SSH Remote Shell with Multiple Commands

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Demonstrates running several commands one after another in a single remote shell session, retrieving each command's output separately. No PTY is requested, so each command is followed by an echoed marker that signals where its output ends.

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.

    // Demonstrates running several commands one after another in a single remote shell session,
    // retrieving each command's output separately.
    //
    // No PTY is requested, so the shell runs non-interactively and never prints a command prompt.
    // Because there is no prompt to synchronize on, each command is followed by an "echo" of a
    // unique marker, and the output is read up to that marker.

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

    const hostname = "ssh.example.com";
    const port = 22;
    ssh.connect(hostname, port) catch {
        std.debug.print("{s}\n", .{try ssh.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.authenticatePw("mySshLogin", password) catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    const channel_num = ssh.openSessionChannel();
    if (channel_num < 0) {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    }

    // Start a shell WITHOUT requesting a PTY.  Without a PTY the shell sees it is connected to a
    // raw data pipe and enters non-interactive mode: it suppresses the command prompt, does not
    // echo typed commands back, and skips interactive login scripts.  The output is therefore
    // clean and easily parseable -- but because no prompt is ever sent, code must not wait for
    // one.  Instead, have each command print a predictable marker, or wait for EOF / channel close.
    ssh.sendReqShell(channel_num) catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    // IMPORTANT: Set a read timeout before receiving until a match.  ReadTimeoutMs defaults to 0,
    // which means no limit -- without it, this call waits forever if the received data never
    // contains a match.
    ssh.setReadTimeoutMs(15000);

    const case_sensitive = true;

    // ---- 1st command: change directory ----
    ssh.channelSendString(channel_num, "cd /tmp; echo END_OF_CMD_1\n", "utf-8") catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    ssh.channelReceiveUntilMatch(channel_num, "END_OF_CMD_1", "utf-8", case_sensitive) catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    // Retrieving the text also clears the receive buffer, which matters: if the next marker were
    // left in the buffer, the following receive would match immediately.
    var cmd_output: [:0]const u8 = ssh.getReceivedText(alloc, channel_num, "utf-8") catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("{s}\n", .{cmd_output});

    // ---- 2nd command: directory listing ----
    ssh.channelSendString(channel_num, "ls; echo END_OF_CMD_2\n", "utf-8") catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    ssh.channelReceiveUntilMatch(channel_num, "END_OF_CMD_2", "utf-8", case_sensitive) catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    cmd_output = ssh.getReceivedText(alloc, channel_num, "utf-8") catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("{s}\n", .{cmd_output});

    // ---- 3rd command: long listing, then finish the session ----
    ssh.channelSendString(channel_num, "ls -l\n", "utf-8") catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    // No more input will be sent.
    ssh.channelSendEof(channel_num) catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    ssh.channelReceiveToClose(channel_num) catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    cmd_output = ssh.getReceivedText(alloc, channel_num, "utf-8") catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("{s}\n", .{cmd_output});

    ssh.disconnect();
}