title: Why is my response not being cached?
body: <p>I am using express to write a response. 
  My code is: </p>
  
  <pre><code> res.set('Cache-Control', 'public, max-age=300');
   res.send(data);
  </code></pre>
  
  <p>The headers I see are: </p>
  
  <pre><code>Remote Address:127.0.0.1:9000
  Request URL:http://localhost:9000/some/path
  Request Method:GET
  Status Code:304 Not Modified
  
  Request Headersview source
  
  Accept:application/json, text/plain, */*
  Accept-Encoding:gzip,deflate,sdch
  Accept-Language:en-US,en;q=0.8,he;q=0.6
  Cache-Control:max-age=0
  Connection:keep-alive
  Cookie:express:sess=eyJ1c2VySWQiOiI1MzgxYTdjMDA0ZmIwMmIxMGI1NTdlZTMifQ==; express:sess.sig=lm-kq5ludtkWdRcFcVxNBL0BdT0
  Host:localhost:9000
  If-None-Match:W/"v9r1H7w4HiaXvycJ9FJ7lg=="
  Referer:http://localhost:9000/
  User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.153 Safari/537.36
  
  Response Headersview source
  
  access-control-allow-headers:Content-Type, X-API-KEY
  access-control-allow-methods:GET, POST, DELETE, PUT
  access-control-allow-origin:*
  cache-control:public, max-age=300
  connection:close
  date:Sat, 03 Jan 2015 08:47:29 GMT
  expires:Sat, 03 Jan 2015 08:52:29 GMT
  etag:W/"v9r1H7w4HiaXvycJ9FJ7lg=="
  x-powered-by:Express
  </code></pre>
  
  <p>However, I see my backend gets the request each and every time. </p>
  
  <p>I have tried it with developers area open and closed and with "cache" on and off. 
  Nothing seems to actually cache the request </p>
  
  <p>What am I doing wrong?</p>