279 lines
6.5 KiB
PHP
279 lines
6.5 KiB
PHP
<?php defined('SYSPATH') OR die('No direct access allowed.');
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/**
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* Captcha library.
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*
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* $Id: Captcha.php 4072 2009-03-13 17:20:38Z jheathco $
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*
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* @package Captcha
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* @author Kohana Team
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* @copyright (c) 2007-2008 Kohana Team
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* @license http://kohanaphp.com/license.html
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*/
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class Captcha_Core {
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// Captcha singleton
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protected static $instance;
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// Style-dependent Captcha driver
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protected $driver;
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// Config values
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public static $config = array
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(
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'style' => 'basic',
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'width' => 150,
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'height' => 50,
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'complexity' => 4,
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'background' => '',
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'fontpath' => '',
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'fonts' => array(),
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'promote' => FALSE,
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);
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/**
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* Singleton instance of Captcha.
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*
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* @return object
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*/
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public static function instance()
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{
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// Create the instance if it does not exist
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empty(Captcha::$instance) and new Captcha;
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return Captcha::$instance;
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}
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/**
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* Constructs and returns a new Captcha object.
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*
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* @param string config group name
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* @return object
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*/
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public static function factory($group = NULL)
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{
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return new Captcha($group);
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}
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/**
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* Constructs a new Captcha object.
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*
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* @throws Kohana_Exception
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* @param string config group name
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* @return void
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*/
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public function __construct($group = NULL)
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{
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// Create a singleton instance once
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empty(Captcha::$instance) and Captcha::$instance = $this;
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// No config group name given
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if ( ! is_string($group))
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{
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$group = 'default';
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}
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// Load and validate config group
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if ( ! is_array($config = Kohana::config('captcha.'.$group)))
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throw new Kohana_Exception('captcha.undefined_group', $group);
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// All captcha config groups inherit default config group
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if ($group !== 'default')
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{
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// Load and validate default config group
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if ( ! is_array($default = Kohana::config('captcha.default')))
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throw new Kohana_Exception('captcha.undefined_group', 'default');
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// Merge config group with default config group
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$config += $default;
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}
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// Assign config values to the object
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foreach ($config as $key => $value)
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{
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if (array_key_exists($key, Captcha::$config))
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{
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Captcha::$config[$key] = $value;
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}
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}
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// Store the config group name as well, so the drivers can access it
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Captcha::$config['group'] = $group;
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// If using a background image, check if it exists
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if ( ! empty($config['background']))
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{
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Captcha::$config['background'] = str_replace('\\', '/', realpath($config['background']));
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if ( ! is_file(Captcha::$config['background']))
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throw new Kohana_Exception('captcha.file_not_found', Captcha::$config['background']);
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}
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// If using any fonts, check if they exist
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if ( ! empty($config['fonts']))
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{
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Captcha::$config['fontpath'] = str_replace('\\', '/', realpath($config['fontpath'])).'/';
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foreach ($config['fonts'] as $font)
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{
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if ( ! is_file(Captcha::$config['fontpath'].$font))
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throw new Kohana_Exception('captcha.file_not_found', Captcha::$config['fontpath'].$font);
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}
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}
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// Set driver name
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$driver = 'Captcha_'.ucfirst($config['style']).'_Driver';
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// Load the driver
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if ( ! Kohana::auto_load($driver))
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throw new Kohana_Exception('core.driver_not_found', $config['style'], get_class($this));
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// Initialize the driver
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$this->driver = new $driver;
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// Validate the driver
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if ( ! ($this->driver instanceof Captcha_Driver))
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throw new Kohana_Exception('core.driver_implements', $config['style'], get_class($this), 'Captcha_Driver');
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Kohana::log('debug', 'Captcha Library initialized');
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}
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/**
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* Validates a Captcha response and updates response counter.
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*
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* @param string captcha response
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* @return boolean
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*/
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public static function valid($response)
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{
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// Maximum one count per page load
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static $counted;
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// User has been promoted, always TRUE and don't count anymore
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if (Captcha::instance()->promoted())
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return TRUE;
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// Challenge result
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$result = (bool) Captcha::instance()->driver->valid($response);
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// Increment response counter
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if ($counted !== TRUE)
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{
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$counted = TRUE;
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// Valid response
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if ($result === TRUE)
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{
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Captcha::instance()->valid_count(Session::instance()->get('captcha_valid_count') + 1);
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}
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// Invalid response
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else
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{
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Captcha::instance()->invalid_count(Session::instance()->get('captcha_invalid_count') + 1);
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}
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}
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return $result;
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}
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/**
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* Gets or sets the number of valid Captcha responses for this session.
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*
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* @param integer new counter value
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* @param boolean trigger invalid counter (for internal use only)
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* @return integer counter value
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*/
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public function valid_count($new_count = NULL, $invalid = FALSE)
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{
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// Pick the right session to use
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$session = ($invalid === TRUE) ? 'captcha_invalid_count' : 'captcha_valid_count';
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// Update counter
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if ($new_count !== NULL)
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{
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$new_count = (int) $new_count;
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// Reset counter = delete session
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if ($new_count < 1)
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{
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Session::instance()->delete($session);
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}
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// Set counter to new value
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else
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{
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Session::instance()->set($session, (int) $new_count);
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}
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// Return new count
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return (int) $new_count;
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}
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// Return current count
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return (int) Session::instance()->get($session);
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}
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/**
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* Gets or sets the number of invalid Captcha responses for this session.
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*
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* @param integer new counter value
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* @return integer counter value
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*/
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public function invalid_count($new_count = NULL)
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{
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return $this->valid_count($new_count, TRUE);
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}
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/**
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* Resets the Captcha response counters and removes the count sessions.
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*
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* @return void
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*/
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public function reset_count()
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{
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$this->valid_count(0);
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$this->valid_count(0, TRUE);
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}
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/**
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* Checks whether user has been promoted after having given enough valid responses.
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*
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* @param integer valid response count threshold
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* @return boolean
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*/
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public function promoted($threshold = NULL)
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{
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// Promotion has been disabled
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if (Captcha::$config['promote'] === FALSE)
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return FALSE;
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// Use the config threshold
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if ($threshold === NULL)
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{
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$threshold = Captcha::$config['promote'];
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}
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// Compare the valid response count to the threshold
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return ($this->valid_count() >= $threshold);
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}
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/**
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* Returns or outputs the Captcha challenge.
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*
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* @param boolean TRUE to output html, e.g. <img src="#" />
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* @return mixed html string or void
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*/
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public function render($html = TRUE)
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{
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return $this->driver->render($html);
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}
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/**
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* Magically outputs the Captcha challenge.
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*
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* @return mixed
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*/
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public function __toString()
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{
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return $this->render();
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}
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} // End Captcha Class
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