Flask Snippets

Nicer Errors with Descriptions from Werkzeug

Posted by Bernd Zeimetz on 2010-05-08 @ 12:42 and filed in Utilities

Writing nice and shiny error messages and assigning them to the application's error handlers can be a lot of work. If you're happy with the default descriptions which are provided by werkzeug, you're done with a few lines of code:

from flask import Markup, render_template
from werkzeug.exceptions import default_exceptions

def show_errormessage(error):
    desc = error.get_description(flask.request.environ)
    return render_template('error.html',
    ), error.code

for _exc in default_exceptions:
    app.error_handlers[_exc] = show_errormessage
del _exc

And here the example template:

{% extends "base.html" %}
{% block title %}Error {{ code }}: {{ name }}{% endblock %}
{% block body %}
  {{ description}}
{% endblock %}

Make sure to either wrap the description with Markup() or to use the |safe filter in the template on the description as it contains HTML.

This snippet by Bernd Zeimetz can be used freely for anything you like. Consider it public domain.