First, we will allow users to share posts by sending them emails. Take a short time to think how you would use views, URLs, and templates to create this functionality using what you have learned in the preceding chapter. Now, check what you need in order to allow your users to send posts by email. You will need to do the following things:

• Create a form for users to fill in their name and email, the email recipient, and optional comments
• Create a view in the views.py file that handles the posted data and sends the email
• Add a URL pattern for the new view in the urls.py file of the blog application
• Create a template to display the form

Let's start by building the form...

Now, we will build a comment system for the blog, wherein the users will be able to comment on posts. To build the comment system, you will need to do the following steps:

1. Create a model to save comments
2. Create a form to submit comments and validate the input data
3. Add a view that processes the form and saves the new comment to the database
4. Edit the post detail template to display the list of comments and the form to add a new comment

First, let's build a model to store comments. Open the models.py file of your blog application and add the following code:

class Comment(models.Model): 
    post = models.ForeignKey(Post,
                             on_delete=models.CASCADE,
                             related_name='comments')
    name = models.CharField(max_length=80) 
    email = models.EmailField() 
    body = models.TextField() 
    created...

After implementing your comment system, you will create a way to tag our posts. You will do this by integrating a third-party Django tagging application in our project. The django-taggit module is a reusable application that primarily offers you a Tag model and a manager to easily add tags to any model. You can take a look at its source code at https://github.com/alex/django-taggit.

First, you will need to install django-taggit via pip by running the following command:

pip install django_taggit==0.22.2

Then, open the settings.py file of the mysite project and add taggit to your INSTALLED_APPS setting, as follows:

INSTALLED_APPS = [
    # ...
    'blog.apps.BlogConfig',
    'taggit',
]

Open the models.py file of your blog application and add the TaggableManager manager provided by django-taggit to the Post model using...

Now that we have implemented tagging for our blog posts, we can do many interesting things with them. Using tags, we can classify our blog posts very well. Posts about similar topics will have several tags in common. We will build a functionality to display similar posts by the number of tags they share. In this way, when a user reads a post, we can suggest to them that they read other related posts.

In order to retrieve similar posts for a specific post, we need to perform the following steps:

1. Retrieve all tags for the current post
2. Get all posts that are tagged with any of those tags
3. Exclude the current post from that list to avoid recommending the same post
4. Order the results by the number of tags shared with the current post
5. In case of two or more posts with the same number of tags, recommend the most recent post
6. Limit the query to the number...

In this chapter, you learned how to work with Django forms and model forms. You created a system to share your site's content by email and created a comment system for your blog. You added tagging to your blog posts, integrating a reusable application, and built complex QuerySets to retrieve objects by similarity.

In the next chapter, you will learn how to create custom template tags and filters. You will also build a custom sitemap and feed for your blog posts and implement the full text search functionality for your blog posts.