title: Regular Expression for retrieving File Extension in HTTP url
body: <p>I am working on the ELK stack and as part of Logstash data transformation i am transforming data in Apache access logs.</p>
  
  <p>One of the metric needed is to get a stat on different content types (aspx, php, gif, etc.).</p>
  
  <p>From the log file I am trying to retrieve request url and then deduce the file type, for ex <code>/c/dataservices/online.jsp?callBack</code> is the request and I would get <code>.aspx</code> using the regular expression 
  <code>\.\w{3,4}</code>.</p>
  
  <p>My regular expression wont work for request say <code>/etc/designs/design/libs.min.1253.css</code> this is returning me <code>.min</code> as the extension. </p>
  
  <p>I am trying to get the last extension but it is not working. Please do suggest other approaches.</p>