C++

Collect Completed SSH Commands with QuickCmdCheck

Demonstrates the Chilkat Ssh.QuickCmdCheck method, which waits for any command started by QuickCmdSend to complete. The only argument is the poll timeout in milliseconds; 0 performs a nonblocking check. It returns the channel number of a completed command, -1 when commands are still pending but none finished before the timeout, or -2 when no quick commands remain or an error occurred.

Background: This is the collection half of the concurrent pattern. Each completed channel is reported only once, so looping until -2 drains every outstanding command exactly once. Distinguish the two negative values carefully: -1 simply means "still working, ask again," while -2 means there is nothing left to wait for — or that the connection failed, so check LastErrorText when the distinction matters. Manually opened exec channels are not reported here.

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C++

#include <CkSsh.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  Demonstrates the Ssh.QuickCmdCheck method, which waits for any command started by
    //  QuickCmdSend to complete.  The only argument is the poll timeout in milliseconds; 0 performs
    //  a nonblocking check.

    CkSsh ssh;

    int sshPort = 22;
    success = ssh.Connect("ssh.example.com",sshPort);
    if (success == false) {
        std::cout << ssh.lastErrorText() << "\r\n";
        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 char *password = "mySshPassword";

    success = ssh.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    //  Start two commands that will finish at different times.
    int channel1 = ssh.QuickCmdSend("sleep 2; echo first done");
    if (channel1 < 0) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    int channel2 = ssh.QuickCmdSend("echo second done");
    if (channel2 < 0) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    //  Collect the results as they complete.  The return value is the channel number of a completed
    //  command, -1 if commands are still pending but none finished before the timeout, or -2 when
    //  no quick commands remain (or an error occurred).
    int pollTimeoutMs = 5000;
    int completedChannel = ssh.QuickCmdCheck(pollTimeoutMs);
    while (completedChannel != -2) {
        if (completedChannel >= 0) {
            const char *output = ssh.getReceivedText(completedChannel,"utf-8");
            if (ssh.get_LastMethodSuccess() == false) {
                std::cout << ssh.lastErrorText() << "\r\n";
                return;
            }

            std::cout << "Channel " << completedChannel << " finished: " << output << "\r\n";
        }

        if (completedChannel == -1) {
            std::cout << "Still waiting for a command to finish..." << "\r\n";
        }

        completedChannel = ssh.QuickCmdCheck(pollTimeoutMs);
    }

    std::cout << "All quick commands have been collected." << "\r\n";

    ssh.Disconnect();
    }