PHP class to replace sensitive strings (source code attached)-PHP Tutorial-php.cn

/**string filter class
* Date: 2013-01-09
* Author: fdipzone
* Ver: v1.0
* Edit: bbs.it-home.org
* Func:
* public replace Replace illegal characters
* public check Check whether it contains illegal characters
* private protect_white_list protect the whitelist
* private resume_white_list restore the whitelist
* private getval whitelist key to value
*/
class StrFilter{ // class start
private $_white_list = array();
private $_black_list = array();
private $_replacement = '*';
private $_LTAG = '[[##';
private $_RTAG = '##]]';
/**
* @param Array $white_list
* @param Array $black_list
* @param String $replacement
*/
public function __construct($white_list=array(), $black_list=array(), $replacement='*'){
$this->_white_list = $white_list;
$this->_black_list = $black_list;
$this->_replacement = $replacement;
}
/**Replace illegal characters
* @param String $content The string to be replaced
* @return String The replaced string
*/
public function replace($content){
if(!isset($content) || $content==''){
return '';
}
// protect white list
$content = $this->protect_white_list($content);
// replace black list
if($this->_black_list){
foreach($this->_black_list as $val){
$content = str_replace($val, $this->_replacement, $content);
}
}
// resume white list
$content = $this->resume_white_list($content);
return $content;
}
/**Check whether it contains illegal self-characters
* @param String $content string
* @return boolean
*/
public function check($content){
if(!isset($content) || $content==''){
return true;
}
// protect white list
$content = $this->protect_white_list($content);
// check
if($this->_black_list){
foreach($this->_black_list as $val){
if(strstr($content, $val)!=''){
return false;
}
}
}
return true;
}
/**Protection whitelist
* @param String $content string
* @return String
*/
private function protect_white_list($content){
if($this->_white_list){
foreach($this->_white_list as $key=>$val){
$content = str_replace($val, $this->_LTAG.$key.$this->_RTAG, $content);
}
}
return $content;
}
/**Restore whitelist
* @param String $content
* @return String
*/
private function resume_white_list($content){
if($this->_white_list){
$content = preg_replace_callback("/[[##(.*?)##]].*?/si", array($this, 'getval'), $content);
}
return $content;
}
/**Whitelist key is restored to value
* @param Array $matches matches the key of white_list
* @return String white_list val
*/
private function getval($matches){
return isset($this->_white_list[$matches[1]])? $this->_white_list[$matches[1]] : ''; // key->val
}
} // class end
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