100 lines
3.7 KiB
Plaintext
100 lines
3.7 KiB
Plaintext
Captcha Plugin Architecture
|
|
===========================
|
|
|
|
This document contains design notes for the plone.app.discussion Captcha plugin
|
|
architecture.
|
|
|
|
|
|
Introduction
|
|
------------
|
|
|
|
When a Captcha plugin (e.g. plone.formwidget.captcha or
|
|
plone.formwidget.recaptcha, collective.akismet) is installed,
|
|
plone.app.discussion extends the comment form with a Captcha field/widget and a
|
|
Captcha validator.
|
|
|
|
The form extender and validator are only registered if there is a plugin
|
|
installed that claims to provide the "plone.app.discussion-captcha" feature in
|
|
its configure.zcml file::
|
|
|
|
<configure
|
|
xmlns:meta="http://namespaces.zope.org/meta"
|
|
xmlns:zcml="http://namespaces.zope.org/zcml">
|
|
|
|
<!-- Declare that plone.formwidget.captcha provides a Captcha field that
|
|
can be used by plone.app.discussion to add a Captcha field to comment
|
|
forms. -->
|
|
<meta:provides feature="plone.app.discussion-captcha" />
|
|
|
|
</configure>
|
|
|
|
.. note::
|
|
|
|
Currently plone.formwidget.captcha, plone.formwidget.recaptcha, and
|
|
collective.akismet provide such a feature. If you want to write your own
|
|
Captcha plugin, it has to provide this feature as well.
|
|
|
|
.. seealso::
|
|
|
|
* https://svn.plone.org/svn/plone/plone.formwidget.captcha/trunk/plone/formwidget/captcha/meta.zcml
|
|
* https://svn.plone.org/svn/plone/plone.formwidget.recaptcha/trunk/plone/formwidget/recaptcha/meta.zcml
|
|
* https://svn.plone.org/svn/collective/collective.akismet/trunk/collective/akismet/meta.zcml
|
|
|
|
|
|
CaptchaExtender
|
|
---------------
|
|
|
|
The CaptchaExtender class extends the comment form with a Captcha field and
|
|
widget. The CaptchaExtender currently uses either the CaptchaFieldWidget from
|
|
plone.formwidget.captcha or the ReCaptchaFieldWidget from
|
|
plone.formwidget.recaptcha. If you want to write your own Captcha solution, you
|
|
have to override the update() method of the CaptchaExtender or write your own
|
|
CaptchaExtender class.
|
|
|
|
.. literalinclude:: ../../plone/app/discussion/browser/captcha.py
|
|
:language: python
|
|
:pyobject: CaptchaExtender
|
|
|
|
|
|
CaptchaValidator
|
|
----------------
|
|
|
|
The CaptchaValidator class provides custom versions of the
|
|
plone.formwidget.captcha and the plone.formwidget.recaptcha validators. It does
|
|
this, because we want to be able to have more than one Captcha solution
|
|
installed in one Plone instance. We also want to be able to easily switch
|
|
between different Captcha implementations inside a single Plone instance.
|
|
|
|
Therefore we have to check which Captcha solution is enabled in the discussion
|
|
control panel and use only the selected Captcha validator. It is not enough to
|
|
check if a Captcha plugin is just installed, because there could be more than
|
|
one.
|
|
|
|
We do two checks. First we check for a suitable Captcha solution (check for the
|
|
plone.app.discussion-captcha feature, see notes above). Second, we check which
|
|
Captcha solution is enabled in the discussion control panel and apply the
|
|
corresponding field validator.
|
|
|
|
The plone.app.discussion captcha validator always checks for a view with the
|
|
name of the captcha plugin. For instance, if plone.formwidget.captcha is enabled
|
|
it checks for a "captcha" view.
|
|
|
|
.. literalinclude:: ../../plone/app/discussion/browser/validator.py
|
|
:language: python
|
|
:pyobject: CaptchaValidator
|
|
|
|
|
|
.. Writing your own Captcha plugin
|
|
-------------------------------
|
|
|
|
If you want to write your own Captcha plugin, you have to add at least the
|
|
following things:
|
|
|
|
1) Add your Captcha plugin to the captcha_vocabulary (vocabularies.py)
|
|
|
|
2) Override the update() method of the CapchaExtender class (browser/captcha.py)
|
|
to show your own Captcha widget.
|
|
|
|
3) Override the validate() method of the CaptchaValidator class
|
|
(browser/validator.py) to use your own Captcha validator.
|