YII Framework框架教程之缓存用法详解

'cache'=>array(
  'class'=>'system.caching.CApcCache'
),

* array(
*   'components'=>array(
*     'cache'=>array(
*       'class'=>'CMemCache',*       'servers'=>array(
*         array(
*           'host'=>'server1',*           'port'=>11211,*           'weight'=>60,*         ),*         array(
*           'host'=>'server2',*           'weight'=>40,*       ),*     ),*   ),* )

<?php
/**
 * CCache is the base class for cache classes with different cache storage implementation.
 *
 * A data item can be stored in cache by calling {@link set} and be retrieved back
 * later by {@link get}. In both operations,a key identifying the data item is required.
 * An expiration time and/or a dependency can also be specified when calling {@link set}.
 * If the data item expires or the dependency changes,calling {@link get} will not
 * return back the data item.
 *
 * Note,by definition,cache does not ensure the existence of a value
 * even if it does not expire. Cache is not meant to be a persistent storage.
 *
 * CCache implements the interface {@link ICache} with the following methods:
 * <ul>
 * <li>{@link get} : retrieve the value with a key (if any) from cache</li>
 * <li>{@link set} : store the value with a key into cache</li>
 * <li>{@link add} : store the value only if cache does not have this key</li>
 * <li>{@link delete} : delete the value with the specified key from cache</li>
 * <li>{@link flush} : delete all values from cache</li>
 * </ul>
 *
 * Child classes must implement the following methods:
 * <ul>
 * <li>{@link getValue}</li>
 * <li>{@link setValue}</li>
 * <li>{@link addValue}</li>
 * <li>{@link deleteValue}</li>
 * <li>{@link flush} (optional)</li>
 * </ul>
 *
 * CCache also implements ArrayAccess so that it can be used like an array.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: CCache.php 3001 2011-02-24 16:42:44Z alexander.makarow $
 * @package system.caching
 * @since 1.0
 */
abstract class CCache extends CApplicationComponent implements ICache,ArrayAccess
{

/**
 * Retrieves a value from cache with a specified key.
 * @param string $id a key identifying the cached value
 * @return mixed the value stored in cache,false if the value is not in the cache,expired or the dependency has changed.
 */
public function get($id)
{
  if(($value=$this->getValue($this->generateUniqueKey($id)))!==false)
  {
    $data=unserialize($value);
    if(!is_array($data))
      return false;
    if(!($data[1] instanceof ICacheDependency) || !$data[1]->getHasChanged())
    {
      Yii::trace('Serving "'.$id.'" from cache','system.caching.'.get_class($this));
      return $data[0];
    }
  }
  return false;
}
/**
 * Retrieves multiple values from cache with the specified keys.
 * Some caches (such as memcache,apc) allow retrieving multiple cached values at one time,* which may improve the performance since it reduces the communication cost.
 * In case a cache doesn't support this feature natively,it will be simulated by this method.
 * @param array $ids list of keys identifying the cached values
 * @return array list of cached values corresponding to the specified keys. The array
 * is returned in terms of (key,value) pairs.
 * If a value is not cached or expired,the corresponding array value will be false.
 * @since 1.0.8
 */
public function mget($ids)
{
  $uniqueIDs=array();
  $results=array();
  foreach($ids as $id)
  {
    $uniqueIDs[$id]=$this->generateUniqueKey($id);
    $results[$id]=false;
  }
  $values=$this->getValues($uniqueIDs);
  foreach($uniqueIDs as $id=>$uniqueID)
  {
    if(!isset($values[$uniqueID]))
      continue;
    $data=unserialize($values[$uniqueID]);
    if(is_array($data) && (!($data[1] instanceof ICacheDependency) || !$data[1]->getHasChanged()))
    {
      Yii::trace('Serving "'.$id.'" from cache','system.caching.'.get_class($this));
      $results[$id]=$data[0];
    }
  }
  return $results;
}
/**
 * Stores a value identified by a key into cache.
 * If the cache already contains such a key,the existing value and
 * expiration time will be replaced with the new ones.
 *
 * @param string $id the key identifying the value to be cached
 * @param mixed $value the value to be cached
 * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
 * @param ICacheDependency $dependency dependency of the cached item. If the dependency changes,the item is labeled invalid.
 * @return boolean true if the value is successfully stored into cache,false otherwise
 */
public function set($id,$value,$expire=0,$dependency=null)
{
  Yii::trace('Saving "'.$id.'" to cache','system.caching.'.get_class($this));
  if($dependency!==null)
    $dependency->evaluateDependency();
  $data=array($value,$dependency);
  return $this->setValue($this->generateUniqueKey($id),serialize($data),$expire);
}
/**
 * Stores a value identified by a key into cache if the cache does not contain this key.
 * Nothing will be done if the cache already contains the key.
 * @param string $id the key identifying the value to be cached
 * @param mixed $value the value to be cached
 * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
 * @param ICacheDependency $dependency dependency of the cached item. If the dependency changes,false otherwise
 */
public function add($id,$dependency=null)
{
  Yii::trace('Adding "'.$id.'" to cache',$dependency);
  return $this->addValue($this->generateUniqueKey($id),$expire);
}
/**
 * Deletes a value with the specified key from cache
 * @param string $id the key of the value to be deleted
 * @return boolean if no error happens during deletion
 */
public function delete($id)
{
  Yii::trace('Deleting "'.$id.'" from cache','system.caching.'.get_class($this));
  return $this->deleteValue($this->generateUniqueKey($id));
}
/**
 * Deletes all values from cache.
 * Be careful of performing this operation if the cache is shared by multiple applications.
 * @return boolean whether the flush operation was successful.
 */
public function flush()
{
  Yii::trace('Flushing cache','system.caching.'.get_class($this));
  return $this->flushValues();
}

Yii::app()->cache->xxx

$id = 'key1';
$value = 'cache value';
Yii::app()->cache->add($id,$value);
var_dump(Yii::app()->cache->get($id));

Yii::app()->cache->set($id,$value);

// 值$value 在缓存中最多保留30秒
Yii::app()->cache->set($id,30);

$value=Yii::app()->cache->get($id);
if($value===false)
{
  // 因为在缓存中没找到 $value,重新生成它,// 并将它存入缓存以备以后使用：
  // Yii::app()->cache->set($id,$value);
}

$cache=Yii::app()->cache;
$cache['var1']=$value1; // 相当于: $cache->set('var1',$value1);
$value2=$cache['var2']; // 相当于: $value2=$cache->get('var2');

// 此值将在30秒后失效
// 也可能因依赖的文件发生了变化而更快失效
Yii::app()->cache->set($id,30,new CFileCacheDependency('FileName'));

...别的HTML内容...
<?php if($this->beginCache($id)) { ?>
...被缓存的内容...
<?php $this->endCache(); } ?>
...别的HTML内容...

...其他HTML内容...
<?php if($this->beginCache($id,array('duration'=>3600))) { ?>
...被缓存的内容...
<?php $this->endCache(); } ?>
...其他HTML内容...

...其他HTML内容...
<?php if($this->beginCache($id,array('dependency'=>array(
    'class'=>'system.caching.dependencies.CDbCacheDependency','sql'=>'SELECT MAX(lastModified) FROM Post')))) { ?>
...被缓存的内容...
<?php $this->endCache(); } ?>
...其他HTML内容...

...其他HTML内容...
<?php if($this->beginCache($id,array('requestTypes'=>array('GET')))) { ?>
...被缓存的内容...
<?php $this->endCache(); } ?>
...其他HTML内容...

...其他HTML内容...
<?php if($this->beginCache($id1)) { ?>
...外部被缓存内容...
  <?php if($this->beginCache($id2)) { ?>
  ...内部被缓存内容...
  <?php $this->endCache(); } ?>
...外部被缓存内容...
<?php $this->endCache(); } ?>
...其他HTML内容...

public function filters()
{
  return array(
    array(
      'COutputCache','duration'=>100,'varyByParam'=>array('id'),),);
}

...别的HTML内容...
<?php if($this->beginCache($id)) { ?>
...被缓存的片段内容...
  <?php $this->renderDynamic($callback); ?>
...被缓存的片段内容...
<?php $this->endCache(); } ?>
...别的HTML内容...