[Sommaire] [Imprimer]

   1  <?php
   2  /**
   3  * PHP Text Cache is a simple caching class for for saving/retrieving local copies of url data
   4  * @package php_text_cache
   5  * @version 0.3-pre
   6  * @copyright (C) 2004 John Heinstein. All rights reserved
   7  * @license  http://www.gnu.org/copyleft/lesser.html LGPL License
   8  * @author John Heinstein <johnkarl@nbnet.nb.ca>
   9  * @link http://www.engageinteractive.com/php_text_cache/ PHP Text Cache Home Page
  10  * PHP Text Cache is Free Software
  11  **/
  12  
  13  if (!defined('PHP_TEXT_CACHE_INCLUDE_PATH')) {
  14      define('PHP_TEXT_CACHE_INCLUDE_PATH', (dirname(__FILE__) . "/"));
  15  }
  16  
  17  require_once (PHP_TEXT_CACHE_INCLUDE_PATH . 'php_http_connector.php');
  18  
  19  /**
  20  * A simple caching class for saving/retrieving local copies of url data
  21  *
  22  * @package php_text_cache
  23  * @author John Heinstein <johnkarl@nbnet.nb.ca>
  24  */
  25  class php_text_cache extends php_http_connector {
  26      /** @var string The directory in which cached files are stored */
  27      var $cacheDir;
  28      /** @var int The amount time of time to wait before a cached file should be updated  */
  29      var $cacheTime;
  30      /** @var boolean True if an HTTP client should be used to establish the connection  */
  31      var $doUseHTTPClient;
  32      /** @var int Time in seconds to disconnect after attempting an http connection  */
  33      var $httpTimeout;
  34  
  35      /**
  36      * Constructor
  37      * @param string Directory in which to store the cache files
  38      * @param int Expiry time for cache file (-1 signifies no expiry limit)
  39      * @param int Time in seconds to disconnect after attempting an http connection
  40      */
  41  	function php_text_cache($cacheDir = './', $cacheTime = -1, $timeout = 0) {
  42          $this->cacheDir = $cacheDir;
  43          $this->cacheTime = $cacheTime;
  44          $this->timeout = $timeout;
  45      } //php_text_cache
  46  
  47      /**
  48      * Specifies the default timeout value for connecting to a host
  49      * @param int The number of seconds to timeout when attempting to connect to a server
  50      */
  51  	function setTimeout($timeout) {
  52          $this->timeout = $timeout;
  53      } //setTimeout
  54  
  55      /**
  56      * Gets data from an url, or its cache file
  57      *
  58      * @param string The url of the data
  59      * @return string The data at the specified url
  60      */
  61  	function getData($url) {
  62          $cacheFile = $this->getCacheFileName($url);
  63  
  64          if (is_file($cacheFile)) {
  65              $fileStats = stat($cacheFile);
  66              $lastChangeTime = $fileStats[9]; //mtime
  67              $currTime = time();
  68  
  69              if (($this->cacheTime != -1) && ($currTime - $lastChangeTime) > $this->cacheTime) { //get data from url
  70                  return $this->fromURL($url, $cacheFile);
  71              }
  72              else { //get data from file
  73                  return $this->fromCache($cacheFile);
  74              }
  75          }
  76          else {
  77              return $this->fromURL($url, $cacheFile);
  78          }
  79      } //getData
  80  
  81      /**
  82      * Given an url, returns the path to the cache file
  83      *
  84      * Uses an md5 hash of the url. This can be
  85      * overridden if a different approach is required
  86      *
  87      * @param string The url of the data
  88      * @return string The cache file name
  89      */
  90  	function getCacheFileName($url) {
  91          return ($this->cacheDir . md5($url));
  92      } //getCacheFileName
  93  
  94      /**
  95      * Establishes a connection, given an url
  96      * @param string The url of the data
  97      */
  98  	function establishConnection($url) {
  99          require_once (PHP_TEXT_CACHE_INCLUDE_PATH . 'php_http_client_generic.php');
 100  
 101          $host = php_http_connection::formatHost($url);
 102          $host = substr($host, 0, strpos($host, '/'));
 103  
 104          $this->setConnection($host, '/', 80, $this->timeout);
 105      } //establishConnection
 106  
 107      /**
 108      * Specifies whether an HTTP client should be used to establish a connection
 109      * @param boolean True if an HTTP client is to be used to establish the connection
 110      */
 111  	function useHTTPClient($truthVal) {
 112          // fixes bug identified here: sarahk.pcpropertymanager.com/blog/using-domit-rss/225/
 113          //$this->doUseHTTPClient = truthVal;
 114          $this->doUseHTTPClient = $truthVal;
 115      } //useHTTPClient
 116  
 117      /**
 118      * Gets data from an url and caches a copy of the data
 119      * @param string The url for the data
 120      * @param string The cache file path
 121      * @return string The contents of the url
 122      */
 123  	function fromURL($url, $cacheFile) {
 124          $fileContents = '';
 125  
 126          if ($this->httpConnection != null) {
 127              $response =& $this->httpConnection->get($url);
 128  
 129              if ($response != null) {
 130                  $fileContents = $response->getResponse();
 131              }
 132          }
 133          else if ($this->doUseHTTPClient) {
 134              $this->establishConnection($url);
 135              $response =& $this->httpConnection->get($url);
 136  
 137              if ($response != null) {
 138                  $fileContents = $response->getResponse();
 139              }
 140          }
 141          else {
 142              $fileContents = $this->fromFile($url);
 143          }
 144  
 145          //if file is empty, might need to establish an
 146          //http connection to get the data
 147          if (($fileContents == '') && !$this->doUseHTTPClient) {
 148              $this->establishConnection($url);
 149              $response =& $this->httpConnection->get($url);
 150  
 151              if ($response != null) {
 152                  $fileContents = $response->getResponse();
 153              }
 154          }
 155  
 156          if ($fileContents != '') {
 157              require_once (PHP_TEXT_CACHE_INCLUDE_PATH . 'php_file_utilities.php');
 158              php_file_utilities::putDataToFile($cacheFile, $fileContents, 'w');
 159          }
 160  
 161          return $fileContents;
 162      } //fromURL
 163  
 164      /**
 165      * Get text from cache file
 166      * @param string The file path
 167      * @return string The text contained in the file, or an empty string
 168      */
 169  	function fromCache($cacheFile) {
 170          return $this->fromFile($cacheFile);
 171      } //fromCache
 172  
 173      /**
 174      * Get text from an url or file
 175      * @param string The url or file path
 176      * @return string The text contained in the url or file, or an empty string
 177      */
 178  	function fromFile($filename) {
 179          if (function_exists('file_get_contents')) {
 180              return @file_get_contents($filename);
 181          }
 182          else {
 183              require_once (PHP_TEXT_CACHE_INCLUDE_PATH . 'php_file_utilities.php');
 184              $fileContents =& php_file_utilities::getDataFromFile($filename, 'r');
 185              return $fileContents;
 186          }
 187  
 188          return '';
 189      } //fromFile
 190  } //php_text_cache
 191  
 192  ?>