title: Python Werkzeug: modify Request values (forms and args) prior to retrieval
body: <p>Is there a way in Werkzeug to edit the request values (forms and args) before using it?</p>
  
  <p>I need to encode the request values from utf8 to iso88591. I created a function to handle this.</p>
  
  <p>I would like to use this function on all form values so that I avoid the second line of the following:</p>
  
  <pre><code>lcl_var = request.form['post_arg']        
  lcl_var = encode_utf8_to_iso88591(lcl_var)
  </code></pre>
  
  <p>I couldn't figure out what I needed from the Werkzeug <a href="http://werkzeug.pocoo.org/docs/wrappers/" rel="nofollow">docs</a>. I imagine there's a way to subclass the Request class and override a one of its methods that handles the values. Would really appreciate a concrete example on how to implement this well.</p>