Apache Zeta Components - high quality PHP components

The use of ezcCacheManager is not required, but recommended. If you only need a few (or maybe just 1) cache instance, you can use and instantiate a ezcCacheStorage class directly.

Usage example for ezcCacheManager:

1.  // Some pre-work, needed by the example
2.  $basePath = dirname( __FILE__ ).'/cache';
3.  function getUniqueId()
4.  {
5.      return 'This is a unique ID';
6.  }
7.  
8.  // Central creation and configuration of the caches
9.  // The ezcCacheManager just stores the configuration right now and
10.  // performs sanity checks. The ezcCacheStorage instances
11.  // will be created on demand, when you use them for the first time
12.  
13.  // Configuration options for a cache (see ezcCacheStorage)
14.  $options = array(
15.      'ttl'   => 60*60*24*2,     // Default would be 1 day, here 2 days
16.  );
17.  
18.  // Create a cache named "content", that resides in /var/cache/content
19.  // The cache instance will use the ezcCacheStorageFileArray class
20.  // to store the cache data. The time-to-live for cache items is set as
21.  // defined above.
22.  ezcCacheManager::createCache( 'content', $basePath.'/content', 'ezcCacheStorageFileArray', $options );
23.  
24.  // Create another cache, called "template" in /var/cache/templates.
25.  // This cache will use the ezcCacheStorageFilePlain class to store
26.  // cache data. It has the same TTL as the cache defined above.
27.  ezcCacheManager::createCache( 'template', $basePath.'/templates', 'ezcCacheStorageFilePlain', $options );
28.  
29.  // Somewhere in the application you can access the caches
30.  
31.  // Get the instance of the cache called "content"
32.  // Now the instance of ezcCacheStorageFileArray is created and
33.  // returned to be used. Next time you access this cache, the created
34.  // instance will be reused.
35.  $cache = ezcCacheManager::getCache( 'content' );
36.  
37.  // Instead of using the createCache()/getCache() mechanism you can also
38.  // create cache on-demand with delayed initialization. You can find
39.  // information on how to use that in the tutorial.
40.  
41.  // Specify any number of attributes to identify the cache item you want
42.  // to store. This attributes can be used later to perform operations
43.  // on a set of cache items, that share a common attribute.
44.  $attributes = array( 'node' => 2, 'area' => 'admin', 'lang' => 'en-GB' );
45.  
46.  // This function is not part of the Cache package. You have to define
47.  // unique IDs for your cache items yourself.
48.  $id = getUniqueId();
49.  
50.  // Initialize the data variable you want to restore
51.  $data = '';
52.  
53.  // Check if data is available in the cache. The restore method returns
54.  // the cached data, if available, or bool false.
55.  if ( ( $data = $cache->restore( $id, $attributes ) ) === false )
56.  {
57.      // The cache item we tried to restore does not exist, so we have to
58.      // generate the data.
59.      $data = array( 'This is some data', 'and some more data.' );
60.      // For testing we echo something here...
61.      echo "No cache data found. Generated some.\n".var_export( $data, true )."\n";
62.      // Now we store the data in the cache. It will be available through
63.      // restore, next time the code is reached
64.      $cache->store( $id, $data, $attributes );
65.  }
66.  else
67.  {
68.      // We found cache data. Let's echo the information.
69.      echo "Cache data found.\n".var_export( $data, true )."\n";
70.  }
71.  
72.  // In some other place you can access the second defined cache.
73.  $cache = ezcCacheManager::getCache( 'template' );
74.  
75.  // Here we are removing cache items. We do not specify an ID (which would
76.  // have meant to delete 1 specific cache item), but only an array of
77.  // attributes. This will result in all cache items to be deleted, that
78.  // have this attribute assigned.
79.  $cache->delete( null, array( 'node' => 5 ) );

This method is used to create a new cache inside the manager. Each cache has a unique ID to access it during the application runtime. Each location may only be used by 1 cache.

The $storageClass parameter must be a subclass of ezcCacheStorage and tells the manager which object will be used for the cache.

The $location parameter depends on the kind of ezcCacheStorage used for the cache you create. Usually this is a directory on your file system, but may also be e.g. a data source name, if you cache in a database or similar. For memory-based storage (ezcCacheStorageApcPlain or ezcCacheStorageMemcachePlain) it is null, but for memory/file hybrid storage (ezcCacheStorageFileApcArray) it should be an existing writeable path.

The $options array consists of several standard attributes and can additionally contain options defined by the ezcCacheStorage class. Standard options are:

1.  array(
2.       'ttl'   => 60*60*24,    // Time-to-life, default: 1 day
3.  );

The cache ID has to be defined before using the ezcCacheManager::createCache() method. If no instance of this cache does exist yet, it's created on the fly. If one exists, it will be reused.