(PowerShell) 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.

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Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

# 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 = New-Object Chilkat.Global
$success = $chilkatGlob.UnlockBundle("Anything for 30-day trial.")
if ($success -ne $true) {
    $($chilkatGlob.LastErrorText)
    exit
}

$tunnel = New-Object Chilkat.Socket

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

# Connect to an SSH server and establish the SSH tunnel:
$success = $tunnel.SshOpenTunnel($sshHostname,$sshPort)
if ($success -ne $true) {
    $($tunnel.LastErrorText)
    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 -ne $true) {
    $($tunnel.LastErrorText)
    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 = New-Object Chilkat.Imap

# Let the IMAP object also use the SSH tunnel
$success = $imap.UseSshTunnel($tunnel)
if ($success -ne $true) {
    $($imap.LastErrorText)
    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 = $true
$imap.Port = 993
$success = $imap.Connect("imap.my-imap-server.com")
if ($success -ne $true) {
    $($imap.LastErrorText)
    exit
}

# Authenticate with the IMAP server via the SSH tunnel.
$success = $imap.Login("myLogin","myPassword")
if ($success -ne $true) {
    $($imap.LastErrorText)
    exit
}

# Select an IMAP mailbox
$success = $imap.SelectMailbox("Inbox")
if ($success -ne $true) {
    $($imap.LastErrorText)
    exit
}

# How many messages in Inbox?
$msgCount = $imap.NumMessages
if ($msgCount -eq 0) {
    $("No messages found.")
    exit
}

$upperBound = 10
if ($msgCount -lt $upperBound) {
    $upperBound = $msgCount
}

# Download up to the 1st 10 messages.

$bUid = $false
for ($i = 1; $i -le $upperBound; $i++) {

    $email = $imap.FetchSingle($i,$bUid)
    if ($imap.LastMethodSuccess -eq $false) {
        $($imap.LastErrorText)
        exit

    }
    else {
        $($email.From)
        $($email.Subject)
        $("----")

    }

}

# Disconnect from the IMAP server.
# The SSH tunnel remains open.
$success = $imap.Disconnect()
if ($success -ne $true) {
    $($imap.LastErrorText)
    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 -ne $true) {
    $($imap.LastErrorText)
    exit
}

# Review the LastErrorText to see that the connection was made via the SSH tunnel:
$($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 -ne $true) {
    $($imap.LastErrorText)
    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 -ne $true) {
    $($imap.LastErrorText)
    exit
}

# This actually closes the SSH tunnel because it's the last object using it.
$success = $tunnel.SshCloseTunnel()
if ($success -ne $true) {
    $($tunnel.LastErrorText)
    exit
}

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