<?php

/**

 * Generates version 4 UUIDs

 * from https://github.com/ramsey/uuid/blob/2.8/src/Uuid.php

 * and http://stackoverflow.com/a/2040279

 *

 * @return string

 */

function genUuid4() {

    if (function_exists('openssl_random_pseudo_bytes')) {

        $bytes = openssl_random_pseudo_bytes(16);

    }

    else {

        $bytes = '';

        mt_srand(crc32(serialize([microtime(true), 'USER_IP', 'ETC'])));

        for ($i = 1; $i <= $length; $i++) {

            $bytes = chr(mt_rand(0, 255)) . $bytes;

        }

    }

    $bytes[6] = chr(ord($bytes[6]) & 0x0f | 0x40); // set version to 0100

    $bytes[8] = chr(ord($bytes[8]) & 0x3f | 0x80); // set bits 6-7 to 10

    return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($bytes), 4));

}

/**

 * get page self url

 * from http://stackoverflow.com/a/2236887

 */

function strleft($s1, $s2) { return substr($s1, 0, strpos($s1, $s2)); }

function selfURL()

{

    $s = empty($_SERVER["HTTPS"]) ? '' : ($_SERVER["HTTPS"] == "on") ? "s" : "";

    $protocol = strleft(strtolower($_SERVER["SERVER_PROTOCOL"]), "/").$s;

    $port = ($_SERVER["SERVER_PORT"] == "80") ? "" : (":".$_SERVER["SERVER_PORT"]);

    return $protocol."://".$_SERVER['SERVER_NAME'].$port.$_SERVER['REQUEST_URI'];

}

function selfBaseURL()

{

    $s = empty($_SERVER["HTTPS"]) ? '' : ($_SERVER["HTTPS"] == "on") ? "s" : "";

    $protocol = strleft(strtolower($_SERVER["SERVER_PROTOCOL"]), "/").$s;

    $port = ($_SERVER["SERVER_PORT"] == "80") ? "" : (":".$_SERVER["SERVER_PORT"]);

    return $protocol."://".$_SERVER['SERVER_NAME'].$port.dirname($_SERVER['REQUEST_URI']);

}