nginx.conf

map $sent_http_content_type $expires
{
  default off;
  text/html 15m;
  text/css 15m;
  application/javascript 15m;
  ~image/ 15m;
}

server {
  listen 3000;
  root /usr/share/nginx/html;
  index index.html;
  etag on;
  expires $expires;
  location / {
    try_files $uri @prerender;
  }

  location @prerender {
    proxy_set_header X-Prerender-Token GsMLRmorzgxywljuDowD;
    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|Screaming Frog SEO Spider") {
      set $prerender 1;
    }

    if ($args ~ "escaped_fragment") {
      set $prerender 1;
    }

    if ($http_user_agent ~ "Prerender") {
      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 $prerender "service.prerender.io";
      rewrite .* /$scheme://$host$request_uri? break;
      proxy_pass http://$prerender;
    }

    if ($prerender = 0) {
      rewrite .* /index.html break;
    }
  }

  error_page 500 502 503 504 /50x.html;

  location = /50x.html {
    root /usr/share/nginx/html;
  }
}