1: <?php
  2: /**
  3:  * CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
  4:  * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
  5:  *
  6:  * Licensed under The MIT License
  7:  * For full copyright and license information, please see the LICENSE.txt
  8:  * Redistributions of files must retain the above copyright notice.
  9:  *
 10:  * @copyright     Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
 11:  * @link          https://cakephp.org CakePHP(tm) Project
 12:  * @since         3.0.0
 13:  * @license       https://opensource.org/licenses/mit-license.php MIT License
 14:  */
 15: namespace Cake\Datasource;
 16: 
 17: use Cake\Cache\Cache;
 18: use Cake\Cache\CacheEngine;
 19: use RuntimeException;
 20: use Traversable;
 21: 
 22: /**
 23:  * Handles caching queries and loading results from the cache.
 24:  *
 25:  * Used by Cake\Datasource\QueryTrait internally.
 26:  *
 27:  * @see \Cake\Datasource\QueryTrait::cache() for the public interface.
 28:  */
 29: class QueryCacher
 30: {
 31:     /**
 32:      * The key or function to generate a key.
 33:      *
 34:      * @var string|callable
 35:      */
 36:     protected $_key;
 37: 
 38:     /**
 39:      * Config for cache engine.
 40:      *
 41:      * @var string|\Cake\Cache\CacheEngine
 42:      */
 43:     protected $_config;
 44: 
 45:     /**
 46:      * Constructor.
 47:      *
 48:      * @param string|\Closure $key The key or function to generate a key.
 49:      * @param string|\Cake\Cache\CacheEngine $config The cache config name or cache engine instance.
 50:      * @throws \RuntimeException
 51:      */
 52:     public function __construct($key, $config)
 53:     {
 54:         if (!is_string($key) && !is_callable($key)) {
 55:             throw new RuntimeException('Cache keys must be strings or callables.');
 56:         }
 57:         $this->_key = $key;
 58: 
 59:         if (!is_string($config) && !($config instanceof CacheEngine)) {
 60:             throw new RuntimeException('Cache configs must be strings or CacheEngine instances.');
 61:         }
 62:         $this->_config = $config;
 63:     }
 64: 
 65:     /**
 66:      * Load the cached results from the cache or run the query.
 67:      *
 68:      * @param object $query The query the cache read is for.
 69:      * @return \Cake\Datasource\ResultSetInterface|null Either the cached results or null.
 70:      */
 71:     public function fetch($query)
 72:     {
 73:         $key = $this->_resolveKey($query);
 74:         $storage = $this->_resolveCacher();
 75:         $result = $storage->read($key);
 76:         if (empty($result)) {
 77:             return null;
 78:         }
 79: 
 80:         return $result;
 81:     }
 82: 
 83:     /**
 84:      * Store the result set into the cache.
 85:      *
 86:      * @param object $query The query the cache read is for.
 87:      * @param \Traversable $results The result set to store.
 88:      * @return bool True if the data was successfully cached, false on failure
 89:      */
 90:     public function store($query, Traversable $results)
 91:     {
 92:         $key = $this->_resolveKey($query);
 93:         $storage = $this->_resolveCacher();
 94: 
 95:         return $storage->write($key, $results);
 96:     }
 97: 
 98:     /**
 99:      * Get/generate the cache key.
100:      *
101:      * @param object $query The query to generate a key for.
102:      * @return string
103:      * @throws \RuntimeException
104:      */
105:     protected function _resolveKey($query)
106:     {
107:         if (is_string($this->_key)) {
108:             return $this->_key;
109:         }
110:         $func = $this->_key;
111:         $key = $func($query);
112:         if (!is_string($key)) {
113:             $msg = sprintf('Cache key functions must return a string. Got %s.', var_export($key, true));
114:             throw new RuntimeException($msg);
115:         }
116: 
117:         return $key;
118:     }
119: 
120:     /**
121:      * Get the cache engine.
122:      *
123:      * @return \Cake\Cache\CacheEngine
124:      */
125:     protected function _resolveCacher()
126:     {
127:         if (is_string($this->_config)) {
128:             return Cache::engine($this->_config);
129:         }
130: 
131:         return $this->_config;
132:     }
133: }
134: