nginx过滤请求中的关键词

#get请求 全局过滤 %0d%0a
set $is_get 0;
set $keywords_found 0;
if ($request_method ~* GET) {set $is_get 1;}
if ($request_uri ~* "%0d%0a") {set $keywords_found 1;}
set $is_keywords_forbidden $is_get$keywords_found;
if ($is_keywords_forbidden = 11) {return 403;}