.. _ref-contrib-comments-example:

.. highlightlang:: html+django

===========================================
Example of using the in-built comments app
===========================================

Follow the first three steps of the quick start guide in the
:ref:`documentation <ref-contrib-comments-index>`.

Now suppose, you have an app (``blog``) with a model (``Post``)
to which you want to attach comments. Let us also suppose that
you have a template called ``blog_detail.html`` where you want
to display the comments list and comment form.

Template
========

First, we should load the ``comment`` template tags in the
``blog_detail.html`` so that we can use it's functionality. So
just like all other custom template tag libraries::

    {% load comments %}

Next, let us add the number of comments attached to the particular
model instance of ``Post``. For this we assume that a context
variable ``object_pk`` is present which gives the ``id`` of the
instance of ``Post``.

The usage of the :ttag:`get_comment_count` tag is like below::

   {% get_comment_count for blog.post object_pk as comment_count %}
   <p>{{ comment_count }} comments have been posted.</p>

If you have the instance (say ``entry``) of the model (``Post``)
available in the context, then you can refer to it directly::

   {% get_comment_count for entry as comment_count %}
   <p>{{ comment_count }} comments have been posted.</p>

To get a list of comments, we make use of the :ttag:`get_comment_list` tag.
This tag's usage is very similar to the :ttag:`get_comment_count` tag. We
need to remember that the :ttag:`get_comment_list` returns a list of comments
and hence we will have to iterate through them to display them::

   {% get_comment_list for blog.post object_pk as comment_list %}
   {% for comment in comment_list %}
   <p>Posted by: {{ comment.user_name }} on {{ comment.submit_date }}</p>
   ...
   <p>Comment: {{ comment.comment }}</p>
   ...
   {% endfor %}

Finally, we display the comment form, enabling users to enter their
comments. There are two ways of doing so. The first is when you want to
display the comments template available under your ``comments/form.html``.
The other method gives you a chance to customize the form.

The first method makes use of the :ttag:`render_comment_form` tag. It's usage
too is similar to the other two tags we have discussed above::

   {% render_comment_form for entry %}

It looks for the ``form.html`` under the following directories
(for our example)::

   comments/blog/post/form.html
   comments/blog/form.html
   comments/form.html

Since we customize the form in the second method, we make use of another
tag called :ttag:`comment_form_target`. This tag on rendering gives the URL
where the comment form is posted. Without any :ref:`customization
<ref-contrib-comments-custom>`, :ttag:`comment_form_target` evaluates to
``/comments/post/``. We use this tag in the form's ``action`` attribute.
The :ttag:`get_comment_form` tag renders a ``form`` for a model instance by
creating a context variable. One can iterate over the ``form`` object to
get individual fields. This gives you fine-grain control over the form::

  {% for field in form %}
  {% ifequal field.name "comment" %}
    <!-- Customize the "comment" field, say, make CSS changes -->
  ...
  {% endfor %}

But let's look at a simple example::

  {% get_comment_form for entry as form %}
  <!-- A context variable called form is created with the necessary hidden
  fields, timestamps and security hashes -->
  <table>
  <form action="{% comment_form_target %}" method="POST">
    {{ form }}
    <tr>
      <td></td>
      <td><input type="submit" name="preview" class="submit-post" value="Preview"></td>
    </tr>
  </form>
  </table>

Flagging
========

If you want your users to be able to flag comments (say for profanity), you
can just direct them (by placing a link in your comment list) to ``/flag/{{
comment.id }}/``. Similarly, a user with requisite permissions (``"Can
moderate comments"``) can approve and delete comments. This can also be
done through the ``admin`` as you'll see later. You might also want to
customize the following templates:

  * ``flag.html``
  * ``flagged.html``
  * ``approve.html``
  * ``approved.html``
  * ``delete.html``
  * ``deleted.html``

found under the directory structure we saw for ``form.html``.

Feeds
=====

Suppose you want to export a :ref:`feed <ref-contrib-syndication>` of the
latest comments, you can use the in-built :class:`LatestCommentFeed`. Just
enable it in your project's ``urls.py``:

.. code-block:: python

  from django.conf.urls.defaults import *
  from django.contrib.comments.feeds import LatestCommentFeed

  feeds = {
      'latest': LatestCommentFeed,
  }

  urlpatterns = patterns('',
  # ...
      (r'^feeds/(?P<url>.*)/$', 'django.contrib.syndication.views.feed',
          {'feed_dict': feeds}),
  # ...
  )

Now you should have the latest comment feeds being served off ``/feeds/latest/``.

Moderation
==========

Now that we have the comments framework working, we might want to have some
moderation setup to administer the comments. The comments framework comes
in-built with :ref:`generic comment moderation
<ref-contrib-comments-moderation>`. The comment moderation has the following
features (all of which or only certain can be enabled):

  * Enable comments for a particular model instance.
  * Close comments after a particular (user-defined) number of days.
  * Email new comments to the site-staff.

To enable comment moderation, we subclass the :class:`CommentModerator` and
register it with the moderation features we want. Let us suppose we want to
close comments after 7 days of posting and also send out an email to the
site staff. In ``blog/models.py``, we register a comment moderator in the
following way:

.. code-block:: python

   from django.contrib.comments.moderation import CommentModerator, moderator
   from django.db import models
   
   class Post(models.Model):
       title   = models.CharField(max_length = 255)
       content = models.TextField()
       posted_date = models.DateTimeField()
   
   class PostModerator(CommentModerator):
       email_notification = True
       auto_close_field   = 'posted_date'
       # Close the comments after 7 days.
       close_after        = 7
   
   moderator.register(Post, PostModerator)

The generic comment moderation also has the facility to remove comments.
These comments can then be moderated by any user who has access to the
``admin`` site and the ``Can moderate comments`` permission (can be set
under the ``Users`` page in the ``admin``).

The moderator can ``Flag``, ``Approve`` or ``Remove`` comments using the
``Action`` drop-down in the ``admin`` under the ``Comments`` page.

.. note::

     Only a super-user will be able to delete comments from the database.
     ``Remove Comments`` only sets the ``is_public`` attribute to
     ``False``.