How to use Cache API in Drupal 8

In this tuto, I'll show you how to use Cache API  in your custom module in Drupal 8.

• Get the default cache bin

Cache storage is separated into "bins", each containing various cache items.

$cache = \Drupal::cache();

• Get a particular cache bin

$render_cache = \Drupal::cache('BIN_NAME');

// Example

$render_cache = \Drupal::cache('render');

List of the cache bins are the following:

• bootstrap: Data needed from the beginning to the end of most requests, that has a very strict limit on variations and is invalidated rarely.
• render: Contains cached HTML strings like cached pages and blocks, can grow to large size.
• data: Contains data that can vary by path or similar context.
• discovery: Contains cached discovery data for things such as plugins, views_data, or YAML discovered data such as library info.

•  Storing cache items

Example:

$tags = array(
  'my_custom_tag',
  'node:1',
  'node:3',
  'user:7',
);
\Drupal::cache()->set($cacheID, $data, CacheBackendInterface::CACHE_PERMANENT, $tags);

set() method contains 4 arguments:

• $cache ID: string by which we can later reference the item.
• $data: value such as a string, array or object you want to save it.
• the expiration time: a timestamp in the future when this cache item will automatically become invalid or -1 which basically means this item never expires. It is best practice to use the Drupal\Core\Cache\CacheBackendInterface::CACHE_PERMANENT constant to represent this value.
• $tags: array of cache tags this item can be later identified by.

• Retrieving cached items

$cache = \Drupal::cache()->get('cacheID');
$data = $cache->data;

• Cache invalidation and removal

You can remove cache using following methods:
invalidate(), invalidateMultiple(), invalidateAll(), delete(), deleteMultiple(), invalidateTags() or deleteAll();

Example: To invalidate cach with tags.

$tags = array(
  'my_custom_tag',
  'node:1',
  'node:3',
  'user:7',
);

\Drupal\Core\Cache\Cache::invalidateTags($tags);

Example:  Delete Cache by cacheID.

  $cacheIDs = ['cid1', 'cid2',];
\Drupal::cache()->delete($cacheIDs);

• Get Cache Tags

If you want to associate the cache tags of entities, or entity listings. You won't have to manually construct cache tags for them — just get their cache tags via:

•  \Drupal\Core\Cache\CacheableDependencyInterface::getCacheTags()
• \Drupal\Core\Entity\EntityTypeInterface::getListCacheTags()

Example How to use Cache API to store data:

$cid = 'mymodule_example:' . \Drupal::languageManager()->getCurrentLanguage()->getId();
$data = NULL;
if ($cache = \Drupal::cache()->get($cid)) {
  $data = $cache->data;
}
else {
  $data = my_module_complicated_calculation();
  \Drupal::cache()->set($cid, $data);
}