old/combine.php

<?php
    $cache = true;
    $cachedir = dirname(__FILE__) . '/assets/cache';
    $cssdir = dirname(__FILE__) . '/assets/css';
    $jsdir = dirname(__FILE__) . '/assets/js';

// Determine the directory and type we should use
    switch ($_GET['type']) {
        case 'css':
            $base = realpath($cssdir);
            break;
        case 'javascript':
            $base = realpath($jsdir);
            break;
        default:
            header("HTTP/1.0 503 Not Implemented");
            exit;
    };

    $type = $_GET['type'];
    $elements = explode(',', $_GET['files']);

// Determine last modification date of the files
    $lastmodified = 0;
    while (list(, $element) = each($elements)) {
        $path = realpath($base . '/' . $element);

        if (($type == 'javascript' && substr($path, -3) != '.js') ||
            ($type == 'css' && substr($path, -4) != '.css')) {
            header("HTTP/1.0 403 Forbidden");
            exit;
        }

        if (substr($path, 0, strlen($base)) != $base || !file_exists($path)) {
            header("HTTP/1.0 404 Not Found");
            exit;
        }

        $lastmodified = max($lastmodified, filemtime($path));
    }

// Send Etag hash
    $hash = $lastmodified . '-' . md5($_GET['files']);
    header("Etag: \"" . $hash . "\"");

    if (isset($_SERVER['HTTP_IF_NONE_MATCH']) &&
        stripslashes($_SERVER['HTTP_IF_NONE_MATCH']) == '"' . $hash . '"') {
        // Return visit and no modifications, so do not send anything
        header("HTTP/1.0 304 Not Modified");
        header('Content-Length: 0');
    } else {
        // First time visit or files were modified
        if ($cache) {
            // Determine supported compression method
            $gzip = strstr($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip');
            $deflate = strstr($_SERVER['HTTP_ACCEPT_ENCODING'], 'deflate');

            // Determine used compression method
            $encoding = $gzip ? 'gzip' : ($deflate ? 'deflate' : 'none');

            // Check for buggy versions of Internet Explorer
            if (!strstr($_SERVER['HTTP_USER_AGENT'], 'Opera') &&
                preg_match('/^Mozilla\/4\.0 \(compatible; MSIE ([0-9]\.[0-9])/i', $_SERVER['HTTP_USER_AGENT'], $matches)) {
                $version = floatval($matches[1]);

                if ($version < 6)
                    $encoding = 'none';

                if ($version == 6 && !strstr($_SERVER['HTTP_USER_AGENT'], 'EV1'))
                    $encoding = 'none';
            }

            // Try the cache first to see if the combined files were already generated
            $cachefile = 'cache-' . $hash . '.' . $type . ($encoding != 'none' ? '.' . $encoding : '');

            if (file_exists($cachedir . '/' . $cachefile)) {
                if ($fp = fopen($cachedir . '/' . $cachefile, 'rb')) {

                    if ($encoding != 'none') {
                        header("Content-Encoding: " . $encoding);
                    }

                    header("Content-Type: text/" . $type);
                    header("Content-Length: " . filesize($cachedir . '/' . $cachefile));

                    fpassthru($fp);
                    fclose($fp);
                    exit;
                }
            }
        }

        // Get contents of the files
        $contents = '';
        reset($elements);
        while (list(, $element) = each($elements)) {
            $path = realpath($base . '/' . $element);
            $contents .= "\n\n" . file_get_contents($path);
//            $contents = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $contents);
//            $contents = str_replace(': ', ':', $contents);
//            $contents = str_replace(array("\r\n", "\r", "\n", "\t", '  ', '    ', '    '), '', $contents);
//        $contents = fn_minify_css($contents);
        }

        // Send Content-Type
        header("Content-Type: text/" . $type);

        if (isset($encoding) && $encoding != 'none') {
            // Send compressed contents
            $contents = gzencode($contents, 9, $gzip ? FORCE_GZIP : FORCE_DEFLATE);
            header("Content-Encoding: " . $encoding);
            header('Content-Length: ' . strlen($contents));
            echo $contents;
        } else {
            // Send regular contents
            header('Content-Length: ' . strlen($contents));
            echo $contents;
        }
        echo strlen($contents);

        // Store cache
        if ($cache) {
            if ($fp = fopen($cachedir . '/' . $cachefile, 'wb')) {
                fwrite($fp, $contents);
                fclose($fp);
            }
        }
    }

    define('MINIFY_STRING', '"(?:[^"\\\]|\\\.)*"|\'(?:[^\'\\\]|\\\.)*\'');
    define('MINIFY_COMMENT_CSS', '/\*[\s\S]*?\*/');
    define('MINIFY_COMMENT_HTML', '<!\-{2}[\s\S]*?\-{2}>');
    define('X', "\x1A");

    function n($s)
    {
        return str_replace(["\r\n", "\r"], "\n", $s);
    }

    function t($a, $b)
    {
        if ($a && strpos($a, $b) === 0 && substr($a, -strlen($b)) === $b) {
            return substr(substr($a, strlen($b)), 0, -strlen($b));
        }
        return $a;
    }

    function fn_minify($pattern, $input)
    {
        return preg_split('#(' . implode('|', $pattern) . ')#', $input, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
    }

    function fn_minify_css($input, $comment = 2, $quote = 2)
    {
        if (!is_string($input) || !$input = n(trim($input))) return $input;
        $output = $prev = "";
        foreach (fn_minify([MINIFY_COMMENT_CSS, MINIFY_STRING], $input) as $part) {
            if (trim($part) === "") continue;
            if ($comment !== 1 && strpos($part, '/*') === 0 && substr($part, -2) === '*/') {
                if (
                    $comment === 2 && (
                        // Detect special comment(s) from the third character. It should be a `!` or `*` → `/*! keep */` or `/** keep */`
                        strpos('*!', $part[2]) !== false ||
                        // Detect license comment(s) from the content. It should contains character(s) like `@license`
                        stripos($part, '@licence') !== false || // noun
                        stripos($part, '@license') !== false || // verb
                        stripos($part, '@preserve') !== false
                    )
                ) {
                    $output .= $part;
                }
                continue;
            }
            if ($part[0] === '"' && substr($part, -1) === '"' || $part[0] === "'" && substr($part, -1) === "'") {
                // Remove quote(s) where possible …
                $q = $part[0];
                if (
                    $quote !== 1 && (
                        // <https://www.w3.org/TR/CSS2/syndata.html#uri>
                        substr($prev, -4) === 'url(' && preg_match('#\burl\($#', $prev) ||
                        // <https://www.w3.org/TR/CSS2/syndata.html#characters>
                        substr($prev, -1) === '=' && preg_match('#^' . $q . '[a-zA-Z_][\w-]*?' . $q . '$#', $part)
                    )
                ) {
                    $part = t($part, $q); // trim quote(s)
                }
                $output .= $part;
            } else {
                $output .= fn_minify_css_union($part);
            }
            $prev = $part;
        }
        return trim($output);
    }

    function fn_minify_css_union($input)
    {
        if (stripos($input, 'calc(') !== false) {
            // Keep important white–space(s) in `calc()`
            $input = preg_replace_callback('#\b(calc\()\s*(.*?)\s*\)#i', function ($m) {
                return $m[1] . preg_replace('#\s+#', X, $m[2]) . ')';
            }, $input);
        }
        $input = preg_replace([
            // Fix case for `#foo<space>[bar="baz"]`, `#foo<space>*` and `#foo<space>:first-child` [^1]
            '#(?<=[\w])\s+(\*|\[|:[\w-]+)#',
            // Fix case for `[bar="baz"]<space>.foo`, `*<space>.foo`, `:nth-child(2)<space>.foo` and `@media<space>(foo: bar)<space>and<space>(baz: qux)` [^2]
            '#([*\]\)])\s+(?=[\w\#.])#', '#\b\s+\(#', '#\)\s+\b#',
            // Minify HEX color code … [^3]
            '#\#([a-f\d])\1([a-f\d])\2([a-f\d])\3\b#i',
            // Remove white–space(s) around punctuation(s) [^4]
            '#\s*([~!@*\(\)+=\{\}\[\]:;,>\/])\s*#',
            // Replace zero unit(s) with `0` [^5]
            '#\b(?<!\d\.)(?:0+\.)?0+(?:[a-z]+\b)#i',
            // Replace `0.6` with `.6` [^6]
            '#\b0+\.(\d+)#',
            // Replace `:0 0`, `:0 0 0` and `:0 0 0 0` with `:0` [^7]
            '#:(0\s+){0,3}0(?=[!,;\)\}]|$)#',
            // Replace `background(?:-position)?:(0|none)` with `background$1:0 0` [^8]
            '#\b(background(?:-position)?):(?:0|none)([;,\}])#i',
            // Replace `(border(?:-radius)?|outline):none` with `$1:0` [^9]
            '#\b(border(?:-radius)?|outline):none\b#i',
            // Remove empty selector(s) [^10]
            '#(^|[\{\}])(?:[^\{\}]+)\{\}#',
            // Remove the last semi–colon and replace multiple semi–colon(s) with a semi–colon [^11]
            '#;+([;\}])#',
            // Replace multiple white–space(s) with a space [^12]
            '#\s+#'
        ], [
            // [^1]
            X . '$1',
            // [^2]
            '$1' . X, X . '(', ')' . X,
            // [^3]
            '#$1$2$3',
            // [^4]
            '$1',
            // [^5]
            '0',
            // [^6]
            '.$1',
            // [^7]
            ':0',
            // [^8]
            '$1:0 0$2',
            // [^9]
            '$1:0',
            // [^10]
            '$1',
            // [^11]
            '$1',
            // [^12]
            ' '
        ], $input);
        return trim(str_replace(X, ' ', $input));
    }