Hooks & Filters

This is a complete reference of all hooks and filters available in MilliCache.

Action Hooks#Copied!

Cache Storage Events#Copied!

millicache_entry_storing

Fires before a cache entry is stored.

 1add_action( 'millicache_entry_storing', function( $hash, $key, $flags, $data ) {
 2    // $hash  - Cache hash
 3    // $key   - Cache key
 4    // $flags - Array of flags
 5    // $data  - Cache data array
 6
 7    error_log( "Storing cache: $key with " . count( $flags ) . " flags" );
 8}, 10, 4 );

millicache_entry_stored

Fires after a cache entry is stored.

 1add_action( 'millicache_entry_stored', function( $hash, $key, $flags, $data ) {
 2    // Notify external CDN
 3    cdn_notify_cached( $key );
 4}, 10, 4 );

millicache_entry_deleting

Fires before a cache entry is deleted.

 1add_action( 'millicache_entry_deleting', function( $hash, $key, $flags ) {
 2    error_log( "Deleting cache: $key" );
 3}, 10, 3 );

millicache_entry_deleted

Fires after a cache entry is deleted.

 1add_action( 'millicache_entry_deleted', function( $hash, $key, $flags ) {
 2    // Notify external systems
 3    cdn_notify_purged( $key );
 4}, 10, 3 );

Cache Clearing Events#Copied!

millicache_cache_cleared_by_posts

Fires after cache is cleared by post IDs.

 1add_action( 'millicache_cache_cleared_by_posts', function( $post_ids, $expire ) {
 2    // $post_ids - Array of post IDs
 3    // $expire   - Whether expire mode was used
 4
 5    foreach ( $post_ids as $post_id ) {
 6        error_log( "Cleared cache for post: $post_id" );
 7    }
 8}, 10, 2 );

millicache_cache_cleared_by_flags

Fires after cache is cleared by flags.

 1add_action( 'millicache_cache_cleared_by_flags', function( $flags, $expire ) {
 2    // $flags  - Array of cleared flags
 3    // $expire - Whether expire mode was used
 4
 5    // Notify external cache
 6    external_cache_purge_by_tags( $flags );
 7}, 10, 2 );

millicache_cache_cleared_by_sites

Fires after cache is cleared by site IDs (multisite).

 1add_action( 'millicache_cache_cleared_by_sites', function( $site_ids, $network_id, $expire ) {
 2    // $site_ids   - Array of site IDs
 3    // $network_id - Network ID (if specified)
 4    // $expire     - Whether expire mode was used
 5}, 10, 3 );

millicache_cleared_by_networks

Fires after cache is cleared by network IDs.

 1add_action( 'millicache_cleared_by_networks', function( $network_ids, $expire ) {
 2    // $network_ids - Array of network IDs
 3    // $expire      - Whether expire mode was used
 4}, 10, 2 );

millicache_cache_cleared

Fires after any cache clearing operation.

 1add_action( 'millicache_cache_cleared', function( $expire ) {
 2    // $expire - Whether expire mode was used
 3
 4    // Log clearing event
 5    error_log( 'MilliCache cleared at ' . current_time( 'mysql' ) );
 6
 7    // Clear external caches
 8    if ( function_exists( 'wp_cache_flush' ) ) {
 9        wp_cache_flush();
10    }
11} );

REST API Events#Copied!

millicache_rest_cache_action_performed

Fires after a REST API cache action is performed.

 1add_action( 'millicache_rest_cache_action_performed', function( $action, $params, $request ) {
 2    // $action  - Action performed (clear, clear_current, clear_targets)
 3    // $params  - Action parameters
 4    // $request - WP_REST_Request object
 5
 6    // Audit log
 7    audit_log( "Cache action: $action by user " . get_current_user_id() );
 8}, 10, 3 );

millicache_rest_settings_action_performed

Fires after a REST API settings action is performed.

 1add_action( 'millicache_rest_settings_action_performed', function( $action, $params, $request ) {
 2    // $action - Action performed (reset, restore)
 3
 4    audit_log( "Settings action: $action" );
 5}, 10, 3 );

Filter Hooks#Copied!

Settings Filters#Copied!

millicache_settings_defaults

Filter default settings.

 1add_filter( 'millicache_settings_defaults', function( $defaults ) {
 2    // Modify defaults
 3    $defaults['cache']['ttl'] = 3600;  // 1 hour default
 4
 5    return $defaults;
 6} );

Cache Clearing Filters#Copied!

millicache_flags_related_to_post

Filter flags that should be cleared when a post is updated.

 1add_filter( 'millicache_flags_related_to_post', function( $flags, $post ) {
 2    // Add custom flags based on post content
 3    if ( has_block( 'myblock/featured', $post ) ) {
 4        $flags[] = 'featured-content';
 5    }
 6
 7    // Add taxonomy-based flags
 8    $categories = get_the_category( $post->ID );
 9    foreach ( $categories as $cat ) {
10        $flags[] = 'category:' . $cat->term_id;
11    }
12
13    return $flags;
14}, 10, 2 );

millicache_settings_clear_site_hooks

Filter hooks that trigger full site cache clearing.

 1add_filter( 'millicache_settings_clear_site_hooks', function( $hooks ) {
 2    // Add a custom hook that should clear the cache
 3    $hooks[] = 'my_custom_global_update';
 4
 5    // Remove a default hook
 6    $key = array_search( 'switch_theme', $hooks );
 7    if ( $key !== false ) {
 8        unset( $hooks[ $key ] );
 9    }
10
11    return $hooks;
12} );

Default hooks:

  • save_post_wp_template_part
  • customize_save_after
  • wp_update_nav_menu
  • switch_theme
  • update_option_permalink_structure
  • update_option_active_plugins

millicache_settings_clear_site_options

Filter options that trigger full site cache clearing when updated.

 1add_filter( 'millicache_settings_clear_site_options', function( $options ) {
 2    // Add a custom option
 3    $options[] = 'my_global_setting';
 4
 5    return $options;
 6} );

Request Flags Filters#Copied!

millicache_flags_for_request

Filter flags assigned to the current request.

 1add_filter( 'millicache_flags_for_request', function( $flags ) {
 2    // Add flags based on content
 3    if ( has_block( 'myblock/weather' ) ) {
 4        $flags[] = 'block:weather';
 5    }
 6
 7    // Add flags for WooCommerce
 8    if ( function_exists( 'is_shop' ) && is_shop() ) {
 9        $flags[] = 'woo:shop';
10    }
11
12    // Add a template-based flag
13    if ( is_page_template( 'templates/landing.php' ) ) {
14        $flags[] = 'template:landing';
15    }
16
17    return $flags;
18} );

Capability Filters#Copied!

millicache_clear_cache_capability

Filter the capability required to clear cache.

 1add_filter( 'millicache_clear_cache_capability', function( $capability ) {
 2    // Require higher capability
 3    return 'manage_options';  // Only administrators
 4
 5    // Or lower for specific sites
 6    // return 'edit_posts';  // Editors can clear
 7} );

Default: publish_pages

REST API Filters#Copied!

millicache_rest_cache_allowed_actions

Filter allowed cache actions via REST API.

 1add_filter( 'millicache_rest_cache_allowed_actions', function( $actions ) {
 2    // Add custom action
 3    $actions[] = 'my_custom_action';
 4
 5    // Remove an action
 6    $key = array_search( 'clear', $actions );
 7    if ( $key !== false ) {
 8        unset( $actions[ $key ] );
 9    }
10
11    return $actions;
12} );

Default: ['clear', 'clear_current', 'clear_targets']

millicache_rest_settings_allowed_actions

Filter allowed settings actions via REST API.

 1add_filter( 'millicache_rest_settings_allowed_actions', function( $actions ) {
 2    // Remove restore action
 3    $key = array_search( 'restore', $actions );
 4    if ( $key !== false ) {
 5        unset( $actions[ $key ] );
 6    }
 7
 8    return $actions;
 9} );

Default: ['reset', 'restore']

millicache_rest_status_response

Filter the REST API status response.

 1add_filter( 'millicache_rest_status_response', function( $status ) {
 2    // Add custom data
 3    $status['custom_metric'] = get_custom_cache_metric();
 4
 5    // Remove sensitive data
 6    unset( $status['storage']['password'] );
 7
 8    return $status;
 9} );

Hook Usage Examples#Copied!

Notify CDN on Cache Clear#Copied!

 1add_action( 'millicache_cache_cleared_by_flags', function( $flags, $expire ) {
 2    // Convert MilliCache flags to CDN tags
 3    $cdn_tags = array_map( function( $flag ) {
 4        return 'millicache-' . sanitize_title( $flag );
 5    }, $flags );
 6
 7    // Purge CDN
 8    cdn_purge_by_tags( $cdn_tags );
 9}, 10, 2 );

Audit Logging#Copied!

 1add_action( 'millicache_cache_cleared', function( $expire ) {
 2    $user = wp_get_current_user();
 3    $method = $expire ? 'expired' : 'deleted';
 4
 5    log_audit_event( 'cache_cleared', [
 6        'user_id'   => $user->ID,
 7        'user_name' => $user->user_login,
 8        'method'    => $method,
 9        'timestamp' => current_time( 'mysql' ),
10    ] );
11} );

Custom Flags for ACF#Copied!

 1add_filter( 'millicache_flags_for_request', function( $flags ) {
 2    if ( ! function_exists( 'get_field' ) ) {
 3        return $flags;
 4    }
 5
 6    // Add a flag for pages with a specific ACF field
 7    if ( is_singular() && get_field( 'enable_dynamic_content' ) ) {
 8        $flags[] = 'acf:dynamic';
 9    }
10
11    return $flags;
12} );
13
14// Clear when the ACF field changes
15add_action( 'acf/save_post', function( $post_id ) {
16    if ( get_field( 'enable_dynamic_content', $post_id ) ) {
17        millicache_clear_cache_by_flags( [ 'acf:dynamic' ] );
18    }
19} );

Restrict Cache Clearing by Role#Copied!

 1add_filter( 'millicache_clear_cache_capability', function( $capability ) {
 2    // Only allow on staging/development
 3    if ( defined( 'WP_ENV' ) && WP_ENV === 'production' ) {
 4        return 'manage_options';  // Admins only in production
 5    }
 6
 7    return 'edit_posts';  // Editors can clear on staging
 8} );

Next Steps#Copied!