Perl Requires Chilkat v11.0.0+

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. Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

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

my $tunnel = Chilkat2::Socket->new;

my $sshHostname = 'sftp.example.com';
my $sshPort = 22;

# Connect to an SSH server and establish the SSH tunnel:
my $success = $tunnel->SshOpenTunnel($sshHostname, $sshPort);
if (!$success) {
    print $tunnel->LastErrorText, "\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) {
    print $tunnel->LastErrorText, "\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.

my $imap = Chilkat2::Imap->new;

# Let the IMAP object also use the SSH tunnel
$success = $imap->UseSshTunnel($tunnel);
if (!$success) {
    print $imap->LastErrorText, "\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->Ssl(1);
$imap->Port(993);
$success = $imap->Connect('imap.my-imap-server.com');
if (!$success) {
    print $imap->LastErrorText, "\n";
    exit;
}

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

# Select an IMAP mailbox
$success = $imap->SelectMailbox('Inbox');
if (!$success) {
    print $imap->LastErrorText, "\n";
    exit;
}

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

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

# Download up to the 1st 10 messages.
my $email = Chilkat2::Email->new;
my $bUid = 0;
for my $i (1 .. $upperBound) {
    $success = $imap->FetchEmail(0, $i, $bUid, $email);
    if (!$success) {
        print $imap->LastErrorText, "\n";
        exit;
    }

    print $email->From, "\n";
    print $email->Subject, "\n";
}

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

# Review the LastErrorText to see that the connection was made via the SSH tunnel:
print $imap->LastErrorText, "\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) {
    print $imap->LastErrorText, "\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) {
    print $imap->LastErrorText, "\n";
    exit;
}

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

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