Spawning node.js processes with PHP

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<?php

class Foo
{
    // ...

    protected function spawnProcess()
    {
        if (!function_exists('proc_open')) {
            throw new \RuntimeException(
                'Unable to spawn a new process. (proc_open is not available on your PHP installation.)'
            );
        }

        $descriptors = array(array('pipe', 'r'), array('pipe', 'w'), array('pipe', 'w'));
        $options = array('suppress_errors' => true, 'binary_pipes' => true, 'bypass_shell' => true);

        $this->process = proc_open(sprintf("node %s", $this->jsPath), $descriptors, $pipes, null, $options);

        if (!is_resource($this->process)) {
            throw new \RuntimeException('Unable to spawn a new process.');
        }

        foreach ($pipes as $pipe) {
            stream_set_blocking($pipe, false);
        }

        // Constantly check the 'running' state of the process until it
        // changes or drop out after a given amount of microseconds
        $status = proc_get_status($this->process);
        $time = 0;
        while (1 == $status['running'] && $time < $this->threshold) {
            $time += 1000;
            usleep(1000);
            $status = proc_get_status($this->process);
        }

        // If the process is not running, check STDERR for error messages
        // and throw exception
        if (0 == $status['running']) {
            $err = stream_get_contents($pipes[2]);
            $msg = 'Process is not running.';
            if (!empty($err)) {
                $msg .= sprintf(" (failed with error: %s", $err);
            }

            throw new \RuntimeException($msg);
        }

        // Close pipes to avoid deadlocks on proc_close
        fclose($pipes[0]);
        fclose($pipes[1]);
        fclose($pipes[2]);
    }

    protected function killProcess()
    {
        if ($this->process) {
            $status = proc_get_status($this->process);
            posix_kill($status['pid'], SIGKILL);
            proc_close($this->process);
            $this->process = null;
        }
    }

    // ...
}