(Node.js) IMAP SSH Tunneling (Port Forwarding)

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

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

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

    var imap = new chilkat.Imap();

    // 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).
    var sshHostname = "www.mysshserver.com";
    var sshPort = 22;

    // Connect to an SSH server and establish the SSH tunnel:
    var success = imap.SshOpenTunnel(sshHostname,sshPort);
    if (success !== true) {
        console.log(imap.LastErrorText);
        return;
    }

    // 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 = imap.SshAuthenticatePw("mySshLogin","mySshPassword");
    if (success !== true) {
        console.log(imap.LastErrorText);
        return;
    }

    // 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.
    imap.Ssl = true;
    imap.Port = 993;
    success = imap.Connect("imap.my-imap-server.com");
    if (success !== true) {
        console.log(imap.LastErrorText);
        return;
    }

    // Authenticate with the IMAP server via the SSH tunnel.
    success = imap.Login("myLogin","myPassword");
    if (success !== true) {
        console.log(imap.LastErrorText);
        return;
    }

    // Select an IMAP mailbox
    success = imap.SelectMailbox("Inbox");
    if (success !== true) {
        console.log(imap.LastErrorText);
        return;
    }

    // How many messages in Inbox?
    var msgCount = imap.NumMessages;
    if (msgCount == 0) {
        console.log("No messages found.");
        return;
    }

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

    // Download up to the 1st 10 messages.
    var i;
    var bUid = false;
    for (i = 1; i <= upperBound; i++) {

        // email: Email
        var email = imap.FetchSingle(i,bUid);
        if (imap.LastMethodSuccess == false) {
            console.log(imap.LastErrorText);
            return;

        }
        else {
            console.log(email.From);
            console.log(email.Subject);
            console.log("----");

        }

    }

    // Disconnect from the IMAP server.
    // The SSH tunnel remains open.
    success = imap.Disconnect();
    if (success !== true) {
        console.log(imap.LastErrorText);
        return;
    }

    // It is possible to re-use the existing SSH tunnel for the next connection:
    success = imap.Connect("imap.my-imap-server2.com");
    if (success !== true) {
        console.log(imap.LastErrorText);
        return;
    }

    // Review the LastErrorText to see that the connection was made via the SSH tunnel:
    console.log(imap.LastErrorText);

    success = imap.Disconnect();
    if (success !== true) {
        console.log(imap.LastErrorText);
        return;
    }

    // Finally, close the SSH tunnel.
    success = imap.SshCloseTunnel();
    if (success !== true) {
        console.log(imap.LastErrorText);
        return;
    }

    console.log("IMAP SSH tunneling example completed.");

}

chilkatExample();