php 替换敏感字符串

StrFilter.class.php

<?php
/**string filter class
* Date:     2013-01-09
* Author:   fdipzone
* Ver:      v1.0
*
* Func:
* public  replace            替换非法字符
* public  check              检查是否含有非法字符
* private protect_white_list 保护白名单
* private resume_white_list  还原白名单
* private getval             白名单 key转为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;
    }

    /**替换非法字符
    * @param  String $content 要替換的字符串
    * @return String          替換后的字符串
    */
    public function replace($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;
    }

    /**检查是否含有非法自符
    * @param  String $content 字符串
    * @return boolean
    */
    public function check($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;
    }

    /**保护白名单
    * @param  String $content 字符串
    * @return String
    */
    private function protect_white_list($content){
        if($this->_white_list){
            foreach($this->_white_list as $key=>$val){
                $content = str_replace($val, $this->_LTAG.$key.$this->_RTAG, $content);
            }
        }
        return $content;
    }

    /**还原白名单
    * @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;
    }

    /**白名单 key还原为value
    * @param  Array  $matches 匹配white_list的key
    * @return String white_list val
    */
    private function getval($matches){
        return isset($this->_white_list[$matches[1]])? $this->_white_list[$matches[1]] : ""; // key->val
    }

} // class end

?>

demo

<?php
	header("content-type:text/html;charset=utf8");

	require("StrFilter.class.php");

	$white = array("屌丝", "曹操");
	$black = array("屌", "操");

	$content = "我操,曹操你是屌丝,我屌你啊";

	$obj = new StrFilter($white, $black);
	echo $obj->replace($content);
?>

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