Show a Custom Error Message

This recipe shows how to handle Zope errors.

This script for "standard_error_message" should be located in the parent folder of your ZMS content object.</>

Features

if an URL containing dashes, '-', the RESPONSE is redirected to an URL with underscores '_'. Status code is set to 301: moved permanently.
otherwise a message is displayed recommending the parent URL.
in any other case it shows the header and footer in the context of the ZMS content object
the error traceback is "hidden" in a non-visible DIV

Remarks

This standard_html_header method only works if the entire DTML code is placed within a try/except block. This seems to be a new 'feature' in current Zope Versions. This script was tested on Zope 2.9.2

<dtml-comment>
----------------------------------------------------------------------------------------
  Exception Handler
  If an URL was requested containing dashes '-', the RESPONSE is redirected to an URL with underscores '_'.
  Otherwise a message is displayed proposing the parent URL.
----------------------------------------------------------------------------------------</dtml-comment>
<dtml-try>
  <dtml-var "standard_html_header(content,REQUEST)">
  <h1>An error occured.</h1>
  <dtml-if "error_type in ['Resource not found','NotFound']">
    <dtml-comment>
    ----------------------------------------------------------------------------------------
      Optionally redirect to an URL without dashes and send a status code '301' (moved permanently)
    ----------------------------------------------------------------------------------------</dtml-comment>
    <dtml-if "URL.find('-')>-1"><dtml-call "RESPONSE.redirect(_.string.lower(URL.replace('-','_')),lock=1,status=301)"></dtml-if>
    <p>Sorry, you are requesting a document (&dtml-URL;) that is not available on our server. </p>
    <p>Please visit <br /><a href="&dtml-URL1;"><dtml-var URL1></a></p>
  <dtml-comment>
  ----------------------------------------------------------------------------------------
    All other errors.
  ----------------------------------------------------------------------------------------</dtml-comment>
  <dtml-else>
    <p>Error-Type: <dtml-var error_type></p>
    <div style="display:none;">
      <dtml-var error_value> <dtml-var error_tb>
    </div>
    <p>Please visit <br /><a href="&dtml-BASE0;"><dtml-var BASE0></a></p>
  </dtml-if>
<dtml-var "standard_html_footer(content,REQUEST)">
<dtml-except>
</dtml-try>