(Node.js) POP3 over Multiple Hop SSH

Demonstrates how to read POP3 email (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => POP3Server

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

    var ssh1 = new chilkat.Ssh();

    // Connect directly to the 1st SSH server.
    var success = ssh1.Connect("serverssh1.com",22);
    if (success !== true) {
        console.log(ssh1.LastErrorText);
        return;
    }

    // Authenticate using login/password:
    success = ssh1.AuthenticatePw("ssh1Login","ssh1Password");
    if (success !== true) {
        console.log(ssh1.LastErrorText);
        return;
    }

    // Connect through the 1st SSH connection to reach a 2nd SSH server.
    // Note: Any number of SSH connections may be simultaneously tunneled through a single
    // existing SSH connection.
    var ssh2 = new chilkat.Ssh();
    success = ssh2.ConnectThroughSsh(ssh1,"serverssh2.com",22);
    if (success !== true) {
        console.log(ssh2.LastErrorText);
        return;
    }

    // Authenticate with ssh2...
    success = ssh2.AuthenticatePw("ssh2Login","ssh2Password");
    if (success !== true) {
        console.log(ssh2.LastErrorText);
        return;
    }

    var mailman = new chilkat.MailMan();

    // Tell the mailman object to connect to the POP3 server though the ssh2 tunnel (which itself is routed through ssh1).
    // The connection looks like this:  Application => ServerSSH1 => ServerSSH2 => POP3Server
    success = mailman.UseSsh(ssh2);
    if (success !== true) {
        console.log(mailman.LastErrorText);
        return;
    }

    // Set the POP3 server's hostname
    mailman.MailHost = "pop.someMailServer.com";

    // Set the POP3 login/password.
    mailman.PopUsername = "myLogin";
    mailman.PopPassword = "myPassword";

    // Establish the POP3 connection through the ssh2 tunnel.
    success = mailman.Pop3BeginSession();
    if (success !== true) {
        console.log(mailman.LastErrorText);
        return;
    }

    // Get the number of messages in the mailbox.
    var numMessages = mailman.GetMailboxCount();

    var i = 1;

    // email: Email
    var email;
    while (i <= numMessages) {

        email = mailman.FetchByMsgnum(i);
        if (mailman.LastMethodSuccess !== true) {
            console.log(mailman.LastErrorText);
            return;
        }

        console.log(email.From + ": " + email.Subject + "\n");

        i = i+1;
    }

    // Close the connection with the POP3 server.  (This closes the tunnel through ssh2)
    // The connection with ssh2 is still alive, and may be used for more connections.
    success = mailman.Pop3EndSession();

    // Close the connection with ssh2.  (This closes the the tunnel through ssh1.)
    // The connection with ssh1 is still alive, and may be used for more connections.

    ssh2.Disconnect();

    ssh1.Disconnect();

}

chilkatExample();