title: Magento remove param and redirect to same url
body: <p>I want to remove some URL parameter (like utm_source, but whatever), put it in session and redirect to same page with URL clean of this specific param</p>
  
  <p>I've done in controller_front_init_before like this:</p>
  
  <pre><code>$frontController = $observer-&gt;getEvent()-&gt;getFront();
  $params = $frontController-&gt;getRequest()-&gt;getParams();
  $myParams = array("b");
  foreach($myParams as $myParam) {
      if (isset($params[$myParam])) {
          $customerSession-&gt;setData(
              $myParam, $params[$myParam]
          );
          unset($params[$myParam]);
      }
  }
  $frontController-&gt;getRequest()-&gt;setParams($params); // &lt;- I don't know what to do with that
  </code></pre>
  
  <p>Now what is the best method to redirect to the same page in request ?</p>
  
  <p>For example redirect <a href="http://example.com?a=1&amp;b=2&amp;c=3" rel="nofollow">http://example.com?a=1&amp;b=2&amp;c=3</a> to <a href="http://example.com?a=1&amp;c=3" rel="nofollow">http://example.com?a=1&amp;c=3</a></p>
  
  <p>Thanks!</p>