---
title: "lzb/cache_expiration"
description: "PHP filter `lzb/cache_expiration` of the Lazy Blocks WordPress plugin."
url: "https://www.lazyblocks.com/docs/php-filters/lzb-cache_expiration/"
source: "php-filters/lzb-cache_expiration.mdx"
---
# lzb/cache_expiration

Sets how long the prepared block list stays in a transient, or turns that transient off.

Lazy Blocks reads every `lazyblocks` post on each request, prepares its controls and stores the result under the `lzb_blocks_cache_` transient for a day. Shorten that while you are debugging a `lzb/block_data` handler, or return `0` on a site whose object cache already keeps transients in memory.

## Attributes

| Name                | Type    | Description                                                |
| ------------------- | ------- | ---------------------------------------------------------- |
| `$cache_expiration` | **Int** | transient lifetime in seconds, `DAY_IN_SECONDS` by default |

## Usage

```php title="PHP"
function my_lzb_cache_expiration( $cache_expiration ) {
  // No transient while a developer is editing block code, one hour otherwise.
  if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
    return 0;
  }

  return HOUR_IN_SECONDS;
}

add_filter( 'lzb/cache_expiration', 'my_lzb_cache_expiration' );
```

The value is compared with `> 0` and then passed straight to `set_transient()`, so `0` and any negative number skip the write and every request rebuilds the list from the database. Only blocks stored in the database go into the transient. Blocks registered from PHP with `lazyblocks()->add_block()` are appended after the cached list is read, so their data is rebuilt on every request regardless of this value.

The transient key is `lzb_blocks_cache_` followed by an MD5 of the registered control types and the number of callbacks on `lzb/block_data` and `lzb/block_defaults`, so activating a plugin that adds a control or a filter produces a new key rather than a stale list. [lzb/cache_cleared](https://www.lazyblocks.com/docs/php-actions/lzb-cache_cleared/) fires whenever the plugin deletes those transients.

## Documentation Index
> Fetch the complete documentation index at: https://www.lazyblocks.com/llms.txt
> Fetch every page in a single file at: https://www.lazyblocks.com/llms-full.txt