php/src/gadgets/ProxyBase.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  * This class contains the shared methods between the Proxy and makeRequest handlers
  23  */
  24 class ProxyBase {
  25   public $context;
  26   protected $disallowedHeaders = array('User-Agent', 'Keep-Alive', 'Host', 'Accept-Encoding', 'Set-Cookie', 'Content-Length', 'Content-Encoding', 'ETag', 'Last-Modified', 'Accept-Ranges', 'Vary', 'Expires', 'Date', 'Pragma', 'Cache-Control', 'Transfer-Encoding', 'If-Modified-Since');
  27
  28   public function __construct($context) {
  29     $this->context = $context;
  30   }
  31
  32   /**
  33    * Retrieves the actual content
  34    *
  35    * @param string $url the url to fetch
  36    * @return the filled in request (RemoteContentRequest)
  37    */
  38   protected function fetchContent($url, $method = 'GET') {
  39     // Check the protocol requested - curl doesn't really support file://
  40     // requests but the 'error' should be handled properly
  41     $protocolSplit = explode('://', $url, 2);
  42     if (count($protocolSplit) < 2) {
  43       throw new Exception("Invalid protocol specified");
  44     } else {
  45       $protocol = strtoupper($protocolSplit[0]);
  46       if ($protocol != "HTTP" && $protocol != "HTTPS") {
  47         throw new Exception("Invalid protocol specified in url: " . htmlentities($protocol));
  48       }
  49     }
  50     if ($method == 'POST') {
  51       $data = isset($_GET['postData']) ? $_GET['postData'] : false;
  52       if (! $data) {
  53         $data = isset($_POST['postData']) ? $_POST['postData'] : false;
  54       }
  55       $postData = '';
  56       if ($data) {
  57         $data = urldecode($data);
  58         $entries = explode('&', $data);
  59         foreach ($entries as $entry) {
  60           $parts = explode('=', $entry);
  61           // Process only if its a valid value=something pair
  62           if (count($parts) == 2) {
  63             $postData .= urlencode($parts[0]) . '=' . urlencode($parts[1]) . '&';
  64           }
  65         }
  66         // chop of the trailing &
  67         if (strlen($postData)) {
  68           $postData = substr($postData, 0, strlen($postData) - 1);
  69         }
  70       }
  71       // even if postData is an empty string, it will still post (since RemoteContentRquest checks if its false)
  72       // so the request to POST is still honored
  73       $request = new RemoteContentRequest($url, null, $postData);
  74       $request = $this->context->getHttpFetcher()->fetch($request, $this->context);
  75     } else {
  76       $request = new RemoteContentRequest($url);
  77       $request = $this->context->getHttpFetcher()->fetch($request, $this->context);
  78     }
  79     return $request;
  80   }
  81
  82   /**
  83    * Sets the caching (Cache-Control & Expires) with a cache age of $lastModified
  84    * or if $lastModified === false, sets Pragma: no-cache & Cache-Control: no-cache
  85    */
  86   protected function setCachingHeaders($lastModified = false) {
  87     $maxAge = $this->context->getIgnoreCache() ? false : $this->context->getRefreshInterval();
  88     if ($maxAge) {
  89       if ($lastModified) {
  90         header("Last-Modified: $lastModified");
  91       }
  92       // time() is a kernel call, so lets avoid it and use the request time instead
  93       $time = $_SERVER['REQUEST_TIME'];
  94       $expires = $maxAge !== false ? $time + $maxAge : $time - 3000;
  95       $public = $maxAge ? 'public' : 'private';
  96       $maxAge = $maxAge === false ? '0' : $maxAge;
  97       header("Cache-Control: {$public}; max-age={$maxAge}", true);
  98       header("Expires: " . gmdate("D, d M Y H:i:s", $expires) . " GMT", true);
  99     } else {
 100       header("Cache-Control: no-cache", true);
 101       header("Pragma: no-cache", true);
 102     }
 103   }
 104
 105   /**
 106    * Does a quick-and-dirty url validation
 107    *
 108    * @param string $url
 109    * @return string the 'validated' url
 110    */
 111   protected function validateUrl($url) {
 112     if (! @parse_url($url)) {
 113       throw new Exception("Invalid Url");
 114     } else {
 115       return $url;
 116     }
 117   }
 118
 119   /**
 120    * Returns the request headers, using the apache_request_headers function if it's
 121    * available, and otherwise tries to guess them from the $_SERVER superglobal
 122    *
 123    * @return unknown
 124    */
 125   protected function request_headers() {
 126     // Try to use apache's request headers if available
 127     if (function_exists("apache_request_headers")) {
 128       if (($headers = apache_request_headers())) {
 129         return $headers;
 130       }
 131     }
 132     // if that failed, try to create them from the _SERVER superglobal
 133     $headers = array();
 134     foreach (array_keys($_SERVER) as $skey) {
 135       if (substr($skey, 0, 5) == "HTTP_") {
 136         $headername = str_replace(" ", "-", ucwords(strtolower(str_replace("_", " ", substr($skey, 0, 5)))));
 137         $headers[$headername] = $_SERVER[$skey];
 138       }
 139     }
 140     return $headers;
 141   }
 142 }