Step21: class based view

Author: yangxg

README.md

@@ -141,6 +141,7 @@ tutorial 分支为项目的主分支，每一篇教程的代码都和历史提
 18. [使用 Certbot 向 Let's Encrypt 免费申请 HTTPS 证书](https://www.zmrenwu.com/courses/hellodjango-blog-tutorial/materials/76/)
 19. [使用 Docker 让部署 Django 项目更加轻松](https://www.zmrenwu.com/courses/hellodjango-blog-tutorial/materials/77/)
 20. [开发博客文章阅读量统计功能](https://www.zmrenwu.com/courses/hellodjango-blog-tutorial/materials/78/)
+21. [Django 官方推荐的姿势：类视图](https://www.zmrenwu.com/courses/hellodjango-blog-tutorial/materials/79/)
 
 ## 公众号
 <p align="center">

blog/urls.py

@@ -4,9 +4,9 @@
 
 app_name = 'blog'
 urlpatterns = [
-    path('', views.index, name='index'),
-    path('posts/<int:pk>/', views.detail, name='detail'),
-    path('archives/<int:year>/<int:month>/', views.archive, name='archive'),
-    path('categories/<int:pk>/', views.category, name='category'),
-    path('tags/<int:pk>/', views.tag, name='tag'),
+    path('', views.IndexView.as_view(), name='index'),
+    path('posts/<int:pk>/', views.PostDetailView.as_view(), name='detail'),
+    path('archives/<int:year>/<int:month>/', views.ArchiveView.as_view(), name='archive'),
+    path('categories/<int:pk>/', views.CategoryView.as_view(), name='category'),
+    path('tags/<int:pk>/', views.TagView.as_view(), name='tag'),
 ]

blog/views.py

@@ -3,52 +3,72 @@
 import markdown
 from django.shortcuts import get_object_or_404, render
 from django.utils.text import slugify
+from django.views.generic import DetailView, ListView
 from markdown.extensions.toc import TocExtension
 
 from .models import Category, Post, Tag
 
 
-def index(request):
-    post_list = Post.objects.all()
-    return render(request, 'blog/index.html', context={'post_list': post_list})
+class IndexView(ListView):
+    model = Post
+    template_name = 'blog/index.html'
+    context_object_name = 'post_list'
 
 
-def archive(request, year, month):
-    post_list = Post.objects.filter(created_time__year=year,
-                                    created_time__month=month
-                                    )
-    return render(request, 'blog/index.html', context={'post_list': post_list})
+class CategoryView(IndexView):
 
+    def get_queryset(self):
+        cate = get_object_or_404(Category, pk=self.kwargs.get('pk'))
+        return super().get_queryset().filter(category=cate)
 
-def category(request, pk):
-    # 记得在开始部分导入 Category 类
-    cate = get_object_or_404(Category, pk=pk)
-    post_list = Post.objects.filter(category=cate)
-    return render(request, 'blog/index.html', context={'post_list': post_list})
 
+class ArchiveView(IndexView):
+    def get_queryset(self):
+        year = self.kwargs.get('year')
+        month = self.kwargs.get('month')
+        return super().get_queryset().filter(created_time__year=year,
+                                             created_time__month=month)
 
-def tag(request, pk):
-    # 记得在开始部分导入 Tag 类
-    t = get_object_or_404(Tag, pk=pk)
-    post_list = Post.objects.filter(tags=t)
-    return render(request, 'blog/index.html', context={'post_list': post_list})
 
+class TagView(IndexView):
+    def get_queryset(self):
+        t = get_object_or_404(Tag, pk=self.kwargs.get('pk'))
+        return super().get_queryset().filter(tags=t)
 
-def detail(request, pk):
-    post = get_object_or_404(Post, pk=pk)
 
-    # 阅读量 +1
-    post.increase_views()
+# 记得在顶部导入 DetailView
+class PostDetailView(DetailView):
+    # 这些属性的含义和 ListView 是一样的
+    model = Post
+    template_name = 'blog/detail.html'
+    context_object_name = 'post'
 
-    md = markdown.Markdown(extensions=[
-        'markdown.extensions.extra',
-        'markdown.extensions.codehilite',
-        # 记得在顶部引入 TocExtension 和 slugify
-        TocExtension(slugify=slugify),
-    ])
-    post.body = md.convert(post.body)
+    def get(self, request, *args, **kwargs):
+        # 覆写 get 方法的目的是因为每当文章被访问一次，就得将文章阅读量 +1
+        # get 方法返回的是一个 HttpResponse 实例
+        # 之所以需要先调用父类的 get 方法，是因为只有当 get 方法被调用后，
+        # 才有 self.object 属性，其值为 Post 模型实例，即被访问的文章 post
+        response = super().get(request, *args, **kwargs)
 
-    m = re.search(r'<div class="toc">\s*<ul>(.*)</ul>\s*</div>', md.toc, re.S)
-    post.toc = m.group(1) if m is not None else ''
+        # 将文章阅读量 +1
+        # 注意 self.object 的值就是被访问的文章 post
+        self.object.increase_views()
 
-    return render(request, 'blog/detail.html', context={'post': post})
+        # 视图必须返回一个 HttpResponse 对象
+        return response
+
+    def get_object(self, queryset=None):
+        # 覆写 get_object 方法的目的是因为需要对 post 的 body 值进行渲染
+        post = super().get_object(queryset=None)
+        md = markdown.Markdown(extensions=[
+            'markdown.extensions.extra',
+            'markdown.extensions.codehilite',
+            # 记得在顶部引入 TocExtension 和 slugify
+            TocExtension(slugify=slugify),
+        ])
+        post.body = md.convert(post.body)
+
+        m = re.search(r'<div class="toc">\s*<ul>(.*)</ul>\s*</div>', md.toc, re.S)
+        post.toc = m.group(1) if m is not None else ''
+
+        return post