Exception Handling In DTML - Being Verbose
( Page 4 of 10 )

Now, what you just saw was a very primitive exception handler, albeit one which isn't very useful on a production site. Ideally, you'd want the message generated by the exception handler to be a little more descriptive, and to contain some information on the source of the error.

DTML satisfies this requirement via two special, pre-defined variables - the "error_name" and "error_type" variables. Take a look:

<dtml-try>
<dtml-var CheckThisOut>
<dtml-except>
<b>Something's wrong 
here! But what?</b><br>
This might help:<br>
Error type - <i><dtml-var 
error_type></i>
<br>
Error value - <i><dtml-var error_value></i>
</dtml-try>

Here's the output:

Something's wrong here! But what?
This might help:
Error type - KeyError
Error 
value - CheckThisOut

And if you flip back a couple of pages to the very first code snippet in this article, you'll notice a remarkable similarity between the default Zope error output, and that of the script above...not surprising, considering that Zope's default error screen also uses the same two variables.

>>> More Zope Articles          >>> More By Harish Kamath, (c) Melonfire