Hi Chris, Chris Withers wrote:
Hi,
I'm doing a back link to go on a page (yes, I know browsers have back buttons, but some people don't like to use them ;-) which is easy enough:
<A href="<dtml-var "REQUEST.environ['HTTP_REFERER']">">Back</A>
except that if there is no referer, you get a key error. So I thought I'd try the following:
<A href="<dtml-var "REQUEST.environ['HTTP_REFERER']" missing='/'>">Back</A>
But I still get a key error. I thought the 'missing' attribute was supposed to catch that?
This counts only for something like <dtml-var ought_to_be_missing missing> In your case you are inside Python when calling with " ". So "missing" cannot catch this exception. (Actually this simple <dtml-var .. > does much magic :) So in your case you should do: <dtml-if "REQUEST.environ.has_key('HTTP_REFERER')"> <A href="<dtml-var "REQUEST.environ['HTTP_REFERER']">">Back</A> </dtml-if> This has the advantage of no blind link if there is no HTTP_REFERER set. Hth Tino Wildenhain