CkPython

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. CkPython

import sys
import chilkat

success = False

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

tunnel = chilkat.CkSocket()

sshHostname = "sftp.example.com"
sshPort = 22

# Connect to an SSH server and establish the SSH tunnel:
success = tunnel.SshOpenTunnel(sshHostname,sshPort)
if (success == False):
    print(tunnel.lastErrorText())
    sys.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 == False):
    print(tunnel.lastErrorText())
    sys.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()

# Let the IMAP object also use the SSH tunnel
success = imap.UseSshTunnel(tunnel)
if (success == False):
    print(imap.lastErrorText())
    sys.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(True)
imap.put_Port(993)
success = imap.Connect("imap.my-imap-server.com")
if (success == False):
    print(imap.lastErrorText())
    sys.exit()

# Authenticate with the IMAP server via the SSH tunnel.
success = imap.Login("myLogin","myPassword")
if (success == False):
    print(imap.lastErrorText())
    sys.exit()

# Select an IMAP mailbox
success = imap.SelectMailbox("Inbox")
if (success == False):
    print(imap.lastErrorText())
    sys.exit()

# How many messages in Inbox?
msgCount = imap.get_NumMessages()
if (msgCount == 0):
    print("No messages found.")
    sys.exit()

upperBound = 10
if (msgCount < upperBound):
    upperBound = msgCount

# Download up to the 1st 10 messages.
email = chilkat.CkEmail()

bUid = False
for i in range(1,(upperBound)-1):

    success = imap.FetchEmail(False,i,bUid,email)
    if (success == False):
        print(imap.lastErrorText())
        sys.exit()

    print(email.ck_from())
    print(email.subject())

# Disconnect from the IMAP server.
# The SSH tunnel remains open.
success = imap.Disconnect()
if (success == False):
    print(imap.lastErrorText())
    sys.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 == False):
    print(imap.lastErrorText())
    sys.exit()

# Review the LastErrorText to see that the connection was made via the SSH tunnel:
print(imap.lastErrorText())

# 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 == False):
    print(imap.lastErrorText())
    sys.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 == False):
    print(imap.lastErrorText())
    sys.exit()

# This actually closes the SSH tunnel because it's the last object using it.
success = tunnel.SshCloseTunnel()
if (success == False):
    print(tunnel.lastErrorText())
    sys.exit()

print("IMAP pre-existing SSH tunnel example completed.")