SEO tag WP

<html><head><title>Meta tag</title><meta charset="utf-8"></head>
<body><form method="post">
<table border="1">
<tr>
<td>URL:<input type="text" name="url" value="/url"></td>
<td>Title:<input type="text" name="title" value=""></td>
<td>Description:<input type="text" name="des" value=""></td>
<td>Keywords:<input type="text" name="kw" value=""></td>
<td><input type="submit"></td>
</tr>
</table>
</form>
<script>
<?php
if(!empty($_POST)){
mysql_connect('localhost','root','');
mysql_select_db('wp');
mysql_query("SET NAMES 'utf8'");
mysql_query("SET CHARACTER SET 'utf8'");
mysql_query("SET SESSION collation_connection = 'utf8_general_ci'");

if(empty($_POST['url']))print('alert("Должен быть указан url!");');
else{
$url=mysql_real_escape_string( ((string)$_POST['url']));

$title= mysql_real_escape_string((string)$_POST['title']);
$des= mysql_real_escape_string((string)$_POST['des']);
$kw= mysql_real_escape_string((string)$_POST['kw']);
mysql_query("INSERT INTO seo_tag  VALUES (null,'$url','$title','$des','$kw') ON DUPLICATE KEY UPDATE title='$title',des='$des',kw='$kw';");
if(mysql_affected_rows())
print('alert("ОК");');
else print('alert("Error");');
}
}
?>
</script>
</body>
</html>

////////function wp

add_action('template_redirect', 'before_header', 0);
add_action('wp_head', 'after_header', 900);
function before_header (){
    ob_start('change_tag');
}
function change_tag($head) {
    //[REQUEST_URI] => /inurl?hjjhjh
    // [SCRIPT_URL] => /inurl
     $url=mysql_real_escape_string(urldecode(((string)$_SERVER['REQUEST_URI'])));
    $rurl=mysql_fetch_assoc(mysql_query("select * from seo_tag where url='$url'"));
    if(empty($rurl)){
    $url=mysql_real_escape_string(((string)$_SERVER['SCRIPT_URL']));
    $rurl=mysql_fetch_assoc(mysql_query("select * from seo_tag where url='$url'"));
    if(empty($rurl))return $head;
    }
    $title =$rurl['title'];
    if (!$title) return $head;
    $head=preg_replace('#<title>[^<]*</title>#', '<title>'.$title.'</title>', $head);

    $des =$rurl['des'];
    $kw =$rurl['kw'];

    if($des){
    if(stripos($head,'description')!==false){
    $head=preg_replace('#<meta[^>]*name=[\"|\']description[\"|\'][^>]*content=[\"]([^\"]*)[\"][^>]*>#i', '<meta name="description" content="'.$des.'"/>', $head);
    }else{
    $head.= '<meta name="description" content="'.$des.'"/>';
        }
    }
    if($kw){
    if(stripos($head,'keywords')!==false){
    $head=preg_replace('#<meta[^>]*name=[\"|\']keywords[\"|\'][^>]*content=[\"]([^\"]*)[\"][^>]*>#i', '<meta name="keywords" content="'.$kw.'"/>', $head);
    }else{
    $head.= '<meta name="keywords" content="'.$kw.'"/>';
    }
    }
return $head;
}
function after_header() {
    ob_end_flush();
}