Partial Form Submission With Turbo Frame

Django ChatGPT Tutorial Series:

Introduction

Create Django Project with Modern Frontend Tooling

Create Chat App

Partial Form Submission With Turbo Frame

Use Turbo Stream To Manipulate DOM Elements

Send Turbo Stream Over Websocket

Using OpenAI Streaming API With Celery

Use Stimulus to Better Organize Javascript Code in Django

Use Stimulus to Render Markdown and Highlight Code Block

Use Stimulus to Improve UX of Message Form

Source Code chatgpt-django-project

In this article, we will learn how to use Turbo Frame to do partial form submission without writing Javascript.

Objective

Learn what is Turbo Frame
Understand how Turbo Frame works

Turbo

Turbo is a package of the Hotwire project. It is a set of complementary techniques for speeding up page changes and form submissions in web applications.

Turbo Drive: accelerates links and form submissions
Turbo Frames: decompose pages into independent contexts like HTML iframe

In this project, we will use Turbo Frame to help us submit form without page reload.

Form

Update chatgpt_django_app/chat/forms.py

from django import forms
from django.core.validators import MinLengthValidator

from .models import Chat, Message


class MessageForm(forms.ModelForm):
    content = forms.CharField(
        label='Content',
        widget=forms.Textarea(
            attrs={
                'class': "rounded-lg border-gray-300 block leading-normal border px-4 text-gray-700 bg-white "
                         "focus:outline-none py-2 appearance-none w-full",
            },
        ),
        validators=[MinLengthValidator(2)]
    )

    class Meta:
        model = Message
        fields = ("content",)

    def __init__(self, *args, **kwargs):
        self.role = kwargs.pop("role")
        self.chat_pk = kwargs.pop("chat_pk")

        super().__init__(*args, **kwargs)

    def save(self, commit=True):
        instance = super().save(commit=False)
        instance.chat_id = self.chat_pk
        instance.role = self.role
        if commit:
            instance.save()
        return instance

Notes:

We add content = forms.CharField to the form and add some css classes to the attrs to make it look nicer with Tailwind CSS.
If you want to know more about form rendering with Tailwind CSS, please check Render Django Form with Tailwind CSS Style
The validators=[MinLengthValidator(2)] is to help us better check failed form validation in a bit.

View

Update chatgpt_django_app/chat/views.py

from django.urls import reverse
from django.views import View
from django.views.generic.edit import CreateView
from django.views.generic.list import ListView
from django.http import HttpResponseRedirect, HttpResponse

from .models import Chat, Message
from .forms import MessageForm


class MessageCreateView(CreateView):
    model = Message
    template_name = "message_create.html"
    form_class = MessageForm

    def get_success_url(self):
        return None

    def get_form_kwargs(self):
        kwargs = super().get_form_kwargs()
        kwargs["chat_pk"] = self.kwargs.get("chat_pk")
        kwargs["role"] = Message.USER
        return kwargs

    def get_empty_form(self):
        """
        Return empty form so we can reset the form
        """
        form_class = self.get_form_class()
        kwargs = self.get_form_kwargs()
        kwargs.pop("data")
        kwargs.pop("files")
        kwargs.pop("instance")
        return form_class(**kwargs)

    def form_valid(self, form):
        super().form_valid(form)

        # reset the form
        new_form = self.get_empty_form()
        return self.render_to_response(self.get_context_data(form=new_form))


message_create_view = MessageCreateView.as_view()

Notes:

We added MessageCreateView to create a new message.
In the get_form_kwargs, we pass chat_pk and role to the form, which are required to create the message instance.
We will return HTML in this view, so we return None in get_success_url method.

URL

Update chatgpt_django_app/chat/urls.py


from django.urls import path

from .views import (
    index_view,
    message_list_view,
    message_create_view,                        # new
)

app_name = "chat"

urlpatterns = [
    path("chat/", index_view, name="index"),
    path("chat/<int:chat_pk>/message/list/", message_list_view, name="message-list"),
    path("chat/<int:chat_pk>/message/create/", message_create_view, name="message-create"),        # new
]

Template

Now we come to the most important part in this chapter

Import Turbo

Update chatgpt_django_app/templates/base.html

{% load webpack_loader static %}

<!DOCTYPE html>
<html>
<head>
  <title>ChatGPT Demo</title>
  <meta charset="utf-8"/>
  <meta name="viewport" content="width=device-width, initial-scale=1.0">

  {% stylesheet_pack 'app' %}
  {% javascript_pack 'app' attrs='defer' %}
  <script src="https://cdn.jsdelivr.net/npm/@hotwired/[email protected]/dist/turbo.es2017-umd.js"></script>
</head>

<body data-turbo="false">

{% block content %}
{% endblock %}

</body>
</html>

Notes:

We import Turbo by adding https://cdn.jsdelivr.net/npm/@hotwired/[email protected]/dist/turbo.es2017-umd.js script to the head.
We add data-turbo="false" to the body tag, so that we can disable Turbo for all pages by default. And we only enable this feature on specific elements in a bit. Since many people do not understand how Turbo Drive work and we I do not plan to talk about it here.
If you want to know more about Turbo Drive, please check The Definitive Guide to Hotwire and Django (2.0.0)

List Page

Update chatgpt_django_app/templates/message_list_page.html

{% extends "base.html" %}

{% block content %}

  <main class="w-full">
    <div class="grid grid-cols-12 gap-2">
      <div class="col-span-12 bg-gray-50 sm:col-span-3">
        <div class="flex flex-col space-y-1 sm:h-screen">

          <form method="post" action="{% url 'chat:index' %}">
            {% csrf_token %}
            <button type="submit" class="bg-green-500 text-white py-2 px-4 rounded m-2">Start a new conversation
            </button>
          </form>

          <ul class="flex flex-col py-4 space-y-2">
            {% for chat in chats %}
              <a class="text-white py-2 px-2 rounded mx-2 bg-blue-500"
                 href="{% url 'chat:message-list' chat.pk %}">Chat: created on <time>{{ chat.created_at }}</time></a>
            {% endfor %}
          </ul>

        </div>
      </div>
      <div class="col-span-12 bg-gray-50 sm:col-span-9">
        <div class="bg-gray-50 sm:h-screen">

          <div class="flex flex-col h-full">

            <!-- Message List -->
            <div class="overflow-y-auto flex-1">
              {% for instance in object_list %}
                <div id="message_{{ instance.pk }}">
                  {% if instance.role_label == 'User' %}
                    <div class="p-4 m-4 max-w-full text-black rounded-lg bg-sky-100 prose" >{{ instance.content }}</div>
                  {% else %}
                    <div class="p-4 m-4 max-w-full bg-gray-200 rounded-lg prose">{{ instance.content }}</div>
                  {% endif %}
                </div>
              {% endfor %}
            </div>

            <!-- Message Form -->
            <div>
              <turbo-frame
                  id="message-create-frame"
                  src="{% url 'chat:message-create' view.kwargs.chat_pk %}"
                  data-turbo="true"
              >
                Loading...
              </turbo-frame>
            </div>
          </div>

        </div>
      </div>
    </div>
  </main>

{% endblock %}

Notes:

As for the Message Form, we add a turbo-frame element.
The id=message-create-frame is the unique id of the turbo frame element.
data-turbo="true" means Turbo will work on this element and children elements.
src="{% url 'chat:message-create' view.kwargs.chat_pk %}" means Turbo will send request to this URL to load the content of this frame.

Let's create chatgpt_django_app/templates/message_create.html

<turbo-frame id="message-create-frame" data-turbo="true">
  <form
      method="post"
      action="{% url 'chat:message-create' view.kwargs.chat_pk %}"
      class="p-2 m-2"
  >
    {% csrf_token %}

    <div class="mb-3">
      {{ form.content }}

      <div class="text-xs italic text-red-500">
        {{ form.content.errors }}
      </div>
    </div>

    <button type="submit"
            class="transition-all bg-blue-500 hover:bg-blue-600 text-white py-2 px-4 rounded"
    >
      Submit
    </button>

  </form>
</turbo-frame>

Notes:

We use turbo-frame to wrap the form, and it also has the same id as the id="message-create-frame"
After Turbo get the server response, it will find the matched element according to the id of the turbo-frame, and update the content of the turbo frame element with the server-side response.

Test 1

Let's run the app

$ npm run start

And then run Django server

(venv)$ python manage.py runserver

Open http://localhost:8000/chat/ in your browser, we should see the message create form is loaded successfully.

If you check in devtool, you will see another request is sent to http://localhost:8000/chat/1/message/create/ to load the content of the turbo frame.

<turbo-frame id="message-create-frame">
  <form
    method="post"
    action="/chat/1/message/create/"
    class="p-2 m-2"
  >
    <input type="hidden" name="csrfmiddlewaretoken" value="mfIm4RDhjERAfnjRzG56PleGJo5h8AYFmAW2cCekDntJ0pFAtLPoHReNDWxwPu0p">

    <div class="mb-3">
      <textarea name="content" cols="40" rows="10" class="rounded-lg border-gray-300 block leading-normal border px-4 text-gray-700 bg-white focus:outline-none py-2 appearance-none w-full" required id="id_content">
</textarea>

      <div class="text-xs italic text-red-500">

      </div>
    </div>

    <button type="submit"
            class="transition-all bg-blue-500 hover:bg-blue-600 text-white py-2 px-4 rounded"
    >
      Submit
    </button>

  </form>
</turbo-frame>

Test 2

Input one character in the form, and submit to trigger the form validation failure.

Open devtools to check the network tab, and we can see HTML returned by http://localhost:8000/chat/1/message/create/

<turbo-frame id="message-create-frame">
  <form
          method="post"
          action="/chat/1/message/create/"
          class="p-2 m-2"
  >
    <input type="hidden" name="csrfmiddlewaretoken" value="rbw1NbabXrqI5q2YlHlveUrfVsUByeezrwKHVWLeha2RQsoHfM5N6qrmP0mQf8gj">

    <div class="mb-3">
      <textarea name="content" cols="40" rows="10" class="rounded-lg border-gray-300 block leading-normal border px-4 text-gray-700 bg-white focus:outline-none py-2 appearance-none w-full" required id="id_content">
3</textarea>

      <div class="text-xs italic text-red-500">
        <ul class="errorlist"><li>Ensure this value has at least 2 characters (it has 1).</li></ul>
      </div>
    </div>

    <button type="submit"
            class="transition-all bg-blue-500 hover:bg-blue-600 text-white py-2 px-4 rounded"
    >
      Submit
    </button>

  </form>
</turbo-frame>

Notes:

With Turbo frame, the page can do partial updates and display the form error message from the server.
We do not write any Javascript to make that happen, just traditional Django form validation code and turbo-frame element.

Test 3

If we input long text in the form, and submit, the form will pass the validation.

A message instance would be created, a new form will be created and returned by http://localhost:8000/chat/1/message/create/

So the form is reset and ready for the next message.

<turbo-frame id="message-create-frame">
  <form
    method="post"
    action="/chat/1/message/create/"
    class="p-2 m-2"
  >
    <input type="hidden" name="csrfmiddlewaretoken" value="KAEbkd8R0ZuwOT9R2xIF1UxuSLJYl5nmKVSRsYJUkI6FzVvAWCsXTqxBMjbd2Zp6">

    <div class="mb-3">
      <textarea name="content" cols="40" rows="10" class="rounded-lg border-gray-300 block leading-normal border px-4 text-gray-700 bg-white focus:outline-none py-2 appearance-none w-full" required id="id_content">
</textarea>

      <div class="text-xs italic text-red-500">

      </div>
    </div>

    <button type="submit"
            class="transition-all bg-blue-500 hover:bg-blue-600 text-white py-2 px-4 rounded"
    >
      Submit
    </button>

  </form>
</turbo-frame>

Django ChatGPT Tutorial Series:

Introduction

Create Django Project with Modern Frontend Tooling

Create Chat App

Partial Form Submission With Turbo Frame

Use Turbo Stream To Manipulate DOM Elements

Send Turbo Stream Over Websocket

Using OpenAI Streaming API With Celery

Use Stimulus to Better Organize Javascript Code in Django

Use Stimulus to Render Markdown and Highlight Code Block

Use Stimulus to Improve UX of Message Form

Source Code chatgpt-django-project