core.php

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     * @param boolean $doNotTestCacheValidity if set to true, the cache validity won't be tested
     * @param boolean $doNotUnserialize do not serialize (even if automatic_serialization is true) => for internal use
     * @return mixed cached datas (or false)
     */
    public function load($id, $doNotTestCacheValidity = false, $doNotUnserialize = false)
    {
        if (!$this->_options['caching']) {
            return false;
        }
        $this->_lastId = $id;        
        self::_validateIdOrTag($id);
        $data = $this->_backend->load($id, $doNotTestCacheValidity);
        if ($data===false) {
            // no cache available
            return false;
        }
        if ((!$doNotUnserialize) && $this->_options['automatic_serialization']) {
            // we need to unserialize before sending the result
            return unserialize($data);
        }
        return $data;
    }

    /**
     * THIS METHOD IS DEPRECATED : USE LOAD() INSTEAD (same syntax) !
     * 
     * it will be removed in ZF 1.1 !
     */
    public function get($id, $doNotTestCacheValidity = false, $doNotUnserialize = false)
    {
        $this->_log("get() method is deprecated => use load() method instead (same syntax) !");
        return $this->load($id, $doNotTestCacheValidity, $doNotUnserialize);
    }

    /**
     * Test if a cache is available for the given id 
     *
     * @param string $id cache id
     * @return boolean true is a cache is available, false else
     */
    public function test($id) 
    {
        if (!$this->_options['caching']) {
            return false;
        }
        self::_validateIdOrTag($id);
        $this->_lastId = $id;
        return $this->_backend->test($id);
    }

    /**
     * Save some data in a cache 
     * 
     * @param mixed $data data to put in cache (can be another type than string if automatic_serialization is on)
     * @param cache $id cache id (if not set, the last cache id will be used)
     * @param array $tags cache tags
     * @param int $specificLifetime if != false, set a specific lifetime for this cache record (null => infinite lifetime)
     * @return boolean true if no problem
     */
    public function save($data, $id = null, $tags = array(), $specificLifetime = false) 
    {
        if (!$this->_options['caching']) {
            return true;
        }
        if (is_null($id)) {
            $id = $this->_lastId;
        }
        self::_validateIdOrTag($id);  
        self::_validateTagsArray($tags);   
        if ($this->_options['automatic_serialization']) {
            // we need to serialize datas before storing them
            $data = serialize($data);
        } else {
            if (!is_string($data)) {
                Zend_Cache::throwException("Datas must be string or set automatic_serialization = true");
            }
        }
        // automatic cleaning 
        if ($this->_options['automatic_cleaning_factor'] > 0) {
            $rand = rand(1, $this->_options['automatic_cleaning_factor']);
            if ($rand==1) {
                $this->clean('old');
            }
        }
        $result = $this->_backend->save($data, $id, $tags, $specificLifetime);
        if (!$result) {
            // maybe the cache is corrupted, so we remove it !
            if ($this->_options['logging']) {
                $this->_log("Zend_Cache_Core::save() : impossible to save cache (id=$id)");
            }
            $this->remove($id);
            return false;
        }
        if ($this->_options['write_control']) {
            $data2 = $this->_backend->load($id, true);
            if ($data!=$data2) {
                $this->_log('Zend_Cache_Core::save() / write_control : written and read data do not match');
                $this->remove($id);
                return false;
            }
        }
        return true;
    }

    /**
     * Remove a cache 
     * 
     * @param string $id cache id to remove
     * @return boolean true if ok
     */
    public function remove($id)
    {
        if (!$this->_options['caching']) {
            return true;
        }
        self::_validateIdOrTag($id);
        return $this->_backend->remove($id);
    }

    /**
     * Clean cache entries
     * 
     * Available modes are :
     * 'all' (default)  => remove all cache entries ($tags is not used)
     * 'old'            => remove too old cache entries ($tags is not used) 
     * 'matchingTag'    => remove cache entries matching all given tags 
     *                     ($tags can be an array of strings or a single string) 
     * 'notMatchingTag' => remove cache entries not matching one of the given tags
     *                     ($tags can be an array of strings or a single string)                            
     * 
     * @param string $mode
     * @param mixed $parameters  
     * @return boolean true if ok
     */
    public function clean($mode = 'all', $tags = array())
    {
        if (!$this->_options['caching']) {
            return true;
        }
        if (!in_array($mode, array(Zend_Cache::CLEANING_MODE_ALL, Zend_Cache::CLEANING_MODE_OLD, Zend_Cache::CLEANING_MODE_MATCHING_TAG, Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG))) {
            Zend_Cache::throwException('Invalid cleaning mode');
        }
        self::_validateTagsArray($tags);
        return $this->_backend->clean($mode, $tags);
    }

    // ------------------------------------
    // --- Private or protected methods ---
    // ------------------------------------

    /**
     * Validate a cache id or a tag (security, reliable filenames, reserved prefixes...)
     * 
     * Throw an exception if a problem is found
     * 
     * @param string $string cache id or tag
     */
    private static function _validateIdOrTag($string)
    {
        if (!is_string($string)) {
            Zend_Cache::throwException('Invalid id or tag : must be a string');
        }
        if (substr($string, 0, 9) == 'internal-') {
            Zend_Cache::throwException('"internal-*" ids or tags are reserved');
        }
        if (!preg_match('~^[\w]+$~', $string)) {
            Zend_Cache::throwException('Invalid id or tag : must use only [a-zA-Z0-9_]');
        }
    }

    /**
     * Validate a tags array (security, reliable filenames, reserved prefixes...)
     * 
     * Throw an exception if a problem is found
     * 
     * @param array $tags array of tags
     */
    private static function _validateTagsArray($tags)
    {
        if (!is_array($tags)) {
            Zend_Cache::throwException('Invalid tags array : must be an array');
        }
        foreach($tags as $tag) {
            self::_validateIdOrTag($tag);
        }
        reset($tags);
    }

    /**
     * Make sure if we enable logging that the Zend_Log class
     * is available.
     * Create a default log object if none is set.
     *
     * @return void
     * @throws Zend_Cache_Exception
     */
    protected function _loggerSanity()
    {
        if (!isset($this->_options['logging']) || !$this->_options['logging']) {
            return;
        }
        try {
            require_once 'Zend/Loader.php';
            Zend_Loader::loadClass('Zend_Log');
        } catch (Zend_Exception $e) {
            Zend_Cache::throwException('Logging feature is enabled but the Zend_Log class is not available');
        }
        if (isset($this->_options['logger']) && $this->_options['logger'] instanceof Zend_Log) {
            return;
        }
        // Create a default logger to the standard output stream
        Zend_Loader::loadClass('Zend_Log_Writer_Stream');
        $logger = new Zend_Log(new Zend_Log_Writer_Stream('php://output'));
        $this->_options['logger'] = $logger;
    }

    /**
     * Log a message at the WARN (4) priority.
     *
     * @param string $message
     * @return void
     * @throws Zend_Cache_Exception
     */
    protected function _log($message, $priority = 4)
    {
        if (!$this->_options['logging']) {
            return;
        }
        if (!(isset($this->_options['logger']) || $this->_options['logger'] instanceof Zend_Log)) {
            Zend_Cache::throwException('Logging is enabled but logger is not set');
        }
        $logger = $this->_options['logger'];
        $logger->log($message, $priority);
    }

}