Cache Flashcards
What are the cache drivers supported by Laravel?
Memcached, Redis & file
What the default cache driver used by Laravel?
The file cache driver
Which of the three supported cache drivers are recommended for larger apps?
Memcached or Redis
In order to use the file/database cache driver what is required to be setup?
When using the database cache driver, you will need to setup a table to contain the cache items. You’ll find an example Schema declaration for the table below:
Schema::create('cache', function ($table) {
$table->string('key')->unique();
$table->text('value');
$table->integer('expiration');
});
Which Artisan Command will generate a migration with the proper schema for the database cache driver?
php artisan cache:table
For Memcached what is the name of the required package?
Memcached PECL package
In which file can you list all of your Memcached servers?
You may list all of your Memcached servers in the config/cache.php configuration file:
'memcached' => [
[
'host' => '127.0.0.1',
'port' => 11211,
'weight' => 100
],
],
Which option in the config/cache.php file can also be set to to a UNIX socket path?
You may also set the host option to a UNIX socket path. If you do this, the port option should be set to 0:
'memcached' => [
[
'host' => '/var/run/memcached/memcached.sock',
'port' => 0,
'weight' => 100
],
],
Before using a Redis cache with Laravel, you will need to either install?
the predis/predis package (~1.0) via Composer or install the PhpRedis PHP extension via PECL
What contracts provide access to Laravel’s cache services?
Illuminate\Contracts\Cache\Factory and Illuminate\Contracts\Cache\Repository
What is the purpose of the factory contract?
The Factory contract provides access to all cache drivers defined for your application.
What is the purpose of the repository contract?
The Repository contract is typically an implementation of the default cache driver for your application as specified by your cache configuration file.
What is the purpose of the Cache Facade?
The Cache facade provides convenient, terse access to the underlying implementations of the Laravel cache contracts:
How are you able to access multiple cache stores?
Using the Cache facade, you may access various cache stores via the store method. The key passed to the store method should correspond to one of the stores listed in the stores configuration array in your cache configuration file:
$value = Cache::store(‘file’)->get(‘foo’);
Cache::store(‘redis’)->put(‘bar’, ‘baz’, 10);
What is the purpose of the get method?
The get method on the Cache facade is used to retrieve items from the cache. If the item does not exist in the cache, null will be returned. If you wish, you may pass a second argument to the get method specifying the default value you wish to be returned if the item doesn’t exist:
$value = Cache::get(‘key’);
$value = Cache::get(‘key’, ‘default’);
What is the purpose of the get method closure?
You may even pass a Closure as the default value. The result of the Closure will be returned if the specified item does not exist in the cache. Passing a Closure allows you to defer the retrieval of default values from a database or other external service:
$value = Cache::get(‘key’, function () {
return DB::table(…)->get();
});
What is the purpose of the has method?
The has method may be used to determine if an item exists in the cache. This method will return false if the value is null or false:
if (Cache::has('key')) {
//
}
What is the purpose of the increment and decrement methods?
The increment and decrement methods may be used to adjust the value of integer items in the cache. Both of these methods accept an optional second argument indicating the amount by which to increment or decrement the item’s value:
Cache::increment(‘key’);
Cache::increment(‘key’, $amount);
Cache::decrement(‘key’);
Cache::decrement(‘key’, $amount);
What is the purpose of the remember method?
Sometimes you may wish to retrieve an item from the cache, but also store a default value if the requested item doesn’t exist. For example, you may wish to retrieve all users from the cache or, if they don’t exist, retrieve them from the database and add them to the cache. You may do this using the Cache::remember method:
$value = Cache::remember(‘users’, $minutes, function () {
return DB::table(‘users’)->get();
});
If the item does not exist in the cache, the Closure passed to the remember method will be executed and its result will be placed in the cache.
What is the purpose of the pull method?
If you need to retrieve an item from the cache and then delete the item, you may use the pull method. Like the get method, null will be returned if the item does not exist in the cache:
$value = Cache::pull(‘key’);
What is the purpose of the put method?
You may use the put method on the Cache facade to store items in the cache. When you place an item in the cache, you need to specify the number of minutes for which the value should be cached:
Cache::put(‘key’, ‘value’, $minutes);
Instead of passing the number of minutes as an integer, you may also pass a DateTime instance representing the expiration time of the cached item:
$expiresAt = Carbon::now()->addMinutes(10);
Cache::put(‘key’, ‘value’, $expiresAt);
What is the purpose of the add method?
The add method will only add the item to the cache if it does not already exist in the cache store. The method will return true if the item is actually added to the cache. Otherwise, the method will return false:
Cache::add(‘key’, ‘value’, $minutes);
What is the purpose of the forever method?
The forever method may be used to store an item in the cache permanently. Since these items will not expire, they must be manually removed from the cache using the forget method:
Cache::forever(‘key’, ‘value’);
What is the purpose of the forget method?
You may remove items from the cache using the forget method:
Cache::forget(‘key’);
