《python编程从入门到实践》day40

# 昨日知识点回顾

编辑条目及创建用户账户

暂没能解决bug：

The view learning_logs.views.edit_entry didn't return an HttpResponse object. It returned None instead.

# 今日知识点学习

19.2.5 注销

提供让用户注销的途径

1.在base.html中添加注销链接

# base.html
<p><a href = "{% url 'learning_logs:index' %}">Learning Log</a> -<a href = "{% url 'learning_logs:topics' %}">Topics</a> -{% if user.is_authenticated %}Hello, {{ user.username }}.<a href="{% url 'users:logout' %}">Log out</a>{% else %}<a href="{% url 'users:login' %}">Log in </a>{% endif %}
</p>{% block content %}{% endblock content %}

2.注销确认页面

# learning_log\users\templates\registration\logged_out.html
{% extends "learning_logs/base.html" %}{% block content %}<p>You have been logged out. Thank you for visiting!</p>
{% endblock content %}

19.2.6 注册页面

1.注册页面的URL模式

# users\urls.py
"""为应用程序users定义URL模式"""from django.urls import path, includefrom . import viewsapp_name = 'users'
urlpatterns = [# 包含默认的身份验证URLpath('', include('django.contrib.auth.urls')),# 注册页面path('register/', views.register, name='register')
]

2.视图函数register()

# # users\views.py
from django.shortcuts import render, redirect
from django.contrib.auth import login
from django.contrib.auth.forms import UserCreationForm# Create your views here.
def register(request):"""注册新用户"""if request.method != 'POST':# 显示空的注册表单form = UserCreationForm()else:# 处理填写好的表单form = UserCreationForm(data=request.POST)if form.is_valid():new_user = form.save()# 让用户自动登录，再重定向主页login(request, new_user)return redirect('learning_logs:index')# 显示空表单或指出表单无效context = {'form': form}return render(request, 'registration/register.html', context)

3.注册模版

# users\templates\registration\register.html
{% extends "learning_logs/base.html" %}{% block content %}<form method='post' action="{% url 'users:register' %}" >{% csrf_token %}{{  form.as_p  }}<button name="submit">Register</button><input type="hidden" name="next"value="{% url 'learning_logs:index' %}"  />		</form>{% endblock content %}

4.链接到注册页面

# base.html
<p><a href = "{% url 'learning_logs:index' %}">Learning Log</a> -<a href = "{% url 'learning_logs:topics' %}">Topics</a> -{% if user.is_authenticated %}Hello, {{ user.username }}.<a href="{% url 'users:logout' %}">Log out</a>{% else %}<a href="{% url 'users:register' %}">Register </a>-<a href="{% url 'users:login' %}">Log in </a>{% endif %}
</p>{% block content %}{% endblock content %}

19.3 让用户拥有自己的数据

19.3.1 使用@login_required限制访问

装饰器：放在函数定义前面的指令，能在函数运行前修改函数代码

1.限制访问显示所有主题的页面

# learning_logs/views.py
from django.shortcuts import render, redirect
from django.contrib.auth.decorators import login_required# 导入所需数据相关联的模型
from .models import Topic, Entry
from .forms import TopicForm, EntryForm# Create your views here.
def index(request):"""学习笔记的主页"""# 传递两个实参：对象request以及一个可用于创建页面的模版return render(request, 'learning_logs/index.html')@login_required
def topics(request):"""显示所有的主题"""topics = Topic.objects.order_by('date_added')
---snip---

# settings.py
---snip(直到末尾）---# 我的设置
LOGIN_URL = 'users:login'

2.全面限制对项目“学习笔记”的访问

# learning_logs\views.py
from django.shortcuts import render, redirect
from django.contrib.auth.decorators import login_required# 导入所需数据相关联的模型
from .models import Topic, Entry
from .forms import TopicForm, EntryForm# Create your views here.
def index(request):"""学习笔记的主页"""# 传递两个实参：对象request以及一个可用于创建页面的模版return render(request, 'learning_logs/index.html')@login_required
def topics(request):"""显示所有的主题"""topics = Topic.objects.order_by('date_added')# 定义一个将要发送模版的上下文context = {'topics': topics}return render(request, 'learning_logs/topics.html', context)@login_required
def topic(request, topic_id):"""显示单个主题"及所有的条目"""topic = Topic.objects.get(id=topic_id)entries = topic.entry_set.order_by('-date_added')context = {'topic': topic, 'entries': entries}return render(request, 'learning_logs/topic.html', context)@login_required
def new_topic(request):"""添加新主题"""if request.method != 'POST':# 未提交数据：创建一个新表单form = TopicForm()else:# POST提交的数据：对数据进行处理form = TopicForm(data=request.POST)if form.is_valid():form.save()return redirect('learning_logs:topics')# 显示空表单后指出表单数据无效context = {'form': form}return render(request, 'learning_logs/new_topic.html', context)@login_required
def new_entry(request, topic_id):"""在特定主题中添加新条目"""topic = Topic.objects.get(id=topic_id)if request.method != 'POST':# 未提交数据：创建一个空表单form = EntryForm()else:# POST提交的数据：对数据进行处理form = EntryForm(data=request.POST)if form.is_valid():new_entry = form.save(commit=False)new_entry.topic = topicnew_entry.save()return redirect('learning_logs:topic', topic_id=topic_id)# 显示空表单或支出表单数据无效context = {'topic': topic, 'form': form}return render(request, 'learning_logs/new_entry.html', context)@login_required
def edit_entry(request, entry_id):"""编辑既有条目"""entry = Entry.objects.get(id=entry_id)topic = entry.topicif request.method != 'POST':# 初次请求：使用当前条目填充表单form =EntryForm(instance=entry)else:# POST提交的数据：对数据进行处理form = EntryForm(instance=entry, data=request.POST)if form.is_valid():form.save()return redirect('learning_logs:topic', topic_id=topic.id)context = {'entry': entry, 'topic': topic, 'form': form}return render(request, 'learning_logs/edit_entry.html', context)

19.3.2 将数据关联到用户

1.修改模型Topic

# models.py
from django.db import models
from django.contrib.auth.models import User# Create your models here.
class Topic(models.Model):"""用户学习的主题"""# 存储少量文本如名称、标题或城市，预留200字符空间text = models.CharField(max_length=200)# 记录日期和时间的数据，为True自动设置为当前日期和时间date_added = models.DateTimeField(auto_now_add=True)owner = models.ForeignKey(User, on_delete=models.CASCADE)def __str__(self):"""返回模型的字符串表示"""# 只显示条目前50字符，省略号指出显示的并非整个条目return f"{self.text[:50]}..."class Entry(models.Model):"""学到某个主题的具体知识"""topic = models.ForeignKey(Topic, on_delete=models.CASCADE)# 外键(foreign key)是一个数据库术语，它指向数据库另一条记录。# 次联删除：on_delete=models.CASCADE让Django在删除主题的同时删除所有与之相关联的条目text = models.TextField()date_added = models.DateTimeField(auto_now_add=True)class Meta:# 存储用于管理模型的额外信息verbose_name_plural = 'entries'

2. 确定当前有哪些用户

3.迁移数据库

重建数据库：python manage.py flush

19.3.3 只允许用户访问自己的主题

# views.py
---snip---
@login_required
def topics(request):"""显示所有的主题"""topics = Topic.objects.filter(owner=request.user).order_by('date_added')# 定义一个将要发送模版的上下文context = {'topics': topics}return render(request, 'learning_logs/topics.html', context)
---snip---

19.3.4 保护用户的主体

# views.py
from django.shortcuts import render, redirect
from django.contrib.auth.decorators import login_required
from django.http import Http404---snip---@login_required
def topic(request, topic_id):"""显示单个主题"及所有的条目"""topic = Topic.objects.get(id=topic_id)# 确认请求的主题属于当前用户if topic.owner != request.user:raise Http404---snip---

19.3.5 保护页面edit_entry

# views.py
---snip---
@login_required
def edit_entry(request, entry_id):"""编辑既有条目"""entry = Entry.objects.get(id=entry_id)topic = entry.topicif topic.owner != request.user:raise Http404---snip---

19.3.6 将新主题关联到当前用户

# views.py
---snip---
@login_required
def new_topic(request):"""添加新主题"""if request.method != 'POST':# 未提交数据：创建一个新表单form = TopicForm()else:# POST提交的数据：对数据进行处理form = TopicForm(data=request.POST)if form.is_valid():new_topic = form.save(commit=False)new_topic.owner = request.usernew_topic.save()            return redirect('learning_logs:topics')# 显示空表单后指出表单数据无效context = {'form': form}return render(request, 'learning_logs/new_topic.html', context)---snip---