nginx 配置增加一个固定的重写规则：报错

现有配置如下，想增加 config.js -> 重写到 config.php 且不允许直接访问config.php，怎么搞哦，谢谢哈。。。

server {

    listen              80;
    server_name         js.mydomain.com;


    charset             utf-8;
    set                 $root '/dat/www/js.mydomain.com/public';
    root                $root;


    add_header          Cache-Control no-cache;
    add_header          Cache-Control private;


    index               index.php index.html index.htm;
    try_files           $uri $uri/ @rewrite ;


    location @rewrite {
        rewrite ^/(.*)$ /index.php?_url=/$1;
    }


    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    location ~ \.php$ {
        root           $root;
        fastcgi_pass   127.0.0.1:9000;
        fastcgi_index  index.php;
        fastcgi_param  PATH_INFO        $fastcgi_path_info;
        fastcgi_param  PATH_TRANSLATED  $document_root$fastcgi_path_info;
        fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
        include        fastcgi_params;
    }
}