Django. Simple Follower System

main.js

// Include before main script file and after jquery (or after jquery if everything in one file)
$(document).ready(function(){
     ...

    //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Cross Site Request Forgery protection~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    function getCookie(name) {
        var cookieValue = null;
        if (document.cookie && document.cookie != '') {
            var cookies = document.cookie.split(';');
            for (var i = 0; i < cookies.length; i++) {
                var cookie = jQuery.trim(cookies[i]);
                // Does this cookie string begin with the name we want?
                if (cookie.substring(0, name.length + 1) == (name + '=')) {
                    cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
                    break;
                }
            }
        }
        return cookieValue;
    }

    var csrftoken = getCookie('csrftoken');

    function csrfSafeMethod(method) {
        // these HTTP methods do not require CSRF protection
        return (/^(GET|HEAD|OPTIONS|TRACE)$/.test(method));
    }

    $.ajaxSetup({
        beforeSend: function(xhr, settings) {
            if (!csrfSafeMethod(settings.type) && !this.crossDomain) {
                xhr.setRequestHeader("X-CSRFToken", csrftoken);
            }
        }
    });
    //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Cross Site Request Forgery protection~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
});

models.py

class Contact(models.Model):
    user_from = models.ForeignKey(User, related_name='rel_from_set')
    user_to = models.ForeignKey(User, related_name='rel_to_set')
    created = models.DateTimeField(auto_now_add=True, db_index=True)

    class Meta:
        ordering = ('-created',)
        unique_together = ('user_from', 'user_to')

    def __str__(self):
        return '{} follows {}'.format(self.user_from, self.user_to)

# Add following field to User dynamically
User.add_to_class('following',
                  models.ManyToManyField('self',
                                         through=Contact,
                                         related_name='followers',
                                         symmetrical=False))

"""
The relationship includes symmetrical=False. When you defie a ManyToManyField to the model itself,
Django forces the relationship to be symmetrical. In this case, we are setting symmetrical=False to
define a non-symmetric relation. This is, if I follow you, it doesn't mean you automatically follow me.
"""

profile.html

<!-- Somewhere in profile page -->

{% with total_followers=user.followers.count %}

    <span class="count">
        <span class="badge total" style="margin: 4px;">{{ total_followers }}</span>
        follower{{ total_followers|pluralize }}
    </span>
    {% if request.user != user %}
        <div style="margin-top: 5px;">
            <a href="#"
               data-id="{{ user.id }}"
               data-action="{% if request.user in user.followers.all %}un{% endif %}follow"
               data-url="{% url "accounts:user_follow" %}"
               class="btn btn-success follow button">
                {% if request.user not in user.followers.all %}
                    Follow
                {% else %}
                    Unfollow
                {% endif %}
            </a>
        </div>
    {% endif %}

{% endwith %}

script.js

$(document).ready(function() {

    $('a.follow').click(function(e){
        e.preventDefault();
        $.ajax({
            type: 'POST',
            url: $(this).data('url'),
            data: {
                id: $(this).data('id'),
                action: $(this).data('action')
            },
            dataType: "json",
            success: function (data, textStatus) {
                if (data['status'] == 'ok')
                {
                    var previous_action = $('a.follow').data('action');

                    // toggle data-action
                    $('a.follow').data('action', previous_action == 'follow' ? 'unfollow' : 'follow');
                    // toggle link text
                    $('a.follow').text(previous_action == 'follow' ? 'Unfollow' : 'Follow');

                    // update total followers
                    var previous_followers = parseInt($('span.count .total').text());
                    $('span.count .total').text(previous_action == 'follow' ? previous_followers + 1 : previous_followers - 1);
                }
            },
            error: function(xhr, status, e) {
                alert(status, e);
            }
        });
    });
});

urls.py

url(r'^users/follow/$', views.UserFollowView.as_view(), name='user_follow'),

usage.txt

You can integrate it in your account app.
Or you can make it as app:
  1) create new app for followers
  2) add it to installed apps.
  3) make migrations and migrate
  3) include url to main file

views.py

class UserFollowView(LoginRequiredMixin, View):
    def post(self, request, *args, **kwargs):
        if request.is_ajax():
            user_id = request.POST.get('id')
            action = request.POST.get('action')
            if user_id and action:
                try:
                    user = User.objects.get(id=user_id)
                except User.DoesNotExist:
                    return JsonResponse({'status': 'ko'})
                if action == 'follow':
                    Contact.objects.get_or_create(user_from=request.user,
                                                  user_to=user)
                else:
                    Contact.objects.filter(user_from=request.user,
                                           user_to=user).delete()
                return JsonResponse({'status': 'ok'})
            else:
                return JsonResponse({'status': 'ko'})
        else:
            return HttpResponseBadRequest()