Naming Content
In the `Adding Objects`_, we made a form that creates new polls and adds them
to a container. But we overlooked a problem in the way that Grok object
traversal works.
This tutorial shows how to implement a simple polling application using Grok.
Page
9
of
14.
When a user calls an URL in a Grok application,
``http://localhost:8080/poller/question`` for example, Grok will try to
traverse the URL "path" item by item. So at first Grok asks from a root
container if it contains an item calles "poller", if it does, then the
traversal moves forward and asks if the "poller" contains "question" and so
on. The traversal system can be customized, but this is the default
behaviour.
The problem in our is the following lines from our add form class:
.. code-block:: python
name = poll.question
self.context[name] = poll
the poll name in the container is the question input by the user, but there is
no validation, in this case it's a string, and it can contain any characters a
Python string can contain; which poses a problem as the same name is used to
traverse the URL's. How do you traverse a poll which question is
"How/do/you/do?", the traverser would split this to objects separated by the
slashes.
The solution is to filter the names, which is easy to do in Python string
manipulation. But you shouldn't do it manually, as you would have to repeat
the code everywhere that works with container names. Instead you can use a
``NameChooser``, which will convert and validate names for containers. But to
use it, we must delve into adapters for a bit.
Typo?
Just thought you should know, and thanks for the tutorial.
Richard Stewart