method, which reports whether a channel number identifies
//  a channel Chilkat currently considers open for application I/O.  The only argument is the
//  channel number.

$ssh = new CkSsh();

$sshPort = 22;
$success = $ssh->Connect('ssh.example.com',$sshPort);
if ($success == false) {
    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 == false) {
    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;
}

if ($ssh->ChannelIsOpen($channelNum)) {
    print 'The channel is open.' . "\n";
}
else {
    print 'The channel is not open.' . "\n";
}

//  Send CLOSE, which immediately marks the channel locally closed.
$success = $ssh->ChannelSendClose($channelNum);
if ($success == false) {
    print $ssh->lastErrorText() . "\n";
    exit;
}

if ($ssh->ChannelIsOpen($channelNum)) {
    print 'Still open.' . "\n";
}
else {
    print 'The channel is now closed.' . "\n";
}

$ssh->Disconnect();

?>