Django中用户权限模块

Django中用户权限模块

1 auth模块

auth模块是Django提供的标准权限管理系统,可以提供用户身份认证, 用户组和权限管理。
auth可以和admin模块配合使用, 快速建立网站的管理系统。
在INSTALLED_APPS中添加'django.contrib.auth'使用该APP, auth模块默认启用。

2 User属性与方法

(1) 属性
User是auth模块中维护用户信息的关系模式(继承了models.Model), 数据库中该表被命名为auth_user.
参照后续源码更清楚的了解User类继承的属性与方法.这里只是展示一部分.

该数据表在数据库中:
'auth_user'
    "id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, 
    "password" varchar(128) NOT NULL, "last_login" datetime NULL, 
    "is_superuser" bool NOT NULL, 
    "first_name" varchar(30) NOT NULL, 
    "last_name" varchar(30) NOT NULL,
    "email" varchar(254) NOT NULL, 
    "is_staff" bool NOT NULL, 
    "is_active" bool NOT NULL,
    "date_joined" datetime NOT NULL,
    "username" varchar(30) NOT NULL UNIQUE
一般当建立关联表时需要与User建立关联,则需要导入使用,比如建议OneToOne联系

from django.contrib.auth.models import User
class Profile(models.Model):
    user = models.OneToOneField(User)  #建立关联到User
    blog = models.CharField(maxlength=128, blank=True)
    location = models.CharField(maxlength=128, blank=True)
    occupation = models.CharField(maxlength=64, blank=True)
(2) 方法
is_anonymous():是否为匿名用户,如果你已经login,则这个方法返回始终为false.
is_authenticated():是否通过验证,也就是通过用户名和密码判断该用户是否存在
get_group_permissions():得到所有该用户所属组别的权限
get_all_permissions():得到该用户所有的权限.
has_perm(perm):判断用户是否具有特定权限,perm的格式是appname.codename
email_user(subject, message, from_email=None):给某用户发送邮件

例如创建一个superuser装饰器:

#登录用户必须为超级用户,只能在类中使用
def superuser_required(func):
    def _wrapper(self,request,*args,**kwargs):
        #User中包含了is_superuser属性
        if not request.user.is_superuser:
            #定义的未登录函数 not_authenticated()
            return not_authenticated()
        return func(self,request,*args,**kwargs)
    return _wrapper
这里设置superuser当然也可以自己设置不同权限的装饰器,这样代码更加简单!!

3 User常见的用法

(1)  新建用户
user = User.objects.create_user(username, password)
user.save()  #保存数据库
auth模块不存储用户密码明文而是存储一个Hash值

(2) 验证登录
from django.contrib.auth import login

username = request.POST['username']
password = request.POST['password']
#login不进行认证,也不检查is_active标志位, 一般和authenticate配合使用:
user = authenticate(username=username, password=password)
if not user:
    if user.is_active:
        return HttpResponse(json.dumps({
          'error':'用户名或者密码错误'
        }))
login(request,user)

login向session中添加SESSION_KEY, 便于对用户进行跟踪.
首先我们要验证这个用户,然后再登陆,登陆成功后,我们可以通过request.user 来得到当前登陆的用户对象

(3) 退出登录
logout会移除request中user信息,并刷新session,清空cookie中sessionid
from django.contrib.auth import logout

def logout_view(request):
    logout(request)

(4) 限制非法用户访问
普通做法通过 request.user.is_authenticated()判定,返回重定向login登录界面
from django.http import HttpResponseRedirect

def my_view(request):
    if not request.user.is_authenticated():
        return HttpResponseRedirect('/login.html/')
这种方法会造成重复判定问题

简单做法采用装饰器语法糖搞定,django中封装了login_required
from django.contrib.auth.decorators import login_required

@login_required  #过滤掉非登录用户
def my_view(request):
    #限定为合法用户访问
这样当你访问my_view的时候,就需要用户需要通过验证,不通过可以重定向来解决

4 Group用户组

django.contrib.auth.models.Group定义了用户组的模型, 每个用户组拥有id和name两个
字段, 该模型在数据库被映射为auth_group数据表。

User对象中有一个名为groups的多对多字段, 多对多关系由auth_user_groups数据表维护。
Group对象可以通过user_set反向查询用户组中的用户。

# 创建create
group = Group.objects.create(name=group_name)
group.save()

#add
用户加入用户组user.groups.add(group)或group.user_set.add(user)

#remove
用户退出用户组user.groups.remove(group)或group.user_set.remove(user)

5 Permission

Django的auth系统提供了模型级的权限控制, 即可以检查用户是否对某个数据表拥有增(add),
 改(change), 删(delete)权限,但无法检查用户对某一篇博文是否拥有管理权限。

user.has_perm('blog.add_article')
user.has_perm('blog.change_article')
user.has_perm('blog.delete_article')
user.has_perm方法用于检查用户是否拥有操作某个模型权限,若拥有权限则返回True。仅是进
行权限检查, 即是用户没有权限它也不会阻止程序员执行相关操作。

permission_required修饰器可以代替has_perm并在用户没有相应权限时重定向到登录页或者抛出异常。
# permission_required(perm[, login_url=None, raise_exception=False])

#给blog中article添加权限,装饰器之后更加简单
@permission_required('blog.add_article')
def post_article(request):
    pass

6 管理用户权限

User和Permission通过多对多字段user.user_permissions关联,在数据库中由
auth_user_user_permissions数据表维护,可以执行添加权限,删除权限,清空权限.

7 User继承的父类

User先继承AbstractUser类,该类的基类为AbstractBaseUser,有兴趣的了解下,可以更深入的发现User类的功能

附上User继承类AbstractUser类的基类AbstractBaseUser的源码:

class AbstractBaseUser(models.Model):

    '''
    常见的子类User继承的属性:
    password    密码
    last_login  最后登录
    is_active   是否在线

    常见定义的方法:
    save  保存
    is_authenticated  登录验证
    set_password  设置密码
    check_password   检查密码
    '''
    password = models.CharField(_('password'), max_length=128)
    last_login = models.DateTimeField(_('last login'), blank=True, null=True)

    is_active = True

    REQUIRED_FIELDS = []

    class Meta:
        abstract = True

    def get_username(self):
        return getattr(self, self.USERNAME_FIELD)

    def __init__(self, *args, **kwargs):
        super(AbstractBaseUser, self).__init__(*args, **kwargs)
        self._password = None

    def __str__(self):
        return self.get_username()

    def clean(self):
        setattr(self, self.USERNAME_FIELD, self.normalize_username(self.get_username()))

    def save(self, *args, **kwargs):
        super(AbstractBaseUser, self).save(*args, **kwargs)
        if self._password is not None:
            password_validation.password_changed(self._password, self)
            self._password = None

    def natural_key(self):
        return (self.get_username(),)

    @property
    def is_anonymous(self):
        """
        Always return False. This is a way of comparing User objects to
        anonymous users.
        """
        return CallableFalse

    @property
    def is_authenticated(self):
        """
        Always return True. This is a way to tell if the user has been
        authenticated in templates.
        """
        return CallableTrue

    def set_password(self, raw_password):
        self.password = make_password(raw_password)
        self._password = raw_password

    def check_password(self, raw_password):
        """
        Return a boolean of whether the raw_password was correct. Handles
        hashing formats behind the scenes.
        """
        def setter(raw_password):
            self.set_password(raw_password)
            # Password hash upgrades shouldn't be considered password changes.
            self._password = None
            self.save(update_fields=["password"])
        return check_password(raw_password, self.password, setter)

    def set_unusable_password(self):
        # Set a value that will never be a valid hash
        self.password = make_password(None)

    def has_usable_password(self):
        return is_password_usable(self.password)

    def get_full_name(self):
        raise NotImplementedError('subclasses of AbstractBaseUser must provide a get_full_name() method')

    def get_short_name(self):
        raise NotImplementedError('subclasses of AbstractBaseUser must provide a get_short_name() method.')

    def get_session_auth_hash(self):
        """
        Return an HMAC of the password field.
        """
        key_salt = "django.contrib.auth.models.AbstractBaseUser.get_session_auth_hash"
        return salted_hmac(key_salt, self.password).hexdigest()

    @classmethod
    def get_email_field_name(cls):
        try:
            return cls.EMAIL_FIELD
        except AttributeError:
            return 'email'

    @classmethod
    def normalize_username(cls, username):
        return unicodedata.normalize('NFKC', force_text(username))

User继承类AbstractUser类的源码:
class AbstractUser(AbstractBaseUser, PermissionsMixin):
   '''
   继承该类常见属性有:
   username    用户名
   first_name  姓
   last_name   名
   email       邮箱
   '''
    username_validator = UnicodeUsernameValidator() if six.PY3 else ASCIIUsernameValidator()

    username = models.CharField(
        _('username'),
        max_length=150,
        unique=True,
        help_text=_('Required. 150 characters or fewer. Letters, digits and @/./+/-/_ only.'),
        validators=[username_validator],
        error_messages={
            'unique': _("A user with that username already exists."),
        },
    )
    first_name = models.CharField(_('first name'), max_length=30, blank=True)
    last_name = models.CharField(_('last name'), max_length=30, blank=True)
    email = models.EmailField(_('email address'), blank=True)
    is_staff = models.BooleanField(
        _('staff status'),
        default=False,
        help_text=_('Designates whether the user can log into this admin site.'),
    )
    is_active = models.BooleanField(
        _('active'),
        default=True,
        help_text=_(
            'Designates whether this user should be treated as active. '
            'Unselect this instead of deleting accounts.'
        ),
    )
    date_joined = models.DateTimeField(_('date joined'), default=timezone.now)

    objects = UserManager()

    EMAIL_FIELD = 'email'
    USERNAME_FIELD = 'username'
    REQUIRED_FIELDS = ['email']

    class Meta:
        verbose_name = _('user')
        verbose_name_plural = _('users')
        abstract = True

    def clean(self):
        super(AbstractUser, self).clean()
        self.email = self.__class__.objects.normalize_email(self.email)

    def get_full_name(self):
        """
        Returns the first_name plus the last_name, with a space in between.
        """
        full_name = '%s %s' % (self.first_name, self.last_name)
        return full_name.strip()

    def get_short_name(self):
        "Returns the short name for the user."
        return self.first_name

    def email_user(self, subject, message, from_email=None, **kwargs):
        """
        Sends an email to this User.
        """
        send_mail(subject, message, from_email, [self.email], **kwargs)

注: 1 权限部分参考了原文:http://www.cnblogs.com/Finley/p/5575305.html 非常感谢!!

​ 2 后续我会提供: 注册/验证/登录/注销封装好的类,感谢大家阅读!!!

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