Anaconda+django写出第一个web app（八）

今天来实现网站的登入和登出功能。

首先我们需要在urls.py中添加路径，注意此处的路径和在导航栏中设置的文字路径保持一致：

from django.urls import path
from . import views

app_name = 'main' #此处为了urls的命名空间

urlpatterns = [
    path('', views.homepage, name='homepage'),
    path('register/', views.register, name='register'),
    path('logout/', views.logout_request, name='logout_request'),
    path('login/', views.login_request, name='login_request'),
]

在view.py中添加登出和登入的函数，登出的函数非常简单，只需要使用logout函数登出并给出登出成功的信息，然后导向主页即可。登入函数需要使用新的表单AuthenticationForm，并判断用户是否存在，如果存在则登入并进入主页，如果不存在则给出错误信息：

from django.shortcuts import render, redirect
from django.http import HttpResponse
from .models import Tutorial
from django.contrib.auth.forms import UserCreationForm, AuthenticationForm
from django.contrib.auth import login, logout, authenticate
from django.contrib import messages
# Create your views here.
def homepage(request):
    return render(request=request,
            template_name='main/home.html',
            context={'tutorials':Tutorial.objects.all})

def register(request):
    if request.method == 'POST':
        form = UserCreationForm(request.POST)
        if form.is_valid():
            user = form.save()
            username = form.cleaned_data.get('username')
            messages.success(request, f"New account created: {username}")
            login(request, user)
            return redirect('main:homepage')
        else:
            for msg in form.error_messages:
                messages.error(request, f"{msg}:{form.error_messages[msg]}")

            return render(request=request,
                template_name='main/register.html',
                context={'form':form})

    form = UserCreationForm
    return render(request=request,
            template_name='main/register.html',
            context={'form':form})

def logout_request(request):
    logout(request)
    messages.info(request, f"Logged out successfully!")
    return redirect('main:homepage')

def login_request(request):
    if request.method == 'POST':
        form = AuthenticationForm(request=request, data=request.POST)
        if form.is_valid():
            username = form.cleaned_data.get('username')
            password = form.cleaned_data.get('password')
            user = authenticate(username=username, password=password)
            if user is not None:
                login(request, user)
                messages.info(request, f"You are now logged in as {username}")
                return redirect('main:homepage')
            else:
                messages.error(request, f"Invalid username or passowrd.")
        else:
            messages.error(request, f"Invalid username or passowrd.")

    form = AuthenticationForm
    return render(request=request,
            template_name='main/login.html',
            context={'form':form})

登入登出及信息显示如下，第二幅图显示“You are now logged in as xiaohonghong”，这个就是toast的效果：

与之前的几节不同，我在这里修改了导航栏的颜色，并添加了container效果，修改方法如下，通过style设置背景颜色，将container加入到div的class中：

  <nav style="background-color: #008E72">
    <div class="nav-wrapper container">

现在使用的注册表单是materialize默认的，我们希望注册的时候可以加入邮箱这个选项，这样忘记密码的时候就可以通过邮箱来找回密码，如何自定义注册表单呢？方法如下，在main文件夹下新建forms.py：

from django.contrib.auth.forms import UserCreationForm
from django import forms
from django.contrib.auth.models import User

class NewUserForm(UserCreationForm):
    email = forms.EmailField(required=True)

    class Meta:
        model = User
        fields = ("username", "email", "password1", "password2")

    def save(self, commit=True):
        user = super(NewUserForm, self).save(commit=False)
        user.email = self.cleaned_data.get('email')
        if commit:
            user.save()
        return user

然后将views.py中的UserCreationForm修改为NewUserForm即可，在浏览器点击Register得到如下界面，可以看到email这一样出现了：

参考链接：

[1] https://pythonprogramming.net/user-login-logout-django-tutorial/?completed=/messages-django-tutorial/