Django 小實例S1 簡易學生選課管理系統 6 實現登錄邏輯

Django 小實例S1 簡易學生選課管理系統 第6節——實現登錄邏輯
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作者自我介紹：b站小UP主，時常直播編程+紅警三，python1對1輔導老師。

1 業務邏輯

本教程第四節里面實現了登錄頁面和一個空的登錄邏輯。
第六節這里就把登錄邏輯補全。

登錄的業務邏輯是：

• 檢查是否注冊
• 未注冊，則提示賬號不存在
• 注冊但密碼不匹配，提示密碼不正確
• 注冊且信息匹配，成功登錄，跳轉到個人主頁，同時通過cookie保存登錄信息。

對於教務管理系統，個人主頁應該是其課程主頁，所以本部分還需要添加課程主頁，這里先只實現一個空的展示其個人信息的課程主頁。

2 修改登錄視圖

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", "賬號長度必須為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", "該賬號不存在.")
                else:
                    user = object_set[0]
                    if form.cleaned_data["password"] != user.password:
                        form.add_error("password", "密碼不正確.")
                    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)

登錄后會在cookie中存儲以下信息：

• kind : 用戶類型，學生或老師
• user : 用戶學號或教師編號

3 添加簡單主頁

目前雖然是個人主頁，但是后面將會是課程主頁，老師的和學生的必然是不同的。
所以我們現在也先提前規划好，將主頁分為學生的和老師的來處理。

course/views.py代碼如下

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":
        # 找到對應學生
        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:
        # 找到對應老師
        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，跳轉到一個帶參數的url，有兩種寫法

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

這兩種寫法返回效果一樣

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">學生選課管理系統</p>
        <p class="sub-title">
            {% if info.kind == "teacher" %}
                教師端
            {% elif info.kind == "student" %}
                學生端
            {% 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"),
]

同時還要去改下主url，即在SSCMS/urls.py的urlpatterns中添加

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

此時運行軟件，登錄賬號后（這里又注冊了一個叫李大爽的用戶），
結果如圖

4 實現退出登錄

退出登錄的視圖方法如下（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"))

添加對應路由（在user/urls.py中的urlpatterns的添加）

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

在修改下登錄后的主頁視圖（即templates/course/nav.html）
在其中的第24行處（即<div class="name-logo">的之前）添加

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

此時登錄后，主頁面如下圖

點擊退出按鈕，就可以退出登錄，返回登錄主頁面。

5 簡化登錄主頁url

每次要打開登錄主頁，都需要在瀏覽器中輸入http://127.0.0.1:8000/user/login
運行django后，控制台只自動給出http://127.0.0.1:8000。
所以這里修改下urlpattern，能夠訪問http://127.0.0.1:8000即得到登錄主頁
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")),
]