Customizing the comments framework

If the built-in comment framework doesn’t quite fit your needs, you can extend the comment app’s behavior to add custom data and logic. The comments framework lets you extend the built-in comment model, the built-in comment form, and the various comment views.

The COMMENTS_APP setting is where this customization begins. Set COMMENTS_APP to the name of the app you’d like to use to provide custom behavior. You’ll use the same syntax as you’d use for INSTALLED_APPS, and the app given must also be in the INSTALLED_APPS list.

For example, if you wanted to use an app named my_comment_app, your settings file would contain:

INSTALLED_APPS = [
    ...
    'my_comment_app',
    ...
]

COMMENTS_APP = 'my_comment_app'

The app named in COMMENTS_APP provides its custom behavior by defining some module-level functions in the app's __init__.py. The complete list of these functions can be found below, but first let's look at a quick example.

An example custom comments app

One of the most common types of customization is modifying the set of fields provided on the built-in comment model. For example, some sites that allow comments want the commentator to provide a title for their comment; the built-in comment model has no field for that title.

To make this kind of customization, we'll need to do three things:

  1. Create a custom comment Model that adds on the "title" field.
  2. Create a custom comment Form that also adds this "title" field.
  3. Inform Django of these objects by defining a few functions in a custom COMMENTS_APP.

So, carrying on the example above, we're dealing with a typical app structure in the my_custom_app directory:

my_custom_app/
    __init__.py
    models.py
    forms.py

In the models.py we'll define a CommentWithTitle model:

from django.db import models
from django.contrib.comments.models import Comment

class CommentWithTitle(Comment):
    title = models.CharField(max_length=300)

Most custom comment models will subclass the Comment model. However, if you want to substantially remove or change the fields available in the Comment model, but don't want to rewrite the templates, you could try subclassing from BaseCommentAbstractModel.

Next, we'll define a custom comment form in forms.py. This is a little more tricky: we have to both create a form and override CommentForm.get_comment_model() and CommentForm.get_comment_create_data() to return deal with our custom title field:

from django import forms
from django.contrib.comments.forms import CommentForm
from my_comment_app.models import CommentWithTitle

class CommentFormWithTitle(CommentForm):
    title = forms.CharField(max_length=300)

    def get_comment_model(self):
        # Use our custom comment model instead of the built-in one.
        return CommentWithTitle

    def get_comment_create_data(self):
        # Use the data of the superclass, and add in the title field
        data = super(CommentFormWithTitle, self).get_comment_create_data()
        data['title'] = self.cleaned_data['title']
        return data

Django provides a couple of "helper" classes to make writing certain types of custom comment forms easier; see django.contrib.comments.forms for more.

Finally, we'll define a couple of methods in my_custom_app/__init__.py to point Django at these classes we've created:

from my_comments_app.models import CommentWithTitle
from my_comments_app.forms import CommentFormWithTitle

def get_model():
    return CommentWithTitle

def get_form():
    return CommentFormWithTitle

The above process should take care of most common situations. For more advanced usage, there are additional methods you can define. Those are explained in the next section.

Custom comment app API

The django.contrib.comments app defines the following methods; any custom comment app must define at least one of them. All are optional, however.

get_model()

Return the Model class to use for comments. This model should inherit from django.contrib.comments.models.BaseCommentAbstractModel, which defines necessary core fields.

The default implementation returns django.contrib.comments.models.Comment.

get_form()

Return the Form class you want to use for creating, validating, and saving your comment model. Your custom comment form should accept an additional first argument, target_object, which is the object the comment will be attached to.

The default implementation returns django.contrib.comments.forms.CommentForm.

Note

The default comment form also includes a number of unobtrusive spam-prevention features (see Notes on the comment form). If replacing it with your own form, you may want to look at the source code for the built-in form and consider incorporating similar features.

get_form_target()

Return the URL for POSTing comments. This will be the <form action> attribute when rendering your comment form.

The default implementation returns a reverse-resolved URL pointing to the post_comment() view.

Note

If you provide a custom comment model and/or form, but you want to use the default post_comment() view, you will need to be aware that it requires the model and form to have certain additional attributes and methods: see the post_comment() view documentation for details.

get_flag_url()

Return the URL for the "flag this comment" view.

The default implementation returns a reverse-resolved URL pointing to the django.contrib.comments.views.moderation.flag() view.

get_delete_url()

Return the URL for the "delete this comment" view.

The default implementation returns a reverse-resolved URL pointing to the django.contrib.comments.views.moderation.delete() view.

get_approve_url()

Return the URL for the "approve this comment from moderation" view.

The default implementation returns a reverse-resolved URL pointing to the django.contrib.comments.views.moderation.approve() view.

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