Subversion Repositories Applications.papyrus

<?php

/*

 * Project:     MagpieRSS: a simple RSS integration tool

 * File:        rss_cache.inc, a simple, rolling(no GC), cache

 *              for RSS objects, keyed on URL.

 * Author:      Kellan Elliott-McCrea <kellan@protest.net>

 * Version:     0.51

 * License:     GPL

 *

 * The lastest version of MagpieRSS can be obtained from:

 * http://magpierss.sourceforge.net

 *

 * For questions, help, comments, discussion, etc., please join the

 * Magpie mailing list:

 * http://lists.sourceforge.net/lists/listinfo/magpierss-general

 *

 */

class RSSCache {

    var $BASE_CACHE = './cache';    // where the cache files are stored

    var $MAX_AGE    = 3600;         // when are files stale, default one hour

    var $ERROR      = "";           // accumulate error messages

    function RSSCache ($base='', $age='') {

        if ( $base ) {

            $this->BASE_CACHE = $base;

        }

        if ( $age ) {

            $this->MAX_AGE = $age;

        }

        // attempt to make the cache directory

        if ( ! file_exists( $this->BASE_CACHE ) ) {

            $status = @mkdir( $this->BASE_CACHE, 0755 );

            // if make failed

            if ( ! $status ) {

                $this->error(

                    "Cache couldn't make dir '" . $this->BASE_CACHE . "'."

                );

            }

        }

    }

/*=======================================================================*\

    Function:   set

    Purpose:    add an item to the cache, keyed on url

    Input:      url from wich the rss file was fetched

    Output:     true on sucess

\*=======================================================================*/

    function set ($url, $rss) {

        $this->ERROR = "";

        $cache_file = $this->file_name( $url );

        $fp = @fopen( $cache_file, 'w' );

        if ( ! $fp ) {

            $this->error(

                "Cache unable to open file for writing: $cache_file"

            );

            return 0;

        }

        $data = $this->serialize( $rss );

        fwrite( $fp, $data );

        fclose( $fp );

        return $cache_file;

    }

/*=======================================================================*\

    Function:   get

    Purpose:    fetch an item from the cache

    Input:      url from wich the rss file was fetched

    Output:     cached object on HIT, false on MISS

\*=======================================================================*/

    function get ($url) {

        $this->ERROR = "";

        $cache_file = $this->file_name( $url );

        if ( ! file_exists( $cache_file ) ) {

            $this->debug(

                "Cache doesn't contain: $url (cache file: $cache_file)"

            );

            return 0;

        }

        $fp = @fopen($cache_file, 'r');

        if ( ! $fp ) {

            $this->error(

                "Failed to open cache file for reading: $cache_file"

            );

            return 0;

        }

        if ($filesize = filesize($cache_file) ) {

        	$data = fread( $fp, filesize($cache_file) );

        	$rss = $this->unserialize( $data );

        	return $rss;

    	}

    	return 0;

    }

/*=======================================================================*\

    Function:   check_cache

    Purpose:    check a url for membership in the cache

                and whether the object is older then MAX_AGE (ie. STALE)

    Input:      url from wich the rss file was fetched

    Output:     cached object on HIT, false on MISS

\*=======================================================================*/

    function check_cache ( $url ) {

        $this->ERROR = "";

        $filename = $this->file_name( $url );

        if ( file_exists( $filename ) ) {

            // find how long ago the file was added to the cache

            // and whether that is longer then MAX_AGE

            $mtime = filemtime( $filename );

            $age = time() - $mtime;

            if ( $this->MAX_AGE > $age ) {

                // object exists and is current

                return 'HIT';

            }

            else {

                // object exists but is old

                return 'STALE';

            }

        }

        else {

            // object does not exist

            return 'MISS';

        }

    }

	function cache_age( $cache_key ) {

		$filename = $this->file_name( $url );

		if ( file_exists( $filename ) ) {

			$mtime = filemtime( $filename );

            $age = time() - $mtime;

			return $age;

		}

		else {

			return -1;

		}

	}

/*=======================================================================*\

    Function:   serialize

\*=======================================================================*/

    function serialize ( $rss ) {

        return serialize( $rss );

    }

/*=======================================================================*\

    Function:   unserialize

\*=======================================================================*/

    function unserialize ( $data ) {

        return unserialize( $data );

    }

/*=======================================================================*\

    Function:   file_name

    Purpose:    map url to location in cache

    Input:      url from wich the rss file was fetched

    Output:     a file name

\*=======================================================================*/

    function file_name ($url) {

        $filename = md5( $url );

        return join( DIRECTORY_SEPARATOR, array( $this->BASE_CACHE, $filename ) );

    }

/*=======================================================================*\

    Function:   error

    Purpose:    register error

\*=======================================================================*/

    function error ($errormsg, $lvl=E_USER_WARNING) {

        // append PHP's error message if track_errors enabled

        if ( isset($php_errormsg) ) {

            $errormsg .= " ($php_errormsg)";

        }

        $this->ERROR = $errormsg;

        if ( MAGPIE_DEBUG ) {

            trigger_error( $errormsg, $lvl);

        }

        else {

            error_log( $errormsg, 0);

        }

    }

    function debug ($debugmsg, $lvl=E_USER_NOTICE) {

        if ( MAGPIE_DEBUG ) {

            $this->error("MagpieRSS [debug] $debugmsg", $lvl);

        }

    }

}

?>