from django.contrib import admin
from django.urls import path
from login import views

urlpatterns = [
    path('admin/', admin.site.urls),
    path('index/', views.index),
    path('login/', views.login),
    path('register/', views.register),
    path('logout/', views.logout),
]

from django.db import models

# Create your models here.


class User(models.Model):

    gender = (
        ('male', "男"),
        ('female', "女"),
    )

    name = models.CharField(max_length=128, unique=True)
    password = models.CharField(max_length=256)
    email = models.EmailField(unique=True)
    sex = models.CharField(max_length=32, choices=gender, default="男")
    c_time = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.name

    class Meta:
        ordering = ["-c_time"]
        verbose_name = "用戶"
        verbose_name_plural = "用戶"

def login(request):
    if request.session.get('is_login', None):  # 不允許重復(fù)登錄
        return redirect('/index/')
    if request.method == 'POST':
        login_form = forms.UserForm(request.POST)   #上一次填寫了這個(gè)表單,所以從這里得到這個(gè)表單的數(shù)據(jù)
        message = '請(qǐng)檢查填寫的內(nèi)容！'
        if login_form.is_valid():
            username = login_form.cleaned_data.get('username')
            password = login_form.cleaned_data.get('password')

            try:
                user = models.User.objects.get(name=username)
            except :
                message = '用戶不存在！'
                return render(request, 'login/login.html', locals())

            if user.password == password:   #如果用戶名和密碼都成功
                # 往session字典內(nèi)寫入用戶狀態(tài)和數(shù)據(jù)：
                request.session['is_login'] = True  #is_login=True表示成功登陸
                request.session['user_id'] = user.id
                request.session['user_name'] = user.name
                return redirect('/index/')  #重定向到主頁(yè)
            else:
                message = '密碼不正確！'
                return render(request, 'login/login.html', locals())
        else:
            return render(request, 'login/login.html', locals())

    # 不是POST的話，統(tǒng)統(tǒng)轉(zhuǎn)去login.html
    login_form = forms.UserForm()
    return render(request, 'login/login.html', locals())

!doctype html>
html lang="en">
  head>
    !-- Required meta tags -->
    meta charset="utf-8">
    meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    !-- 上述meta標(biāo)簽*必須*放在最前面，任何其他內(nèi)容都*必須*跟隨其后！ -->
    !-- Bootstrap CSS -->
    link  rel="stylesheet">
    title>登錄/title>
  /head>
  body>
    div class="container">
            div class="col">
                form class="form-login" action="/login/" method="post">
                  {% if message %}
                    div class="alert alert-warning">{{ message }}/div>
                  {% endif %}
                  {% csrf_token %}
                  h3 class="text-center">歡迎登錄/h3>

                  {{ login_form }}

                  div>
                      a href="/register/" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" class="text-success " >ins>新用戶注冊(cè)/ins>/a>
                      button type="submit" class="btn btn-primary float-right">登錄/button>
                  /div>
                /form>
            /div>
    /div> !-- /container -->

    !-- Optional JavaScript -->
    !-- jQuery first, then Popper.js, then Bootstrap JS -->
    {#    以下三者的引用順序是固定的#}
    script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.js">/script>
    script src="https://cdn.bootcss.com/popper.js/1.15.0/umd/popper.js">/script>
    script src="https://cdn.bootcss.com/twitter-bootstrap/4.3.1/js/bootstrap.min.js">/script>

  /body>
/html>

def index(request):
    if not request.session.get('is_login', None):   #如果不在登陸狀態(tài),就重定向到login
        return redirect('/login/')
    return render(request, 'login/index.html')  #如果在登陸狀態(tài),就進(jìn)入index.html的模板文件

!DOCTYPE html>
    !-- Optional JavaScript -->
    !-- jQuery first, then Popper.js, then Bootstrap JS -->
    {#    以下三者的引用順序是固定的#}
    script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.js">/script>
    script src="https://cdn.bootcss.com/popper.js/1.15.0/umd/popper.js">/script>
    script src="https://cdn.bootcss.com/twitter-bootstrap/4.3.1/js/bootstrap.min.js">/script>
​
  /body>
/html>

def index(request):
    if not request.session.get('is_login', None):   #如果不在登陸狀態(tài),就重定向到login
        return redirect('/login/')
    return render(request, 'login/index.html')  #如果在登陸狀態(tài),就進(jìn)入index.html的模板文件

html lang="en">
head>
    meta charset="UTF-8">
    title>首頁(yè)/title>
/head>
body>
h1>{{ request.session.user_name }}!  歡迎回來(lái)！/h1>
p>
    a href="/logout/">登出/a>
/p>
/body>
/html>

def logout(request):    #登出
    if not request.session.get('is_login', None):   #如果不在登陸狀態(tài),就直接轉(zhuǎn)發(fā)到登陸界面
        # 如果本來(lái)就未登錄，也就沒(méi)有登出一說(shuō)
        return redirect("/login/")

    request.session.flush() #清空session
    # 或者使用下面的方法
    # del request.session['is_login']
    # del request.session['user_id']
    # del request.session['user_name']
    return redirect("/login/")  #重定向到login界面