itemimage.php

<?php
/*
 Stendhal website - a website to manage and ease playing of Stendhal game
 Copyright (C) 2008  Miguel Angel Blanch Lardin

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

require_once 'configuration.php';

/**
 * There is a Quest that request the player to identify a fish.
 * So to avoid revealing the quest the fish image is replaced
 * with a generic one.
 *
 * @param string $resource
 */
function hideFishes($resource) {
  $shouldHide=false;

  $listOfFishes=array(
    '/arctic_char.png',
    '/clown-fish.png',
    '/cod.png',
    '/mackerel.png',
    '/perch.png',
    '/roach.png',
    '/surgeonfish.png',
    '/trout.png',
  );

  foreach($listOfFishes as $fish) {
    if(!(strpos($resource,$fish)===false)) {
      $shouldHide=true;
      break;
    }
  }

  $result=$resource;
  if($shouldHide) {
    $result="images/game/generic_fish.png";
  }

  return $result;
}

function createImageData($url) {

	// We want to hide the fishes so we don't spoil the fisherman quest.
	$url = hideFishes($url);

	$result=imagecreate(32, 32);
	// preserve alpha
	imagealphablending($result, false);
	imagesavealpha($result, true);

	$white=imagecolorallocatealpha($result, 255, 255, 255, 127);
	imagefilledrectangle($result, 0, 0,32, 32, $white);

	$baseIm=imagecreatefrompng($url);
	imagecopy($result, $baseIm,0,0,0,0,32,32);
	return $result;
}

$url = $_GET['url'];
if ((strpos($url, '..') !== false) || (strpos($url, 'data/sprites/') !== 0) || (strpos($url, '.') < strlen($url) - 4)) {
	header('HTTP/1.1 404 Not Found', true, 404);
	die("Access denied.");
}

$etag = STENDHAL_VERSION.'-'.sha1($url);
if (isset($_SERVER['HTTP_IF_NONE_MATCH'])) {
	$requestedEtag = $_SERVER['HTTP_IF_NONE_MATCH'];
}
header("Content-type: image/png");
header("Cache-Control: max-age=3888000, public"); // 45 * 24 * 60 * 60
header('Pragma: cache');
header('Etag: "'.$etag.'"');

if (isset($requestedEtag) && (($requestedEtag == $etag) || ($requestedEtag == '"'.$etag.'"'))) {
	header('HTTP/1.0 304 Not modified');
} else {
	imagepng(createImageData($url));
}