有人可以帮我看看这个脚本吗？ django

Question

我在网上找到了一个脚本，它可以帮助我将登录更改为同时使用用户名和电子邮件，而不仅仅是用户名，但有很多部分我并不真正理解。

就像，我非常了解每一行的含义，但我不明白为什么这样做会使我的登录与电子邮件一起使用。

class EmailBackend(object):
    def authenticate(self, username=None, password=None):
        user_cls = get_user_model()
        try:
            user = user_cls.objects.get(email=username)
            if user.check_password(password):
                return user
        except user_cls.DoesNotExist:
            return None
        except:
            return None

    def get_user(self, user_id):
        user_cls = get_user_model()
        try:
            return user_cls.objects.get(pk=user_id)
        except user_cls.DoesNotExist:
            return None

提前致谢。

Answer 1

检查 cmets :-

class EmailBackend(object):
    def authenticate(self, username=None, password=None):
        user_cls = get_user_model() #Getting user object in one variable

        try:
            user = user_cls.objects.get(email=username) #Check any user exist with input email(username) with database email(consider as an username)
            if user.check_password(password): #if user match then check is password match or not 
                return user #If both email and password match then return user information
        except user_cls.DoesNotExist: #if user not exist then return None
            return None
        except: #got any error in middle return None
            return None

    def get_user(self, user_id):
        user_cls = get_user_model() #Get user object in one variable
        try:
            return user_cls.objects.get(pk=user_id) #check user with this user_id exist or not, may be PK (some unique id consider as an user_id)
        except user_cls.DoesNotExist: #if user_id(PK) not exist return None 
            return None