Nginx "Ping" via HTTP with CORS and without any files and backends

gistfile1.txt

# Ping location
location /ping {
    add_header "Allow" "GET, OPTIONS, HEAD" always;
    # CORS headers
    add_header "Access-Control-Allow-Origin" "*";
    add_header "Access-Control-Allow-Methods" "GET, OPTIONS, HEAD";
    add_header "Access-Control-Allow-Headers" "Accept,Accept-Encoding,Cache-Control,Content-Type,DNT,If-Modified-Since,Origin,User-Agent,X-Requested-With";

    if ( $request_method !~ ^(GET|OPTIONS|HEAD)$ ) {
        return 405 "Only GET, OPTIONS, HEAD allowed";
    }

    add_header "Content-Type" "text/plain";
    return 200 "pong";
}