3.投票-1创建项目和子应用

创建项目

• 命令

  $ python django-admin startproject mysite
  

• 目录结构

  
  
  mysite/               # 项目容器、可任意命名
      manage.py         # 命令行工具
      mysite/           # 纯 Python 包 # 你引用任何东西都要用到它
          __init__.py   # 空文件 告诉Python这个目录是Python包
          settings.py   # Django 项目配置文件
          urls.py       # URL 声明  # 就像网站目录
          asgi.py       # 部署时用的配置 # 运行在ASGI兼容的Web服务器上的 入口
          wsgi.py       # 部署时用的配置 # 运行在WSGI兼容的Web服务器上的 
  
  

• 初始化数据库 迁移

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

Django 简易服务器

• 用于开发使用，Django 在网络框架方面很NB， 但在网络服务器方面不行~

  专业的事让专业的程序做嘛，最后部署到 Nginx Apache 等专业网络服务器上就行啦。

• 自动重启服务器

  对每次访问请求、重新载入一遍 Python 代码

  新添加文件等一些操作 不会触发重启

• 命令

  $ python manage.py runserver
  

  E:PYTHONCODEmysite>
  E:PYTHONCODEmysite>python manage.py runserver
  Watching for file changes with StatReloader
  Performing system checks...
  
  System check identified no issues (0 silenced).
  June 29, 2022 - 22:35:10
  Django version 4.0.5, using settings "mysite.settings"
  Starting development server at http://127.0.0.1:8000/
  Quit the server with CTRL-BREAK.
  

• 指定端口

  $ python manage.py runserver 8080
  

创建应用

• 命令

  $ python manage.py startapp polls
  

• 目录结构

  polls/
      __init__.py
      admin.py
      apps.py
      migrations/
          __init__.py
      models.py
      tests.py
      views.py
  

编写应用视图

• 视图函数

  # polls/views.py
  
  from django.shortcuts import render
  
  # Create your views here.
  
  from django.http import HttpRespose
  
  
  def index(rquest):
  
      return HttpResponse("投票应用 -首页")
  

配置路由

• 配置路由

  # polls/urls.py  子应用路由
  
  from django.urls import path
  
  from . import views
  
  urlpatterns = [
      path("", views.index, name="index"),
  ]
  

  # mysite/urls.py  全局路由 include（）即插即用
  
  from django.contrib import admin
  from django.urls import include, path
  
  urlpatterns = [
      path("polls/", include("polls.urls")),
      path("admin/", admin.site.urls),
  ]
  

• 效果

path() 参数含义

path("", views.index, name="index"),

path("polls/", include("polls.urls"))

• route 路径

  一个匹配URL的规则，类似正则表达式。不匹配GET、POST传参 、域名

• view 视图函数

   Django 调用这个函数，默认传给函数一个 HttpRequest 参数
  

• kwargs 视图函数参数

  字典格式

• name 给这条URL取一个温暖的名子~

  可以在 Django 的任意地方唯一的引用。允许你只改一个文件就能全局地修改某个 URL 模式。

3.投票-2本地化和数据库API

本地化配置

• 时区和语言

  # mysite/mysite/settings.py
  
  # Internationalization
  # https://docs.djangoproject.com/en/4.0/topics/i18n/
  
  LANGUAGE_CODE = "zh-hans"   # "en-us"
  
  TIME_ZONE = "UTC"
  
  USE_I18N = True
  
  USE_TZ = True
  
  

• 为啥要在数据库之前？

  配置时区，数据库可以以此做相应配置。比如时间的存放是以UTC还是本地时间…

数据库配置

• django 支持 sqlite mysql postgresql oracle
• 默认是sqlite 它是本地的一个文件name 哪里直接写了文件的绝对路径

  # mysite/mysite/settings.py
  
  # Database
  # https://docs.djangoproject.com/en/4.0/ref/settings/#databases
  
  DATABASES = {
      "default": {
          "ENGINE": "django.db.backends.sqlite3",
          "NAME": BASE_DIR / "db.sqlite3",
      }
  }
  
  

• 迁移 主要为Django默认的模型建表

  python manage.py migrate
  

创建模型

• 编写

  # mysite/polls/models.py
  
  from django.db import models
  
  
  class Question(models.Model):
      question_text = models.CharField(max_length=200)
      pub_date = models.DateTimeField("date published")
  
  
  class Choice(models.Model):
      question = models.ForeignKey(Question, on_delete=models.CASCADE)
      choice_text = models.CharField(max_length=200)
      votes = models.IntegerField(default=0)
  

• 很多数据库的知识 都可以用到里面

  Question Choice 类都是基于models.Model， 是它的子类。

  类的属性——–表的字段

  类名———–表名

  还有pub_date on_delete=models.CASCAD 级联删除, pub_date 的字段描述， vo tes的默认值, 都和数据库很像。

  而且max_length这个个字段，让Django可以在前端自动校验我们的数据

激活模型

• 把配置注册到项目

  # mysite/mysite/settings.py
  
  # Application definition
  
  INSTALLED_APPS = [
      "polls.apps.PollsConfig",
  
      "django.contrib.admin",
      "django.contrib.auth",
      "django.contrib.contenttypes",
      "django.contrib.sessions",
      "django.contrib.messages",
      "django.contrib.staticfiles",
  ]
  

• 做迁移-

  仅仅把模型的配置信息转化成 Sql 语言

  (venv) E:PYTHONCODEmysite>python manage.py makemigrations polls
  Migrations for "polls":
    pollsmigrations001_initial.py
      - Create model Question
      - Create model Choice
  

  查看 Sql 语言 (对应我们配的 Sqlite 数据库的语法)

(venv) E:PYTHONCODEmysite>python manage.py sqlmigrate polls 0001
BEGIN;
--
  -- Create model Question
  --
  
  CREATE TABLE "polls_question" ("id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, "question_text" varchar(200) NOT NULL, "pub_data" datetime NOT NULL
);
--
  -- Create model Choice
  --
  
  CREATE TABLE "polls_choice" ("id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, "choice_text" varchar(200) NOT NULL, "votes" integer NOT NULL, "quest
ion_id" bigint NOT NULL REFERENCES "polls_question" ("id") DEFERRABLE INITIALLY DEFERRED);
CREATE INDEX "polls_choice_question_id_c5b4b260" ON "polls_choice" ("question_id");
COMMIT;
  

• 执行迁移

  (venv) E:PYTHONCODEmysite>python manage.py migrate
  Operations to perform:
    Apply all migrations: admin, auth, contenttypes, polls, sessions
  Running migrations:
    Applying polls.0001_initial... OK
  
  (venv) E:PYTHONCODEmysite>
  
  

API 的初体验

• 进入shell

  python manage.py shell
  

• 增

  - (venv) E:PYTHONCODEmysite>python manage.py shell
  Python 3.9.1 (tags/v3.9.1:1e5d33e, Dec  7 2020, 17:08:21) [MSC v.1927 64 bit (AMD64)] on win32
  Type "help", "copyright", "credits" or "license" for more information.
  (InteractiveConsole)
  >>>
  >>> from polls.models import Question, Choice
  >>> from django.utils import timezone
  >>>
  >>> q = Question( question_text = "what"s up ?", pub_date=timezone.now() )
  >>>
  >>> q.save()
  >>>
  
  

• 查看字段

  >>> q.id
  1
  >>> q.question_text
  "what"s up ?"
  >>>
  >>> q.pub_date
  datetime.datetime(2022, 7, 6, 5, 46, 10, 997140, tzinfo=datetime.timezone.utc)
  >>>
  

• 改

  >>> q.question_text = "are you kidding me ?"
  >>> q.save()
  >>>
  >>> q.question_text
  "are you kidding me ?"
  >>>
  
  >>>
  >>>
  >>> Question.objects.all()
  <QuerySet [<Question: Question object (1)>]>
  >>>
  >>>
  

下面写点更人性化的方法

• __str__方法

  默认打印自己的text字段，便于查看

  后台展示对象数据也会用这个字段

  class Question(models.Model):
      ...
      
      def __str__(self):
          return self.question_text
  
  
  class Choice(models.Model):
      ...
      
      def __str__(self):
          return self.choice_text
  

• 自定义方法

  class Question(models.Model):
      ...
  
      def was_published_recently(self):
          return self.pub_date >= timezone.now()-datetime.timedelta(days=1)
  

• __str__方法效果

  (venv) E:PYTHONCODEmysite>python manage.py shell
  Python 3.9.1 (tags/v3.9.1:1e5d33e, Dec  7 2020, 17:08:21) [MSC v.1927 64 bit (AMD64)] on win32
  Type "help", "copyright", "credits" or "license" for more information.
  (InteractiveConsole)
  >>>
  >>> from polls.models import Question, Choice
  >>>
  >>> Question.objects.all()
  <QuerySet [<Question: are you kidding me ?>]>
  >>>
  >>> Question.objects.filter(id=1)
  <QuerySet [<Question: are you kidding me ?>]>
  >>>
  
  

• 按属性查

  
  >>>
  >>> Question.objects.filter(question_text__startswith="are")
  <QuerySet [<Question: are you kidding me ?>]>
  >>>
  
  
  >>> from django.utils import timezone
  >>>
  >>> current_year = timezone.now().year
  >>> Question.objects.get(pub_date__year=current_year)
  <Question: are you kidding me ?>
  >>>
  
  
  >>> Question.objects.get(id=2)
  Traceback (most recent call last):
    File "<console>", line 1, in <module>
    File "E:PYTHONCODEStudyBuddyvenvlibsite-packagesdjangodbmodelsmanager.py", line 85, in manager_method
      return getattr(self.get_queryset(), name)(*args, **kwargs)
    File "E:PYTHONCODEStudyBuddyvenvlibsite-packagesdjangodbmodelsquery.py", line 496, in get
      raise self.model.DoesNotExist(
  polls.models.Question.DoesNotExist: Question matching query does not exist.
  >>>
  >>>
  

• 更多操作

  用pk找更保险一些，有的model 不以id 为主键

  >>> Question.objects.get(pk=1)  
  <Question: are you kidding me ?>
  >>>
  # 自定义查找条件
  >>> q = Question.objects.get(pk=1)
  >>> q.was_published_recently()
  True
  >>>
  
  # 安主键获取对象
  >>> q = Question.objects.get(pk=1)
  >>> q.choice_set.all()
  <QuerySet []>
  >>>
  
  # 增  问题对象关系到选项对象
  >>> q.choice_set.create(choice_text="Not much", votes=0)
  <Choice: Not much>
  >>>
  >>> q.choice_set.create(choice_text="The sky", votes=0)
  <Choice: The sky>
  >>>
  >>> q.choice_st.create(choice_text="Just hacking agin", votes=0)
  Traceback (most recent call last):
    File "<console>", line 1, in <module>
  AttributeError: "Question" object has no attribute "choice_st"
  >>>
  >>> q.choice_set.create(choice_text="Just hacking agin", votes=0)
  <Choice: Just hacking agin>
  >>>
  >>>
  >>> c = q.choice_set.create(choic_text="Oh my god.", votes=0)
  Traceback (most recent call last):
    File "<console>", line 1, in <module>
    File "E:PYTHONCODEStudyBuddyvenvlibsite-packagesdjangodbmodelsfieldselated_descriptors.py", line 747, in create
      return super(RelatedManager, self.db_manager(db)).create(**kwargs)
    File "E:PYTHONCODEStudyBuddyvenvlibsite-packagesdjangodbmodelsmanager.py", line 85, in manager_method
      return getattr(self.get_queryset(), name)(*args, **kwargs)
    File "E:PYTHONCODEStudyBuddyvenvlibsite-packagesdjangodbmodelsquery.py", line 512, in create
      obj = self.model(**kwargs)
    File "E:PYTHONCODEStudyBuddyvenvlibsite-packagesdjangodbmodelsase.py", line 559, in __init__
      raise TypeError(
  TypeError: Choice() got an unexpected keyword argument "choic_text"
  >>>
  
  
  # 选项 关系 到问题
  >>> c = q.choice_set.create(choice_text="Oh my god.", votes=0)
  >>>
  >>> c.question
  <Question: are you kidding me ?>
  >>>
  >>> q.choice_set.all()
  <QuerySet [<Choice: Not much>, <Choice: The sky>, <Choice: Just hacking agin>, <Choice: Oh my god.>]>
  >>>
  >>>
  >>> q.choice_set.count()
  4
  >>>
  >>> Choice.objects.filter(question__pub_date__year=current_year)
  <QuerySet [<Choice: Not much>, <Choice: The sky>, <Choice: Just hacking agin>, <Choice: Oh my god.>]>
  >>>
  >>>
  
  
  

• 删

  >>> c = q.choice_set.filter(choice_text__startswith="Just hacking")
  >>> c.delete()
  (1, {"polls.Choice": 1})
  >>>
  >>> q.choice_set.all()
  <QuerySet [<Choice: Not much>, <Choice: The sky>, <Choice: Oh my god.>]>
  >>>
  >>>
  

管理页面

• 创建用户

  (venv) E:PYTHONCODEmysite>python manage.py createsuperuser
  
  
  用户名: admin
  电子邮件地址: admin@qq.com
  Password:
  Password (again):
  密码长度太短。密码必须包含至少 8 个字符。
  这个密码太常见了。
  Bypass password validation and create user anyway? [y/N]: y
  Superuser created successfully.
  
  

• 启动 开发服务器

  python manage.py runserver
  

• login

  http://localhost:8000/admin/
  

• 让我们的polls 投票应用也展示在后台

  # mysite/polls/admin.py
  
  
  from .models import Question, Choice
  
  admin.site.register(Question)
  admin.site.register(Choice)
  

3.投票-3模板和路由

编写更多视图

# polls/views.py

...

def detail(request, question_id):
    
    return HttpResponse(f"当前问题id：{question_id}")


def results(request, question_id):
    
    return HttpResponse(f"问题id：{question_id}的投票结果")


def vote(request, question_id):
    
    return HttpResponse(f"给问题id:{question_id}投票")

添加url

• 全局我们已经加过

  
  urlpatterns = [
      path("admin/", admin.site.urls),
      path("polls/", include("polls.urls")),
      
  ]
  

• 应用程序添加如下

  # polls/urls.py
  
  from django.urls import path
  
  from . import views
  
  urlpatterns = [
      path("", views.index, name="index"),
  
      path("<int:question_id>/", views.detail, name="detail"),
  
      path("<int:question_id>/results/", views.results, name="results"),
  
      path("<int:question_id>/vote/", views.vote, name="vote"),
  ]
  

看看效果

• path 里的参数很敏感 结尾含/ 的访问时也必须含 / 否则404

• 以 /polls/1/ 为例分析匹配过程

  • 从mysite/settings.py 载入 ROOT_URLCONF = "mysite.urls"
  • 从urls.py 的“polls/”匹配到 polls/ 载入 polls.urls
  • 从polls/urls.py 的“int:question_id/”匹配到 1/ ,获取int型的 1 转发给视图函数 views.details

升级index 视图 展示近期5个投票问题

• 编写视图

  def index(request):
      latest_question_list = Question.objects.order_by("-pub_date")[:5]
      output = ",".join([q.question_text for q  in latest_question_list])
  
      return HttpResponse(output)
  

• 好吧，总共就一个
  

• 加点

这里直接把页面内容，写到了视图函数里，写死的。很不方便，下面用模板文件来处理这个问题

模板文件

• 创建polls存放 模板文件的 文件夹 为什么里面多套了一层polls？没看出他有区分的作用，第一个polls不已经区分过了？

  polls/templates/polls/
  

• 主要内容

  # polls/templates/polls/index.html
  
  {% if latest_question_list %}
    <ul>
      {% for question in latest_question_list %}
          <li>
            <a href="/polls/{{ question.id }}/">{{question.question_text}}</a>
          </li>
      {% endfor %}
    </ul>
  {% else %}
      <p>暂时没有开放的投票。</p>
  {% endif %}
  

• 修改视图函数

  这里函数载入index.html模本，还传给他一个上下文字典context，字典把模板里的变量映射成了Python 对象

  # polls/views.py
  
  ...
  from django.template import loader
  
  
  def index(request):
      latest_question_list = Question.objects.order_by("-pub_date")[:5]
  
      template = loader.get_template("polls/index.html")
      context = {
          "latest_question_list": latest_question_list,
      }
  
      return HttpResponse(template.render(context, request))
      
  ...
  

• 效果

• 快捷函数 render（）

  上面的视图函数用法很普遍，有种更简便的函数替代这一过程

  # polls/views.py
  ...
  from django.template import loader
  
  import django.shortcuts import render
  
  def index(request):
      latest_question_list = Question.objects.order_by("-pub_date")[:5]
  
      #template = loader.get_template("polls/index.html")
      context = {
          "latest_question_list": latest_question_list,
      }
  
      #return HttpResponse(template.render(context, request))
      return render(request, "polls/index.html", context)
      
  ...
  

优雅的抛出 404

• 修改 detail 视图函数

  # polls/views.py
  
  ...
  
  def detail(request, question_id):
      try:
          question = Question.objects.get(pk=question_id)
  
      except:
          raise Http404("问题不存在 !")
  
      # return HttpResponse(f"当前问题id：{question_id}")
      return render(request, "polls/detail.html", {"question": question})
  
  

• 编写模板

  # polls/templates/polls/detail.html
  
  
  {{ question }}
  
  

• 效果
  

• 快捷函数 get_object_or_404()

  # polls/views.py
  from django.shortcuts import render, get_object_or_404
  
  ...
  
  def detail(request, question_id):
      
      question = get_object_or_404(Question, pk=question_id)
      return render(request, "polls/detail.html", {"question": question})
  

• 效果
  

使用模板系统

• 对detail.html获取的question变量进行分解 展示

  • 模板系统用.来访问变量属性

  • 如question.question_text先对question用字典查找nobj.get(str)——>属性查找obj.str———->列表查找obj[int]当然在第二步就成功的获取了question_text属性，不在继续进行。

  • 其中 question.choice_set.all解释为Python代码question.choice_set.all()

  # polls/templates/polls/detail.html
  
  <h1>{{ question.question_text }}</h1>
  <ul>
      {% for choice in question.choice_set.all %}
          <li>{{ choice.choice_text }}</li>
      {% endfor %}
  </ul>
  

• 效果
  

去除 index.html里的硬编码

• 其中的”detail” 使我们在urls.py 定义的名称

  # polls/urls.py
  
  path("<int:question_id>/", views.detail, name="detail"),
  

  # polls/templates/polls/index.html
  
  <!--<li>-->
  <!--       <a href="/polls/{{ question.id }}/">{{question.question_text}}</a>-->
  <!--</li>-->
  
  <li>
         <a href="{% url "detail" question.id %}">{{question.question_text}}</a>
  </li>
  

• 有啥用？

  • 简单明了 书写方便

  • 我们修改.html 的真实位置后， 只需在urls.py 同步修改一条记录， 就会在所有模板文件的无数个连接中生效

    大大的节省时间

为URL添加命名空间

• 为什么？

  上面去除硬链接方便了我们。我们只有1个应用polls有自己的detail.html模板，但有多个应用同时有名字为detail.html的模板时呢？

  Django看到{% url %} 咋知道是哪个应用呢？

• 怎么加 ？

  # polls/urls.py
  
  app_name = "polls"
  
  ...
  

• 修改.html模板文件

  # polls/templates/polls/index.html
  
  <!--<li>-->
  <!--       <a href="/polls/{{ question.id }}/">{{question.question_text}}</a>-->
  <!--</li>-->
  
  <!--<li>-->
  <!--       <a href="{% url "detail" question.id %}">{{question.question_text}}</a>-->
  <!--</li>-->
  
  <li>
         <a href="{% url "polls:detail" question.id %}">{{question.question_text}}</a>
  </li>
  

3.投票-4投票结果保存 和 Django通用模板

投票结果保存

前端

# polls/templates/polls/detail.html

{#<h1>{{ question.question_text }}</h1>#}
{#<ul>#}
{#    {% for choice in question.choice_set.all %}#}
{#        <li>{{ choice.choice_text }}</li>#}
{#    {% endfor %}#}
{#</ul>#}


<form action="{% url "polls:vote" question.id %}" method="post">
    {% csrf_token %}
    <fieldset>
    
        ...
        
    </fieldset>
    <input type="submit" value="投票">
</form>

# polls/templates/polls/detail.html


<form action="{% url "polls:vote" question.id %}" method="post">
    {% csrf_token %}
    <fieldset>

        <legend><h1>{{ question.question_text }}</h1></legend>

        {% if error_message  %}
            <strong><p>{{ error_message }}</p></strong>
        {% endif %}

        {% for choice in question.choice_set.all %}
            <input type="radio" name="choice" id="choice{{ forloop.counter }}" value="{{ choice.id }}">
            <label for="choice{{ forloop.counter }}">{{ choice.choice_text }}</label>
        {% endfor %}

    </fieldset>
    <input type="submit" value="投票">
</form>

路由

# polls/urls.py

path("<int:question_id>/vote/", views.vote, name="vote"),

视图

vote

# polls/views.py¶

# ...

from django.http import HttpResponseRedirect
from django.urls import reverse

# ...


# def vote(request, question_id):
#     return HttpResponse(f"给问题id:{question_id}投票")

def vote(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    try:
        selected_choice = question.choice_set.get(pk=request.POST["choice"])
    except (KeyError, Choice.DoesNotExist):
        return render(request, "polls/detail.html", {
            "question": question,
            "error_message": "选择为空, 无法提交 ！"
        })
    else:
        selected_choice.votes += 1
        selected_choice.save()
        # 重定向到其他页面 防止误触重复投票
        return HttpResponse(reverse("polls:results", args=(question.id, )))

result

# polls/views.py¶

from django.shortcuts import get_object_or_404, render


def results(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    return render(request, "polls/results.html", {"question": question})

前端

新建文件

# polls/templates/polls/results.html¶

<h1>{{ question.question_text }}</h1>

<ul>
    {% for choice in question.choice_set.all %}
        <li>{{ choice.choice_text }} -- {{ choice.votes }} vote {{ choice.votes|pluralize }}</li>
    {% endfor %}
</ul>

<a href="{% url "polls:detail" question.id %}">继续投票</a>

降低冗余 URLConf

修改url

# mysite/polls/urls.py

from django.urls import path

from . import views

app_name = "polls"

# urlpatterns = [
#
#     path("", views.index, name="index"),
#
#     path("<int:question_id>/", views.detail, name="detail"),
#
#     path("<int:question_id>/results/", views.results, name="results"),
#
#     path("<int:question_id>/vote/", views.vote, name="vote"),
#
#
# ]

urlpatterns = [
    path("", views.IndexView.as_view(), name="index"),
    path("<int:pk>/", views.DeatilView.as_view(), name="detail"),
    path("<int:pl>/results/", views.ResultsViews.as_view(), name="results"),
    path("<int:question_id>/vote/", views.vote, name="vote")
]

修改视图

ListView 和 DetailView 。这两个视图分别抽象“显示一个对象列表”和“显示一个特定类型对象的详细信息页面”这两种概念。

每个通用视图需要知道它将作用于哪个模型。 这由 model 属性提供。

template_name 属性是用来告诉 Django 使用一个指定的模板名字，而不是自动生成的默认名字。

自动生成的 context 变量是 question_list。为了覆盖这个行为，我们提供 context_object_name 属性，表示我们想使用 latest_question_list。作为一种替换方案，

# polls/views.py

from django.urls import reverse
# ...

# def index(request):
#     latest_question_list = Question.objects.order_by("-pub_date")[:5]
#
#     template = loader.get_template("polls/index.html")
#     context = {
#         "latest_question_list": latest_question_list,
#     }
#
#     return HttpResponse(template.render(context, request))

# 用Django 通用视图 重写index, detail, results视图


class IndexView(generic.ListView):
    template_name = "polls/index.html"
    context_object_name = "latest_question_list"
    
    def get_queryset(self):
        """返回最近的 5 个投票问题"""
        return Question.objects.order_by("-pub_date")[:5]

    
class DetailView(generic.DetailView):
    model = Question
    template_name = "polls/detail.html"


class ResultsView(generic.DetailView):
    model = Question
    template_name = "polls/detail.html"
    
    

# def detail(request, question_id):
#     # try:
#     #     question = Question.objects.get(pk=question_id)
#     #
#     # except:
#     #     raise Http404("问题不存在 !")
# 
#     # return HttpResponse(f"当前问题id：{question_id}")
# 
#     question = get_object_or_404(Question, pk=question_id)
#     return render(request, "polls/detail.html", {"question": question})
# 
# 
# # def results(request, question_id):
# #     return HttpResponse(f"问题id：{question_id}的投票结果")
# 
# def results(request, question_id):
#     question = get_object_or_404(Question, pk=question_id)
#     return render(request, "polls/results.html", {"question": question})


# def vote(request, question_id):
#     return HttpResponse(f"给问题id:{question_id}投票")

3.投票-5自动化测试 模型

自动化测试

一个bug

当设定发布时间为很远的未来的时间时，函数.was_published_recently()竟然返回True

$ python manage.py shell

>>> import datetime
>>> from django.utils import timezone
>>> from polls.models import Question
>>> # create a Question instance with pub_date 30 days in the future
>>> future_question = Question(pub_date=timezone.now() + datetime.timedelta(days=30))
>>> # was it published recently?
>>> future_question.was_published_recently()
True

编写测试用例

针对上面的bug写个脚本，用来测试这个bug

# polls/tests.py

import datetime

from django.test import TestCase
from django.utils import timezone

from .models import Question


class QuestionModelTests(TestCase):

    def test_was_published_recently_with_future_question(self):
        """
        was_published_recently() returns False for questions whose pub_date
        is in the future.
        """
        time = timezone.now() + datetime.timedelta(days=30)
        future_question = Question(pub_date=time)
        self.assertIs(future_question.was_published_recently(), False)

我们创建了一个 django.test.TestCase 的子类，并添加了一个方法，此方法创建一个 pub_date 时未来某天的 Question 实例。然后检查它的 was_published_recently() 方法的返回值——它 应该 是 False。

运行

# python manage.py test polls

(venv) E:PYTHONCODEmysite>
(venv) E:PYTHONCODEmysite>python manage.py test polls
Found 1 test(s).
Creating test database for alias "default"...
System check identified no issues (0 silenced).
E
======================================================================
ERROR: test_was_published_recently_with_future_questsion (polls.tests.QuestionModelTests)
当日期为 未来 时间时 was_published_recently() 应该返回 False
----------------------------------------------------------------------
Traceback (most recent call last):
  File "E:PYTHONCODEmysitepolls	ests.py", line 16, in test_was_published_recently_with_future_questsion
    time = timezone.now() + datetime.timedelta(day=30)
TypeError: "day" is an invalid keyword argument for __new__()

----------------------------------------------------------------------
Ran 1 test in 0.001s

FAILED (errors=1)
Destroying test database for alias "default"...

(venv) E:PYTHONCODEmysite>

修复Bug

限制下界为当前

# mysite/polls/models.py

#...

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField("date published")

    def __str__(self):
        return self.question_text

    # def was_published_recently(self):
    #
    #     return self.pub_date >= timezone.now()-datetime.timedelta(days=1)
    def was_published_recently(self):
        now = timezone.now()
        # 发布时间比现在小 比一天之前大 （即最近一天发布）
        return now - datetime.timedelta(days=1) <= self.pub_date <= now
        
#...

测试其他时间段情况

class QuestionModelTests(TestCase):

    def test_was_published_recently_with_future_question(self):
        """
        当日期为 未来 时间时 was_published_recently() 应该返回 False
        """
        time = timezone.now() + datetime.timedelta(days=30)
        future_question = Question(pub_date=time)
        self.assertIs(future_question.was_published_recently(), False)

    def test_was_published_recently_with_recent_question(self):
        """
        当日期为 最近 时间时 was_published_recently() 应该返回 False
        """
        time = timezone.now() - datetime.timedelta(hours=23, minutes=59, seconds=59)
        future_question = Question(pub_date=time)
        self.assertIs(future_question.was_published_recently(), True)

    def test_was_published_recently_with_old_question(self):
        """
        当日期为 过去（至少一天前） 时间时 was_published_recently() 应该返回 False
        """
        time = timezone.now() + datetime.timedelta(days=1, seconds=1)
        future_question = Question(pub_date=time)
        self.assertIs(future_question.was_published_recently(), False)

运行

Microsoft Windows [版本 10.0.22000.978]
(c) Microsoft Corporation。保留所有权利。
(venv) E:PYTHONCODEmysite>python manage.py polls test
Unknown command: "polls"
Type "manage.py help" for usage.

(venv) E:PYTHONCODEmysite>python manage.py test polls
Found 3 test(s).
Creating test database for alias "default"...
System check identified no issues (0 silenced).
...
----------------------------------------------------------------------
Ran 3 tests in 0.002s

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

(venv) E:PYTHONCODEmysite>

3.投票-6自动化测试 视图

Client 一个工具

这个很像我之前学过的，requests

但他更细节更贴合Django的视图，它可以直接捕获视图函数传过来的参数

Microsoft Windows [版本 10.0.22000.978]
(c) Microsoft Corporation。保留所有权利。

(venv) E:PYTHONCODEmysite>python manage.py shell
Python 3.9.1 (tags/v3.9.1:1e5d33e, Dec  7 2020, 17:08:21) [MSC v.1927 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>>
>>>
>>> from django.test.utils import setup_test_environment
>>>
>>> setup_test_environment()
>>>
>>>
>>> from django.test import Client
>>>
>>> client = Client()
>>>
>>> r = client.get("/")
Not Found: /
>>>
>>> r.status_code
404
>>>
>>> from django.urls import reverse
>>>
>>> r = client.get(reverse("polls:index"))
>>>
>>> r .status_code
200
>>>
>>>
>>>
>>>
>>>
>>> r.content
b"
  <ul>
    
        <li>
          <a href="/polls/5/">Django is nice?</a>
        </li>
    
        <li>
          <a href="/polls/4/">I love Lisa.</a>
        </li>
    
n        <li>
          <a href="/polls/3/">do you lik ch best?</a>
        </li>
    
        <li>
          <a href="/polls/2/">are you okay?</a>
        </li>
    
        <li
>
          <a href="/polls/1/">are you kidding me ?</a>
        </li>
    
  </ul>

"
>>>
>>>
>>>
>>>
>>>
>>> r.context["latest_question_list"]
<QuerySet [<Question: Django is nice?>, <Question: I love Lisa.>, <Question: do you lik ch best?>, <Question: are you okay?>, <Question: are you kidding me ?>]>
>>>
>>>

一个 Bug

按照逻辑，当投票发布时间是未来时，视图应当忽略这些投票

修复 Bug

# polls/views.py

class IndexView(generic.ListView):
    template_name = "polls/index.html"
    context_object_name = "latest_question_list"

    def get_queryset(self):
        """返回最近的 5 个投票问题"""
        #return Question.objects.order_by("-pub_date")[:5]
        return Question.objects.filter(pub_date__lte=timezone.now()).order_by("-pub_date")[:5]

测试用例

写个投票脚本，用于产生数据

# polls/test.py

def create_question(question_text, days):
    """
    一个公用的快捷函数用于创建投票问题
    """
    time = timezone.now() + datetime.timedelta(days=days)
    return Question.objects.create(question_text=question_text, pub_date=time)

测试类

class QuestionIndexViewTests(TestCase):
    def test_no_questions(self):
        """
        不存在 questions 时候 显示
        """
        res = self.client.get(reverse("polls:index"))
        self.assertEqual(res.status_code, 200)
        #self.assertContains(res, "没有【正在进行】的投票。")  # 是否显示“没有【正在进行】的投票。”字样
        self.assertQuerysetEqual(res.context["latest_question_list"], [])

    def test_past_question(self):
        """
        发布时间是 past 的 question 显示到首页
        """
        question = create_question(question_text="Past question.", days=-30)
        res = self.client.get(reverse("polls:index"))
        self.assertQuerysetEqual(
            res.context["latest_question_list"],
            [question],
        )

    def test_future_question(self):
        """
        发布时间是 future 不显示
        """
        create_question(question_text="未来问题!", days=30)
        res = self.client.get(reverse("polls:index"))
        #self.assertContains(res, "没有【可用】的投票")
        self.assertQuerysetEqual(res.context["latest_question_list"], [])

    def test_future_question_and_past_question(self):
        """
        存在 past 和 future 的 questions 仅仅显示 past
        """
        question = create_question(question_text="【过去】问题！", days=-30)
        create_question(question_text="【未来】问题！", days=30)
        response = self.client.get(reverse("polls:index"))
        self.assertQuerysetEqual(
            response.context["latest_question_list"],
            [question],
        )

    def test_two_past_question(self):
        """
        首页可能展示 多个 questions
        """
        q1 = create_question(question_text="过去 问题 1", days=-30)
        q2 = create_question(question_text="过去 问题 2", days=-5)
        res = self.client.get(reverse("polls:index"))
        self.assertQuerysetEqual(
            res.context["latest_question_list"],
            [q2, q1],
        )

运行

(venv) E:PYTHONCODEmysite>
(venv) E:PYTHONCODEmysite>python manage.py test polls
Found 8 test(s).
Creating test database for alias "default"...
System check identified no issues (0 silenced).
........
----------------------------------------------------------------------
Ran 8 tests in 0.030s

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

(venv) E:PYTHONCODEmysite>

3.投票-7自动化测试 业务逻辑

一个bug

发布日期时未来的那些投票不会在目录页 index 里出现，但是如果用户知道或者猜到正确的 URL ，还是可以访问到它们。所以我们得在 DetailView 里增加一些约束：

修复

加强限制，搜寻结果只返回时间小于当前的投票

# polls/views.py

class DetailView(generic.DetailView): 
    ...
    def get_queryset(self):
        """
        Excludes any questions that aren"t published yet.
        """
        return Question.objects.filter(pub_date__lte=timezone.now())

测试用例

检验

# polls/tests.py

class QuestionDetailViewTests(TestCase):
    def test_future_question(self):
        """
        The detail view of a question with a pub_date in the future
        returns a 404 not found.
        """
        future_question = create_question(question_text="Future question.", days=5)
        url = reverse("polls:detail", args=(future_question.id,))
        response = self.client.get(url)
        self.assertEqual(response.status_code, 404)

    def test_past_question(self):
        """
        The detail view of a question with a pub_date in the past
        displays the question"s text.
        """
        past_question = create_question(question_text="Past Question.", days=-5)
        url = reverse("polls:detail", args=(past_question.id,))
        response = self.client.get(url)
        self.assertContains(response, past_question.question_text)

3.投票-8应用的界面和风格

a 标签

新建 mysite/polls/static 目录 ，写入下面的文件

static/        #框架会从此处收集所有子应用静态文件 所以需要建一个新的polls目录区分不同应用
  polls/       #所以写一个重复的polls很必要 否则Django直接使用找到的第一个style.css
    style.css   
   

定义 a 标签

# /style.css

li a{
    color: green;
}

背景图

新建 images 目录

static/        #框架会从此处收集所有子应用静态文件 所以需要建一个新的polls目录区分不同应用
  polls/
    style.css   
    images/
      bg.jpg

定义 背景

# /style.css

li a{
    color: green;
}

body {
    background: white url("images/bg.jpg") no-repeat;
}

效果

3.投票-9自定义后台表单

字段顺序

替换注释部分

# /mysite/polls/templates/admin.py


# admin.site.register(Question)


class QuestionAdmin(admin.ModelAdmin):
    fields = ["question_text", "pub_date"]  # 列表里的顺序 表示后台的展示顺序

admin.site.register(Question,QuestionAdmin)

效果

字段集

当字段比较多时，可以把多个字段分为几个字段集

注意变量 fields 变为 fieldsets

class QuestionAdmin(admin.ModelAdmin):
    #fields = ["question_text", "pub_date"]  # 列表里的顺序 表示后台的展示顺序
    fieldsets = [
        (None, {"fields": ["question_text"]}),
        ("日期信息", {"fields": ["pub_date"]}),

    ]

效果

关联选项

这样可以在创建 question 时 同时创建 choice

# /mysite/polls/templates/admin.py

效果

让卡槽更紧凑

替换 StackedInline 为 TabularInline

#class ChoiceInline(admin.StackedInline):
class ChoiceInline(admin.TabularInline):
    model = Choice
    extra = 3  # 默认有三个卡槽 后面还可以点击增加

效果

展示question的更多字段

Django默认返回模型的 str 方法里写的内容

添加字段 list_display 让其同时展示更多

方法was_published_recently 和他的返回内容 也可以当做字段展示

# mysite/polls/templates/admin.py

# class QuestionAdmin(admin.ModelAdmin):
#     # fields = ["question_text", "pub_date"]  # 列表里的顺序 表示后台的展示顺序
#     fieldsets = [
#         (None, {"fields": ["question_text"]}),
#         ("日期信息", {"fields": ["pub_date"]}),

#     ]
    
#     inlines = [ChoiceInline]  # 引用模型

    list_display = ("question_text", "pub_date", "was_published_recently")

效果 点击还可以按照该字段名排序

3.投票-9自定义后台表单-2

用装饰器优化 方法 的显示

方法 was_published_recently 默认用空格替换下划线展示字段

用装饰器优化一下

# /mysite/polls/templates/models.py

from django.contrib import admin  # 装饰器

class Question(models.Model):
    #....

    @admin.display(
            boolean=True,
            ordering="pub_date",
            description="最近发布的吗 ?",
        )
    def was_published_recently(self):
        now = timezone.now()
        # 发布时间距离现在不超过24小时 比现在小 比一天之前大 （即最近一天发布）

        return (now - datetime.timedelta(days=1)) <= self.pub_date <= now

效果

添加过滤器

添加一个 list_filter 字段即可

# mysite/polls/templates/admin.py

# class QuestionAdmin(admin.ModelAdmin):
#     # fields = ["question_text", "pub_date"]  # 列表里的顺序 表示后台的展示顺序
#     fieldsets = [
#         (None, {"fields": ["question_text"]}),
#         ("日期信息", {"fields": ["pub_date"]}),

#     ]

#     inlines = [ChoiceInline]  # 引用模型

#     list_display = ("question_text", "pub_date", "was_published_recently")

    list_filter = ["pub_date"]  # 过滤器
    
    

效果

检索框

同上

#...
search_fields = ["question_text", "pub_date"]  # 检索框 可添加多个字段

效果

3.投票-10自定义后台风格界面

改掉 “Django 管理”

自定义工程模板（就是在manage.py的同级目录哪里） 再建一个templates

/mysite
  /templates  # 新建

修改 mysite/settings.py DIR是一个待检索路径 在django启动时加载

把所有模板文件存放在同一个templates中也可以 但分开会方便以后扩展复用代码

 #...

# TEMPLATES = [
#     {
#         "BACKEND": "django.template.backends.django.DjangoTemplates",
        #"DIRS": [],
        "DIRS": [BASE_DIR / "templates"],
#         "APP_DIRS": True,
#         "OPTIONS": {
#             "context_processors": [
#                 "django.template.context_processors.debug",
#                 "django.template.context_processors.request",
#                 "django.contrib.auth.context_processors.auth",
#                 "django.contrib.messages.context_processors.messages",
#             ],
#         },
#     },
# ]

新建一个admin文件夹 复制 base_site.html 复制到里面

base_site.html 是django默认的模板 它存放在 django/contrib/admin/templates 的 admin/base_site.html 里面

可以用 ...> py -c "import django; print(django.__path__)"命令查找源文件django位置

/mysite
  /templates  # 新建
    /admin   # 新建
      base_site.html  # 本地是到E:PYTHONCODEStudyBuddyvenvLibsite-packages
                      #     djangocontribadmin	emplatesadmin            复制
  

修改 base_site.html 内容

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

<!--{% block title %}{% if subtitle %}{{ subtitle }} | {% endif %}{{ title }} | {{ site_title|default:_("Django site admin") }}{% endblock %}-->

<!--{% block branding %}-->
<!--<h1 id="site-name"><a href="{% url "admin:index" %}">{{ site_header|default:_("Django administration") }}</a></h1>-->
<h1 id="site-name"><a href="{% url "admin:index" %}">投票 管理</a></h1>
<!--{% endblock %}-->

<!--{% block nav-global %}{% endblock %}-->

效果

注意，所有的 Django 默认后台模板均可被复写。若要复写模板，像你修改 base_site.html 一样修改其它文件——先将其从默认目录中拷贝到你的自定义目录，再做修改

当然 也可以用 django.contrib.admin.AdminSite.site_header 来进行简单的定制。

自定义 子应用 的模板

机智的同学可能会问： DIRS 默认是空的，Django 是怎么找到默认的后台模板的？因为 APP_DIRS 被置为 True，Django 会自动在每个应用包内递归查找 templates/ 子目录（不要忘了 django.contrib.admin 也是一个应用）。

我们的投票应用不是非常复杂，所以无需自定义后台模板。不过，如果它变的更加复杂，需要修改 Django 的标准后台模板功能时，修改 应用 的模板会比 工程 的更加明智。这样，在其它工程包含这个投票应用时，可以确保它总是能找到需要的自定义模板文件。

更多关于 Django 如何查找模板的文档，参见 加载模板文档。

自定义 后台 首页的模板

同之前base_site.html

复制 E:PYTHONCODEStudyBuddyvenvLibsite-packagesdjangocontribadmin emplatesadminindex.html

到mysite/templates/admin/index.html 直接修改

结束 撒花！ ：）