DB_cache.php 5.76 KB
Newer Older
Phạm Văn Đoan committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221
<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2018, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package	CodeIgniter
 * @author	EllisLab Dev Team
 * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright	Copyright (c) 2014 - 2018, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	http://opensource.org/licenses/MIT	MIT License
 * @link	https://codeigniter.com
 * @since	Version 1.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * Database Cache Class
 *
 * @category	Database
 * @author		EllisLab Dev Team
 * @link		https://codeigniter.com/user_guide/database/
 */
class CI_DB_Cache {

	/**
	 * CI Singleton
	 *
	 * @var	object
	 */
	public $CI;

	/**
	 * Database object
	 *
	 * Allows passing of DB object so that multiple database connections
	 * and returned DB objects can be supported.
	 *
	 * @var	object
	 */
	public $db;

	// --------------------------------------------------------------------

	/**
	 * Constructor
	 *
	 * @param	object	&$db
	 * @return	void
	 */
	public function __construct(&$db)
	{
		// Assign the main CI object to $this->CI and load the file helper since we use it a lot
		$this->CI =& get_instance();
		$this->db =& $db;
		$this->CI->load->helper('file');

		$this->check_path();
	}

	// --------------------------------------------------------------------

	/**
	 * Set Cache Directory Path
	 *
	 * @param	string	$path	Path to the cache directory
	 * @return	bool
	 */
	public function check_path($path = '')
	{
		if ($path === '')
		{
			if ($this->db->cachedir === '')
			{
				return $this->db->cache_off();
			}

			$path = $this->db->cachedir;
		}

		// Add a trailing slash to the path if needed
		$path = realpath($path)
			? rtrim(realpath($path), DIRECTORY_SEPARATOR).DIRECTORY_SEPARATOR
			: rtrim($path, '/').'/';

		if ( ! is_dir($path))
		{
			log_message('debug', 'DB cache path error: '.$path);

			// If the path is wrong we'll turn off caching
			return $this->db->cache_off();
		}

		if ( ! is_really_writable($path))
		{
			log_message('debug', 'DB cache dir not writable: '.$path);

			// If the path is not really writable we'll turn off caching
			return $this->db->cache_off();
		}

		$this->db->cachedir = $path;
		return TRUE;
	}

	// --------------------------------------------------------------------

	/**
	 * Retrieve a cached query
	 *
	 * The URI being requested will become the name of the cache sub-folder.
	 * An MD5 hash of the SQL statement will become the cache file name.
	 *
	 * @param	string	$sql
	 * @return	string
	 */
	public function read($sql)
	{
		$segment_one = ($this->CI->uri->segment(1) == FALSE) ? 'default' : $this->CI->uri->segment(1);
		$segment_two = ($this->CI->uri->segment(2) == FALSE) ? 'index' : $this->CI->uri->segment(2);
		$filepath = $this->db->cachedir.$segment_one.'+'.$segment_two.'/'.md5($sql);

		if ( ! is_file($filepath) OR FALSE === ($cachedata = file_get_contents($filepath)))
		{
			return FALSE;
		}

		return unserialize($cachedata);
	}

	// --------------------------------------------------------------------

	/**
	 * Write a query to a cache file
	 *
	 * @param	string	$sql
	 * @param	object	$object
	 * @return	bool
	 */
	public function write($sql, $object)
	{
		$segment_one = ($this->CI->uri->segment(1) == FALSE) ? 'default' : $this->CI->uri->segment(1);
		$segment_two = ($this->CI->uri->segment(2) == FALSE) ? 'index' : $this->CI->uri->segment(2);
		$dir_path = $this->db->cachedir.$segment_one.'+'.$segment_two.'/';
		$filename = md5($sql);

		if ( ! is_dir($dir_path) && ! @mkdir($dir_path, 0750))
		{
			return FALSE;
		}

		if (write_file($dir_path.$filename, serialize($object)) === FALSE)
		{
			return FALSE;
		}

		chmod($dir_path.$filename, 0640);
		return TRUE;
	}

	// --------------------------------------------------------------------

	/**
	 * Delete cache files within a particular directory
	 *
	 * @param	string	$segment_one
	 * @param	string	$segment_two
	 * @return	void
	 */
	public function delete($segment_one = '', $segment_two = '')
	{
		if ($segment_one === '')
		{
			$segment_one  = ($this->CI->uri->segment(1) == FALSE) ? 'default' : $this->CI->uri->segment(1);
		}

		if ($segment_two === '')
		{
			$segment_two = ($this->CI->uri->segment(2) == FALSE) ? 'index' : $this->CI->uri->segment(2);
		}

		$dir_path = $this->db->cachedir.$segment_one.'+'.$segment_two.'/';
		delete_files($dir_path, TRUE);
	}

	// --------------------------------------------------------------------

	/**
	 * Delete all existing cache files
	 *
	 * @return	void
	 */
	public function delete_all()
	{
		delete_files($this->db->cachedir, TRUE, TRUE);
	}

}