第 6 章：博客网站¶

# Windows
$ cd onedrive\desktop\code
$ mkdir blog
$ cd blog
$ python -m venv .venv
$ .venv\Scripts\Activate.ps1
(.venv) $

# macOS
$ cd ~/desktop/code
$ mkdir blog
$ cd blog
$ python3 -m venv .venv
$ source .venv/bin/activate
(.venv) $

(.venv) $ python -m pip install django~=5.0.0
(.venv) $ python -m pip install black
(.venv) $ django-admin startproject django_project .
(.venv) $ python manage.py startapp blog
(.venv) $ python manage.py migrate

# django_project/settings.py
INSTALLED_APPS = [
    "django.contrib.admin",
    "django.contrib.auth",
    "django.contrib.contenttypes",
    "django.contrib.sessions",
    "django.contrib.messages",
    "django.contrib.staticfiles",
    "blog",  # new
]

(.venv) $ python manage.py runserver

Post Database Table
Post
--------
TITLE           AUTHOR          BODY
Hello, World!   wsv             My first blog post. Woohoo!
Goals Today     wsv             Learn Django and build a blog application.
3rd Post        wsv             This is my 3rd entry.

# blog/models.py
from django.db import models

class Post(models.Model):
    title = models.CharField(max_length=200)
    author = models.CharField(max_length=200)
    body = models.TextField()

    def __str__(self):
        return self.title

(.venv) $ python manage.py makemigrations blog
Migrations for 'blog':
  blog/migrations/0001_initial.py
    - Create model Post
(.venv) $ python manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, blog, contenttypes, sessions
Running migrations:
  Applying blog.0001_initial... OK

Post Schema
Post
--------
primary_key
title
author
body

Post Schema
Post
--------
post_id
title
author
body

Post Database Table
Post
--------
POST_ID   TITLE           AUTHOR    BODY
1         Hello, World!   wsv       My first blog post. Woohoo!
2         Goals Today     wsv       Learn Django and build a blog application.
3         3rd Post        wsv       This is my 3rd entry.

Post and User Schema
Post                User
--------            --------
post_id             user_id
title               username
author              first_name
body                last_name
                    email
                    password
                    groups
                    user_permissions
                    is_staff
                    is_active
                    is_superuser
                    last_login
                    date_joined

# blog/models.py
from django.db import models

class Post(models.Model):
    title = models.CharField(max_length=200)
    author = models.ForeignKey(  # new
        "auth.User",
        on_delete=models.CASCADE,
    )
    body = models.TextField()

    def __str__(self):
        return self.title

(.venv) $ python manage.py makemigrations blog
Migrations for 'blog':
  blog/migrations/0002_alter_post_author.py
    - Alter field author on post
(.venv) $ python manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, blog, contenttypes, sessions
Running migrations:
  Applying blog.0002_alter_post_author... OK

(.venv) $ python manage.py createsuperuser
Username (leave blank to use 'wsv'): wsv
Email:
Password:
Password (again):
Superuser created successfully.

# blog/admin.py
from django.contrib import admin
from .models import Post

admin.site.register(Post)

# blog/admin.py
from django.contrib import admin
from .models import Post

class PostAdmin(admin.ModelAdmin):  # new
    list_display = (
        "title",
        "author",
        "body",
    )

admin.site.register(Post, PostAdmin)  # new

# blog/views.py
from django.shortcuts import render
from .models import Post

def post_list(request):
    posts = Post.objects.all()
    return render(request, 'home.html', {'posts': posts})

# blog/urls.py
from django.urls import path
from .views import post_list

urlpatterns = [
    path("", post_list, name="home"),
]

# django_project/urls.py
from django.contrib import admin
from django.urls import path, include  # new

urlpatterns = [
    path("admin/", admin.site.urls),
    path("", include("blog.urls")),  # new
]

(.venv) $ mkdir templates

# django_project/settings.py
TEMPLATES = [
    {
        ...
        "DIRS": [BASE_DIR / "templates"],  # new
        ...
    },
]

<!-- templates/base.html -->
<html>
<head>
    <title>Django blog</title>
</head>
<body>
    <header>
        <h1><a href="{% url 'home' %}">Django blog</a></h1>
    </header>
    <div>
        {% block content %}
        {% endblock content %}
    </div>
</body>
</html>

<!-- templates/home.html -->
{% extends "base.html" %}

{% block content %}
    {% for post in posts %}
    <div class="post-entry">
        <h2><a href="">{{ post.title }}</a></h2>
        <p>Author: {{ post.author }}</p>
        <p>{{ post.body }}</p>
    </div>
    {% endfor %}
{% endblock content %}

# django_project/settings.py
STATIC_URL = "static/"

(.venv) $ mkdir static

# django_project/settings.py
STATIC_URL = "static/"
STATICFILES_DIRS = [BASE_DIR / "static"]  # new

(.venv) $ mkdir static/css

/* static/css/base.css */
header h1 a {
    color: red;
}

<!-- templates/base.html -->
{% load static %}
<html>
<head>
    <title>Django blog</title>
    <link rel="stylesheet" href="{% static 'css/base.css' %}">
</head>
...

<!-- templates/base.html -->
{% load static %}
<html>
<head>
    <title>Django blog</title>
    <link href="https://fonts.googleapis.com/css?family=Source+Sans+Pro:400"
        rel="stylesheet">
    <link href="{% static 'css/base.css' %}" rel="stylesheet">
</head>
...

/* static/css/base.css */
body {
    font-family: 'Source Sans Pro', sans-serif;
    font-size: 18px;
}
header {
    border-bottom: 1px solid #999;
    margin-bottom: 2rem;
    display: flex;
}
header h1 a {
    color: red;
    text-decoration: none;
}
.nav-left {
    margin-right: auto;
}
.nav-right {
    display: flex;
    padding-top: 2rem;
}
.post-entry {
    margin-bottom: 2rem;
}
.post-entry h2 {
    margin: 0.5rem 0;
}
.post-entry h2 a,
.post-entry h2 a:visited {
    color: blue;
    text-decoration: none;
}
.post-entry p {
    margin: 0;
    font-weight: 400;
}
.post-entry h2 a:hover {
    color: red;
}

# blog/views.py
from django.shortcuts import render, get_object_or_404  # new
from .models import Post

def post_list(request):
    posts = Post.objects.all()
    return render(request, 'home.html', {'posts': posts})

def post_detail(request, pk):  # new
    post = get_object_or_404(Post, pk=pk)
    return render(request, "post_detail.html", {"post": post})

# blog/urls.py
from django.urls import path
from .views import post_list, post_detail  # new

urlpatterns = [
    path("post/<int:pk>/", post_detail, name="post_detail"),  # new
    path("", post_list, name="home"),
]

<!-- templates/post_detail.html -->
{% extends "base.html" %}

{% block content %}
<div class="post-entry">
    <h2>{{ post.title }}</h2>
    <p>{{ post.body }}</p>
</div>
{% endblock content %}

<!-- templates/home.html -->
{% extends "base.html" %}

{% block content %}
    {% for post in posts %}
    <div class="post-entry">
        <h2><a href="{% url 'post_detail' post.pk %}">{{ post.title }}</a></h2>
        <p>{{ post.body }}</p>
    </div>
    {% endfor %}
{% endblock content %}

# blog/models.py
from django.db import models
from django.urls import reverse  # new

class Post(models.Model):
    title = models.CharField(max_length=200)
    author = models.ForeignKey(
        "auth.User",
        on_delete=models.CASCADE,
    )
    body = models.TextField()

    def __str__(self):
        return self.title

    def get_absolute_url(self):  # new
        return reverse("post_detail", kwargs={"pk": self.pk})

<!-- templates/home.html -->
{% extends "base.html" %}

{% block content %}
    {% for post in posts %}
    <div class="post-entry">
        <h2><a href="{{ post.get_absolute_url }}">{{ post.title }}</a></h2> <!-- new -->
        <p>{{ post.body }}</p>
    </div>
    {% endfor %}
{% endblock content %}

# blog/tests.py
from django.contrib.auth import get_user_model
from django.test import TestCase
from .models import Post

class BlogTests(TestCase):
    @classmethod
    def setUpTestData(cls):
        cls.user = get_user_model().objects.create_user(
            username="testuser", email="test@email.com", password="secret"
        )
        cls.post = Post.objects.create(
            title="A good title",
            body="Nice body content",
            author=cls.user,
        )

    def test_post_model(self):
        self.assertEqual(self.post.title, "A good title")
        self.assertEqual(self.post.body, "Nice body content")
        self.assertEqual(self.post.author.username, "testuser")
        self.assertEqual(str(self.post), "A good title")
        self.assertEqual(self.post.get_absolute_url(), "/post/1/")

(.venv) $ python manage.py test
Found 1 test(s).
Creating test database for alias 'default'...
System check identified no issues (0 silenced).
.
----------------------------------------------------------------------
Ran 1 test in 0.088s

OK
Destroying test database for alias 'default'...

# blog/tests.py
from django.contrib.auth import get_user_model
from django.test import TestCase
from django.urls import reverse  # new
from .models import Post

class BlogTests(TestCase):
    @classmethod
    def setUpTestData(cls):
        cls.user = get_user_model().objects.create_user(
            username="testuser", email="test@email.com", password="secret"
        )
        cls.post = Post.objects.create(
            title="A good title",
            body="Nice body content",
            author=cls.user,
        )

    def test_post_model(self):
        self.assertEqual(self.post.title, "A good title")
        self.assertEqual(self.post.body, "Nice body content")
        self.assertEqual(self.post.author.username, "testuser")
        self.assertEqual(str(self.post), "A good title")
        self.assertEqual(self.post.get_absolute_url(), "/post/1/")

    def test_url_exists_at_correct_location_listview(self):  # new
        response = self.client.get("/")
        self.assertEqual(response.status_code, 200)

    def test_url_exists_at_correct_location_detailview(self):  # new
        response = self.client.get("/post/1/")
        self.assertEqual(response.status_code, 200)

    def test_post_listview(self):  # new
        response = self.client.get(reverse("home"))
        self.assertEqual(response.status_code, 200)
        self.assertContains(response, "Nice body content")
        self.assertTemplateUsed(response, "home.html")

    def test_post_detailview(self):  # new
        response = self.client.get(reverse("post_detail",
            kwargs={"pk": self.post.pk}))
        no_response = self.client.get("/post/100000/")
        self.assertEqual(response.status_code, 200)
        self.assertEqual(no_response.status_code, 404)
        self.assertContains(response, "A good title")
        self.assertTemplateUsed(response, "post_detail.html")

(.venv) $ python manage.py test
Found 5 test(s).
Creating test database for alias 'default'...
System check identified no issues (0 silenced).
.....
----------------------------------------------------------------------
Ran 5 tests in 0.095s

OK
Destroying test database for alias 'default'...

(.venv) $ git init
(.venv) $ git status

# .gitignore
.venv/
__pycache__/
db.sqlite3

(.venv) $ git status
(.venv) $ git add -A
(.venv) $ git commit -m "initial commit"