python版本3.7，django版本2.2

from django.shortcuts import render
from django.contrib.auth import authenticate, login
from django.contrib.auth.backends import ModelBackend
from django.views.generic.base import View
from .models import UserProfile
from django.db.models import Q


# Create your views here.
class CustomBackend(ModelBackend):
    def authenticate(self, username=None, password=None, **kwargs):
        try:
            user = UserProfile.objects.get(Q(username=username) | Q(email=username))
            if user.check_password(password):
                return user
        except Exception as e:
            return None


class LoginView(View):
    def get(self, request):
        return render(request, "login.html", {})

    def post(self, request):
        user_name = request.POST.get("username", "")
        pass_word = request.POST.get("password", "")
        user = authenticate(username=user_name, password=pass_word)
        print(user)
        if user is not None:
            login(request, user)
            return render(request, 'index.html')
        else:
            return render(request, "login.html", {"msg": "用户名或密码错误！"})