Retrieving cached data in WordPress using wp_cache_get
The wp_cache_get function is a part of WordPress’s object caching system. This function is designed to retrieve the cached value for a given key from the cache. If the value is found in the cache, it is returned to the caller. If the value is not found, the function returns false.
Object caching is a process that stores database query results in order to speed up subsequent queries. Using the wp_cache_get function can help reduce the load on your database by storing the results of complex queries in memory. This way, if the same data is needed again, it can be quickly retrieved from the cache instead of executing a new database query.
While this function can be beneficial in certain scenarios, it’s important to note that it may not provide significant improvements if your website has low traffic or if your hosting environment already implements effective caching mechanisms at the server level.
Parameters Accepted by the wp_cache_get Function
The wp_cache_get function in WordPress accepts several parameters which are used to control the retrieval of cached data. These parameters are:
$key(int|string) – This is a required parameter that identifies the specific cache content to be retrieved. The key is essentially the name under which the cache content is stored.$group(string) – This is an optional parameter, with a default value of an empty string (”). This parameter allows you to specify the group where the cache contents are stored. This is useful for categorizing and organizing your cache contents.$force(bool) – This is also an optional parameter, with a default value of false. If set to true, it forces an update of the local cache from the persistent cache. This can be useful when you want to ensure that you are working with the most recent cache contents.$found(bool) – This is another optional parameter, with a default value of null. This parameter is used to indicate whether the key was found in the cache. It is passed by reference and helps to clarify a return of false, which could mean that the value is storable.
Return Value of the wp_cache_get Function
The wp_cache_get function returns either the cached content or a boolean false. If the function is successful in retrieving the cached content, it will return the content. However, if it fails to retrieve the cached content, it will return false. This return value can be used to check whether the function was successful in fetching the desired cache content.
Examples
How to Retrieve Data from Cache
<?php
$my_data = wp_cache_get( 'my_key' );
if ( $my_data === false ) {
$my_data = 'My data';
wp_cache_set( 'my_key', $my_data );
}
echo $my_data;
?>
In this example, we are using the wp_cache_get function to retrieve data from the cache. If the data does not exist (which is indicated by the function returning false), we then set the data in the cache using wp_cache_set. The key we are using to store and retrieve the data is ‘my_key’.
How to Retrieve Data from Cache with a Group
<?php
$my_data = wp_cache_get( 'my_key', 'my_group' );
if ( $my_data === false ) {
$my_data = 'My data';
wp_cache_set( 'my_key', $my_data, 'my_group' );
}
echo $my_data;
?>
In this example, we are using a cache group ‘my_group’ along with our key to store and retrieve data. Cache groups can be used to categorize cache data and can be useful when you need to delete all cache data in a specific group.
Conclusion
In summary, the wp_cache_get function is a part of WordPress’s object cache API. It is used to retrieve data that has been previously stored in the cache. This function can be used to improve the performance of a website by reducing the need for repeated database queries. It takes two parameters, the key and the group, and returns the cached data associated with the given key from the specified group. If the data is not found in the cache, the function will return false. Therefore, the wp_cache_get function is a key tool in the development of efficient, high-performance WordPress sites.