"""
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.models import Site
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
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
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:
if self._get_delta(datetime.datetime.now(), getattr(content_object, self.auto_close_field)).days >= self.close_after:
return False
return True
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:
if self._get_delta(datetime.datetime.now(), getattr(content_object, self.auto_moderate_field)).days >= self.moderate_after:
return True
return False
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"' % (Site.objects.get_current().name,
content_object)
message = t.render(c)
send_mail(subject, message, settings.DEFAULT_FROM_EMAIL, recipient_list, fail_silently=True)
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()
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.module_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.module_name)
del self._registry[model]
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
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()
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