wp_cache_get( int|string $key, string $group = '', bool $force = false, bool $found = null ): mixed|false

Retrieves the cache contents from the cache by key and group.

Contents

Description

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See also

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Parameters

$key int|string Required
The key under which the cache contents are stored.
$group string Optional
Where the cache contents are grouped.

Default: ''

$force bool Optional
Whether to force an update of the local cache from the persistent cache.

Default: false

$found bool Optional
Whether the key was found in the cache (passed by reference).
Disambiguates a return of false, a storable value.

Default: null

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Return

mixed|false The cache contents on success, false on failure to retrieve contents.

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Source

File: wp-includes/cache.php. View all references 

function wp_cache_get( $key, $group = '', $force = false, &$found = null ) {
	global $wp_object_cache;

	return $wp_object_cache->get( $key, $group, $force, $found );
}

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Used By

Used By
Used By Description
wp_get_global_styles_custom_css() wp-includes/global-styles-and-settings.php

Gets the global styles custom css from theme.json.
wp_get_global_styles_svg_filters() wp-includes/global-styles-and-settings.php

Returns a string containing the SVGs to be referenced as filters (duotone).
wp_get_global_settings() wp-includes/global-styles-and-settings.php

Gets the settings resulting of merging core, theme, and user data.
wp_get_global_stylesheet() wp-includes/global-styles-and-settings.php

Returns the stylesheet resulting of merging core, theme, and user data.
get_metadata_raw() wp-includes/meta.php

Retrieves raw metadata value for the specified object.
_find_post_by_old_slug() wp-includes/query.php

Find the post ID for redirecting an old slug.
_find_post_by_old_date() wp-includes/query.php

Find the post ID for redirecting an old date.
WP_Privacy_Requests_Table::get_request_counts() wp-admin/includes/class-wp-privacy-requests-table.php

Count number of requests for each status.
WP_Embed::find_oembed_post_id() wp-includes/class-wp-embed.php

Finds the oEmbed cache post ID for a given cache key.
WP_Customize_Manager::find_changeset_post_id() wp-includes/class-wp-customize-manager.php

Finds the changeset post ID for a given changeset UUID.
wp_cache_get_last_changed() wp-includes/functions.php

Gets last changed date for the specified cache group.
WP_Term_Query::get_terms() wp-includes/class-wp-term-query.php

Retrieves the query results.
WP_Network_Query::get_networks() wp-includes/class-wp-network-query.php

Gets a list of networks matching the query vars.
WP_Site::get_details() wp-includes/class-wp-site.php

Retrieves the details for this site.
ms_load_current_site_and_network() wp-includes/ms-load.php

Identifies the network and site of a requested domain and path and populates the corresponding network and site global objects as part of the multisite bootstrap process.
WP_Site_Query::get_sites() wp-includes/class-wp-site-query.php

Retrieves a list of sites matching the query vars.
WP_Site::get_instance() wp-includes/class-wp-site.php

Retrieves a site from the database by its ID.
WP_Network::get_instance() wp-includes/class-wp-network.php

Retrieves a network from the database by its ID.
WP_Comment::get_instance() wp-includes/class-wp-comment.php

Retrieves a WP_Comment instance.
WP_Comment_Query::fill_descendants() wp-includes/class-wp-comment-query.php

Fetch descendants for located comments.
WP_Term::get_instance() wp-includes/class-wp-term.php

Retrieve WP_Term instance.
update_network_option() wp-includes/option.php

Updates the value of a network option that was already added.
add_network_option() wp-includes/option.php

Adds a new network option.
get_network_option() wp-includes/option.php

Retrieves a network’s option value based on the option name.
WP_MS_Sites_List_Table::column_users() wp-admin/includes/class-wp-ms-sites-list-table.php

Handles the users column output.
WP_Comment_Query::get_comments() wp-includes/class-wp-comment-query.php

Get a list of comments matching the query vars.
get_plugins() wp-admin/includes/plugin.php

Checks the plugins directory and retrieve all plugin files with plugin data.
WP_User::get_data_by() wp-includes/class-wp-user.php

Returns only the main user fields.
wp_get_archives() wp-includes/general-template.php

Displays archive links based on type and format.
get_calendar() wp-includes/general-template.php

Displays calendar with days that have posts as links.
get_usermeta() wp-includes/deprecated.php

Retrieve user metadata.
WP_Theme::cache_get() wp-includes/class-wp-theme.php

Gets theme data from cache.
WP_Query::get_posts() wp-includes/class-wp-query.php

Retrieves an array of posts based on query variables.
is_blog_installed() wp-includes/functions.php

Determines whether WordPress is already installed.
get_object_term_cache() wp-includes/taxonomy.php

Retrieves the cached term objects for the given object ID.
get_objects_in_term() wp-includes/taxonomy.php

Retrieves object IDs of valid taxonomy and term.
get_adjacent_post() wp-includes/link-template.php

Retrieves the adjacent post.
get_site_transient() wp-includes/option.php

Retrieves the value of a site transient.
get_transient() wp-includes/option.php

Retrieves the value of a transient.
wp_load_alloptions() wp-includes/option.php

Loads and caches all autoloaded options, if available or all options.
update_option() wp-includes/option.php

Updates the value of an option that was already added.
add_option() wp-includes/option.php

Adds a new option.
get_option() wp-includes/option.php

Retrieves an option value based on an option name.
WP_Post::get_instance() wp-includes/class-wp-post.php

Retrieve WP_Post instance.
wp_mime_type_icon() wp-includes/post.php

Retrieves the icon for a MIME type or attachment.
_get_last_post_time() wp-includes/post.php

Gets the timestamp of the last time any post was modified or published.
get_all_page_ids() wp-includes/post.php

Gets a list of page IDs.
get_page_by_path() wp-includes/post.php

Retrieves a page given its path.
get_pages() wp-includes/post.php

Retrieves an array of pages (or hierarchical post type items).
wp_count_posts() wp-includes/post.php

Counts number of posts of a post type and if user has permissions to view.
wp_count_attachments() wp-includes/post.php

Counts number of attachments for the mime type(s).
get_blog_id_from_url() wp-includes/ms-functions.php

Gets a blog’s numeric ID from its URL.
get_bookmark() wp-includes/bookmark.php

Retrieves bookmark data.
get_bookmarks() wp-includes/bookmark.php

Retrieves the list of bookmarks.
get_blog_details() wp-includes/ms-blogs.php

Retrieves the details for a blog from the blogs table and blog options.
wp_count_comments() wp-includes/comment.php

Retrieves the total comment counts for the whole site or a single post.
get_lastcommentmodified() wp-includes/comment.php

Retrieves the date the last comment was modified.
metadata_exists() wp-includes/meta.php

Determines if a meta field with the given key exists for the given object ID.
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Changelog

Changelog
Version Description
2.0.0 Introduced.

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User Contributed Notes

  1. Skip to note 1 content
    You must log in to vote on the helpfulness of this noteVote results for this note: 1You must log in to vote on the helpfulness of this note
    Contributed by Mayeenul Islam — 
    function prefix_get_post_count( $post_status = 'publish' ) {
    $cache_key = 'prefix_post_count_'. $post_status;
    $_posts = wp_cache_get( $cache_key );
    if ( false === $_posts ) {
        $_posts = $wpdb->get_var(
                    $wpdb->prepare(
                        "SELECT COUNT(*) FROM $wpdb->posts WHERE post_type = 'post' AND post_status = %s",
                        $post_status
                    ));
 
        wp_cache_set( $cache_key, $_posts );
    }
 
    return $_posts;
}
  2. Skip to note 2 content
    You must log in to vote on the helpfulness of this noteVote results for this note: 1You must log in to vote on the helpfulness of this note
    Contributed by Aamer Shahzad — 
    /**
 * Handles the users column output.
 *
 * @since 4.3.0
 *
 * @param array $blog Current site.
 */
public function column_users( $blog ) {
    $user_count = wp_cache_get( $blog['blog_id'] . '_user_count', 'blog-details' );
    if ( ! $user_count ) {
        $blog_users = new WP_User_Query(
            array(
                'blog_id'     => $blog['blog_id'],
                'fields'      => 'ID',
                'number'      => 1,
                'count_total' => true,
            )
        );
        $user_count = $blog_users->get_total();
        wp_cache_set( $blog['blog_id'] . '_user_count', $user_count, 'blog-details', 12 * HOUR_IN_SECONDS );
    }

    printf(
        '<a href="%s">%s</a>',
        esc_url( network_admin_url( 'site-users.php?id=' . $blog['blog_id'] ) ),
        number_format_i18n( $user_count )
    );
}
  3. Skip to note 3 content
    You must log in to vote on the helpfulness of this noteVote results for this note: 1You must log in to vote on the helpfulness of this note
    Contributed by Michael Nelson —

    It seems some cache dropins (like those used on WPEngine) may define `wp_cache_get` WITHOUT the 4th parameter, `$found`. This means `$found` might not be populated by `wp_cache_get()` (it will always be `null`, regardless of whether the value was cached or not), and you can also get a ton of warnings as reported here and here.

    The workaround? Pretend `$found` isn’t an argument, and never use `wp_cache_set()` to cache a value of `false` (because you won’t be able to differentiate a cached value of `false` from the lack of a cached value, where `wp_cache_get()` also returns `false`.)

    Eg
    [PHP]
    $result = wp_get_cache(‘my_key’);
    if( $result === false){
    // calculate the result, and use `0` or `null` instead of `false`
    if( $result === false){
    $result = 0;
    }
    wp_cache_set(‘my_key’, $result);
    }
    [/php]

  4. Skip to note 4 content
    You must log in to vote on the helpfulness of this noteVote results for this note: 1You must log in to vote on the helpfulness of this note
    Contributed by sun —

    Here is how you use the $found parameter in your code – it is passed by reference, so you do not need to define the variable upfront, its value will be set by the called function instead:

    $value = wp_cache_get( 'wpdocs_mykey', 'wpdocs_mygroup', false, $found );

if ( ! $found) {
    $value = wpdocs_my_expensive_function();
    wp_cache_set( 'wpdocs_mykey', $value, 'wpdocs_mygroup' );
}

return $value;

    You need to use the $found parameter if there is a slightest chance that the value you are caching can be zero, false, null, or otherwise equivalent to false (falsy) like an empty array.

    If you are not sure, or if you are looking for a general rule of thumb – always use the $found parameter.

    If some object caches are not implementing the $found parameter correctly, then that is a good reason to fix those implementations (or use better maintained ones) and not a reason to not use the parameter.

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