php 过滤html标记属性类(附源码)

<?php 
/** HTML Attribute Filter
*   Date:   2013-09-22
*   Author: fdipzone
*   ver:    1.0
*   edit: www.jbxue.com
*   Func:
*   public  strip              过滤属性
*   public  setAllow           设置允许的属性
*   public  setException       设置特例
*   public  setIgnore          设置忽略的标记
*   private findElements       搜寻需要处理的元素
*   private findAttributes     搜寻属性
*   private removeAttributes   移除属性
*   private isException        判断是否特例
*   private createAttributes   创建属性
*   private protect            特殊字符转义
*/ 
 
class HtmlAttributeFilter{ // class start 
 
    private $_str = '';            // 源字符串 
    private $_allow = array();     // 允许保留的属性 例如:array('id','class','title') 
    private $_exception = array(); // 特例 例如:array('a'=>array('href','class'),'span'=>array('class')) 
    private $_ignore = array();    // 忽略过滤的标记 例如:array('span','img') 
 
    /** 处理HTML,过滤不保留的属性
    * @param  String $str 源字符串
    * @return String
    */ 
    public function strip($str){ 
        $this->_str = $str; 
 
        if(is_string($this->_str) && strlen($this->_str)>0){ // 判断字符串 
 
            $this->_str = strtolower($this->_str); // 转成小写 
 
            $res = $this->findElements(); 
            if(is_string($res)){ 
                return $res; 
            } 
            $nodes = $this->findAttributes($res); 
            $this->removeAttributes($nodes); 
        } 
 
        return $this->_str; 
    } 
 
    /** 设置允许的属性
    * @param Array $param
    */ 
    public function setAllow($param=array()){ 
        $this->_allow = $param; 
    }
 
    /** 设置特例
    * @param Array $param
    */ 
    public function setException($param=array()){ 
        $this->_exception = $param; 
    }
 
    /** 设置忽略的标记
    * @param Array $param
    */ 
    public function setIgnore($param=array()){ 
        $this->_ignore = $param; 
    }
 
    /** 搜寻需要处理的元素 */ 
    private function findElements(){ 
        $nodes = array(); 
        preg_match_all("/<([^ !\/\>\n]+)([^>]*)>/i", $this->_str, $elements); 
        foreach($elements[1] as $el_key => $element){ 
            if($elements[2][$el_key]){ 
                $literal = $elements[0][$el_key]; 
                $element_name = $elements[1][$el_key]; 
                $attributes = $elements[2][$el_key]; 
                if(is_array($this->_ignore) && !in_array($element_name, $this->_ignore)){ 
                    $nodes[] = array('literal'=>$literal, 'name'=>$element_name, 'attributes'=>$attributes); 
                } 
            } 
        }
 
        if(!$nodes[0]){ 
            return $this->_str; 
        }else{ 
            return $nodes; 
        } 
    } 
 
 
    /** 搜寻属性
    *  @param Array $nodes 需要处理的元素
    */ 
    private function findAttributes($nodes){ 
        foreach($nodes as &$node){ 
            preg_match_all("/([^ =]+)\s*=\s*[\"|']{0,1}([^\"']*)[\"|']{0,1}/i", $node['attributes'], $attributes); 
            if($attributes[1]){ 
                foreach($attributes[1] as $att_key=>$att){ 
                    $literal = $attributes[0][$att_key]; 
                    $attribute_name = $attributes[1][$att_key]; 
                    $value = $attributes[2][$att_key]; 
                    $atts[] = array('literal'=>$literal, 'name'=>$attribute_name, 'value'=>$value); 
                } 
            }else{ 
                $node['attributes'] = null; 
            } 
            $node['attributes'] = $atts; 
            unset($atts); 
        } 
        return $nodes; 
    } 
   
    /** 移除属性
    *  @param Array $nodes 需要处理的元素
    */ 
    private function removeAttributes($nodes){ 
        foreach($nodes as $node){ 
            $node_name = $node['name']; 
            $new_attributes = ''; 
            if(is_array($node['attributes'])){ 
                foreach($node['attributes'] as $attribute){ 
                    if((is_array($this->_allow) && in_array($attribute['name'], $this->_allow)) || $this->isException($node_name, $attribute['name'], $this->_exception)){ 
                        $new_attributes = $this->createAttributes($new_attributes, $attribute['name'], $attribute['value']); 
                    } 
                } 
            } 
            $replacement = ($new_attributes) ? "<$node_name $new_attributes>" : "<$node_name>"; 
            $this->_str = preg_replace('/'.$this->protect($node['literal']).'/', $replacement, $this->_str); 
        } 
    }
 
    /** 判断是否特例
    * @param String $element_name   元素名
    * @param String $attribute_name 属性名
    * @param Array  $exceptions     允许的特例
    * @return boolean
    */ 
    private function isException($element_name, $attribute_name, $exceptions){ 
        if(array_key_exists($element_name, $this->_exception)){ 
            if(in_array($attribute_name, $this->_exception[$element_name])){ 
                return true; 
            } 
        } 
        return false; 
    }

    /** 创建属性
    * @param  String $new_attributes
    * @param  String $name
    * @param  String $value
    * @return String
    */ 
    private function createAttributes($new_attributes, $name, $value){ 
        if($new_attributes){ 
            $new_attributes .= " "; 
        } 
        $new_attributes .= "$name=\"$value\""; 
        return $new_attributes; 
    }
 
    /** 特殊字符转义
    * @param  String $str 源字符串
    * @return String
    */ 
    private function protect($str){ 
        $conversions = array( 
            "^" => "\^",  
            "[" => "\[",  
            "." => "\.",  
            "$" => "\$",  
            "{" => "\{",  
            "*" => "\*",  
            "(" => "\(",  
            "\\" => "\\\\",  
            "/" => "\/",  
            "+" => "\+",  
            ")" => "\)",  
            "|" => "\|",  
            "?" => "\?",  
            "<" => "\<",  
            ">" => "\>"  
        ); 
        return strtr($str, $conversions); 
    } 
 
} // class end 
 
?>

<?php 
require('HtmlAttributeFilter.class.php'); 
 
$str = '<div class="bd clearfix" id="index_hilite_ul"><ul class="list"><li><img src="http://su.bdimg.com/static/skin/img/logo_white.png" width="118" height="148"><div class="cover"><a class="text" href="http://www.jbxue.com"><strong>yuna</strong><p>love</p></a><strong class="t g">want to know</strong><a href="/login.html" class="ppBtn"><strong class="text">YES</strong></a></div></li></ul></div>'; 
 
$obj = new HtmlAttributeFilter(); 
 
// 允许id属性 
$obj->setAllow(array('id')); 
 
$obj->setException(array( 
                    'a' => array('href'),   // a 标签允许有 href属性特例 
                    'ul' => array('class')  // ul 标签允许有 class属性特例 
)); 
 
// img 标签忽略,不过滤任何属性 
$obj->setIgnore(array('img')); 
 
echo 'source str:<br>'; 
echo htmlspecialchars($str).'<br><br>'; 
echo 'filter str:<br>'; 
echo htmlspecialchars($obj->strip($str)); 
?>