在django app中,每个用户只允许一次并发登录

AUTHENTICATION_BACKENDS = [
    'django.contrib.auth.backends.ModelBackend',
    'django.contrib.auth.backends.SessionAuthentication',
]

class UserTokenMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        if request.user.is_authenticated:
            token = request.session.get('user_token')
            if token != request.user.token:
                logout(request)
        return self.get_response(request)

MIDDLEWARE = [
    # ...
    'myapp.middleware.UserTokenMiddleware',
]