чат, message, Django, chat, сообщение

According to the tradition, I will tell you about my experiences on the introduction of new functionality on the site. At the moment, this functionality is a personal message between users. Of course, this now does not work as well as in well-known social networks ... but in the end everything will work. The main feedback on the forum, please.

So. I really wanted to add personal messages on the site, especially since I already mentioned this six months ago. The question remained, how to do it. When searching on the Internet it was possible to stumble upon an option when the following data model is being formed.

• Id of the message
• from_user - sender
• to_user - recipient
• pub_date - the date of the message
• message - message content

Tried to implement this option, but I was stopped by the fact that suddenly after personal messages I want to make chats? So why not immediately lay the foundation for chats?

Chat and Message models

This would be an excellent option for further development of the resource. But in this case, you need to create two models of Chat and Message .

# -*- coding: utf-8 -*-

from django.db import models
from django.contrib.auth.models import User
from django.utils import timezone
from django.utils.translation import ugettext_lazy as _


class Chat(models.Model):
    DIALOG = 'D'
    CHAT = 'C'
    CHAT_TYPE_CHOICES = (
        (DIALOG, _('Dialog')),
        (CHAT, _('Chat'))
    )

    type = models.CharField(
        _('Тип'),
        max_length=1,
        choices=CHAT_TYPE_CHOICES,
        default=DIALOG
    )
    members = models.ManyToManyField(User, verbose_name=_("Member"))

    @models.permalink
    def get_absolute_url(self):
        return 'users:messages', (), {'chat_id': self.pk }


class Message(models.Model):
    chat = models.ForeignKey(Chat, verbose_name=_("Chat"))
    author = models.ForeignKey(User, verbose_name=_("User"))
    message = models.TextField(_("Message"))
    pub_date = models.DateTimeField(_('Message date'), default=timezone.now)
    is_readed = models.BooleanField(_('Readed'), default=False)

    class Meta:
        ordering=['pub_date']

    def __str__(self):
        return self.message

If the Message model should be clear. There is a text message, status, whether it was read, the author of the message and the chat in which it was sent, as well as the date the message was sent.

That's the model of Chat somewhat more difficult to be. First, chats can be the spirit of species. The first is a personal conversation between two people. The second kind is a collective chat. Why was this done? This was necessary in order to simplify the search for the desired chat, when sending a message to the user from his personal page. Unfortunately at the moment, only such a way is done to send the first message to the user. That is, go to his page and click the button to write a message. In the future, you can find the user from the dialog page on your personal page. This is still a temporary limitation within the first User Story, which I wrote myself.

Each chat has many-to-many connection, which is responsible for the list of participants within the chat. Due to this, you can limit the viewing of chats, as well as the ability to write to chats, if the user was not invited to this chat room.

urls.py

What kind of views will we need and what routes can be done? To implement this functionality in the simplest form, I had to write three views and three routes to urls.py respectively.

url(r'^dialogs/$', login_required(views.DialogsView.as_view()), name='dialogs'),
url(r'^dialogs/create/(?P<user_id>\d+)/$', login_required(views.CreateDialogView.as_view()), name='create_dialog'),
url(r'^dialogs/(?P<chat_id>\d+)/$', login_required(views.MessagesView.as_view()), name='messages'),

We will not go deep into which particular application we will use these routes - this is not a matter of principle.

In fact, there are three views, one for the list of dialogues for the user, another for creating a dialog from the page of another user, and the third for the messages in the dialog.

Message form

In this case, you can use the form for the model. We indicate the model, as well as which fields should be displayed with the label removed from the input field.

By default, you will have the usual textarea. I use my own WYSIWYG editor.

class MessageForm(ModelForm):
    class Meta:
        model = Message
        fields = ['message']
        labels = {'message': ""}

Views and Templates

Display a list of dialogs

To get a list of all the dialogs in which the user is involved, you need to filter all chats by participants, that is, by the Many-toMany members.

class DialogsView(View):
    def get(self, request):
        chats = Chat.objects.filter(members__in=[request.user.id])
        return render(request, 'users/dialogs.html', {'user_profile': request.user, 'chats': chats})

In this case, I have a template for dialogs, in which I send an authorized user and a chat list. An active user will be needed to correctly display the messages read and not read in the dialog list.

The most interesting is the list of dialogs and its layout, so only the part responsible for the layout will be represented from the template.

<div class="panel">
        {% load tz %}
        {% if chats.count == 0 %}
            <div class="panel panel-body">{% trans "There is not a single dialogue started" %}</div>
        {% endif %}
        {% for chat in chats %}
            {% if chat.message_set.count != 0 %}
                {% with last_message=chat.message_set.last %}
                    {% get_companion user chat as companion %}
                    <a class="list-group-item {% if companion == last_message.author and not last_message.is_readed %}unreaded{% endif %}" href="{{ chat.get_absolute_url }}">
                        <img class="avatar-messages" src="{{ companion.userprofile.get_avatar }}">
                        <div class="reply-body">
                            <ul class="list-inline">
                                <li class="drop-left-padding">
                                    <strong class="list-group-item-heading">{{ companion.username }}</strong>
                                </li>
                                <li class="pull-right text-muted"><small>{{ last_message.pub_date|utc }}</small></li>
                            </ul>
                            {% if companion != last_message.author %}
                                <div>
                                    <img class="avatar-rounded-sm" src="{{ last_message.author.userprofile.get_avatar }}">
                                    <div class="attached-reply-body {% if not last_message.is_readed %}unreaded{% endif %}">{{ last_message.message|truncatechars_html:"200"|safe|striptags }}</div>
                                </div>
                            {% else %}
                                <div>{{ last_message.message|truncatechars_html:"200"|safe|striptags }}</div>
                            {% endif %}
                        </div>
                    </a>
                {% endwith %}
            {% endif %}
        {% endfor %}
    </div>

You can see my custom inline tag in the template. This tag is responsible for returning the interlocutor in the dialog in order to build on the information about the interlocutor an adequate layout for the list of dialogues and indication of the read and unread messages in the dialog list.

@register.simple_tag
def get_companion(user, chat):
    for u in chat.members.all():
        if u != user:
            return u
    return None

Thus, the list of dialogs will look like this:

Current dialog and messages

To display the current dialog and messages, you will need more complex logic. The fact is that here the access to the chat is carried out by ID, but it is necessary to make not only an attempt to get a dialogue, but also to check if there is a user in the list of participants who is trying to get into this chat room. If it does not exist in the list of participants, then access to this chat room is forbidden to him. Among other things, the same view treats the sending of messages and the marking of messages read.

class MessagesView(View):
    def get(self, request, chat_id):
        try:
            chat = Chat.objects.get(id=chat_id)
            if request.user in chat.members.all():
                chat.message_set.filter(is_readed=False).exclude(author=request.user).update(is_readed=True)
            else:
                chat = None
        except Chat.DoesNotExist:
            chat = None

        return render(
            request,
            'users/messages.html',
            {
                'user_profile': request.user,
                'chat': chat,
                'form': MessageForm()
            }
        )

    def post(self, request, chat_id):
        form = MessageForm(data=request.POST)
        if form.is_valid():
            message = form.save(commit=False)
            message.chat_id = chat_id
            message.author = request.user
            message.save()
        return redirect(reverse('users:messages', kwargs={'chat_id': chat_id}))

Message list template

{% if not chat %}
    <div class="panel panel-body">
        {% trans "It's impossible to start a conversation. No user is found or you do not have access to this conversation." %}
    </div>
{% else %}
    {% load tz %}
    {% if chat %}
        <div id="messages" class="panel">
            <div id="innerMessages">
                {% for message in chat.message_set.all %}
                        {% include 'users/message.html' with message_item=message %}
                {% endfor %}
            </div>
        </div>
    {% endif %}
    <div id="message_form">
        <form id="message-form" class="panel panel-body" method="post" >
            {% load bootstrap3 %}
            {% csrf_token %}
            {% bootstrap_form form %}
            <button type="submit" class="btn btn-default btn-sm" onclick="return ETextEditor.validateForm('message-form')"><span class="ico ico-comment"></span>{% trans "Отправить" %}</button>
        </form>
    </div>
{% endif %}

Template of the message itself

{% url 'users:profile' message_item.author.username as the_user_url%}
{% load tz %}
<div class="list-group-item {% if not message_item.is_readed %}unreaded{% endif %}">
    <a href="{{ the_user_url }}"><img class="avatar-comment" src="{{ message_item.author.userprofile.get_avatar }}"></a>
    <div class="reply-body">
        <ul class="list-inline">
            <li class="drop-left-padding">
                <strong class="list-group-item-heading"><a href="{{ the_user_url }}">{{ message_item.author.username }}</a></strong>
            </li>
            <li class="pull-right text-muted"><small>{{ message_item.pub_date|utc }}</small></li>
        </ul>
        <div>{{ message_item.message|safe }}</div>
    </div>
</div>

Example of the resulting dialog

Starting a conversation with the user

At the moment, only one method is implemented to start a conversation with the user. It is necessary to go to the user's page and click on the "Write a message" button, then a link will be sent through the link in which the chat will be created or an already existing chat with this user is found. This is used to check whether the chat is a dialogue or a conversation between several users. This makes it possible to simplify the search for the necessary dialog.

class CreateDialogView(View):
    def get(self, request, user_id):
        chats = Chat.objects.filter(members__in=[request.user.id, user_id], type=Chat.DIALOG).annotate(c=Count('members')).filter(c=2)
        if chats.count() == 0:
            chat = Chat.objects.create()
            chat.members.add(request.user)
            chat.members.add(user_id)
        else:
            chat = chats.first()
        return redirect(reverse('users:messages', kwargs={'chat_id': chat.id}))

Be sure to check for the number of users, since there can be only two users in a personal conversation, well, we check that these users are our authorized users, and also the user with whom we are trying to start a conversation.

After the chat is created, we redirect to the message page.

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