Session.php 19 KB
Newer Older
Qiang Xue committed
1 2 3
<?php
/**
 * @link http://www.yiiframework.com/
Qiang Xue committed
4
 * @copyright Copyright (c) 2008 Yii Software LLC
Qiang Xue committed
5 6 7
 * @license http://www.yiiframework.com/license/
 */

Qiang Xue committed
8 9
namespace yii\web;

Qiang Xue committed
10
use Yii;
Qiang Xue committed
11 12 13
use yii\base\Component;
use yii\base\InvalidParamException;

Qiang Xue committed
14
/**
Qiang Xue committed
15
 * Session provides session data management and the related configurations.
Qiang Xue committed
16
 *
Qiang Xue committed
17 18
 * Session is a Web application component that can be accessed via `Yii::$app->session`.

Qiang Xue committed
19 20
 * To start the session, call [[open()]]; To complete and send out session data, call [[close()]];
 * To destroy the session, call [[destroy()]].
Qiang Xue committed
21
 *
Qiang Xue committed
22 23
 * By default, [[autoStart]] is true which means the session will be started automatically
 * when the session component is accessed the first time.
Qiang Xue committed
24
 *
Qiang Xue committed
25
 * Session can be used like an array to set and get session data. For example,
Qiang Xue committed
26
 *
Qiang Xue committed
27 28 29 30 31 32 33 34
 * ~~~
 * $session = new Session;
 * $session->open();
 * $value1 = $session['name1'];  // get session variable 'name1'
 * $value2 = $session['name2'];  // get session variable 'name2'
 * foreach ($session as $name => $value) // traverse all session variables
 * $session['name3'] = $value3;  // set session variable 'name3'
 * ~~~
Qiang Xue committed
35
 *
Qiang Xue committed
36
 * Session can be extended to support customized session storage.
Qiang Xue committed
37 38 39 40
 * To do so, override [[useCustomStorage()]] so that it returns true, and
 * override these methods with the actual logic about using custom storage:
 * [[openSession()]], [[closeSession()]], [[readSession()]], [[writeSession()]],
 * [[destroySession()]] and [[gcSession()]].
Qiang Xue committed
41
 *
Qiang Xue committed
42 43 44 45 46
 * Session also supports a special type of session data, called *flash messages*.
 * A flash message is available only in the current request and the next request.
 * After that, it will be deleted automatically. Flash messages are particularly
 * useful for displaying confirmation messages. To use flash messages, simply
 * call methods such as [[setFlash()]], [[getFlash()]].
Qiang Xue committed
47 48
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
Qiang Xue committed
49
 * @since 2.0
Qiang Xue committed
50
 */
Qiang Xue committed
51
class Session extends Component implements \IteratorAggregate, \ArrayAccess, \Countable
Qiang Xue committed
52 53
{
	/**
Qiang Xue committed
54
	 * @var boolean whether the session should be automatically started when the session component is initialized.
Qiang Xue committed
55
	 */
Qiang Xue committed
56
	public $autoStart = true;
Qiang Xue committed
57 58 59 60
	/**
	 * @var string the name of the session variable that stores the flash message data.
	 */
	public $flashVar = '__flash';
Qiang Xue committed
61

62 63 64 65
	/**
	 * @var array parameter-value pairs to override default session cookie parameters
	 */
	public $cookieParams = array(
Qiang Xue committed
66
		'httpOnly' => true
67 68
	);

Qiang Xue committed
69 70 71 72 73 74 75
	/**
	 * Initializes the application component.
	 * This method is required by IApplicationComponent and is invoked by application.
	 */
	public function init()
	{
		parent::init();
Qiang Xue committed
76
		if ($this->autoStart) {
Qiang Xue committed
77
			$this->open();
Qiang Xue committed
78 79
		}
		register_shutdown_function(array($this, 'close'));
Qiang Xue committed
80 81 82 83
	}

	/**
	 * Returns a value indicating whether to use custom session storage.
Qiang Xue committed
84 85 86
	 * This method should be overridden to return true by child classes that implement custom session storage.
	 * To implement custom session storage, override these methods: [[openSession()]], [[closeSession()]],
	 * [[readSession()]], [[writeSession()]], [[destroySession()]] and [[gcSession()]].
Qiang Xue committed
87 88 89 90 91 92 93
	 * @return boolean whether to use custom storage.
	 */
	public function getUseCustomStorage()
	{
		return false;
	}

Qiang Xue committed
94 95
	private $_opened = false;

Qiang Xue committed
96
	/**
Qiang Xue committed
97
	 * Starts the session.
Qiang Xue committed
98 99 100
	 */
	public function open()
	{
Qiang Xue committed
101 102 103
		// this is available in PHP 5.4.0+
		if (function_exists('session_status')) {
			if (session_status() == PHP_SESSION_ACTIVE) {
Qiang Xue committed
104
				$this->_opened = true;
Qiang Xue committed
105 106 107 108
				return;
			}
		}

Qiang Xue committed
109 110 111 112 113 114 115 116 117 118 119
		if (!$this->_opened) {
			if ($this->getUseCustomStorage()) {
				@session_set_save_handler(
					array($this, 'openSession'),
					array($this, 'closeSession'),
					array($this, 'readSession'),
					array($this, 'writeSession'),
					array($this, 'destroySession'),
					array($this, 'gcSession')
				);
			}
Qiang Xue committed
120

121 122
			$this->setCookieParams($this->cookieParams);

Qiang Xue committed
123
			@session_start();
Qiang Xue committed
124

Qiang Xue committed
125 126 127 128
			if (session_id() == '') {
				$this->_opened = false;
				$error = error_get_last();
				$message = isset($error['message']) ? $error['message'] : 'Failed to start session.';
129
				Yii::error($message, __METHOD__);
Qiang Xue committed
130 131 132 133
			} else {
				$this->_opened = true;
				$this->updateFlashCounters();
			}
Qiang Xue committed
134 135 136 137 138 139 140 141
		}
	}

	/**
	 * Ends the current session and store session data.
	 */
	public function close()
	{
Qiang Xue committed
142
		$this->_opened = false;
Qiang Xue committed
143
		if (session_id() !== '') {
Qiang Xue committed
144
			@session_write_close();
Qiang Xue committed
145
		}
Qiang Xue committed
146 147 148 149 150 151 152
	}

	/**
	 * Frees all session variables and destroys all data registered to a session.
	 */
	public function destroy()
	{
Qiang Xue committed
153
		if (session_id() !== '') {
Qiang Xue committed
154 155 156 157 158 159 160 161
			@session_unset();
			@session_destroy();
		}
	}

	/**
	 * @return boolean whether the session has started
	 */
Qiang Xue committed
162
	public function getIsActive()
Qiang Xue committed
163
	{
Qiang Xue committed
164 165 166 167 168
		if (function_exists('session_status')) {
			// available in PHP 5.4.0+
			return session_status() == PHP_SESSION_ACTIVE;
		} else {
			// this is not very reliable
Qiang Xue committed
169
			return $this->_opened && session_id() !== '';
Qiang Xue committed
170
		}
Qiang Xue committed
171 172 173 174 175
	}

	/**
	 * @return string the current session ID
	 */
Qiang Xue committed
176
	public function getId()
Qiang Xue committed
177 178 179 180 181 182 183
	{
		return session_id();
	}

	/**
	 * @param string $value the session ID for the current session
	 */
Qiang Xue committed
184
	public function setId($value)
Qiang Xue committed
185 186 187 188 189
	{
		session_id($value);
	}

	/**
Qiang Xue committed
190 191
	 * Updates the current session ID with a newly generated one .
	 * Please refer to [[http://php.net/session_regenerate_id]] for more details.
Qiang Xue committed
192 193
	 * @param boolean $deleteOldSession Whether to delete the old associated session file or not.
	 */
Qiang Xue committed
194
	public function regenerateID($deleteOldSession = false)
Qiang Xue committed
195 196 197 198 199 200 201
	{
		session_regenerate_id($deleteOldSession);
	}

	/**
	 * @return string the current session name
	 */
Qiang Xue committed
202
	public function getName()
Qiang Xue committed
203 204 205 206 207
	{
		return session_name();
	}

	/**
Qiang Xue committed
208 209
	 * @param string $value the session name for the current session, must be an alphanumeric string.
	 * It defaults to "PHPSESSID".
Qiang Xue committed
210
	 */
Qiang Xue committed
211
	public function setName($value)
Qiang Xue committed
212 213 214 215 216 217 218 219 220 221 222 223 224
	{
		session_name($value);
	}

	/**
	 * @return string the current session save path, defaults to '/tmp'.
	 */
	public function getSavePath()
	{
		return session_save_path();
	}

	/**
Qiang Xue committed
225 226
	 * @param string $value the current session save path. This can be either a directory name or a path alias.
	 * @throws InvalidParamException if the path is not a valid directory
Qiang Xue committed
227 228 229
	 */
	public function setSavePath($value)
	{
Qiang Xue committed
230
		$path = Yii::getAlias($value);
Qiang Xue committed
231
		if (is_dir($path)) {
Qiang Xue committed
232
			session_save_path($path);
Qiang Xue committed
233
		} else {
Qiang Xue committed
234
			throw new InvalidParamException("Session save path is not a valid directory: $value");
Qiang Xue committed
235
		}
Qiang Xue committed
236 237 238 239 240 241 242 243
	}

	/**
	 * @return array the session cookie parameters.
	 * @see http://us2.php.net/manual/en/function.session-get-cookie-params.php
	 */
	public function getCookieParams()
	{
Qiang Xue committed
244 245 246 247 248 249
		$params = session_get_cookie_params();
		if (isset($params['httponly'])) {
			$params['httpOnly'] = $params['httponly'];
			unset($params['httponly']);
		}
		return $params;
Qiang Xue committed
250 251 252 253 254 255
	}

	/**
	 * Sets the session cookie parameters.
	 * The effect of this method only lasts for the duration of the script.
	 * Call this method before the session starts.
Qiang Xue committed
256
	 * @param array $value cookie parameters, valid keys include: `lifetime`, `path`, `domain`, `secure` and `httpOnly`.
Qiang Xue committed
257
	 * @throws InvalidParamException if the parameters are incomplete.
Qiang Xue committed
258 259 260 261
	 * @see http://us2.php.net/manual/en/function.session-set-cookie-params.php
	 */
	public function setCookieParams($value)
	{
Qiang Xue committed
262
		$data = $this->getCookieParams();
Qiang Xue committed
263 264
		extract($data);
		extract($value);
Qiang Xue committed
265 266
		if (isset($lifetime, $path, $domain, $secure, $httpOnly)) {
			session_set_cookie_params($lifetime, $path, $domain, $secure, $httpOnly);
Qiang Xue committed
267
		} else {
Qiang Xue committed
268
			throw new InvalidParamException('Please make sure these parameters are provided: lifetime, path, domain, secure and httpOnly.');
Qiang Xue committed
269
		}
Qiang Xue committed
270 271 272
	}

	/**
Qiang Xue committed
273 274 275
	 * Returns the value indicating whether cookies should be used to store session IDs.
	 * @return boolean|null the value indicating whether cookies should be used to store session IDs.
	 * @see setUseCookies()
Qiang Xue committed
276
	 */
Qiang Xue committed
277
	public function getUseCookies()
Qiang Xue committed
278
	{
Qiang Xue committed
279
		if (ini_get('session.use_cookies') === '0') {
Qiang Xue committed
280 281 282
			return false;
		} elseif (ini_get('session.use_only_cookies') === '1') {
			return true;
Qiang Xue committed
283
		} else {
Qiang Xue committed
284
			return null;
Qiang Xue committed
285
		}
Qiang Xue committed
286 287 288
	}

	/**
Qiang Xue committed
289 290 291 292 293 294 295 296
	 * Sets the value indicating whether cookies should be used to store session IDs.
	 * Three states are possible:
	 *
	 * - true: cookies and only cookies will be used to store session IDs.
	 * - false: cookies will not be used to store session IDs.
	 * - null: if possible, cookies will be used to store session IDs; if not, other mechanisms will be used (e.g. GET parameter)
	 *
	 * @param boolean|null $value the value indicating whether cookies should be used to store session IDs.
Qiang Xue committed
297
	 */
Qiang Xue committed
298
	public function setUseCookies($value)
Qiang Xue committed
299
	{
Qiang Xue committed
300
		if ($value === false) {
Qiang Xue committed
301 302
			ini_set('session.use_cookies', '0');
			ini_set('session.use_only_cookies', '0');
Qiang Xue committed
303 304 305
		} elseif ($value === true) {
			ini_set('session.use_cookies', '1');
			ini_set('session.use_only_cookies', '1');
Qiang Xue committed
306
		} else {
Qiang Xue committed
307 308
			ini_set('session.use_cookies', '1');
			ini_set('session.use_only_cookies', '0');
Qiang Xue committed
309 310 311 312
		}
	}

	/**
Qiang Xue committed
313
	 * @return float the probability (percentage) that the GC (garbage collection) process is started on every session initialization, defaults to 1 meaning 1% chance.
Qiang Xue committed
314 315 316
	 */
	public function getGCProbability()
	{
Qiang Xue committed
317
		return (float)(ini_get('session.gc_probability') / ini_get('session.gc_divisor') * 100);
Qiang Xue committed
318 319 320
	}

	/**
Qiang Xue committed
321 322
	 * @param float $value the probability (percentage) that the GC (garbage collection) process is started on every session initialization.
	 * @throws InvalidParamException if the value is not between 0 and 100.
Qiang Xue committed
323 324 325
	 */
	public function setGCProbability($value)
	{
Qiang Xue committed
326
		if ($value >= 0 && $value <= 100) {
Qiang Xue committed
327 328 329
			// percent * 21474837 / 2147483647 ≈ percent * 0.01
			ini_set('session.gc_probability', floor($value * 21474836.47));
			ini_set('session.gc_divisor', 2147483647);
Qiang Xue committed
330
		} else {
Qiang Xue committed
331
			throw new InvalidParamException('GCProbability must be a value between 0 and 100.');
Qiang Xue committed
332
		}
Qiang Xue committed
333 334 335 336 337 338 339
	}

	/**
	 * @return boolean whether transparent sid support is enabled or not, defaults to false.
	 */
	public function getUseTransparentSessionID()
	{
Qiang Xue committed
340
		return ini_get('session.use_trans_sid') == 1;
Qiang Xue committed
341 342 343 344 345 346 347
	}

	/**
	 * @param boolean $value whether transparent sid support is enabled or not.
	 */
	public function setUseTransparentSessionID($value)
	{
Qiang Xue committed
348
		ini_set('session.use_trans_sid', $value ? '1' : '0');
Qiang Xue committed
349 350 351
	}

	/**
Qiang Xue committed
352 353
	 * @return integer the number of seconds after which data will be seen as 'garbage' and cleaned up.
	 * The default value is 1440 seconds (or the value of "session.gc_maxlifetime" set in php.ini).
Qiang Xue committed
354 355 356 357 358 359 360 361 362 363 364
	 */
	public function getTimeout()
	{
		return (int)ini_get('session.gc_maxlifetime');
	}

	/**
	 * @param integer $value the number of seconds after which data will be seen as 'garbage' and cleaned up
	 */
	public function setTimeout($value)
	{
Qiang Xue committed
365
		ini_set('session.gc_maxlifetime', $value);
Qiang Xue committed
366 367 368 369
	}

	/**
	 * Session open handler.
Qiang Xue committed
370
	 * This method should be overridden if [[useCustomStorage()]] returns true.
Qiang Xue committed
371 372 373 374 375
	 * Do not call this method directly.
	 * @param string $savePath session save path
	 * @param string $sessionName session name
	 * @return boolean whether session is opened successfully
	 */
Qiang Xue committed
376
	public function openSession($savePath, $sessionName)
Qiang Xue committed
377 378 379 380 381 382
	{
		return true;
	}

	/**
	 * Session close handler.
Qiang Xue committed
383
	 * This method should be overridden if [[useCustomStorage()]] returns true.
Qiang Xue committed
384 385 386 387 388 389 390 391 392 393
	 * Do not call this method directly.
	 * @return boolean whether session is closed successfully
	 */
	public function closeSession()
	{
		return true;
	}

	/**
	 * Session read handler.
Qiang Xue committed
394
	 * This method should be overridden if [[useCustomStorage()]] returns true.
Qiang Xue committed
395 396 397 398 399 400 401 402 403 404 405
	 * Do not call this method directly.
	 * @param string $id session ID
	 * @return string the session data
	 */
	public function readSession($id)
	{
		return '';
	}

	/**
	 * Session write handler.
Qiang Xue committed
406
	 * This method should be overridden if [[useCustomStorage()]] returns true.
Qiang Xue committed
407 408 409 410 411
	 * Do not call this method directly.
	 * @param string $id session ID
	 * @param string $data session data
	 * @return boolean whether session write is successful
	 */
Qiang Xue committed
412
	public function writeSession($id, $data)
Qiang Xue committed
413 414 415 416 417 418
	{
		return true;
	}

	/**
	 * Session destroy handler.
Qiang Xue committed
419
	 * This method should be overridden if [[useCustomStorage()]] returns true.
Qiang Xue committed
420 421 422 423 424 425 426 427 428 429 430
	 * Do not call this method directly.
	 * @param string $id session ID
	 * @return boolean whether session is destroyed successfully
	 */
	public function destroySession($id)
	{
		return true;
	}

	/**
	 * Session GC (garbage collection) handler.
Qiang Xue committed
431
	 * This method should be overridden if [[useCustomStorage()]] returns true.
Qiang Xue committed
432 433 434 435 436 437 438 439 440 441 442 443
	 * Do not call this method directly.
	 * @param integer $maxLifetime the number of seconds after which data will be seen as 'garbage' and cleaned up.
	 * @return boolean whether session is GCed successfully
	 */
	public function gcSession($maxLifetime)
	{
		return true;
	}

	/**
	 * Returns an iterator for traversing the session variables.
	 * This method is required by the interface IteratorAggregate.
Qiang Xue committed
444
	 * @return SessionIterator an iterator for traversing the session variables.
Qiang Xue committed
445 446 447
	 */
	public function getIterator()
	{
Qiang Xue committed
448
		return new SessionIterator;
Qiang Xue committed
449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471
	}

	/**
	 * Returns the number of items in the session.
	 * @return integer the number of session variables
	 */
	public function getCount()
	{
		return count($_SESSION);
	}

	/**
	 * Returns the number of items in the session.
	 * This method is required by Countable interface.
	 * @return integer number of items in the session.
	 */
	public function count()
	{
		return $this->getCount();
	}

	/**
	 * Returns the session variable value with the session variable name.
Qiang Xue committed
472 473
	 * If the session variable does not exist, the `$defaultValue` will be returned.
	 * @param string $key the session variable name
Qiang Xue committed
474 475 476
	 * @param mixed $defaultValue the default value to be returned when the session variable does not exist.
	 * @return mixed the session variable value, or $defaultValue if the session variable does not exist.
	 */
Qiang Xue committed
477
	public function get($key, $defaultValue = null)
Qiang Xue committed
478 479 480 481 482 483
	{
		return isset($_SESSION[$key]) ? $_SESSION[$key] : $defaultValue;
	}

	/**
	 * Adds a session variable.
Qiang Xue committed
484 485
	 * If the specified name already exists, the old value will be overwritten.
	 * @param string $key session variable name
Qiang Xue committed
486 487
	 * @param mixed $value session variable value
	 */
Qiang Xue committed
488
	public function set($key, $value)
Qiang Xue committed
489
	{
Qiang Xue committed
490
		$_SESSION[$key] = $value;
Qiang Xue committed
491 492 493 494
	}

	/**
	 * Removes a session variable.
Qiang Xue committed
495
	 * @param string $key the name of the session variable to be removed
Qiang Xue committed
496 497 498 499
	 * @return mixed the removed value, null if no such session variable.
	 */
	public function remove($key)
	{
Qiang Xue committed
500 501
		if (isset($_SESSION[$key])) {
			$value = $_SESSION[$key];
Qiang Xue committed
502 503
			unset($_SESSION[$key]);
			return $value;
Qiang Xue committed
504
		} else {
Qiang Xue committed
505
			return null;
Qiang Xue committed
506
		}
Qiang Xue committed
507 508 509 510 511
	}

	/**
	 * Removes all session variables
	 */
Qiang Xue committed
512
	public function removeAll()
Qiang Xue committed
513
	{
Qiang Xue committed
514
		foreach (array_keys($_SESSION) as $key) {
Qiang Xue committed
515
			unset($_SESSION[$key]);
Qiang Xue committed
516
		}
Qiang Xue committed
517 518 519 520 521 522
	}

	/**
	 * @param mixed $key session variable name
	 * @return boolean whether there is the named session variable
	 */
Qiang Xue committed
523
	public function has($key)
Qiang Xue committed
524 525 526 527 528 529 530 531 532 533 534 535
	{
		return isset($_SESSION[$key]);
	}

	/**
	 * @return array the list of all session variables in array
	 */
	public function toArray()
	{
		return $_SESSION;
	}

Qiang Xue committed
536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594
	/**
	 * Updates the counters for flash messages and removes outdated flash messages.
	 * This method should only be called once in [[init()]].
	 */
	protected function updateFlashCounters()
	{
		$counters = $this->get($this->flashVar, array());
		if (is_array($counters)) {
			foreach ($counters as $key => $count) {
				if ($count) {
					unset($counters[$key], $_SESSION[$key]);
				} else {
					$counters[$key]++;
				}
			}
			$_SESSION[$this->flashVar] = $counters;
		} else {
			// fix the unexpected problem that flashVar doesn't return an array
			unset($_SESSION[$this->flashVar]);
		}
	}

	/**
	 * Returns a flash message.
	 * A flash message is available only in the current request and the next request.
	 * @param string $key the key identifying the flash message
	 * @param mixed $defaultValue value to be returned if the flash message does not exist.
	 * @return mixed the flash message
	 */
	public function getFlash($key, $defaultValue = null)
	{
		$counters = $this->get($this->flashVar, array());
		return isset($counters[$key]) ? $this->get($key, $defaultValue) : $defaultValue;
	}

	/**
	 * Returns all flash messages.
	 * @return array flash messages (key => message).
	 */
	public function getAllFlashes()
	{
		$counters = $this->get($this->flashVar, array());
		$flashes = array();
		foreach (array_keys($counters) as $key) {
			if (isset($_SESSION[$key])) {
				$flashes[$key] = $_SESSION[$key];
			}
		}
		return $flashes;
	}

	/**
	 * Stores a flash message.
	 * A flash message is available only in the current request and the next request.
	 * @param string $key the key identifying the flash message. Note that flash messages
	 * and normal session variables share the same name space. If you have a normal
	 * session variable using the same name, its value will be overwritten by this method.
	 * @param mixed $value flash message
	 */
Qiang Xue committed
595
	public function setFlash($key, $value = true)
Qiang Xue committed
596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635
	{
		$counters = $this->get($this->flashVar, array());
		$counters[$key] = 0;
		$_SESSION[$key] = $value;
		$_SESSION[$this->flashVar] = $counters;
	}

	/**
	 * Removes a flash message.
	 * Note that flash messages will be automatically removed after the next request.
	 * @param string $key the key identifying the flash message. Note that flash messages
	 * and normal session variables share the same name space.  If you have a normal
	 * session variable using the same name, it will be removed by this method.
	 * @return mixed the removed flash message. Null if the flash message does not exist.
	 */
	public function removeFlash($key)
	{
		$counters = $this->get($this->flashVar, array());
		$value = isset($_SESSION[$key], $counters[$key]) ? $_SESSION[$key] : null;
		unset($counters[$key], $_SESSION[$key]);
		$_SESSION[$this->flashVar] = $counters;
		return $value;
	}

	/**
	 * Removes all flash messages.
	 * Note that flash messages and normal session variables share the same name space.
	 * If you have a normal session variable using the same name, it will be removed
	 * by this method.
	 */
	public function removeAllFlashes()
	{
		$counters = $this->get($this->flashVar, array());
		foreach (array_keys($counters) as $key) {
			unset($_SESSION[$key]);
		}
		unset($_SESSION[$this->flashVar]);
	}

	/**
Qiang Xue committed
636
	 * Returns a value indicating whether there is a flash message associated with the specified key.
Qiang Xue committed
637 638 639 640 641 642 643 644
	 * @param string $key key identifying the flash message
	 * @return boolean whether the specified flash message exists
	 */
	public function hasFlash($key)
	{
		return $this->getFlash($key) !== null;
	}

Qiang Xue committed
645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669
	/**
	 * This method is required by the interface ArrayAccess.
	 * @param mixed $offset the offset to check on
	 * @return boolean
	 */
	public function offsetExists($offset)
	{
		return isset($_SESSION[$offset]);
	}

	/**
	 * This method is required by the interface ArrayAccess.
	 * @param integer $offset the offset to retrieve element.
	 * @return mixed the element at the offset, null if no element is found at the offset
	 */
	public function offsetGet($offset)
	{
		return isset($_SESSION[$offset]) ? $_SESSION[$offset] : null;
	}

	/**
	 * This method is required by the interface ArrayAccess.
	 * @param integer $offset the offset to set element
	 * @param mixed $item the element value
	 */
Qiang Xue committed
670
	public function offsetSet($offset, $item)
Qiang Xue committed
671
	{
Qiang Xue committed
672
		$_SESSION[$offset] = $item;
Qiang Xue committed
673 674 675 676 677 678 679 680 681 682 683
	}

	/**
	 * This method is required by the interface ArrayAccess.
	 * @param mixed $offset the offset to unset element
	 */
	public function offsetUnset($offset)
	{
		unset($_SESSION[$offset]);
	}
}