Squid ESI and choose/when

[Marcel Alburg <alb@xxxxxxxxxx>]

Hello,

i wanna try the new ESI support in squid but the choose/when doesn't  
work for me

<esi:choose>
 <esi:when test="$(HTTP_COOKIE{sess_id}) != '')">
   <esi:vars>
     Cookies: $(HTTP_COOKIE{sess_id})<br>
   </esi:vars>
 </esi:when>
 <esi:otherwise>
   No Session
 </esi:otherwise>
</esi:choose>


How it is possible to Check if a Cookie is set ?

Thanks in advance

Marcel