php/src/gadgets/ProxyHandler.php

   1 <?php
   2 /**
   3  * Licensed to the Apache Software Foundation (ASF) under one
   4  * or more contributor license agreements.  See the NOTICE file
   5  * distributed with this work for additional information
   6  * regarding copyright ownership.  The ASF licenses this file
   7  * to you under the Apache License, Version 2.0 (the
   8  * "License"); you may not use this file except in compliance
   9  * with the License.  You may obtain a copy of the License at
  10  *
  11  *     http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing,
  14  * software distributed under the License is distributed on an
  15  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  16  * KIND, either express or implied.  See the License for the
  17  * specific language governing permissions and limitations
  18  * under the License.
  19  */
  20
  21 /**
  22  * The ProxyHandler class does the actual proxy'ing work. it deals both with
  23  * GET and POST based input, and peforms a request based on the input, headers and
  24  * httpmethod params.
  25  *
  26  */
  27 class ProxyHandler extends ProxyBase {
  28
  29   /**
  30    * Fetches the content and returns it as-is using the headers as returned
  31    * by the remote host.
  32    *
  33    * @param string $url the url to retrieve
  34    */
  35   public function fetch($url) {
  36     $url = $this->validateUrl($url);
  37     $request = $this->buildRequest($url, 'GET');
  38     $request->getOptions()->ignoreCache = $this->context->getIgnoreCache();
  39     $result = $this->context->getHttpFetcher()->fetch($request);
  40     $httpCode = (int)$result->getHttpCode();
  41     $isShockwaveFlash = false;
  42     foreach ($result->getResponseHeaders() as $key => $val) {
  43       if (! in_array($key, $this->disallowedHeaders)) {
  44         header("$key: $val", true);
  45       }
  46       if ($key == 'Content-Type' && strtolower($val) == 'application/x-shockwave-flash') {
  47         // We're skipping the content disposition header for flash due to an issue with Flash player 10
  48         // This does make some sites a higher value phishing target, but this can be mitigated by
  49         // additional referer checks.
  50         $isShockwaveFlash = true;
  51       }
  52     }
  53     if (! $isShockwaveFlash) {
  54       header('Content-Disposition: attachment;filename=p.txt');
  55     }
  56     $lastModified = $result->getResponseHeader('Last-Modified') != null ? $result->getResponseHeader('Last-Modified') : gmdate('D, d M Y H:i:s', $result->getCreated()) . ' GMT';
  57     $notModified = false;
  58     if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) && $lastModified && ! isset($_SERVER['HTTP_IF_NONE_MATCH'])) {
  59       $if_modified_since = strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']);
  60       // Use the request's Last-Modified, otherwise fall back on our internal time keeping (the time the request was created)
  61       $lastModified = strtotime($lastModified);
  62       if ($lastModified <= $if_modified_since) {
  63         $notModified = true;
  64       }
  65     }
  66     if ($httpCode == 200) {
  67       // only set caching headers if the result was 'OK'
  68       $this->setCachingHeaders($lastModified);
  69       // was the &gadget=<gadget url> specified in the request? if so parse it and check the rewrite settings
  70       if (isset($_GET['gadget'])) {
  71         $this->rewriteContent($_GET['gadget'], $result);
  72       }
  73     }
  74     // If the cached file time is within the refreshInterval params value, return not-modified
  75     if ($notModified) {
  76       header('HTTP/1.0 304 Not Modified', true);
  77       header('Content-Length: 0', true);
  78     } else {
  79       // then echo the content
  80       echo $result->getResponseContent();
  81     }
  82   }
  83
  84   private function rewriteContent($gadgetUrl, RemoteContentRequest &$result) {
  85     try {
  86       // At the moment we're only able to rewrite CSS files, so check the content type and/or the file extension before rewriting
  87       $headers = $result->getResponseHeaders();
  88       $isCss = false;
  89       if (isset($headers['Content-Type']) && strtolower($headers['Content-Type'] == 'text/csss')) {
  90         $isCss = true;
  91       } else {
  92         $ext = substr($_GET['url'], strrpos($_GET['url'], '.') + 1);
  93         $isCss = strtolower($ext) == 'css';
  94       }
  95       if ($isCss) {
  96         $gadget = $this->createGadget($gadgetUrl);
  97         $rewrite = $gadget->gadgetSpec->rewrite;
  98         if (is_array($rewrite)) {
  99           $contentRewriter = new ContentRewriter($this->context, $gadget);
 100           $result->setResponseContent($contentRewriter->rewriteCSS($result->getResponseContent()));
 101         }
 102       }
 103     } catch (Exception $e) {
 104       // ignore, not being able to rewrite anything isn't fatal
 105     }
 106
 107   }
 108
 109   /**
 110    * Uses the GadgetFactory to instrance the specified gadget
 111    *
 112    * @param string $gadgetUrl
 113    */
 114   private function createGadget($gadgetUrl) {
 115     // Only include these files if appropiate, else it would slow down the entire proxy way to much
 116     require_once 'src/gadgets/GadgetSpecParser.php';
 117     require_once 'src/gadgets/GadgetBlacklist.php';
 118     require_once 'src/gadgets/sample/BasicGadgetBlacklist.php';
 119     require_once 'src/gadgets/GadgetContext.php';
 120     require_once 'src/gadgets/GadgetFactory.php';
 121     require_once 'src/gadgets/GadgetSpec.php';
 122     require_once 'src/gadgets/Gadget.php';
 123     require_once 'src/gadgets/GadgetException.php';
 124     require_once 'src/gadgets/rewrite/GadgetRewriter.php';
 125     require_once 'src/gadgets/rewrite/DomRewriter.php';
 126     require_once 'src/gadgets/rewrite/ContentRewriter.php';
 127     // make sure our context returns the gadget url and not the proxied document url
 128     $this->context->setUrl($gadgetUrl);
 129     // and create & return the gadget
 130     $gadgetSpecFactory = new GadgetFactory($this->context, null);
 131     $gadget = $gadgetSpecFactory->createGadget();
 132     return $gadget;
 133   }
 134 }