Zig Requires Chilkat v11.0.0+

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

Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

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

    const ssh1 = try chilkat.Ssh.init();
    defer ssh1.deinit();

    // Connect directly to the 1st SSH server.
    ssh1.connect("serverssh1.com", 22) catch {
        std.debug.print("{s}\n", .{try ssh1.getLastErrorText(alloc)});
        return;
    };

    // Authenticate using login/password:
    ssh1.authenticatePw("ssh1Login", "ssh1Password") catch {
        std.debug.print("{s}\n", .{try ssh1.getLastErrorText(alloc)});
        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.
    const ssh2 = try chilkat.Ssh.init();
    defer ssh2.deinit();
    ssh2.connectThroughSsh(ssh1, "serverssh2.com", 22) catch {
        std.debug.print("{s}\n", .{try ssh2.getLastErrorText(alloc)});
        return;
    };

    // Authenticate with ssh2...
    ssh2.authenticatePw("ssh2Login", "ssh2Password") catch {
        std.debug.print("{s}\n", .{try ssh2.getLastErrorText(alloc)});
        return;
    };

    const mailman = try chilkat.MailMan.init();
    defer mailman.deinit();

    // 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
    mailman.useSsh(ssh2) catch {
        std.debug.print("{s}\n", .{try mailman.getLastErrorText(alloc)});
        return;
    };

    // Set the POP3 server's hostname
    mailman.setMailHost("pop.example.com");

    // Set the POP3 login/password.
    mailman.setPopUsername("myLogin");
    mailman.setPopPassword("myPassword");

    // Establish the POP3 connection through the ssh2 tunnel.
    mailman.pop3BeginSession() catch {
        std.debug.print("{s}\n", .{try mailman.getLastErrorText(alloc)});
        return;
    };

    // Get the number of messages in the mailbox.
    const num_messages = mailman.getMailboxCount();

    const email = try chilkat.Email.init();
    defer email.deinit();
    var i: i32 = 1;
    while (i <= num_messages) {
        // Fetch by the message number (not by the UIDL)
        mailman.fetchOne(false, 0, i, email) catch {
            std.debug.print("{s}\n", .{try mailman.getLastErrorText(alloc)});
            return;
        };

        std.debug.print("{s}: {s}\n\n", .{ try email.getFrom(alloc), try email.getSubject(alloc) });

        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.
    try 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();
}