Start a Remote Shell with QuickShell

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Demonstrates the Chilkat Ssh.QuickShell method, which starts a remote shell using the simplified sequence OpenSessionChannel → SendReqPty → SendReqShell. It takes no arguments and returns the shell channel number, or -1 on failure. The default PTY size is 80 columns by 24 rows.

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

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

    // Demonstrates the Ssh.QuickShell method, which starts a remote shell using the simplified
    // sequence OpenSessionChannel, SendReqPty, and SendReqShell.  It takes no arguments and returns
    // the shell channel number, or -1 on failure.  The default PTY size is 80 columns by 24 rows.

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

    const ssh_port = 22;
    ssh.connect("ssh.example.com", ssh_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;
    };

    // Start the shell.  Note that QuickShell allocates a PTY, so the remote shell runs
    // interactively: it prints a command prompt and echoes the commands that are sent to it.
    const channel_num = ssh.quickShell();
    if (channel_num < 0) {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    }

    // QuickShell returns as soon as the shell request is accepted -- it does not wait for or
    // consume the initial login text or prompt.
    ssh.channelSendString(channel_num, "uname -a; echo DONE_MARKER\n", "utf-8") 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 = false;
    ssh.channelReceiveUntilMatch(channel_num, "DONE_MARKER", "utf-8", case_sensitive) catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

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

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

    ssh.disconnect();
}