<?php
namespace React\Cache;
use React\Promise\PromiseInterface;
interface CacheInterface
{
/**
* Retrieves an item from the cache.
*
* This method will resolve with the cached value on success or with the
* given `$default` value when no item can be found or when an error occurs.
* Similarly, an expired cache item (once the time-to-live is expired) is
* considered a cache miss.
*
* ```php
* $cache
* ->get('foo')
* ->then('var_dump');
* ```
*
* This example fetches the value of the key `foo` and passes it to the
* `var_dump` function. You can use any of the composition provided by
* [promises](https://github.com/reactphp/promise).
*
* @param string $key
* @param mixed $default Default value to return for cache miss or null if not given.
* @return PromiseInterface
*/
public function get($key, $default = null);
/**
* Stores an item in the cache.
*
* This method will resolve with `true` on success or `false` when an error
* occurs. If the cache implementation has to go over the network to store
* it, it may take a while.
*
* The optional `$ttl` parameter sets the maximum time-to-live in seconds
* for this cache item. If this parameter is omitted (or `null`), the item
* will stay in the cache for as long as the underlying implementation
* supports. Trying to access an expired cache item results in a cache miss,
* see also [`get()`](#get).
*
* ```php
* $cache->set('foo', 'bar', 60);
* ```
*
* This example eventually sets the value of the key `foo` to `bar`. If it
* already exists, it is overridden.
*
* @param string $key
* @param mixed $value
* @param ?float $ttl
* @return PromiseInterface Returns a promise which resolves to `true` on success or `false` on error
*/
public function set($key, $value, $ttl = null);
/**
* Deletes an item from the cache.
*
* This method will resolve with `true` on success or `false` when an error
* occurs. When no item for `$key` is found in the cache, it also resolves
* to `true`. If the cache implementation has to go over the network to
* delete it, it may take a while.
*
* ```php
* $cache->delete('foo');
* ```
*
* This example eventually deletes the key `foo` from the cache. As with
* `set()`, this may not happen instantly and a promise is returned to
* provide guarantees whether or not the item has been removed from cache.
*
* @param string $key
* @return PromiseInterface Returns a promise which resolves to `true` on success or `false` on error
*/
public function delete($key);
}