Implements: Kohana_Cache_GarbageCollect
Kohana Cache File driver. Provides a file based driver for the Kohana Cache library. This is one of the slowest caching methods.
Below is an example of a file server configuration.
return array(
'file' => array( // File driver group
'driver' => 'file', // using File driver
'cache_dir' => APPPATH.'cache/.kohana_cache', // Cache location
),
)
In cases where only one cache group is required, if the group is named default
there is
no need to pass the group name when instantiating a cache instance.
Below are the settings available to all types of cache driver.
Name | Required | Description |
---|---|---|
driver | YES | (string) The driver type to use |
cache_dir | NO | (string) The cache directory to use for this cache instance |
Class declared in MODPATH/cache/classes/kohana/cache/file.php on line 41.
integer 3600
string
$defaultdefault driver to use
string(4) "file"
Kohana_Cache
$instancesinstances
array(0)
string
$_cache_dirthe caching directory
Config
$_configDelete a cache entry based on id
// Delete 'foo' entry from the file group
Cache::instance('file')->delete('foo');
string
$id
required - Id to remove from cacheboolean
public function delete($id)
{
$filename = Cache_File::filename($this->_sanitize_id($id));
$directory = $this->_resolve_directory($filename);
return $this->_delete_file(new SplFileInfo($directory.$filename), NULL, TRUE);
}
Delete all cache entries.
Beware of using this method when using shared memory cache systems, as it will wipe every entry within the system for all clients.
// Delete all cache entries in the file group
Cache::instance('file')->delete_all();
boolean
public function delete_all()
{
return $this->_delete_file($this->_cache_dir, TRUE);
}
Garbage collection method that cleans any expired cache entries from the cache.
void
public function garbage_collect()
{
$this->_delete_file($this->_cache_dir, TRUE, FALSE, TRUE);
return;
}
Retrieve a cached value entry by id.
// Retrieve cache entry from file group
$data = Cache::instance('file')->get('foo');
// Retrieve cache entry from file group and return 'bar' if miss
$data = Cache::instance('file')->get('foo', 'bar');
string
$id
required - Id of cache to entrystring
$default
= NULL - Default value to return if cache missmixed
public function get($id, $default = NULL)
{
$filename = Cache_File::filename($this->_sanitize_id($id));
$directory = $this->_resolve_directory($filename);
// Wrap operations in try/catch to handle notices
try
{
// Open file
$file = new SplFileInfo($directory.$filename);
// If file does not exist
if ( ! $file->isFile())
{
// Return default value
return $default;
}
else
{
// Open the file and extract the json
$json = $file->openFile()->current();
// Decode the json into PHP object
$data = json_decode($json);
// Test the expiry
if ($data->expiry < time())
{
// Delete the file
$this->_delete_file($file, NULL, TRUE);
// Return default value
return $default;
}
else
{
return ($data->type === 'string') ? $data->payload : unserialize($data->payload);
}
}
}
catch (ErrorException $e)
{
// Handle ErrorException caused by failed unserialization
if ($e->getCode() === E_NOTICE)
{
throw new Kohana_Cache_Exception(__METHOD__.' failed to unserialize cached object with message : '.$e->getMessage());
}
// Otherwise throw the exception
throw $e;
}
}
Set a value to cache with id and lifetime
$data = 'bar';
// Set 'bar' to 'foo' in file group, using default expiry
Cache::instance('file')->set('foo', $data);
// Set 'bar' to 'foo' in file group for 30 seconds
Cache::instance('file')->set('foo', $data, 30);
string
$id
required - Id of cache entrystring
$data
required - Data to set to cacheinteger
$lifetime
= NULL - Lifetime in secondsboolean
public function set($id, $data, $lifetime = NULL)
{
$filename = Cache_File::filename($this->_sanitize_id($id));
$directory = $this->_resolve_directory($filename);
// If lifetime is NULL
if ($lifetime === NULL)
{
// Set to the default expiry
$lifetime = Arr::get($this->_config, 'default_expire', Cache::DEFAULT_EXPIRE);
}
// Open directory
$dir = new SplFileInfo($directory);
// If the directory path is not a directory
if ( ! $dir->isDir())
{
// Create the directory
if ( ! mkdir($directory, 0777, TRUE))
{
throw new Kohana_Cache_Exception(__METHOD__.' unable to create directory : :directory', array(':directory' => $directory));
}
// chmod to solve potential umask issues
chmod($directory, 0777);
}
// Open file to inspect
$resouce = new SplFileInfo($directory.$filename);
$file = $resouce->openFile('w');
try
{
$type = gettype($data);
// Serialize the data
$data = json_encode( (object) array(
'payload' => ($type === 'string') ? $data : serialize($data),
'expiry' => time() + $lifetime,
'type' => $type
));
$size = strlen($data);
}
catch (ErrorException $e)
{
// If serialize through an error exception
if ($e->getCode() === E_NOTICE)
{
// Throw a caching error
throw new Kohana_Cache_Exception(__METHOD__.' failed to serialize data for caching with message : '.$e->getMessage());
}
// Else rethrow the error exception
throw $e;
}
try
{
$file->fwrite($data, $size);
return (bool) $file->fflush();
}
catch (Exception $e)
{
throw $e;
}
}
Overload the __clone() method to prevent cloning
void
public function __clone()
{
throw new Kohana_Cache_Exception('Cloning of Kohana_Cache objects is forbidden');
}
Creates a singleton of a Kohana Cache group. If no group is supplied the default cache group is used.
// Create an instance of the default group
$default_group = Cache::instance();
// Create an instance of a group
$foo_group = Cache::instance('foo');
// Access an instantiated group directly
$foo_group = Cache::$instances['default'];
string
$group
= NULL - The name of the cache group to use [Optional]Cache
public static function instance($group = NULL)
{
// If there is no group supplied
if ($group === NULL)
{
// Use the default setting
$group = Cache::$default;
}
if (isset(Cache::$instances[$group]))
{
// Return the current group if initiated already
return Cache::$instances[$group];
}
$config = Kohana::config('cache');
if ( ! $config->offsetExists($group))
{
throw new Kohana_Cache_Exception('Failed to load Kohana Cache group: :group', array(':group' => $group));
}
$config = $config->get($group);
// Create a new cache type instance
$cache_class = 'Cache_'.ucfirst($config['driver']);
Cache::$instances[$group] = new $cache_class($config);
// Return the instance
return Cache::$instances[$group];
}
Constructs the file cache driver. This method cannot be invoked externally. The file cache driver must
be instantiated using the Cache::instance()
method.
array
$config
required - Configprotected function __construct(array $config)
{
// Setup parent
parent::__construct($config);
try
{
$directory = Arr::get($this->_config, 'cache_dir', Kohana::$cache_dir);
$this->_cache_dir = new SplFileInfo($directory);
}
// PHP < 5.3 exception handle
catch (ErrorException $e)
{
$this->_cache_dir = $this->_make_directory($directory, 0777, TRUE);
}
// PHP >= 5.3 exception handle
catch (UnexpectedValueException $e)
{
$this->_cache_dir = $this->_make_directory($directory, 0777, TRUE);
}
// If the defined directory is a file, get outta here
if ($this->_cache_dir->isFile())
{
throw new Kohana_Cache_Exception('Unable to create cache directory as a file already exists : :resource', array(':resource' => $this->_cache_dir->getRealPath()));
}
// Check the read status of the directory
if ( ! $this->_cache_dir->isReadable())
{
throw new Kohana_Cache_Exception('Unable to read from the cache directory :resource', array(':resource' => $this->_cache_dir->getRealPath()));
}
// Check the write status of the directory
if ( ! $this->_cache_dir->isWritable())
{
throw new Kohana_Cache_Exception('Unable to write to the cache directory :resource', array(':resource' => $this->_cache_dir->getRealPath()));
}
}
Deletes files recursively and returns FALSE on any errors
// Delete a file or folder whilst retaining parent directory and ignore all errors
$this->_delete_file($folder, TRUE, TRUE);
SplFileInfo
$file
required - Fileboolean
$retain_parent_directory
= bool FALSE - Retain the parent directoryboolean
$ignore_errors
= bool FALSE - Ignore_errors to prevent all exceptions interrupting execboolean
$only_expired
= bool FALSE - Only expired filesboolean
protected function _delete_file(SplFileInfo $file, $retain_parent_directory = FALSE, $ignore_errors = FALSE, $only_expired = FALSE)
{
// Allow graceful error handling
try
{
// If is file
if ($file->isFile())
{
try
{
// If only expired is not set
if ($only_expired === FALSE)
{
// We want to delete the file
$delete = TRUE;
}
// Otherwise...
else
{
// Assess the file expiry to flag it for deletion
$json = $file->openFile('r')->current();
$data = json_decode($json);
$delete = $data->expiry < time();
}
// If the delete flag is set
if ($delete === TRUE)
{
// Try to delete
unlink($file->getRealPath());
}
}
catch (ErrorException $e)
{
// Catch any delete file warnings
if ($e->getCode() === E_WARNING)
{
throw new Kohana_Cache_Exception(__METHOD__.' failed to delete file : :file', array(':file' => $file->getRealPath()));
}
}
}
// Else, is directory
elseif ($file->isDir())
{
// Create new DirectoryIterator
$files = new DirectoryIterator($file->getPathname());
// Iterate over each entry
while ($files->valid())
{
// Extract the entry name
$name = $files->getFilename();
// If the name is not a dot
if ($name != '.' AND $name != '..' AND substr($file->getFilename(), 0, 1) == '.')
{
// Create new file resource
$fp = new SplFileInfo($files->getRealPath());
// Delete the file
$this->_delete_file($fp);
}
// Move the file pointer on
$files->next();
}
// If set to retain parent directory, return now
if ($retain_parent_directory)
{
return TRUE;
}
try
{
// Remove the files iterator
// (fixes Windows PHP which has permission issues with open iterators)
unset($files);
// Try to remove the parent directory
return rmdir($file->getRealPath());
}
catch (ErrorException $e)
{
// Catch any delete directory warnings
if ($e->getCode() === E_WARNING)
{
throw new Kohana_Cache_Exception(__METHOD__.' failed to delete directory : :directory', array(':directory' => $file->getRealPath()));
}
}
}
}
// Catch all exceptions
catch (Exception $e)
{
// If ignore_errors is on
if ($ignore_errors === TRUE)
{
// Return
return FALSE;
}
// Throw exception
throw $e;
}
}
Makes the cache directory if it doesn't exist. Simply a wrapper for
mkdir
to ensure DRY principles
string
$directory
required - $directoryinteger
$mode
= integer 511 - $modeboolean
$recursive
= bool FALSE - $recursiveresource
$context
= NULL - $contextSplFileInfo
protected function _make_directory($directory, $mode = 0777, $recursive = FALSE, $context = NULL)
{
if ( ! mkdir($directory, $mode, $recursive, $context))
{
throw new Kohana_Cache_Exception('Failed to create the defined cache directory : :directory', array(':directory' => $directory));
}
chmod($directory, $mode);
return new SplFileInfo($directory);
}
Resolves the cache directory real path from the filename
// Get the realpath of the cache folder
$realpath = $this->_resolve_directory($filename);
string
$filename
required - Filename to resolvestring
protected function _resolve_directory($filename)
{
return $this->_cache_dir->getRealPath().DIRECTORY_SEPARATOR.$filename[0].$filename[1].DIRECTORY_SEPARATOR;
}
Creates a hashed filename based on the string. This is used to create shorter unique IDs for each cache filename.
// Create the cache filename
$filename = Cache_File::filename($this->_sanitize_id($id));
string
$string
required - String to hash into filenamestring
protected static function filename($string)
{
return sha1($string).'.json';
}
Replaces troublesome characters with underscores.
// Sanitize a cache id
$id = $this->_sanitize_id($id);
string
$id
required - Id of cache to sanitizestring
protected function _sanitize_id($id)
{
// Change slashes and spaces to underscores
return str_replace(array('/', '\\', ' '), '_', $id);
}