title: Meteor - What is the purpose of "ROOT_URL" and to what should it be defined?
body: <p>I'm getting some problems to make spiderable work with PhantomJS on my Ubuntu server. I saw this troubleshooting on <a href="http://www.meteorpedia.com/read/spiderable">Meteorpedia</a>:</p>
  
  <blockquote>
    <p>Ensure that the ROOT_URL that your Meteor server is configured to use
    is accessible from the server itself. (Since v0.8.1.3[1])</p>
  </blockquote>
  
  <p>I think that this could be a possible answer to why it is not working. What is exactly the purpose of this environment variable?</p>
  
  <p>My application is publicly accessible on <code>http://gentlenode.com/</code> but my <code>proxy_pass</code> on nginx is set to <code>http://gentlenode/</code>.</p>
  
  <pre><code># HTTPS Server
  server {
      listen 443;
      server_name gentlenode.com;
      # ...
  
      location / {
          proxy_pass http://gentlenode/;
          proxy_http_version 1.1;
          # ...
      }
  }
  </code></pre>
  
  <p>Should I set <code>ROOT_URL</code> to <code>http://gentlenode.com/</code>, to <code>http://gentlenode/</code> or to <code>http://localhost/</code>?</p>
  
  <p>You can find my nginx configuration here: <a href="https://gist.github.com/LeCoupa/9877434">https://gist.github.com/LeCoupa/9877434</a></p>