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Connect to an SSH Server Through Another (Jump Host)

Demonstrates the Chilkat Ssh.ConnectThroughSsh method, which connects to a second SSH server through an already connected and authenticated Ssh object. The first argument is the first (jump-host) Ssh object, and the second and third are the destination hostname and port.

Background: This is SSH chaining through a "jump host" (bastion): the application connects to a reachable gateway, then tunnels onward to a target that is only accessible from inside the network. Each hop is authenticated separately with its own credentials. The result is a normal Ssh object for the target that happens to be routed through the first connection.

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

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

    // Demonstrates the Ssh.ConnectThroughSsh method, which connects to a second SSH server through
    // an already connected and authenticated Ssh object (a jump host).  The 1st argument is the
    // first Ssh object, and the 2nd and 3rd are the destination hostname and port.

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

    // Connect and authenticate to the first SSH server (the jump host).
    const ssh_port = 22;
    ssh_jump.connect("jump.example.com", ssh_port) catch {
        std.debug.print("{s}\n", .{try ssh_jump.getLastErrorText(alloc)});
        return;
    };

    // Normally you would not hard-code the password in source.  You should instead obtain it
    // from an interactive prompt, environment variable, or a secrets vault.
    const password = "mySshPassword";

    ssh_jump.authenticatePw("jumpUser", password) catch {
        std.debug.print("{s}\n", .{try ssh_jump.getLastErrorText(alloc)});
        return;
    };

    // Connect to the target SSH server through the jump host.
    const ssh_target = try chilkat.Ssh.init();
    defer ssh_target.deinit();
    ssh_target.connectThroughSsh(ssh_jump, "target.example.com", ssh_port) catch {
        std.debug.print("{s}\n", .{try ssh_target.getLastErrorText(alloc)});
        return;
    };

    // Authenticate to the target server (separate credentials).
    ssh_target.authenticatePw("targetUser", password) catch {
        std.debug.print("{s}\n", .{try ssh_target.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("Connected to the target through the jump host.\n", .{});

    ssh_target.disconnect();
    ssh_jump.disconnect();
}