PHP获取页面中指定内容的类

<?php 
/** grep class
*   Date:   2013-06-15
*   Author: fdipzone
*   Ver:    1.0
*   Edit: www.jb200.com
*   Func:
*
*   set:        设置内容
*   get:        返回指定的内容
*   replace:    返回替换后的内容
*   get_pattern 根据type返回pattern
*/ 
 
class Grep{ // class start
    private $_pattern = array( 
                            'url' => '/<a.*?href="((http(s)?://).*?)".*?/si', 
                            'email' => '/([w-.]+@[w-.]+(.w+))/', 
                            'image' => '/<img.*?src="(http://.+.(jpg|jpeg|gif|bmp|png))">/i' 
                        ); 
 
    private $_content = ''; // 源内容 
 
    /* 設置搜尋的內容
    *  @param String $content
    */ 
    public function set($content=''){ 
        $this->_content = $content; 
    }
 
    /* 获取指定内容
    *  @param String $type
    *  @param int    $unique 0:all 1:unique
    *  @return Array
    */ 
    public function get($type='', $unique=0){
        $type = strtolower($type); 
 
        if($this->_content=='' || !in_array($type, array_keys($this->_pattern))){ 
            return array(); 
        } 
 
        $pattern = $this->get_pattern($type); // 获取pattern 
        preg_match_all($pattern, $this->_content, $matches);
        return isset($matches[1])? ( $unique==0? $matches[1] : array_unique($matches[1]) ) : array();
    }
 
    /* 获取替换后的内容
    *  @param String $type
    *  @param String $callback
    *  @return String
    */ 
    public function replace($type='', $callback=''){
        $type = strtolower($type); 
        if($this->_content=='' || !in_array($type, array_keys($this->_pattern)) || $callback==''){ 
            return $this->_content; 
        }
        $pattern = $this->get_pattern($type); 
        return preg_replace_callback($pattern, $callback, $this->_content);
    }
 
    /* 根据type获取pattern
    *  @param String $type
    *  @return String
    */ 
    private function get_pattern($type){ 
        return $this->_pattern[$type]; 
    }
 
} // class end 
?>

<?php
/**
* 获取页面中的指定内容
* by www.jb200.com
*/
header('content-type:text/htm;charset=utf8'); 
 
require('Grep.class.php');  
$content = file_get_contents('http://www.jb200.com/'); 
 
$obj = new Grep(); 
$obj->set($content); 
 
$url = $obj->get('url', 0); 
$email = $obj->get('email', 1); 
$image = $obj->get('image', 1); 
 
print_r($url); 
print_r($email); 
print_r($image); 
 
$url_new = $obj->replace('url', 'replace_url'); 
echo $url_new; 
 
function replace_url($matches){ 
    return isset($matches[1])? '[url]'.$matches[1].'[/url]' : ''; 
} 
?>