第 15 章：评论¶

# articles/models.py
...
class Comment(models.Model):                                      # new
    article = models.ForeignKey(Article, on_delete=models.CASCADE)
    comment = models.CharField(max_length=140)
    author = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
    )

    def __str__(self):
        return self.comment

    def get_absolute_url(self):
        return reverse("article_list")

(.venv) $ python manage.py makemigrations articles
Migrations for 'articles':
  articles/migrations/0002_comment.py
    - Create model Comment
(.venv) $ python manage.py migrate
Operations to perform:
  Apply all migrations: accounts, admin, articles, auth, contenttypes, sessions
Running migrations:
  Applying articles.0002_comment... OK

# articles/admin.py
from django.contrib import admin
from .models import Article, Comment                               # new

class ArticleAdmin(admin.ModelAdmin):
    list_display = [
        "title",
        "body",
        "author",
    ]

admin.site.register(Article, ArticleAdmin)
admin.site.register(Comment)                                       # new

# articles/admin.py
from django.contrib import admin
from .models import Article, Comment

class CommentInline(admin.StackedInline):                          # new
    model = Comment

class ArticleAdmin(admin.ModelAdmin):                              # new
    inlines = [
        CommentInline,
    ]
    list_display = [
        "title",
        "body",
        "author",
    ]

admin.site.register(Article, ArticleAdmin)                         # new
admin.site.register(Comment)

# articles/admin.py
...
class CommentInline(admin.StackedInline):
    model = Comment
    extra = 0                                                      # new

# articles/admin.py
from django.contrib import admin
from .models import Article, Comment

class CommentInline(admin.TabularInline):                          # new
    model = Comment
    extra = 0
#
class ArticleAdmin(admin.ModelAdmin):
    inlines = [
        CommentInline,
    ]
    list_display = [
        "title",
        "body",
        "author",
    ]

admin.site.register(Article, ArticleAdmin)
admin.site.register(Comment)

<!-- templates/article_list.html -->
...
<div class="card-body">
  {{ article.body }}
  {% if article.author.pk == request.user.pk %}
    <a href="{% url 'article_edit' article.pk %}">Edit</a>
    <a href="{% url 'article_delete' article.pk %}">Delete</a>
  {% endif %}
</div>
<div class="card-footer">
  {% for comment in article.comment_set.all %}
    <p>
      <span class="fw-bold">
        {{ comment.author }} &middot;
      </span>
      {{ comment }}
    </p>
  {% endfor %}
</div>
</div>
<br/>
{% endfor %}
{% endblock content %}

<!-- templates/article_detail.html -->
{% extends "base.html" %}
{% block content %}
<div class="article-entry">
  <h2>{{ object.title }}</h2>
  <p>by {{ object.author }} | {{ object.date }}</p>
  <p>{{ object.body }}</p>
</div>

<!-- Changes start here! -->
<hr>
<h4>Comments</h4>
{% for comment in article.comment_set.all %}
  <p>{{ comment.author }} &middot; {{ comment }}</p>
{% endfor %}
<hr>
<!-- Changes end here! -->

{% if article.author.pk == request.user.pk %}
  <p><a href="{% url 'article_edit' article.pk %}">Edit</a>
  <a href="{% url 'article_delete' article.pk %}">Delete</a>
  </p>
{% endif %}
<p>Back to <a href="{% url 'article_list' %}">All Articles</a>.</p>
{% endblock content %}

# articles/forms.py
from django import forms
from .models import Comment

class CommentForm(forms.ModelForm):
    class Meta:
        model = Comment
        fields = ("comment",)

# articles/views.py
...
from .models import Article
from .forms import CommentForm                                     # new

class ArticleDetailView(LoginRequiredMixin, DetailView):
    model = Article
    template_name = "article_detail.html"

    def get_context_data(self, **kwargs):                          # new
        context = super().get_context_data(**kwargs)
        context["form"] = CommentForm()
        return context

<!-- templates/article_detail.html -->
{% extends "base.html" %}
{% load crispy_forms_tags %} <!-- new! -->
{% block content %}
<div class="article-entry">
  <h2>{{ object.title }}</h2>
  <p>by {{ object.author }} | {{ object.date }}</p>
  <p>{{ object.body }}</p>
</div>
<hr>
<h4>Comments</h4>
{% for comment in article.comment_set.all %}
  <p>{{ comment.author }} &middot; {{ comment }}</p>
{% endfor %}
<hr>

<!-- Changes start here! -->
<h4>Add a comment</h4>
<form action="" method="post">{% csrf_token %}
  {{ form|crispy }}
  <button class="btn btn-success ms-2" type="submit">Save</button>
</form>
<!-- Changes end here! -->

<div>
  {% if article.author.pk == request.user.pk %}
    <p><a href="{% url 'article_edit' article.pk %}">Edit</a>
    <a href="{% url 'article_delete' article.pk %}">Delete</a>
    </p>
  {% endif %}
  <p>Back to <a href="{% url 'article_list' %}">All Articles</a>.</p>
</div>
{% endblock content %}

# articles/views.py
from django.contrib.auth.mixins import LoginRequiredMixin, UserPassesTestMixin
from django.views import View                                      # new
from django.views.generic import ListView, DetailView
...
class CommentGet(DetailView):                                      # new
    model = Article
    template_name = "article_detail.html"

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context["form"] = CommentForm()
        return context

class CommentPost():                                               # new
    pass

class ArticleDetailView(LoginRequiredMixin, View):                 # new
    def get(self, request, *args, **kwargs):
        view = CommentGet.as_view()
        return view(request, *args, **kwargs)

    def post(self, request, *args, **kwargs):
        view = CommentPost.as_view()
        return view(request, *args, **kwargs)
...

# articles/views.py
from django.contrib.auth.mixins import LoginRequiredMixin, UserPassesTestMixin
from django.views import View
from django.views.generic import ListView, DetailView, FormView    # new
from django.views.generic.detail import SingleObjectMixin          # new
from django.views.generic.edit import UpdateView, DeleteView, CreateView
from django.urls import reverse_lazy, reverse                      # new

from .forms import CommentForm
from .models import Article
...
class CommentPost(SingleObjectMixin, FormView):                    # new
    model = Article
    form_class = CommentForm
    template_name = "article_detail.html"

    def post(self, request, *args, **kwargs):
        self.object = self.get_object()
        return super().post(request, *args, **kwargs)

    def form_valid(self, form):
        comment = form.save(commit=False)
        comment.article = self.object
        comment.author = self.request.user
        comment.save()
        return super().form_valid(form)

    def get_success_url(self):
        article = self.object
        return reverse("article_detail", kwargs={"pk": article.pk})
...

<!-- templates/article_list.html -->
...
<div class="card-body">
  <p>{{ article.body }}</p>
  {% if article.author.pk == request.user.pk %}
    <a href="{% url 'article_edit' article.pk %}">Edit</a>
    <a href="{% url 'article_delete' article.pk %}">Delete</a>
  {% endif %}
  <a href="{{ article.get_absolute_url }}">New Comment</a> <!-- new -->
</div>

(.venv) $ git status
(.venv) $ git add -A
(.venv) $ git commit -m "comments app"
(.venv) $ git push origin main