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:
- Create a custom comment Model that adds on the “title” field.
- Create a custom comment Form that also adds this “title” field.
- 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_comment_app directory:
my_comment_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_comment_app/__init__.py to point Django at these classes we’ve created:
from my_comment_app.models import CommentWithTitle from my_comment_app.forms import CommentFormWithTitle def get_model(): return CommentWithTitle def get_form(): return CommentFormWithTitle
Be careful not to create cyclic imports in your custom comments app. If you feel your comment configuration isn’t being used as defined – for example, if your comment moderation policy isn’t being applied – you may have a cyclic import problem.
If you are having unexplained problems with comments behavior, check if your custom comments application imports (even indirectly) any module that itself imports Django’s comments module.
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.
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.
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.
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.
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.
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 django.contrib.comments.views.post_comment() view for details.
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.
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.
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.