Django认证流程源码及自定义 Backend

Django自己的认证方法只能认证用户名和密码

user = authenticate(**credentials)
# authenticate会自动校验用户名和密码

authenticate 源码

def authenticate(request=None, **credentials):
    """
    If the given credentials are valid, return a User object.
    """
    # _get_backends 是Django的配置文件中的AUTHENTICATION_BACKENDS 列表里面定义的认证方式
    # 如果你自己项目的配置文件中配置了AUTHENTICATION_BACKENDS就会去你自己的配置文件中找
    for backend, backend_path in _get_backends(return_tuples=True):
        backend_signature = inspect.signature(backend.authenticate)
        try:
            backend_signature.bind(request, **credentials)
        except TypeError:
            continue
        try:
            # 每循环一个backend 都会去调用authenticate方法
            # 如果你自己重写了authenticate方法 就会走你自己写的
            user = backend.authenticate(request, **credentials)
        except PermissionDenied:
            break
        if user is None:
            continue
        user.backend = backend_path
        return user

如果自己没有配置AUTHENTICATION_BACKENDS

# 会从Django的配置文件中找
# from django.conf import global_settings

AUTH_USER_MODEL = 'auth.User'

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

导入django.contrib.auth.backends.ModelBackend

from django.contrib.auth.backends import ModelBackend

# 源码如下
class ModelBackend(BaseBackend):
    """
    Authenticates against settings.AUTH_USER_MODEL.
    """
    def authenticate(self, request, username=None, password=None, **kwargs):
        if username is None:
            username = kwargs.get(UserModel.USERNAME_FIELD)
        if username is None or password is None:
            return
        try:
            # 通过自然键(USERNAME_FIELD)获取 user 对象
            user = UserModel._default_manager.get_by_natural_key(username)
        except UserModel.DoesNotExist:
            UserModel().set_password(password)
        else:
            # 检查密码和是否是活跃用户，然后返回一个 user 对象，否则什么也不返回 就是 None
            if user.check_password(password) and self.user_can_authenticate(user):
                return user

自定义Backend 实现简单的认证方式，如下：

因为Django自带的authenticate只能帮你验证用户名和密码，当你需要验证使用如手机号登录、邮箱登录、验证码登录等时，需要自己重写authenticate方法，自定义认证方式

from django.contrib.auth.backends import ModelBackend

# 继承ModelBackend重写里面的authenticate方法 自定义认证方式
class LoginBackend(ModelBackend):
    def authenticate(self, request, username=None, password=None, **kwargs):
        user = UserInfo.objects.get(Q(username=username) | Q(phone=username) | Q(email=username))
        if user is not None and user.check_password(password):
            return user

最后settings.py中需要配置

AUTHENTICATION_BACKENDS = [
    'app01.backends.LoginBackend'
]
# 配置完之后再走校验的话就会先从你自己写的这个类里面去执行authenticate方法
# 会用你自己的校验方式