4.用户账户

4.1 让用户能够输入数据

添加新主题

# untitled/learning_logs/forms.py
from django import formsfrom .models import Topic, Entryclass TopicForm(forms.ModelForm):class Meta:model = Topicfields = ['text']labels = {'text':''}

"""定义learning_logs的URL模式"""
# untitled/learning_logs/urls.py
from django.conf.urls import urlfrom . import viewsapp_name = 'learning_logs'urlpatterns = [# 主页url(r'^$', views.index, name='index'),url(r'^topics/$', views.topics, name='topics'),url(r'^topics/(?P<topic_id>\d+)/$', views.topic, name='topic'),url(r'^new_topic/$', views.new_topic, name='new_topic'),
]

# untitled/learning_logs/views.py
from django.http import HttpResponseRedirect
from django.shortcuts import render
from django.urls import reversefrom learning_logs.forms import TopicForm
from learning_logs.models import Topic#···def new_topic(request):"""添加新主题"""if request.method != 'POST':form = TopicForm()else:form = TopicForm(request.POST)if form.is_valid():form.save()return HttpResponseRedirect(reverse('learning_logs:topics'))context = {'form':form}return render(request, 'learning_logs/new_topic.html', context)#···

<!-- untitled/templates/learning_logs/new_topic.html -->
{% extends "learning_logs/base.html" %}{% block content %}<p>Add a new topic:</p><form action="{% url 'learning_logs:new_topic' %}" method='post'>{% csrf_token %}{{ form.as_p }}<button name="submit">add topic</button></form>{% endblock content %}

添加新条目
（略）
编辑新条目
（略）

4.2 创建用户账户

应用程序users

# untitled/untitled/settings.py
# ···
INSTALLED_APPS = ['django.contrib.admin','django.contrib.auth','django.contrib.contenttypes','django.contrib.sessions','django.contrib.messages','django.contrib.staticfiles',# 我的应用程序'learning_logs','users'
]# ···

# untitled/untitled/urls.py
from django.contrib import admin
from django.urls import path
from django.conf.urls import include, urlurlpatterns = [path('admin/', admin.site.urls),url(r'^users/', include('users.urls', namespace='users')),url(r'', include('learning_logs.urls', namespace='learning_logs')),
]

4.2.1 登录

由于Django版本的问题，下面的URL模式跟《Python编程从入门到实践》的示例有点不一样。

"""为应用程序users定义URL模式"""
# untitled/users/urls.py
from django.contrib.auth.views import LoginView
from django.urls import pathapp_name = 'users'urlpatterns = [path('login/', LoginView.as_view(template_name='users/login.html'), name="login"),
]

<!-- untitled/templates/users/login.html -->
{% extends "learning_logs/base.html" %}{% block content %}{% if form.errors %}<p>Your username and password didn't match. Please try again.</p>{% endif %}<form method="post" action="{% url 'users:login' %}">{% csrf_token %}{{ form.as_p }}<button name="submit">log in</button><input type="hidden" name="next" value="{% url 'learning_logs:index' %}" /></form>{% endblock content %}

<!-- untitled/templates/learning_logs/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 }}.{% else %}<a href="{% url 'users:login' %}">log in</a>{% endif %}
</p>{% block content %}{% endblock %}

4.2.2 注销

# untitled/users/urls.py
from django.contrib.auth.views import LoginView
from django.urls import path
from django.conf.urls import urlfrom . import viewsapp_name = 'users'urlpatterns = [path('login/', LoginView.as_view(template_name='users/login.html'), name="login"),url(r'^logout/$', views.logout_view, name='logout'),
]

注意下面导入的是from django.urls import reverse，而不是from django.core.urlresolvers import reverse。

# untitled/users/views.py
from django.http import HttpResponseRedirect
from django.urls import reverse
from django.contrib.auth import logoutdef logout_view(request):"""Log the user out."""logout(request)return HttpResponseRedirect(reverse('learning_logs:index'))

4.2.3 注册

# untitled/users/views.py
from django.contrib.auth.forms import UserCreationForm
from django.http import HttpResponseRedirect
from django.shortcuts import render
from django.urls import reverse
from django.contrib.auth import logout, authenticate, login# ···def register(request):if request.method != 'POST':form = UserCreationForm()else:form = UserCreationForm(data=request.POST)if form.is_valid():new_user = form.save()authenticated_user = authenticate(username=new_user.username, password=request.POST['password1'])login(request, authenticated_user)return HttpResponseRedirect(reverse('learning_logs:index'))context = {'form':form}return render(request, "users/register.html", context)

<!-- untitled/templates/users/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 %}

4.3 让用户拥有自己的数据

使用@login_required限制访问

# untitled/learning_logs/views.py
from django.contrib.auth.decorators import login_required
from django.http import HttpResponseRedirect
from django.shortcuts import render# ···@login_required
def topics(request):topics = Topic.objects.order_by('date_added')context = {'topics' : topics}return render(request, 'learning_logs/topics.html', context)# ···

# untitled/untitled/settings.py# ···LOGIN_URL = '/users/login/'

将数据关联到用户
注意这行代码owner = models.ForeignKey('auth.User', on_delete=models.CASCADE)的写法。

# untitled/learning_logs/models.py
from django.db import models
from django.contrib.auth.models import Userclass Topic(models.Model):"""A topic the user is learning about."""text = models.CharField(max_length=200)date_added = models.DateTimeField(auto_now_add=True)owner = models.ForeignKey('auth.User', on_delete=models.CASCADE)def __str__(self):"""Return a string representation of the model."""return self.text

我们迁移数据库时，Django将对数据库进行修改，使其能够存储主题和用户之间的关联。
执行python manage.py makemigrations learning_logs时，我们为外键值指定默认值。

只允许用户访问自己的主题

# untitled/learning_logs/views.py# ···@login_required
def topics(request):topics = Topic.objects.filter(owner=request.user).order_by('date_added')context = {'topics' : topics}return render(request, 'learning_logs/topics.html', context)# ···

保护用户的主题

# untitled/learning_logs/views.py# ···@login_required
def topic(request, topic_id):topic = Topic.objects.get(id=topic_id)if topic.owner != request.user:raise Http404entries = topic.entry_set.order_by('-date_added')context = {'topic': topic, 'entries': entries}return render(request, 'learning_logs/topic.html', context)# ···

保护页面edit_entry

# untitled/learning_logs/views.py# ···@login_required
def edit_entry(request, entry_id):"""Edit an existing entry."""entry = Entry.objects.get(id=entry_id)topic = entry.topicif topic.owner != request.user:raise Http404if request.method != 'POST':# Initial request; pre-fill form with the current entry.form = EntryForm(instance=entry)else:# POST data submitted; process data.form = EntryForm(instance=entry, data=request.POST)if form.is_valid():form.save()return HttpResponseRedirect(reverse('learning_logs:topic',args=[topic.id]))context = {'entry': entry, 'topic': topic, 'form': form}return render(request, 'learning_logs/edit_entry.html', context)

将新主题关联到当前用户

# untitled/learning_logs/views.py# ···@login_required
def new_topic(request):"""添加新主题"""if request.method != 'POST':form = TopicForm()else:form = TopicForm(request.POST)if form.is_valid():new_topic = form.save(commit=False)new_topic.owner = request.usernew_topic.save()return HttpResponseRedirect(reverse('learning_logs:topics'))context = {'form':form}return render(request, 'learning_logs/new_topic.html', context)# ···

参考资料：《Python编程从入门到实践》—【美】Eric Matthes 著