php execute a background process

Question

I need to execute a directory copy upon a user action, but the directories are quite large, so I would like to be able to perform such an action without the user being aware

Answer 1

Use this function to run your program in background. It cross-platform and fully customizable.

 is_string($redirectStdout) ? array('file', $redirectStdout, 'w') : array('pipe', 'w'),
        2 => is_string($redirectStderr) ? array('file', $redirectStderr, 'w') : array('pipe', 'w'),
    );
    if (is_string($stdin)) {
        $descriptorspec[0] = array('pipe', 'r');
    }
    $proc = proc_open($command, $descriptorspec, $pipes, $cwd, $env, $other_options);
    if (!is_resource($proc)) {
        throw new \Exception("Failed to start background process by command: $command");
    }
    if (is_string($stdin)) {
        fwrite($pipes[0], $stdin);
        fclose($pipes[0]);
    }
    if (!is_string($redirectStdout)) {
        fclose($pipes[1]);
    }
    if (!is_string($redirectStderr)) {
        fclose($pipes[2]);
    }
    return $proc;
}

Note that after command started, by default this function closes the stdin and stdout of running process. You can redirect process output into some file via $redirectStdout and $redirectStderr arguments.

Note for windows users:
You cannot redirect stdout/stderr to nul in the following manner:

startBackgroundProcess('ping yandex.com', null, 'nul', 'nul');

However, you can do this:

startBackgroundProcess('ping yandex.com >nul 2>&1');

Notes for *nix users:

1) Use exec shell command if you want get actual PID:

$proc = startBackgroundProcess('exec ping yandex.com -c 15', null, '/dev/null', '/dev/null');
print_r(proc_get_status($proc));

2) Use $stdin argument if you want to pass some data to the input of your program:

startBackgroundProcess('cat > input.txt', "Hello world!\n");