Source code for django.contrib.comments.moderation

"""
A generic comment-moderation system which allows configuration of
moderation options on a per-model basis.

To use, do two things:

1. Create or import a subclass of ``CommentModerator`` defining the
   options you want.

2. Import ``moderator`` from this module and register one or more
   models, passing the models and the ``CommentModerator`` options
   class you want to use.


Example
-------

First, we define a simple model class which might represent entries in
a Weblog::

    from django.db import models

    class Entry(models.Model):
        title = models.CharField(maxlength=250)
        body = models.TextField()
        pub_date = models.DateField()
        enable_comments = models.BooleanField()

Then we create a ``CommentModerator`` subclass specifying some
moderation options::

    from django.contrib.comments.moderation import CommentModerator, moderator

    class EntryModerator(CommentModerator):
        email_notification = True
        enable_field = 'enable_comments'

And finally register it for moderation::

    moderator.register(Entry, EntryModerator)

This sample class would apply two moderation steps to each new
comment submitted on an Entry:

* If the entry's ``enable_comments`` field is set to ``False``, the
  comment will be rejected (immediately deleted).

* If the comment is successfully posted, an email notification of the
  comment will be sent to site staff.

For a full list of built-in moderation options and other
configurability, see the documentation for the ``CommentModerator``
class.

"""

import datetime

from django.conf import settings
from django.core.mail import send_mail
from django.contrib.comments import signals
from django.db.models.base import ModelBase
from django.template import Context, loader
from django.contrib import comments
from django.contrib.sites.shortcuts import get_current_site
from django.utils import timezone

class AlreadyModerated(Exception):
    """
    Raised when a model which is already registered for moderation is
    attempting to be registered again.

    """
    pass

class NotModerated(Exception):
    """
    Raised when a model which is not registered for moderation is
    attempting to be unregistered.

    """
    pass

[docs]class CommentModerator(object): """ Encapsulates comment-moderation options for a given model. This class is not designed to be used directly, since it doesn't enable any of the available moderation options. Instead, subclass it and override attributes to enable different options:: ``auto_close_field`` If this is set to the name of a ``DateField`` or ``DateTimeField`` on the model for which comments are being moderated, new comments for objects of that model will be disallowed (immediately deleted) when a certain number of days have passed after the date specified in that field. Must be used in conjunction with ``close_after``, which specifies the number of days past which comments should be disallowed. Default value is ``None``. ``auto_moderate_field`` Like ``auto_close_field``, but instead of outright deleting new comments when the requisite number of days have elapsed, it will simply set the ``is_public`` field of new comments to ``False`` before saving them. Must be used in conjunction with ``moderate_after``, which specifies the number of days past which comments should be moderated. Default value is ``None``. ``close_after`` If ``auto_close_field`` is used, this must specify the number of days past the value of the field specified by ``auto_close_field`` after which new comments for an object should be disallowed. Default value is ``None``. ``email_notification`` If ``True``, any new comment on an object of this model which survives moderation will generate an email to site staff. Default value is ``False``. ``enable_field`` If this is set to the name of a ``BooleanField`` on the model for which comments are being moderated, new comments on objects of that model will be disallowed (immediately deleted) whenever the value of that field is ``False`` on the object the comment would be attached to. Default value is ``None``. ``moderate_after`` If ``auto_moderate_field`` is used, this must specify the number of days past the value of the field specified by ``auto_moderate_field`` after which new comments for an object should be marked non-public. Default value is ``None``. Most common moderation needs can be covered by changing these attributes, but further customization can be obtained by subclassing and overriding the following methods. Each method will be called with three arguments: ``comment``, which is the comment being submitted, ``content_object``, which is the object the comment will be attached to, and ``request``, which is the ``HttpRequest`` in which the comment is being submitted:: ``allow`` Should return ``True`` if the comment should be allowed to post on the content object, and ``False`` otherwise (in which case the comment will be immediately deleted). ``email`` If email notification of the new comment should be sent to site staff or moderators, this method is responsible for sending the email. ``moderate`` Should return ``True`` if the comment should be moderated (in which case its ``is_public`` field will be set to ``False`` before saving), and ``False`` otherwise (in which case the ``is_public`` field will not be changed). Subclasses which want to introspect the model for which comments are being moderated can do so through the attribute ``_model``, which will be the model class. """ auto_close_field = None auto_moderate_field = None close_after = None email_notification = False enable_field = None moderate_after = None def __init__(self, model): self._model = model def _get_delta(self, now, then): """ Internal helper which will return a ``datetime.timedelta`` representing the time between ``now`` and ``then``. Assumes ``now`` is a ``datetime.date`` or ``datetime.datetime`` later than ``then``. If ``now`` and ``then`` are not of the same type due to one of them being a ``datetime.date`` and the other being a ``datetime.datetime``, both will be coerced to ``datetime.date`` before calculating the delta. """ if now.__class__ is not then.__class__: now = datetime.date(now.year, now.month, now.day) then = datetime.date(then.year, then.month, then.day) if now < then: raise ValueError("Cannot determine moderation rules because date field is set to a value in the future") return now - then
[docs] def allow(self, comment, content_object, request): """ Determine whether a given comment is allowed to be posted on a given object. Return ``True`` if the comment should be allowed, ``False otherwise. """ if self.enable_field: if not getattr(content_object, self.enable_field): return False if self.auto_close_field and self.close_after is not None: close_after_date = getattr(content_object, self.auto_close_field) if close_after_date is not None and self._get_delta(timezone.now(), close_after_date).days >= self.close_after: return False return True
[docs] def moderate(self, comment, content_object, request): """ Determine whether a given comment on a given object should be allowed to show up immediately, or should be marked non-public and await approval. Return ``True`` if the comment should be moderated (marked non-public), ``False`` otherwise. """ if self.auto_moderate_field and self.moderate_after is not None: moderate_after_date = getattr(content_object, self.auto_moderate_field) if moderate_after_date is not None and self._get_delta(timezone.now(), moderate_after_date).days >= self.moderate_after: return True return False
[docs] def email(self, comment, content_object, request): """ Send email notification of a new comment to site staff when email notifications have been requested. """ if not self.email_notification: return recipient_list = [manager_tuple[1] for manager_tuple in settings.MANAGERS] t = loader.get_template('comments/comment_notification_email.txt') c = Context({'comment': comment, 'content_object': content_object}) subject = '[%s] New comment posted on "%s"' % (get_current_site(request).name, content_object) message = t.render(c) send_mail(subject, message, settings.DEFAULT_FROM_EMAIL, recipient_list, fail_silently=True)
[docs]class Moderator(object): """ Handles moderation of a set of models. An instance of this class will maintain a list of one or more models registered for comment moderation, and their associated moderation classes, and apply moderation to all incoming comments. To register a model, obtain an instance of ``Moderator`` (this module exports one as ``moderator``), and call its ``register`` method, passing the model class and a moderation class (which should be a subclass of ``CommentModerator``). Note that both of these should be the actual classes, not instances of the classes. To cease moderation for a model, call the ``unregister`` method, passing the model class. For convenience, both ``register`` and ``unregister`` can also accept a list of model classes in place of a single model; this allows easier registration of multiple models with the same ``CommentModerator`` class. The actual moderation is applied in two phases: one prior to saving a new comment, and the other immediately after saving. The pre-save moderation may mark a comment as non-public or mark it to be removed; the post-save moderation may delete a comment which was disallowed (there is currently no way to prevent the comment being saved once before removal) and, if the comment is still around, will send any notification emails the comment generated. """ def __init__(self): self._registry = {} self.connect()
[docs] def connect(self): """ Hook up the moderation methods to pre- and post-save signals from the comment models. """ signals.comment_will_be_posted.connect(self.pre_save_moderation, sender=comments.get_model()) signals.comment_was_posted.connect(self.post_save_moderation, sender=comments.get_model())
def register(self, model_or_iterable, moderation_class): """ Register a model or a list of models for comment moderation, using a particular moderation class. Raise ``AlreadyModerated`` if any of the models are already registered. """ if isinstance(model_or_iterable, ModelBase): model_or_iterable = [model_or_iterable] for model in model_or_iterable: if model in self._registry: raise AlreadyModerated("The model '%s' is already being moderated" % model._meta.model_name) self._registry[model] = moderation_class(model) def unregister(self, model_or_iterable): """ Remove a model or a list of models from the list of models whose comments will be moderated. Raise ``NotModerated`` if any of the models are not currently registered for moderation. """ if isinstance(model_or_iterable, ModelBase): model_or_iterable = [model_or_iterable] for model in model_or_iterable: if model not in self._registry: raise NotModerated("The model '%s' is not currently being moderated" % model._meta.model_name) del self._registry[model]
[docs] def pre_save_moderation(self, sender, comment, request, **kwargs): """ Apply any necessary pre-save moderation steps to new comments. """ model = comment.content_type.model_class() if model not in self._registry: return content_object = comment.content_object moderation_class = self._registry[model] # Comment will be disallowed outright (HTTP 403 response) if not moderation_class.allow(comment, content_object, request): return False if moderation_class.moderate(comment, content_object, request): comment.is_public = False
[docs] def post_save_moderation(self, sender, comment, request, **kwargs): """ Apply any necessary post-save moderation steps to new comments. """ model = comment.content_type.model_class() if model not in self._registry: return self._registry[model].email(comment, comment.content_object, request) # Import this instance in your own code to use in registering # your models for moderation.
moderator = Moderator()