(Perl) IMAP Use Existing SSH Tunnel

Demonstrates how to connect to an IMAP server using an existing SSH tunnel. This creates a new channel within the SSH tunnel, which can be a TCP or TLS connection, and is connected to a remote IMAP server through port forwarding.

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

# Starting in v9.5.0.49, all Chilkat classes can be unlocked at once at the beginning of a program
# by calling UnlockBundle.  It requires a Bundle unlock code.
$chilkatGlob = chilkat::CkGlobal->new();
$success = $chilkatGlob->UnlockBundle("Anything for 30-day trial.");
if ($success != 1) {
    print $chilkatGlob->lastErrorText() . "\r\n";
    exit;
}

$tunnel = chilkat::CkSocket->new();

$sshHostname = "www.my-ssh-server.com";
$sshPort = 22;

# Connect to an SSH server and establish the SSH tunnel:
$success = $tunnel->SshOpenTunnel($sshHostname,$sshPort);
if ($success != 1) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

# Authenticate with the SSH server via a login/password
# or with a public key.  
# This example demonstrates SSH password authentication.
# Note: This is not authenticating with the IMAP server, it is
# for authenticating with the SSH server, which is separate.
$success = $tunnel->SshAuthenticatePw("mySshLogin","mySshPassword");
if ($success != 1) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

# OK, the SSH tunnel is setup.  Now open a channel within the tunnel.
# Once the channel is obtained, the Socket API may
# be used exactly the same as usual, except all communications
# are sent through the channel in the SSH tunnel.
# Any number of channels may be created from the same SSH tunnel.
# Multiple channels may coexist at the same time.

$imap = chilkat::CkImap->new();

# Let the IMAP object also use the SSH tunnel
$success = $imap->UseSshTunnel($tunnel);
if ($success != 1) {
    print $imap->lastErrorText() . "\r\n";
    exit;
}

# Connect to an IMAP server via the already established SSH tunnel.
# Because the SSH tunnel has been previously setup,
# this does not establish a direct connection with the IMAP
# server.  It directs the SSH server to establish the connection.

# In this example, the IMAP server requires SSL/TLS.  The TLS connection
# will be enclosed within the SSH tunnel.
$imap->put_Ssl(1);
$imap->put_Port(993);
$success = $imap->Connect("imap.my-imap-server.com");
if ($success != 1) {
    print $imap->lastErrorText() . "\r\n";
    exit;
}

# Authenticate with the IMAP server via the SSH tunnel.
$success = $imap->Login("myLogin","myPassword");
if ($success != 1) {
    print $imap->lastErrorText() . "\r\n";
    exit;
}

# Select an IMAP mailbox
$success = $imap->SelectMailbox("Inbox");
if ($success != 1) {
    print $imap->lastErrorText() . "\r\n";
    exit;
}

# How many messages in Inbox?
$msgCount = $imap->get_NumMessages();
if ($msgCount == 0) {
    print "No messages found." . "\r\n";
    exit;
}

$upperBound = 10;
if ($msgCount < $upperBound) {
    $upperBound = $msgCount;
}

# Download up to the 1st 10 messages.

$bUid = 0;
for ($i = 1; $i <= $upperBound; $i++) {

    # email is a Email
    $email = $imap->FetchSingle($i,$bUid);
    if ($imap->get_LastMethodSuccess() == 0) {
        print $imap->lastErrorText() . "\r\n";
        exit;

    }
    else {
        print $email->ck_from() . "\r\n";
        print $email->subject() . "\r\n";
        print "----" . "\r\n";

    }

}

# Disconnect from the IMAP server.
# The SSH tunnel remains open.
$success = $imap->Disconnect();
if ($success != 1) {
    print $imap->lastErrorText() . "\r\n";
    exit;
}

# It is possible to re-use the existing SSH tunnel for the next connection:
$success = $imap->Connect("imap.my-imap-server2.com");
if ($success != 1) {
    print $imap->lastErrorText() . "\r\n";
    exit;
}

# Review the LastErrorText to see that the connection was made via the SSH tunnel:
print $imap->lastErrorText() . "\r\n";

# This closes the SSH channel, which is the connection with the IMAP server.
# It does not close the SSH tunnel
$success = $imap->Disconnect();
if ($success != 1) {
    print $imap->lastErrorText() . "\r\n";
    exit;
}

# Finally, close the SSH tunnel.

# Note: If other objects are using the same SSH tunnel, the tunnel is not 
# actually closed.  It is only closed when the last object using the tunnel closes it.

# At this point, both the imap and tunnel objects have references to the internal
# SSH tunnel.  We need to close each.

# This call doesn't actually close the tunnel yet, because the tunnel object still
# holds an internal reference.
$success = $imap->SshCloseTunnel();
if ($success != 1) {
    print $imap->lastErrorText() . "\r\n";
    exit;
}

# This actually closes the SSH tunnel because it's the last object using it.
$success = $tunnel->SshCloseTunnel();
if ($success != 1) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

print "IMAP pre-existing SSH tunnel example completed." . "\r\n";