duri - data:// URI based, non-javascript anonymous redirect script

duri.php

<?php
/**
 * duri - data:// URI based, non-javascript anonymous redirect script
 *
 * Redirects tested to ...
 *   ... work with:
 *     - Firefox (23.0.1)
 *     - Chrome (29.0.1547.76 m)
 *     - Google URL shortener <http://goo.gl/>
 *  ... not work with:
 *     - Internet Explorer (6.x)
 *     - curl (7.21.6)
 *
 * Usage:
 *    u ABSOLUTE-URI - generate base64 encoded HTML fragment for the anomyzing redirect
 *    r BASE64-CHUNK - generate HTTP location header based response to data-uri contain-
 *                     ning the base64 payload as text/html (301)
 *
 * RFC2397 - The "data" URL scheme 
 *   <http://tools.ietf.org/html/rfc2397>
 *
 * RFC2616 - Hypertext Transfer Protocol -- HTTP/1.1
 *   <http://tools.ietf.org/html/rfc2616>
 *   4.2 Message Headers - <http://tools.ietf.org/html/rfc2616#section-4.2>
 *   10.3.2 301 Moved Permanently - <http://tools.ietf.org/html/rfc2616#section-10.3.2>
 *   14.30 Location - <http://tools.ietf.org/html/rfc2616#section-14.30>
 */

if (@$_GET['u']) 
{
    $dataBase64 = Duri_GenerateBase64EncodedHtmlRefreshBody($_GET['u']);

    echo "Base64 encoded HTML: <input type=\"text\" value=\"", $dataBase64, "\"><br>\n";
    echo "<a href=\"?r=", $dataBase64, "\">Link (relative).</a><br>\n";

    $self = SapiHttpRequest::getRequestUri(FALSE);
    if (FALSE !== $self) {
        $self .= "?r=" . $dataBase64;
        echo "<a href=\"", $self,"\">Link (absolute).</a><br>\n";
    }
    
    if (isset($_GET['t'])) 
    {
        $uri = 'data:text/html;base64,' . $dataBase64;
        $tinyUrl = preg_replace('~^http://~i', 'https://', TinyUrlApi::getShortened($uri));
        echo "TinyURL (data:): <tt><a href=\"", Duri_EncodeHtmlAttributeValue($tinyUrl), "\">",Duri_EncodeHtmlText($tinyUrl),"</a></tt><br>\n";

        $tinyUrl = preg_replace('~^http://~i', 'https://', TinyUrlApi::getShortened($self));
        echo "TinyURL (chain+data:): <tt><a href=\"", Duri_EncodeHtmlAttributeValue($tinyUrl), "\">",Duri_EncodeHtmlText($tinyUrl),"</a></tt><br>\n";
    }
}


if (@$_GET['r']) {
    $url = strtr($_GET['r'], ' ', '+'); # Work around PHP oldskool URL decoding plusses to spaces by reverting it. 
                                        # Note: This is for older PHP versions,
    if (preg_match('~\s~', $url)) {
        return;
    }
    $url = 'data:text/html;base64,' . $url;
    header('Location: ' . $url, TRUE, 301);

    echo '<a href="'. Duri_EncodeHtmlAttributeValue($url) . '">Redirecting.</a>';
    return;
}

function Duri_GenerateBase64EncodedHtmlRefreshBody($absoluteUri) {
    $uriAttribute = Duri_EncodeHtmlAttributeValue($absoluteUri);
    $html = sprintf(
        '<meta http-equiv="refresh" content="0; url=%s"><a href="%1$s">Moved.</a>'
        , $uriAttribute
    );
    return rtrim(base64_encode($html), '=');
}

function Duri_EncodeHtmlText($text) {
    return htmlspecialchars($text, ENT_COMPAT, 'ISO-8859-1');
}

function Duri_EncodeHtmlAttributeValue($value) {
    return htmlspecialchars($value, ENT_COMPAT, 'ISO-8859-1');
}

/**
 * PHP Sapi Http Request abstraction
 */
class SapiHttpRequest
{
    public static function getRequestUri($includeQuery = TRUE) {
        $server = $_SERVER;

        $s = empty($server["HTTPS"]) ? '' : ($server["HTTPS"] == "on") ? "s" : "";
        
        // NOTE: This block seems superfluous, SERVER_PROTOCOL not always available,
        //       the only use is to verify it is set to some HTTP protocol if set.
        if (isset($server["SERVER_PROTOCOL"])) {
            $sp  = strtolower($server["SERVER_PROTOCOL"]);
            $spn = substr($sp, 0, strpos($sp, "/"));            
            if ($spn !== 'http') {
                trigger_error(sprintf('SERVER_PROTOCOL not HTTP: "%s"', $server["SERVER_PROTOCOL"]));
            }
        }
        $protocol = 'http' . $s;

        if (!isset($server["SERVER_PORT"])) {
            $server["SERVER_PORT"] = $s ? "443" : "80";
        }
        
        $port = ($server["SERVER_PORT"] === $s ? "443" : "80") ? "" : (":".$server["SERVER_PORT"]);
        $host = isset($server['HTTP_HOST']) ? $server['HTTP_HOST'] : $server['SERVER_NAME'];

        // codepad.viper-7.com fix PHP_SELF (indirect for REQUEST_URI)
        if ($server ["HTTP_HOST"] === "codepad.viper-7.com" && 0 === strpos($server["PHP_SELF"], $server["DOCUMENT_ROOT"])) {
            $server["PHP_SELF"] = substr($server["PHP_SELF"], strlen($server["DOCUMENT_ROOT"])) . "/55dev";
        }
        
        if (!isset($server['REQUEST_URI'])) {
            $rurib = $server["PHP_SELF"];
            isset($server["QUERY_STRING"]) && $rurib .= "?" . $server["QUERY_STRING"];
            $server['REQUEST_URI'] = $rurib;
        }

        $ruri = $server['REQUEST_URI'];

        if (!$includeQuery && FALSE !== $qpos = strpos($ruri, "?")) {
            $ruri = substr($ruri, 0, $qpos);            
        }

        return $protocol . "://" .  $host . $port . $ruri;
    }
}

/**
 * Uri Shortener Service - TinyURL implementation
 */
class TinyUrlApi
{
    public static function getShortened($uri) {
        // http://tinyurl.com/api-create.php?url=%s
        $api = new self();
        return $api->getShortenedAppspot($uri);
    }

    /**
     * TinyUrl API implementation for Appspot JSON Adapter
     * Endpoint: http://json-tinyurl.appspot.com/?url=%s
     *
     */
    private function getShortenedAppspot($uri) {
        $apiUrl      = sprintf('http://json-tinyurl.appspot.com/?url=%s', rawurlencode($uri));
        $resultJson  = @file_get_contents($apiUrl);
        if (FALSE === $resultJson) {
            return FALSE;
        }
        $result = json_decode($resultJson, TRUE);
        if ($result === NULL || !isset($result['tinyurl'], $result['ok'])) {
            return FALSE;
        }

        return $result['tinyurl'];        
    }
}

?>
<form>
  <input name="u" type="text" size="80"<?php @$_GET['u'] ? printf(' value="%s"', Duri_EncodeHtmlAttributeValue($_GET['u'])) : NULL; ?>><br>
  <label><input type="checkbox" name="t"<?php @$_GET['t'] ? printf(' checked') : NULL; ?>> Create TinyURL link</label><br>
  <input type="submit">
  <a href="?">Clear.</a>
</form>