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<?php |
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/** |
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* Project: MagpieRSS: a simple RSS integration tool |
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* File: rss_cache.inc, a simple, rolling(no GC), cache |
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* for RSS objects, keyed on URL. |
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* Author: Kellan Elliott-McCrea <[email protected]> |
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* Version: 0.51 |
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* License: GPL |
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* |
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* The lastest version of MagpieRSS can be obtained from: |
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* http://magpierss.sourceforge.net |
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* |
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* For questions, help, comments, discussion, etc., please join the |
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* Magpie mailing list: |
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* http://lists.sourceforge.net/lists/listinfo/magpierss-general |
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* @package chamilo.include.rss |
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*/ |
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/** |
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* @package chamilo.include.rss |
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*/ |
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class RSSCache { |
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public $BASE_CACHE = './cache'; // where the cache files are stored |
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public $MAX_AGE = 3600; // when are files stale, default one hour |
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public $ERROR = ""; // accumulate error messages |
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public function RSSCache ($base='', $age='') { |
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if ( $base ) { |
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$this->BASE_CACHE = $base; |
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} |
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if ( $age ) { |
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$this->MAX_AGE = $age; |
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} |
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// attempt to make the cache directory |
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if ( ! file_exists( $this->BASE_CACHE ) ) { |
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$status = @mkdir( $this->BASE_CACHE, 0755 ); |
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// if make failed |
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if ( ! $status ) { |
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$this->error( |
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"Cache couldn't make dir '" . $this->BASE_CACHE . "'." |
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); |
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} |
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} |
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} |
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/*=======================================================================*\ |
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Function: set |
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Purpose: add an item to the cache, keyed on url |
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Input: url from wich the rss file was fetched |
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Output: true on sucess |
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\*=======================================================================*/ |
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public function set ($url, $rss) { |
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$this->ERROR = ""; |
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$cache_file = $this->file_name( $url ); |
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$fp = @fopen( $cache_file, 'w' ); |
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if ( ! $fp ) { |
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$this->error( |
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"Cache unable to open file for writing: $cache_file" |
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); |
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return 0; |
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} |
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$data = $this->serialize( $rss ); |
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fwrite( $fp, $data ); |
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fclose( $fp ); |
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return $cache_file; |
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} |
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/*=======================================================================*\ |
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Function: get |
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Purpose: fetch an item from the cache |
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Input: url from wich the rss file was fetched |
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Output: cached object on HIT, false on MISS |
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\*=======================================================================*/ |
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public function get ($url) { |
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$this->ERROR = ""; |
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$cache_file = $this->file_name( $url ); |
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if ( ! file_exists( $cache_file ) ) { |
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$this->debug( |
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"Cache doesn't contain: $url (cache file: $cache_file)" |
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); |
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return 0; |
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} |
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$fp = @fopen($cache_file, 'r'); |
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if ( ! $fp ) { |
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$this->error( |
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"Failed to open cache file for reading: $cache_file" |
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); |
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return 0; |
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} |
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if ($filesize = filesize($cache_file) ) { |
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$data = fread( $fp, filesize($cache_file) ); |
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$rss = $this->unserialize( $data ); |
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return $rss; |
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} |
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return 0; |
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} |
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/*=======================================================================*\ |
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Function: check_cache |
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Purpose: check a url for membership in the cache |
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and whether the object is older then MAX_AGE (ie. STALE) |
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Input: url from wich the rss file was fetched |
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Output: cached object on HIT, false on MISS |
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\*=======================================================================*/ |
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public function check_cache ( $url ) { |
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$this->ERROR = ""; |
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$filename = $this->file_name( $url ); |
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if ( file_exists( $filename ) ) { |
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// find how long ago the file was added to the cache |
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// and whether that is longer then MAX_AGE |
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$mtime = filemtime( $filename ); |
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$age = time() - $mtime; |
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if ( $this->MAX_AGE > $age ) { |
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// object exists and is current |
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return 'HIT'; |
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} |
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else { |
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// object exists but is old |
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return 'STALE'; |
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} |
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} |
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else { |
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// object does not exist |
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return 'MISS'; |
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} |
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} |
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public function cache_age( $url ) { |
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$filename = $this->file_name( $url); |
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if ( file_exists( $filename ) ) { |
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$mtime = filemtime( $filename ); |
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$age = time() - $mtime; |
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return $age; |
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} |
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else { |
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return -1; |
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} |
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} |
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/*=======================================================================*\ |
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Function: serialize |
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\*=======================================================================*/ |
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public function serialize ( $rss ) { |
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return serialize( $rss ); |
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} |
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/*=======================================================================*\ |
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Function: unserialize |
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\*=======================================================================*/ |
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public function unserialize ( $data ) { |
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return unserialize( $data ); |
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} |
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/*=======================================================================*\ |
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Function: file_name |
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Purpose: map url to location in cache |
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Input: url from wich the rss file was fetched |
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Output: a file name |
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\*=======================================================================*/ |
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public function file_name ($url) { |
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$filename = md5( $url ); |
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return join( DIRECTORY_SEPARATOR, array( $this->BASE_CACHE, $filename ) ); |
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} |
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/*=======================================================================*\ |
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Function: error |
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Purpose: register error |
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\*=======================================================================*/ |
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public function error ($errormsg, $lvl=E_USER_WARNING) { |
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// append PHP's error message if track_errors enabled |
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if ( isset($php_errormsg) ) { |
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$errormsg .= " ($php_errormsg)"; |
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} |
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$this->ERROR = $errormsg; |
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if ( MAGPIE_DEBUG ) { |
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trigger_error( $errormsg, $lvl); |
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} |
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else { |
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error_log( $errormsg, 0); |
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} |
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} |
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public function debug ($debugmsg, $lvl=E_USER_NOTICE) { |
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if ( MAGPIE_DEBUG ) { |
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$this->error("MagpieRSS [debug] $debugmsg", $lvl); |
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} |
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} |
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} |
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This check looks for assignments to scalar types that may be of the wrong type.
To ensure the code behaves as expected, it may be a good idea to add an explicit type cast.