Django 小实例S1 简易学生选课管理系统 6 实现登录逻辑

Django 小实例S1 简易学生选课管理系统 第6节——实现登录逻辑
点击查看教程总目录
作者自我介绍：b站小UP主，时常直播编程+红警三，python1对1辅导老师。

1 业务逻辑

本教程第四节里面实现了登录页面和一个空的登录逻辑。
第六节这里就把登录逻辑补全。

登录的业务逻辑是：

• 检查是否注册
• 未注册，则提示账号不存在
• 注册但密码不匹配，提示密码不正确
• 注册且信息匹配，成功登录，跳转到个人主页，同时通过cookie保存登录信息。

对于教务管理系统，个人主页应该是其课程主页，所以本部分还需要添加课程主页，这里先只实现一个空的展示其个人信息的课程主页。

2 修改登录视图

修改user/views.py中的login方法如下：

def login(request, kind):
    if kind not in ["teacher", "student"]:
        return HttpResponse(INVALID_KIND)

    if request.method == 'POST':
        if kind == "teacher":
            form = TeaLoginForm(data=request.POST)
        else:
            form = StuLoginForm(data=request.POST)

        if form.is_valid():
            uid = form.cleaned_data["uid"]
            if len(uid) != 10:
                form.add_error("uid", "账号长度必须为10")
            else:
                if kind == "teacher":
                    department_no = uid[:3]
                    number = uid[3:]
                    object_set = Teacher.objects.filter(department_no=department_no, number=number)
                else:
                    grade = uid[:4]
                    number = uid[4:]
                    object_set = Student.objects.filter(grade=grade, number=number)
                if object_set.count() == 0:
                    form.add_error("uid", "该账号不存在.")
                else:
                    user = object_set[0]
                    if form.cleaned_data["password"] != user.password:
                        form.add_error("password", "密码不正确.")
                    else:
                        request.session['kind'] = kind
                        request.session['user'] = uid
                        request.session['id'] = user.id

                        return redirect("course", kind=kind)

            return render(request, 'user/login_detail.html', {'form': form, 'kind': kind})
    else:
        context = {'kind': kind}
        if request.GET.get('uid'):
            uid = request.GET.get('uid')
            context['uid'] = uid
            if kind == "teacher":
                form = TeaLoginForm({"uid": uid, 'password': '12345678'})
            else:
                form = StuLoginForm({"uid": uid, 'password': '12345678'})
        else:
            if kind == "teacher":
                form = TeaLoginForm()
            else:
                form = StuLoginForm()
        context['form'] = form
        if request.GET.get('from_url'):
            context['from_url'] = request.GET.get('from_url')

        return render(request, 'user/login_detail.html', context)

登录后会在cookie中存储以下信息：

• kind : 用户类型，学生或老师
• user : 用户学号或教师编号

3 添加简单主页

目前虽然是个人主页，但是后面将会是课程主页，老师的和学生的必然是不同的。
所以我们现在也先提前规划好，将主页分为学生的和老师的来处理。

course/views.py代码如下

from django.http.response import HttpResponse
from django.shortcuts import render, reverse, redirect

from user.models import Student, Teacher
from constants import INVALID_KIND


def get_user(request, kind):
    """

    :param request:
    :param kind: teacher or student
    :return: return Teacher instance or Student instance
    """
    if request.session.get('kind', '') != kind or kind not in ["student", "teacher"]:
        return None

    if len(request.session.get('user', '')) != 10:
        return None

    uid = request.session.get('user')
    if kind == "student":
        # 找到对应学生
        grade = uid[:4]
        number = uid[4:]
        student_set = Student.objects.filter(grade=grade, number=number)
        if student_set.count() == 0:
            return None
        return student_set[0]
    else:
        # 找到对应老师
        department_no = uid[:3]
        number = uid[3:]
        teacher_set = Teacher.objects.filter(department_no=department_no, number=number)
        if teacher_set.count() == 0:
            return None
        return teacher_set[0]


# Create your views here.
def home(request, kind):
    if kind == "teacher":
        return teacher_home(request)
    elif kind == "student":
        return student_home(request)
    return HttpResponse(INVALID_KIND)


def teacher_home(request):
    kind = "teacher"
    user = get_user(request, kind)

    if not user:
        return redirect('login', kind=kind)

    info = {
        "name": user.name,
        "kind": kind
    }

    context = {
        "info": info
    }

    return render(request, 'course/nav.html', context)

def student_home(request):
    kind = "student"
    user = get_user(request, kind)

    if not user:
        return redirect('login', kind = kind)

    info = {
        "name": user.name,
        "kind": kind
    }

    context = {
        "info": info
    }

    return render(request, 'course/nav.html', context)

注意，跳转到一个带参数的url，有两种写法

• return redirect(reverse("login", kwargs={"kind": kind}))
• return redirect('login', kind = kind)

这两种写法返回效果一样

添加模板文件templates/course/nav.html

<!DOCTYPE html>
<html lang="en">
{% load static %}
<head>
    <meta charset="UTF-8">
    <title>
        {% block title %}{% endblock %}
    </title>
</head>
<body>
<div class="nav">
    <div class="nav-title">
        <a href="{% url 'course' kind=info.kind %}">
        <p class="main-title">学生选课管理系统</p>
        <p class="sub-title">
            {% if info.kind == "teacher" %}
                教师端
            {% elif info.kind == "student" %}
                学生端
            {% endif %}</p>
        </a>
    </div>

    <div class="name-logo">
        <div class="user-name">
            {{ info.name }}
        </div>
    </div>
</div>

<div class="main-content">
    {% block content %}{% endblock %}
</div>


</body>
</html>

然后添加course/urls.py如下

from django.urls import path
from course.views import *

urlpatterns = [
    path('<slug:kind>/', home, name="course"),
]

同时还要去改下主url，即在SSCMS/urls.py的urlpatterns中添加

path('course/', include("course.urls")),

此时运行软件，登录账号后（这里又注册了一个叫李大爽的用户），
结果如图

4 实现退出登录

退出登录的视图方法如下（在user/views.py中添加）

def logout(request):
    if request.session.get("kind", ""):
        del request.session["kind"]
    if request.session.get("user", ""):
        del request.session["user"]
    if request.session.get("id", ""):
        del request.session["id"]
    return redirect(reverse("login"))

添加对应路由（在user/urls.py中的urlpatterns的添加）

path('logout/', views.logout, name="logout")

在修改下登录后的主页视图（即templates/course/nav.html）
在其中的第24行处（即<div class="name-logo">的之前）添加

    <div class="log-out">
        <a href="{% url "logout" %}">退出</a>
    </div>

此时登录后，主页面如下图

点击退出按钮，就可以退出登录，返回登录主页面。

5 简化登录主页url

每次要打开登录主页，都需要在浏览器中输入http://127.0.0.1:8000/user/login
运行django后，控制台只自动给出http://127.0.0.1:8000。
所以这里修改下urlpattern，能够访问http://127.0.0.1:8000即得到登录主页
修改后的SSCMS/urls.py如下

from django.urls import path, include
from user.views import home

urlpatterns = [
    path('', home, name="login"),
    path('user/', include("user.urls")),
    path('course/', include("course.urls")),
]