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CFileCache

Package system.caching
Inheritance class CFileCache » CCache » CApplicationComponent » CComponent
Implements ArrayAccess, ICache, IApplicationComponent
Source Code framework/caching/CFileCache.php
CFileCache provides a file-based caching mechanism.

For each data value being cached, CFileCache will use store it in a separate file under cachePath which defaults to 'protected/runtime/cache'. CFileCache will perform garbage collection automatically to remove expired cache files.

See CCache manual for common cache operations that are supported by CFileCache.

Public Properties

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PropertyTypeDescriptionDefined By
behaviors array the behaviors that should be attached to this component. CApplicationComponent
cacheFileSuffix string cache file suffix. CFileCache
cachePath string the directory to store cache files. CFileCache
directoryLevel integer the level of sub-directories to store cache files. CFileCache
embedExpiry boolean whether cache entry expiration time should be embedded into a physical file. CFileCache
gCProbability integer the probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. CFileCache
hashKey boolean whether to md5-hash the cache key for normalization purposes. CCache
isInitialized boolean Checks if this application component has been initialized. CApplicationComponent
keyPrefix string a string prefixed to every cache key so that it is unique. CCache
serializer array|boolean the functions used to serialize and unserialize cached data. CCache

Public Methods

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MethodDescriptionDefined By
__call() Calls the named method which is not a class method. CComponent
__get() Returns a property value, an event handler list or a behavior based on its name. CComponent
__isset() Checks if a property value is null. CComponent
__set() Sets value of a component property. CComponent
__unset() Sets a component property to be null. CComponent
add() Stores a value identified by a key into cache if the cache does not contain this key. CCache
asa() Returns the named behavior object. CComponent
attachBehavior() Attaches a behavior to this component. CComponent
attachBehaviors() Attaches a list of behaviors to the component. CComponent
attachEventHandler() Attaches an event handler to an event. CComponent
canGetProperty() Determines whether a property can be read. CComponent
canSetProperty() Determines whether a property can be set. CComponent
delete() Deletes a value with the specified key from cache CCache
detachBehavior() Detaches a behavior from the component. CComponent
detachBehaviors() Detaches all behaviors from the component. CComponent
detachEventHandler() Detaches an existing event handler. CComponent
disableBehavior() Disables an attached behavior. CComponent
disableBehaviors() Disables all behaviors attached to this component. CComponent
enableBehavior() Enables an attached behavior. CComponent
enableBehaviors() Enables all behaviors attached to this component. CComponent
evaluateExpression() Evaluates a PHP expression or callback under the context of this component. CComponent
flush() Deletes all values from cache. CCache
gc() Removes expired cache files. CFileCache
get() Retrieves a value from cache with a specified key. CCache
getEventHandlers() Returns the list of attached event handlers for an event. CComponent
getGCProbability() Returns the probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance. CFileCache
getIsInitialized() Checks if this application component has been initialized. CApplicationComponent
hasEvent() Determines whether an event is defined. CComponent
hasEventHandler() Checks whether the named event has attached handlers. CComponent
hasProperty() Determines whether a property is defined. CComponent
init() Initializes this application component. CFileCache
mget() Retrieves multiple values from cache with the specified keys. CCache
offsetExists() Returns whether there is a cache entry with a specified key. CCache
offsetGet() Retrieves the value from cache with a specified key. CCache
offsetSet() Stores the value identified by a key into cache. CCache
offsetUnset() Deletes the value with the specified key from cache CCache
raiseEvent() Raises an event. CComponent
set() Stores a value identified by a key into cache. CCache
setGCProbability() Sets the probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance. This number should be between 0 and 1000000. A value 0 meaning no GC will be performed at all. CFileCache

Protected Methods

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MethodDescriptionDefined By
addValue() Stores a value identified by a key into cache if the cache does not contain this key. CFileCache
deleteValue() Deletes a value with the specified key from cache CFileCache
flushValues() Deletes all values from cache. CFileCache
generateUniqueKey() CCache
getCacheFile() Returns the cache file path given the cache key. CFileCache
getValue() Retrieves a value from cache with a specified key. CFileCache
getValues() Retrieves multiple values from cache with the specified keys. CCache
setValue() Stores a value identified by a key in cache. CFileCache

Property Details

cacheFileSuffix property
public string $cacheFileSuffix;

cache file suffix. Defaults to '.bin'.

cachePath property
public string $cachePath;

the directory to store cache files. Defaults to null, meaning using 'protected/runtime/cache' as the directory.

directoryLevel property
public integer $directoryLevel;

the level of sub-directories to store cache files. Defaults to 0, meaning no sub-directories. If the system has huge number of cache files (e.g. 10K+), you may want to set this value to be 1 or 2 so that the file system is not over burdened. The value of this property should not exceed 16 (less than 3 is recommended).

embedExpiry property (available since v1.1.14)
public boolean $embedExpiry;

whether cache entry expiration time should be embedded into a physical file. Defaults to false meaning that the file modification time will be used to store expire value. True value means that first ten bytes of the file would be reserved and used to store expiration time. On some systems PHP is not allowed to change file modification time to be in future even with 777 permissions, so this property could be useful in this case.

gCProbability property
public integer getGCProbability()
public void setGCProbability(integer $value)

the probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance.

Method Details

addValue() method
protected boolean addValue(string $key, string $value, integer $expire)
$key string the key identifying the value to be cached
$value string the value to be cached
$expire integer the number of seconds in which the cached value will expire. 0 means never expire.
{return} boolean true if the value is successfully stored into cache, false otherwise
Source Code: framework/caching/CFileCache.php#164 (show)
protected function addValue($key,$value,$expire)
{
    
$cacheFile=$this->getCacheFile($key);
    if(
$this->filemtime($cacheFile)>time())
        return 
false;
    return 
$this->setValue($key,$value,$expire);
}

Stores a value identified by a key into cache if the cache does not contain this key. This is the implementation of the method declared in the parent class.

deleteValue() method
protected boolean deleteValue(string $key)
$key string the key of the value to be deleted
{return} boolean if no error happens during deletion
Source Code: framework/caching/CFileCache.php#178 (show)
protected function deleteValue($key)
{
    
$cacheFile=$this->getCacheFile($key);
    return @
unlink($cacheFile);
}

Deletes a value with the specified key from cache This is the implementation of the method declared in the parent class.

flushValues() method (available since v1.1.5)
protected boolean flushValues()
{return} boolean whether the flush operation was successful.
Source Code: framework/caching/CFileCache.php#100 (show)
protected function flushValues()
{
    
$this->gc(false);
    return 
true;
}

Deletes all values from cache. This is the implementation of the method declared in the parent class.

gc() method
public void gc(boolean $expiredOnly=true, string $path=NULL)
$expiredOnly boolean whether only expired cache files should be removed. If false, all cache files under cachePath will be removed.
$path string the path to clean with. If null, it will be cachePath.
Source Code: framework/caching/CFileCache.php#211 (show)
public function gc($expiredOnly=true,$path=null)
{
    if(
$path===null)
        
$path=$this->cachePath;
    if((
$handle=opendir($path))===false)
        return;
    while((
$file=readdir($handle))!==false)
    {
        if(
$file[0]==='.')
            continue;
        
$fullPath=$path.DIRECTORY_SEPARATOR.$file;
        if(
is_dir($fullPath))
            
$this->gc($expiredOnly,$fullPath);
        elseif(
$expiredOnly && $this->filemtime($fullPath)<time() || !$expiredOnly)
            @
unlink($fullPath);
    }
    
closedir($handle);
}

Removes expired cache files.

getCacheFile() method
protected string getCacheFile(string $key)
$key string cache key
{return} string the cache file path
Source Code: framework/caching/CFileCache.php#189 (show)
protected function getCacheFile($key)
{
    if(
$this->directoryLevel>0)
    {
        
$base=$this->cachePath;
        for(
$i=0;$i<$this->directoryLevel;++$i)
        {
            if((
$prefix=substr($key,$i+$i,2))!==false)
                
$base.=DIRECTORY_SEPARATOR.$prefix;
        }
        return 
$base.DIRECTORY_SEPARATOR.$key.$this->cacheFileSuffix;
    }
    else
        return 
$this->cachePath.DIRECTORY_SEPARATOR.$key.$this->cacheFileSuffix;
}

Returns the cache file path given the cache key.

getGCProbability() method
public integer getGCProbability()
{return} integer the probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance.
Source Code: framework/caching/CFileCache.php#74 (show)
public function getGCProbability()
{
    return 
$this->_gcProbability;
}

getValue() method
protected string|boolean getValue(string $key)
$key string a unique key identifying the cached value
{return} string|boolean the value stored in cache, false if the value is not in the cache or expired.
Source Code: framework/caching/CFileCache.php#112 (show)
protected function getValue($key)
{
    
$cacheFile=$this->getCacheFile($key);
    if((
$time=$this->filemtime($cacheFile))>time())
        return @
file_get_contents($cacheFile,false,null,$this->embedExpiry 10 : -1);
    elseif(
$time>0)
        @
unlink($cacheFile);
    return 
false;
}

Retrieves a value from cache with a specified key. This is the implementation of the method declared in the parent class.

init() method
public void init()
Source Code: framework/caching/CFileCache.php#61 (show)
public function init()
{
    
parent::init();
    if(
$this->cachePath===null)
        
$this->cachePath=Yii::app()->getRuntimePath().DIRECTORY_SEPARATOR.'cache';
    if(!
is_dir($this->cachePath))
        
mkdir($this->cachePath,0777,true);
}

Initializes this application component. This method is required by the IApplicationComponent interface.

setGCProbability() method
public void setGCProbability(integer $value)
$value integer the probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance. This number should be between 0 and 1000000. A value 0 meaning no GC will be performed at all.
Source Code: framework/caching/CFileCache.php#84 (show)
public function setGCProbability($value)
{
    
$value=(int)$value;
    if(
$value<0)
        
$value=0;
    if(
$value>1000000)
        
$value=1000000;
    
$this->_gcProbability=$value;
}

setValue() method
protected boolean setValue(string $key, string $value, integer $expire)
$key string the key identifying the value to be cached
$value string the value to be cached
$expire integer the number of seconds in which the cached value will expire. 0 means never expire.
{return} boolean true if the value is successfully stored into cache, false otherwise
Source Code: framework/caching/CFileCache.php#131 (show)
protected function setValue($key,$value,$expire)
{
    if(!
$this->_gced && mt_rand(0,1000000)<$this->_gcProbability)
    {
        
$this->gc();
        
$this->_gced=true;
    }

    if(
$expire<=0)
        
$expire=31536000// 1 year
    
$expire+=time();

    
$cacheFile=$this->getCacheFile($key);
    if(
$this->directoryLevel>0)
        @
mkdir(dirname($cacheFile),0777,true);
    if(@
file_put_contents($cacheFile,$this->embedExpiry $expire.$value $value,LOCK_EX)!==false)
    {
        @
chmod($cacheFile,0777);
        return 
$this->embedExpiry true : @touch($cacheFile,$expire);
    }
    else
        return 
false;
}

Stores a value identified by a key in cache. This is the implementation of the method declared in the parent class.

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