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Receive an SSH Channel Until Close

Demonstrates the Chilkat Ssh.ChannelReceiveToClose method, which receives data on a channel until the server sends and Chilkat processes channel CLOSE. The only argument is the channel number. EOF alone does not complete this method.

Important: Set the ReadTimeoutMs property before calling this method. It defaults to 0, meaning no limit, so without it the call waits forever if the server never sends channel close.

Background: This is the simplest and most reliable way to collect the complete output of a one-shot exec command, because the server closes the channel when the command finishes. It is not appropriate for an interactive shell, which never closes on its own — use the poll-based methods there instead. Both stdout and stderr are processed, merged or kept separate according to StderrToStdout.

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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.ChannelReceiveToClose method, which receives data on a channel until the
    // server sends channel CLOSE.  The only argument is the channel number.  EOF alone does not
    // complete this method.

    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;
    };

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

    ssh.sendReqExec(channel_num, "ls -l /tmp") catch {
        std.debug.print("{s}\n", .{try ssh.getLastErrorText(alloc)});
        return;
    };

    // IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
    // it, this call waits forever if the server never sends channel close.
    ssh.setReadTimeoutMs(15000);

    // Receive everything the command produces, up to and including channel close.
    ssh.channelReceiveToClose(channel_num) 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();
}