| 1 | <?php |
| 2 | /* |
| 3 | * Project: MagpieRSS: a simple RSS integration tool |
| 4 | * File: rss_cache.inc, a simple, rolling(no GC), cache |
| 5 | * for RSS objects, keyed on URL. |
| 6 | * Author: Kellan Elliott-McCrea <kellan@protest.net> |
| 7 | * Version: 0.3 |
| 8 | * License: GPL |
| 9 | * |
| 10 | * The lastest version of MagpieRSS can be obtained from: |
| 11 | * http://magpierss.sourceforge.net |
| 12 | * |
| 13 | * For questions, help, comments, discussion, etc., please join the |
| 14 | * Mapgie mailing list: |
| 15 | * http://lists.sourceforge.net/lists/listinfo/magpierss-general |
| 16 | * |
| 17 | */ |
| 18 | |
| 19 | class RSSCache { |
| 20 | var $BASE_CACHE = './cache'; // where the cache files are stored |
| 21 | var $MAX_AGE = 3600; // when are files stale, default one hour |
| 22 | var $ERROR = ""; // accumulate error messages |
| 23 | |
| 24 | function RSSCache ($base, $age) { |
| 25 | if ( $base ) { |
| 26 | $this->BASE_CACHE = $base; |
| 27 | } |
| 28 | if ( $age ) { |
| 29 | $this->MAX_AGE = $age; |
| 30 | } |
| 31 | |
| 32 | // attempt to make the cache directory |
| 33 | if ( ! file_exists( $this->BASE_CACHE ) ) { |
| 34 | $status = @mkdir( $this->BASE_CACHE, 0755 ); |
| 35 | |
| 36 | // if make failed |
| 37 | if ( ! $status ) { |
| 38 | $this->error( |
| 39 | "Cache couldn't make dir '" . $this->BASE_CACHE . "'." |
| 40 | ); |
| 41 | } |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | /*=======================================================================*\ |
| 46 | Function: set |
| 47 | Purpose: add an item to the cache, keyed on url |
| 48 | Input: url from wich the rss file was fetched |
| 49 | Output: true on sucess |
| 50 | \*=======================================================================*/ |
| 51 | function set ($url, $rss) { |
| 52 | $this->ERROR = ""; |
| 53 | $cache_file = $this->file_name( $url ); |
| 54 | $fp = @fopen( $cache_file, 'w' ); |
| 55 | |
| 56 | if ( ! $fp ) { |
| 57 | $this->error( |
| 58 | "Cache unable to open file for writing: $cache_file" |
| 59 | ); |
| 60 | return 0; |
| 61 | } |
| 62 | |
| 63 | |
| 64 | $data = $this->serialize( $rss ); |
| 65 | fwrite( $fp, $data ); |
| 66 | fclose( $fp ); |
| 67 | |
| 68 | return $cache_file; |
| 69 | } |
| 70 | |
| 71 | /*=======================================================================*\ |
| 72 | Function: get |
| 73 | Purpose: fetch an item from the cache |
| 74 | Input: url from wich the rss file was fetched |
| 75 | Output: cached object on HIT, false on MISS |
| 76 | \*=======================================================================*/ |
| 77 | function get ($url) { |
| 78 | $this->ERROR = ""; |
| 79 | $cache_file = $this->file_name( $url ); |
| 80 | |
| 81 | if ( ! file_exists( $cache_file ) ) { |
| 82 | $this->error( |
| 83 | "Cache doesn't contain: $url (cache file: $cache_file)" |
| 84 | ); |
| 85 | return 0; |
| 86 | } |
| 87 | |
| 88 | $fp = @fopen($cache_file, 'r'); |
| 89 | if ( ! $fp ) { |
| 90 | $this->error( |
| 91 | "Failed to open cache file for reading: $cache_file" |
| 92 | ); |
| 93 | return 0; |
| 94 | } |
| 95 | |
| 96 | $data = fread( $fp, filesize($cache_file) ); |
| 97 | $rss = $this->unserialize( $data ); |
| 98 | |
| 99 | return $rss; |
| 100 | } |
| 101 | |
| 102 | /*=======================================================================*\ |
| 103 | Function: check_cache |
| 104 | Purpose: check a url for membership in the cache |
| 105 | and whether the object is older then MAX_AGE (ie. STALE) |
| 106 | Input: url from wich the rss file was fetched |
| 107 | Output: cached object on HIT, false on MISS |
| 108 | \*=======================================================================*/ |
| 109 | function check_cache ( $url ) { |
| 110 | $this->ERROR = ""; |
| 111 | $filename = $this->file_name( $url ); |
| 112 | |
| 113 | if ( file_exists( $filename ) ) { |
| 114 | // find how long ago the file was added to the cache |
| 115 | // and whether that is longer then MAX_AGE |
| 116 | $mtime = filemtime( $filename ); |
| 117 | $age = time() - $mtime; |
| 118 | if ( $this->MAX_AGE > $age ) { |
| 119 | // object exists and is current |
| 120 | return 'HIT'; |
| 121 | } |
| 122 | else { |
| 123 | // object exists but is old |
| 124 | return 'STALE'; |
| 125 | } |
| 126 | } |
| 127 | else { |
| 128 | // object does not exist |
| 129 | return 'MISS'; |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | /*=======================================================================*\ |
| 134 | Function: serialize |
| 135 | \*=======================================================================*/ |
| 136 | function serialize ( $rss ) { |
| 137 | return serialize( $rss ); |
| 138 | } |
| 139 | |
| 140 | /*=======================================================================*\ |
| 141 | Function: unserialize |
| 142 | \*=======================================================================*/ |
| 143 | function unserialize ( $data ) { |
| 144 | return unserialize( $data ); |
| 145 | } |
| 146 | |
| 147 | /*=======================================================================*\ |
| 148 | Function: file_name |
| 149 | Purpose: map url to location in cache |
| 150 | Input: url from wich the rss file was fetched |
| 151 | Output: a file name |
| 152 | \*=======================================================================*/ |
| 153 | function file_name ($url) { |
| 154 | $filename = md5( $url ); |
| 155 | return join( DIRECTORY_SEPARATOR, array( $this->BASE_CACHE, $filename ) ); |
| 156 | } |
| 157 | |
| 158 | /*=======================================================================*\ |
| 159 | Function: error |
| 160 | Purpose: register error |
| 161 | \*=======================================================================*/ |
| 162 | function error ($errormsg, $lvl=E_USER_WARNING) { |
| 163 | // append PHP's error message if track_errors enabled |
| 164 | if ( $php_errormsg ) { |
| 165 | $errormsg .= " ($php_errormsg)"; |
| 166 | } |
| 167 | $this->ERROR = $errormsg; |
| 168 | if ( MAGPIE_DEBUG ) { |
| 169 | trigger_error( $errormsg, $lvl); |
| 170 | } |
| 171 | else { |
| 172 | error_log( $errormsg, 0); |
| 173 | } |
| 174 | } |
| 175 | } |
| 176 | |
| 177 | ?> |