Run a php server if file launched from CLI (from PayPal-PHP-SDK)

index.php

<?php

if (PHP_SAPI == 'cli') {
    // If the index.php is called using console, we would try to host
    // the built in PHP Server
    if (version_compare(phpversion(), '5.4.0', '>=') === true) {
        //exec('php -S -t ' . __DIR__ . '/');
        $cmd = "php -S localhost:5000 -t " . __DIR__;
        $descriptors = array(
            0 => array("pipe", "r"),
            1 => STDOUT,
            2 => STDERR,
        );
        $process = proc_open($cmd, $descriptors, $pipes);
        if ($process === false) {
            fprintf(STDERR,
                "Unable to launch PHP's built-in web server.\n");
            exit(2);
        }
        fclose($pipes[0]);
        $exit = proc_close($process);
        exit($exit);
    } else {
        echo "You must be running PHP version less than 5.4. You would have to manually host the website on your local web server.\n";
        exit(2);
    }
} ?>