server {
    listen 80 default_server;
    root /usr/share/nginx/html;
    index index.html;

    proxy_http_version 1.1;
    proxy_cache_bypass $http_upgrade;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection 'upgrade';
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;

    server_name _;

    server_tokens off;

    location / {
        if ($http_user_agent ~* "baiduspider|twitterbot|facebookexternalhit|rogerbot|linkedinbot|embedly|quora link preview|showyoubot|outbrain|pinterest|slackbot|vkShare|W3C_Validator") {
            proxy_pass http://${META_SERVER_HOSTNAME};
            break;
        }

        try_files $uri /index.html;

        gzip on;
        gzip_proxied any;
        gzip_comp_level 4;
        gzip_types text/css application/javascript image/svg+xml;
    }
}