Wordpress检测文章手否被百度收录

/*
Plugin Name: Baidu-Accept
Plugin URI: http://www.d4v.com.cn
Description: 判断当前文章是否被百度收录，若没有被收录则可点击提交至百度，加速收录！(此插件在文章页面仅管理员可见) 
Version: 1.0
Author: Jovae
Author URI: http://www.d4v.com.cn
License: GPL
*/
function d4v($url){
    $url='http://www.baidu.com/s?wd='.$url;
    $curl=curl_init();
    curl_setopt($curl,CURLOPT_URL,$url);
    curl_setopt($curl,CURLOPT_RETURNTRANSFER,1);
    $rs=curl_exec($curl);
    curl_close($curl);
    if(!strpos($rs,'没有找到')){
        return 1;
    }else{
        return 0;
    }
}
add_filter( 'the_content',  'baidu_submit' );
function baidu_submit( $content ) {
    if( is_single() && current_user_can( 'manage_options') )
        if(d4v(get_permalink()) == 1)
            $content="<p align=right>百度已收录(仅管理员可见)</p>".$content;
        else
            $content="<p align=right><b><a style=color:red target=_blank href=http://zhanzhang.baidu.com/sitesubmit/index?sitename=".get_permalink().">百度未收录!点击此处提交</a></b>(仅管理员可见)</p>".$content;
        return $content;
    }