Nginx Nodejs CORS to subdomain

nginx-nodejs-cors

server {
        listen 80;

        server_name subdomain.example.com;
        access_log /var/log/nginx/example.access.log;

        location / {

            if ($http_origin ~* "https?://.*\.example\.com(:[0-9]+)?") {
                set $cors "true";
            }

            if ($request_method = 'OPTIONS') {
                set $cors "${cors}options";  
            }

            if ($request_method = 'GET') {
                set $cors "${cors}get";  
            }
            if ($request_method = 'POST') {
                set $cors "${cors}post";
            }

            if ($cors = "trueget") {
                add_header 'Access-Control-Allow-Origin' "$http_origin";
                add_header 'Access-Control-Allow-Credentials' 'true';
            }

            if ($cors = "truepost") {
                add_header 'Access-Control-Allow-Origin' "$http_origin";
                add_header 'Access-Control-Allow-Credentials' 'true';
            }

            if ($cors = "trueoptions") {
                add_header 'Access-Control-Allow-Origin' "$http_origin";
                add_header 'Access-Control-Allow-Credentials' 'true';
                add_header 'Access-Control-Max-Age' 1728000;
                add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
                add_header 'Access-Control-Allow-Headers' 'Authorization,Content-Type,Accept,Origin,User-Agent,DNT,Cache-Control,X-Mx-ReqToken,Keep-Alive,X-Requested-With,If-Modified-Since';
                add_header 'Content-Length' 0;
                add_header 'Content-Type' 'text/plain charset=UTF-8';
                return 204;
            }

            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Host $http_host;
            proxy_set_header X-NginX-Proxy true;
            proxy_pass_header Set-Cookie;
            proxy_cache_bypass $cookie_nocache $arg_nocache $arg_comment;
            proxy_pass http://127.0.0.1:8675;
            proxy_redirect off;
        }
}