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:\PYTHON\0CODE\mysite>
E:\PYTHON\0CODE\mysite>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

# 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:\PYTHON\0CODE\mysite>python manage.py makemigrations polls
Migrations for 'polls':
  polls\migrations\0001_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:\PYTHON\0CODE\mysite>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:\PYTHON\0CODE\mysite>python manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, polls, sessions
Running migrations:
  Applying polls.0001_initial... OK

(venv) E:\PYTHON\0CODE\mysite>

API 的初体验

进入shell
```
python manage.py shell
```

增

- (venv) E:\PYTHON\0CODE\mysite>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:\PYTHON\0CODE\mysite>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:\PYTHON\0CODE\StudyBuddy\venv\lib\site-packages\django\db\models\manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "E:\PYTHON\0CODE\StudyBuddy\venv\lib\site-packages\django\db\models\query.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:\PYTHON\0CODE\StudyBuddy\venv\lib\site-packages\django\db\models\fields\related_descriptors.py", line 747, in create
    return super(RelatedManager, self.db_manager(db)).create(**kwargs)
  File "E:\PYTHON\0CODE\StudyBuddy\venv\lib\site-packages\django\db\models\manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "E:\PYTHON\0CODE\StudyBuddy\venv\lib\site-packages\django\db\models\query.py", line 512, in create
    obj = self.model(**kwargs)
  File "E:\PYTHON\0CODE\StudyBuddy\venv\lib\site-packages\django\db\models\base.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:\PYTHON\0CODE\mysite>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:\PYTHON\0CODE\mysite>
(venv) E:\PYTHON\0CODE\mysite>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:\PYTHON\0CODE\mysite\polls\tests.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:\PYTHON\0CODE\mysite>

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:\PYTHON\0CODE\mysite>python manage.py polls test
Unknown command: 'polls'
Type 'manage.py help' for usage.

(venv) E:\PYTHON\0CODE\mysite>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:\PYTHON\0CODE\mysite>

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:\PYTHON\0CODE\mysite>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'\n  <ul>\n    \n        <li>\n          <a href="/polls/5/">Django is nice?</a>\n        </li>\n    \n        <li>\n          <a href="/polls/4/">I love Lisa.</a>\n        </li>\n    \
n        <li>\n          <a href="/polls/3/">do you lik ch best?</a>\n        </li>\n    \n        <li>\n          <a href="/polls/2/">are you okay?</a>\n        </li>\n    \n        <li
>\n          <a href="/polls/1/">are you kidding me ?</a>\n        </li>\n    \n  </ul>\n\n'
>>>
>>>
>>>
>>>
>>>
>>> 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:\PYTHON\0CODE\mysite>
(venv) E:\PYTHON\0CODE\mysite>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:\PYTHON\0CODE\mysite>

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:\PYTHON\0CODE\StudyBuddy\venv\Lib\site-packages\
                      #     django\contrib\admin\templates\admin            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