title: How to know the browser the user is using?
body: <p>We have started developing an application for location aware emergency service. The users can connect through computer,smart phone or even through WAP. We want to use cloud servers (GAE or AWS). We want to optimize the site for the user's device.</p>
  
  <p>I can not find out exactly how to know the device or the browser the user is using. From apache, by analyzing browser request, we could know the browser type. But how to learn that in Cloud servers like GAE or AWS? Is there any other way to learn which browser or device the user is using? Also is it possible to know the ip address of the user in GAE or AWS?</p>
  
  <p>Thanks in advance.</p>