Generic comment moderation¶
Django’s bundled comments application is extremely useful on its own,
but the amount of comment spam circulating on the Web today
essentially makes it necessary to have some sort of automatic
moderation system in place for any application which makes use of
comments. To make this easier to handle in a consistent fashion,
django.contrib.comments.moderation provides a generic, extensible
comment-moderation system which can be applied to any model or set of
models which want to make use of Django’s comment system.
The entire system is contained within
and uses a two-step process to enable moderation for any given model:
- A subclass of
CommentModeratoris defined which specifies the moderation options the model wants to enable.
- The model is registered with the moderation system, passing in the model class and the class which specifies its moderation options.
A simple example is the best illustration of this. Suppose we have the following model, which would 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()
Now, suppose that we want the following steps to be applied whenever a
new comment is posted on an
- If the
False, the comment will simply be disallowed (i.e., immediately deleted).
- If the
True, the comment will be allowed to save.
- Once the comment is saved, an email should be sent to site staff notifying them of the new comment.
Accomplishing this is fairly straightforward and requires very little code:
from django.contrib.comments.moderation import CommentModerator, moderator class EntryModerator(CommentModerator): email_notification = True enable_field = 'enable_comments' moderator.register(Entry, EntryModerator)
CommentModerator class pre-defines a number of useful moderation
options which subclasses can enable or disable as desired, and
knows how to work with them to determine whether to allow a comment, whether
to moderate a comment which will be allowed to post, and whether to email
notifications of new comments.
Built-in moderation options¶
Most common comment-moderation needs can be handled by subclassing
CommentModeratorand changing the values of pre-defined attributes; the full range of built-in options is as follows.
If this is set to the name of a
DateTimeFieldon 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
auto_close_field, but instead of outright deleting new comments when the requisite number of days have elapsed, it will simply set the
is_publicfield of new comments to
Falsebefore 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
auto_close_fieldis used, this must specify the number of days past the value of the field specified by
auto_close_fieldafter which new comments for an object should be disallowed. Allowed values are
None, 0 (which disallows comments immediately), or any positive integer. Default value is
True, any new comment on an object of this model which survives moderation (i.e., is not deleted) will generate an email to site staff. Default value is
If this is set to the name of a
BooleanFieldon 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
Falseon the object the comment would be attached to. Default value is
auto_moderate_fieldis used, this must specify the number of days past the value of the field specified by
auto_moderate_fieldafter which new comments for an object should be marked non-public. Allowed values are
None, 0 (which moderates comments immediately), or any positive integer. Default value is
CommentModerator and changing the values of these
options will automatically enable the various moderation methods for any
models registered using the subclass.
Adding custom moderation methods¶
For situations where the built-in options listed above are not
sufficient, subclasses of
CommentModerator can also override
the methods which actually perform the moderation, and apply any logic
CommentModerator defines three methods which
determine how moderation will take place; each method will be called
by the moderation system and passed two arguments:
is the new comment being posted,
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(comment, content_object, request)¶
Trueif the comment should be allowed to post on the content object, and
Falseotherwise (in which case the comment will be immediately deleted).
If email notification of the new comment should be sent to site staff or moderators, this method is responsible for sending the email.
moderate(comment, content_object, request)¶
Trueif the comment should be moderated (in which case its
is_publicfield will be set to
Falsebefore saving), and
Falseotherwise (in which case the
is_publicfield will not be changed).
Registering models for moderation¶
The moderation system, represented by
django.contrib.comments.moderation.moderator is an instance of the class
Moderator, which allows registration and “unregistration” of models
via two methods:
Takes two arguments: the first should be either a model class or list of model classes, and the second should be a subclass of
CommentModerator, and register the model or models to be moderated using the options defined in the
CommentModeratorsubclass. If any of the models are already registered for moderation, the exception
AlreadyModeratedwill be raised.
Takes one argument: a model class or list of model classes, and removes the model or models from the set of models which are being moderated. If any of the models are not currently being moderated, the exception
NotModeratedwill be raised.
Customizing the moderation system¶
Most use cases will work easily with simple subclassing of
CommentModerator and registration with the provided
Moderator instance, but customization of global moderation behavior
can be achieved by subclassing
Moderator and instead registering
models with an instance of the subclass.
Determines how moderation is set up globally. The base implementation in
Moderatordoes this by attaching listeners to the
comment_was_postedsignals from the comment models.
pre_save_moderation(sender, comment, request, **kwargs)¶
In the base implementation, applies all pre-save moderation steps (such as determining whether the comment needs to be deleted, or whether it needs to be marked as non-public or generate an email).
post_save_moderation(sender, comment, request, **kwargs)¶
In the base implementation, applies all post-save moderation steps (currently this consists entirely of deleting comments which were disallowed).