UpdateViewの使い方をマスターしよう

$ git clone https://github.com/yheihei/base_diary.git
$ cd base_diary
$ git fetch && git checkout feature/#14

$ python manage.py migrate
$ python manage.py loaddata initial.json

UserName: yhei
Password: password

# 完成版ブランチを見たい場合はこちら
$ git fetch && git checkout feature/#16

from .models import Post
from django.views.generic.edit import UpdateView


class PostUpdateView(UpdateView):
  model = Post
  fields = ['user', 'title', 'body', 'categories']

  fields = ['user', 'title', 'body', 'categories']

class Post(models.Model):
  ...
  user = models.ForeignKey(User, on_delete=CASCADE)
  title = models.CharField(max_length=2048)
  body = models.TextField()
  ...
  categories = models.ManyToManyField(
    ...
  )

from django.urls import path
from . import views
from diary.views import PostDetailView, PostUpdateView

app_name = "diary"
urlpatterns = [
  path("", views.index, name="index"),
  path('<int:pk>/', PostDetailView.as_view(), name='post-detail'),
  # UpdateViewにルーティングさせる
  path('<int:pk>/update/', PostUpdateView.as_view(), name='post-update'),
]

{% extends 'diary/base.html' %}
{% block content %}
<article>
  <h2>記事の更新</h2>
  <div class="mt-3">
    <form method="POST">
      {% csrf_token %}
      {% for field in form.visible_fields %}
        <div class="form-group">
          <label>{{ field.label }}</label>
          {{ field }}
          {{ field.errors }}
          {{ field.help_text }}
        </div>
      {% endfor %}
      {% for field in form.hidden_fields %}
        {{ field }}
      {% endfor %}
      <input class="btn btn-primary" type="submit" value="投稿" />
    </form>
  </div>
</article>
{% endblock %}

from django.contrib.auth.mixins import LoginRequiredMixin
from django.urls import reverse_lazy


class PostUpdateView(LoginRequiredMixin, UpdateView):
  # ログインURLも指定する
  login_url = reverse_lazy('admin:login')
  ...

class Post(models.Model):
  ...
  updated_by = models.ForeignKey(
    User,
    default=None,
    on_delete=models.SET_NULL,
    null=True,
    blank=True,
    related_name='updated_posts',
  )

$ python manage.py makemigrations
$ python manage.py migrate

class PostUpdateView(LoginRequiredMixin, UpdateView):
  ...
  # fields = ['user', 'title', 'body', 'categories']
  fields = ['title', 'body', 'categories']

  def form_valid(self, form):
    object: Post = form.save(commit=False)
    object.updated_by = self.request.user
    object.save()
    return super().form_valid(form)

class PostUpdateView(LoginRequiredMixin, UpdateView):
  ...
  def get_success_url(self):
    '''
    更新完了したらどこに遷移させるか
    '''
    return reverse('diary:post-detail', kwargs={'pk': self.object.pk})