default-nginx.conf

server {
  listen 8080;
  root   /usr/share/nginx/html;
  index  index.html;
  location / {
    try_files $uri @prerender;
  }
  location @prerender {
    set $prerender 0;
    if ($http_user_agent ~* "googlebot|bingbot|yandex|baiduspider|twitterbot|facebookexternalhit|rogerbot|linkedinbot|embedly|quora link preview|showyoubot|outbrain|pinterest\/0\.|pinterestbot|slackbot|vkShare|W3C_Validator|whatsapp") {
      set $prerender 1;
    }
    if ($args ~ "_escaped_fragment_") {
      add_header X-debug-message "_escaped_fragment_ TRUE" always;
      set $prerender 1;
    }
    if ($http_user_agent ~ "Prerender") {
      add_header X-debug-message "_escaped_fragment_ FALSE" always;
      set $prerender 0;
    }
    if ($uri ~* "\.(js|css|xml|less|png|jpg|jpeg|gif|pdf|doc|txt|ico|rss|zip|mp3|rar|exe|wmv|doc|avi|ppt|mpg|mpeg|tif|wav|mov|psd|ai|xls|mp4|m4a|swf|dat|dmg|iso|flv|m4v|torrent|ttf|woff|svg|eot)") {
      set $prerender 0;
    }
    #resolve using Google's DNS server to force DNS resolution and prevent caching of IPs
    resolver 8.8.8.8;
    if ($prerender = 1) {
      #setting prerender as a variable forces DNS resolution since nginx caches IPs and doesnt play well with load balancing
      set $prerender "prerender.app.orbitsystems.gr";
      rewrite .* /https://$host$request_uri? break;
        proxy_pass https://$prerender;
    }
    if ($prerender = 0) {
      rewrite .* /index.html break;
    }
  }
}