(Tcl) IMAP SSH Tunneling (Port Forwarding)

Demonstrates how to setup and use an SSH tunnel for IMAP.

Note: This example requires Chilkat v11.0.0 or greater.

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load ./chilkat.dll

set success 0

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

set imap [new_CkImap]

# The SSH hostname may be a hostname or an 
# IP address, such as "192.168.1.108".
# The port is typically 22 (the standard port for SSH).
set sshHostname "www.mysshserver.com"
set sshPort 22

# Connect to an SSH server and establish the SSH tunnel:
set success [CkImap_SshOpenTunnel $imap $sshHostname $sshPort]
if {$success == 0} then {
    puts [CkImap_lastErrorText $imap]
    delete_CkImap $imap
    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.
set success [CkImap_SshAuthenticatePw $imap "mySshLogin" "mySshPassword"]
if {$success == 0} then {
    puts [CkImap_lastErrorText $imap]
    delete_CkImap $imap
    exit
}

# OK, the SSH tunnel is setup.  The IMAP component may
# be used exactly the same as usual, except all communications
# are sent through the SSH tunnel.

# Connect to an IMAP server via the 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.
CkImap_put_Ssl $imap 1
CkImap_put_Port $imap 993
set success [CkImap_Connect $imap "imap.my-imap-server.com"]
if {$success == 0} then {
    puts [CkImap_lastErrorText $imap]
    delete_CkImap $imap
    exit
}

# Authenticate with the IMAP server via the SSH tunnel.
set success [CkImap_Login $imap "myLogin" "myPassword"]
if {$success == 0} then {
    puts [CkImap_lastErrorText $imap]
    delete_CkImap $imap
    exit
}

# Select an IMAP mailbox
set success [CkImap_SelectMailbox $imap "Inbox"]
if {$success == 0} then {
    puts [CkImap_lastErrorText $imap]
    delete_CkImap $imap
    exit
}

# How many messages in Inbox?
set msgCount [CkImap_get_NumMessages $imap]
if {$msgCount == 0} then {
    puts "No messages found."
    delete_CkImap $imap
    exit
}

set upperBound 10
if {$msgCount < $upperBound} then {
    set upperBound $msgCount
}

# Download up to the 1st 10 messages.
set email [new_CkEmail]

set bUid 0
for {set i 1} {$i <= $upperBound} {incr i} {

    set success [CkImap_FetchEmail $imap 0 $i $bUid $email]
    if {$success == 0} then {
        puts [CkImap_lastErrorText $imap]
        delete_CkImap $imap
        delete_CkEmail $email
        exit
    }

    puts [CkEmail_from $email]
    puts [CkEmail_subject $email]
    puts "----"
}

# Disconnect from the IMAP server.
# The SSH tunnel remains open.
set success [CkImap_Disconnect $imap]
if {$success == 0} then {
    puts [CkImap_lastErrorText $imap]
    delete_CkImap $imap
    delete_CkEmail $email
    exit
}

# It is possible to re-use the existing SSH tunnel for the next connection:
set success [CkImap_Connect $imap "imap.my-imap-server2.com"]
if {$success == 0} then {
    puts [CkImap_lastErrorText $imap]
    delete_CkImap $imap
    delete_CkEmail $email
    exit
}

# Review the LastErrorText to see that the connection was made via the SSH tunnel:
puts [CkImap_lastErrorText $imap]

set success [CkImap_Disconnect $imap]
if {$success == 0} then {
    puts [CkImap_lastErrorText $imap]
    delete_CkImap $imap
    delete_CkEmail $email
    exit
}

# Finally, close the SSH tunnel.
set success [CkImap_SshCloseTunnel $imap]
if {$success == 0} then {
    puts [CkImap_lastErrorText $imap]
    delete_CkImap $imap
    delete_CkEmail $email
    exit
}

puts "IMAP SSH tunneling example completed."

delete_CkImap $imap
delete_CkEmail $email