App_Cache

Cache.php

<?php

/**
 * Based on FileCache class by Erik Giberti,
 * http://af-design.com/blog/2010/07/30/simple-file-based-caching-in-php/
 *
 * @author nebiros
 */
class App_Cache {
    /**
     *
     * @var string
     */
    protected $_dir = null;

    /**
     *
     * @var string
     */
    protected $_key = null;

    /**
     *
     * @param string $dir
     */
    public function __construct( $dir = null ) {
        if ( null === $dir ) {
            $this->_dir = sys_get_temp_dir();
        } else {
            $this->_dir = $dir;
        }
    }

    /**
     *
     * @param string $dir
     * @return App_Cache
     */
    public function setDir( $dir ) {
        $this->_dir = $dir;
        return $this;
    }

    /**
     *
     * @param string $key
     * @param mixed $data
     * @param int $ttl
     * @return boolean
     */
    public function save( $key, $data = null, $ttl = 3600 ) {
        if ( true === empty( $key ) ) {
            throw new Exception( "invalid key" );
        }

        $dataPath = $this->_buildPath( $key );
        $metaPath = $this->_buildPath( $key . "_meta" );

        $metadata = array( "ttl" => time() + $ttl );

        if ( false === $this->_put( $metaPath, $metadata ) ) {
            return false;
        }
       
        return $this->_put( $dataPath, $data );
    }
    
    /**
     *
     * @param string $path
     * @param mixed $data
     * @return boolean 
     */
    protected function _put( $path, $data ) {
        $status = false;

        $fh = @fopen( $path, "ab+" );

        if ( @flock( $fh, LOCK_EX ) ) {             
            fseek( $fh, 0 );
            ftruncate( $fh, 0 );
            $tmp = @fwrite( $fh, serialize( $data ) );
            if ( false !== $tmp ) {
                $status = true;
            }
            @flock( $fh, LOCK_UN );            
        }

        @fclose( $fh );

        return $status;        
    }

    /**
     *
     * @param string $key
     * @return mixed|false
     */
    public function load( $key ){
        if ( true === empty( $key ) ) {
            throw new Exception( "invalid key" );
        }

        $dataPath = $this->_buildPath( $key );

        if ( false === is_file( $dataPath ) ) {
            return false;
        }
        
        $data = $this->_get( $dataPath );
        
        $metaPath = $this->_buildPath( $key . "_meta" );
        $metadata = $this->_get( $metaPath );
        
        if ( false === empty( $data ) ) {
            if ( $metadata["ttl"] < time() ) {
                @unlink( $path );
                return false;
            }
        }        
        
        return $data;
    }
    
    /**
     *
     * @param string $path
     * @return mixed 
     */
    protected function _get( $path ) {
        $data = null;

        $fh = @fopen( $path, "rb" );

        if ( @flock( $fh, LOCK_SH ) ) {
            $data = stream_get_contents( $fh );
        }

        @fclose( $fh );

        return @unserialize( $data );
    }

    /**
     *
     * @param string $key
     * @return bool
     */
    public function exist( $key ) {
        if ( true === empty( $key ) ) {
            throw new Exception( "invalid key" );
        }

        $path = $this->_buildPath( $key );

        return is_file( $path );
    }

    /**
     *
     * @param string $key
     * @return bool
     */
    public function delete( $key ) {
        if ( true === empty( $key ) ) {
            throw new Exception( "invalid key" );
        }

        $dataPath = $this->_buildPath( $key );
        $metaPath = $this->_buildPath( $key . "_meta" );

        if ( true === is_file( $dataPath ) ) {
            @unlink( $dataPath );
            @unlink( $metaPath );
        }

        return true;
    }

    /**
     *
     * @param string $key
     * @param bool $lowercase
     * @param string $glue
     * @return void
     */
    protected function _buildKey( $key, $lowercase = true, $glue = "-" ) {
        if ( true === $lowercase ) {
            $key = strtolower( $key );
        }

        $this->_key = preg_replace( "/[^a-zA-Z0-9_-]/", "", preg_replace( "/\s+/", $glue, $key ) );
    }

    /**
     *
     * @return string
     */
    public function getKey() {
        return $this->_key;
    }

    /**
     *
     * @param string $key
     * @return string
     */
    protected function _buildPath( $key ) {
        $this->_buildKey( $key );
        return $this->_dir . "/" . $this->_key;
    }
}