django权限管理(Permission)

什么是权限管理

• 权限管理，一般指根据系统设置的安全规则或者安全策略，用户可以访问而且只能访问自
  己被授权的资源
• 权限管理好比如钥匙，有了钥匙就能把门打开，但是权限设置是有级别之分的，假如这个
  系统有多个权限级别就如一间屋有多个门，想要把所有门都打开您必须要取得所有的钥
  匙，就如系统一样。

django权限机制

• django权限机制能够约束用户行为，控制页面的显示内容，也能使API更加安全和灵活；用好权限机制，能让系统更加强大和健壮

django权限控制

• Django用user,group和permission完成了权限机制，这个权限机制是将属于model的某个permission赋予user或group，可以理解为全局的权限，即如果用户A对数据模型（model）B有可写权限，那么A能修改model B的所有实例（objects）。group的权限也是如此，如果为group C 赋予model B的可写权限，则隶属于group C的所有用户，都可以修改model B的所有
  实例。

Django的权限项

• Django用permission对象存储权限项，每个model默认都有三个permission，即add
  model, change model和delete model
  permission总是与model对应的，如果一个object不是model的实例，我们无法为它创建
  /分配权限

默认权限

• 在 INSTALLED_APPS 设置中列出django.contrib.auth 后，安装的各个应用中的每个 Django 模
  型默认都有三个权限:添加、修改和删除。每次运行 manage.py migrate 命令创建新模型时都
  会为其赋予这三个权限。

分组

• django.contrib.auth.models.Group 模型是为用户分类的通用方式，这样便可以为一批用户
  赋予权限或添加其 他标注。用户所属的分组数量不限。一个分组中的用户自动获得赋予那
  个分组的权限。
• 除了权限之外，分组还是为用户分类的便捷方式，分组后可以给用户添加标签，或者扩展功能

权限应用

• Permission
• User Permission
• Group Permission
• 权限检查

Permission

• Django定义每个model后，默认都会添加该model的add, change和delete三个
  permission，自定义的permission可以在我们定义model时手动添加

class Server(models.Model):
...
class Meta:
    permissions = (
    ("view_server", "can view server"),
    ("change_server_status", "Can change the status of server"),
    )
    #codename == view_server权限验证项
    #name == can view server 可读的名称

• 每个permission都是django.contrib.auth.Permission类型的实例，该类型包含三个字段
  name, codename 和 content_type

content_type反应了permission属于哪个model，
codename 如上面的view_server，代码逻辑中检查权限时要用，
name是permission的描述，将permission打印到屏幕或页面时默认显示的就是name

User Permission

• User对象的user_permission字段管理用户的权限

user = User.objects.get(username="rock")
user.user_permissions = [permission_list]
user.user_permissions.add(permission, permission, …) #增加权限
user.user_permissions.remove(permission, permission, …) #删除权限
user.user_permissions.clear() #清空权限
user.get_all_permissions() #列出用户的所有权限
user.get_group_permissions() # 列出用户所属group的权限

• 练习

	
In [1]: from django.contrib.auth.models import  Group,User,Permission
In [3]: user  = User.objects.get(username='rock-1')
In [4]: user.groups.all
Out[4]: <bound method BaseManager.all of <django.db.models.fields.related_descriptors.create_forward_many_to_many_manager.<locals>.ManyRelatedManager object at 0x7fd86cf49ef0>>
In [5]: user.groups.all()
Out[5]: <QuerySet [<Group: 51reboot>]>

In [6]: user.user_permissions.all()
Out[6]: <QuerySet []>
In [7]: per = Permission.objects.get(id=21)
In [8]: per.codename
Out[8]: 'delete_idc'

In [9]: user.user_permissions.add(per)

In [10]: user.user_permissions.all()
Out[10]: <QuerySet [<Permission: resources | idc | Can delete idc>]>

In [11]: user.user_permissions.remove(per)

In [12]: user.user_permissions.all()
Out[12]: <QuerySet []>

In [13]: user.user_permissions.add(per)

In [14]: user.user_permissions.clear()

In [15]: user.user_permissions.add(per)

In [16]: user.get_all_permissions()
Out[16]: 
{'admin.add_logentry',
 'admin.change_logentry',
 'admin.delete_logentry',
 'auth.add_group',
 'auth.add_permission',
 'auth.add_user',
 'auth.change_group',
 'auth.change_permission',
 'auth.change_user',
 'auth.delete_group',
 'auth.delete_permission',
 'auth.delete_user',
 'contenttypes.add_contenttype',
 'contenttypes.change_contenttype',
 'contenttypes.delete_contenttype',
 'resources.add_idc',
 'resources.change_idc',
 'resources.delete_idc',
 'sessions.add_session',
 'sessions.change_session',
 'sessions.delete_session'}

In [17]: user.groups.clear()

In [18]: user.get_all_permissions()
Out[18]: 
{'admin.add_logentry',
 'admin.change_logentry',
 'admin.delete_logentry',
 'auth.add_group',
 'auth.add_permission',
 'auth.add_user',
 'auth.change_group',
 'auth.change_permission',
 'auth.change_user',
 'auth.delete_group',
 'auth.delete_permission',
 'auth.delete_user',
 'contenttypes.add_contenttype',
 'contenttypes.change_contenttype',
 'contenttypes.delete_contenttype',
 'resources.add_idc',
 'resources.change_idc',
 'resources.delete_idc',
 'sessions.add_session',
 'sessions.change_session',
 'sessions.delete_session'}

In [19]: user.get_group_permissions()
Out[19]: 
{'admin.add_logentry',
 'admin.change_logentry',
 'admin.delete_logentry',
 'auth.add_group',
 'auth.add_permission',
 'auth.add_user',
 'auth.change_group',
 'auth.change_permission',
 'auth.change_user',
 'auth.delete_group',
 'auth.delete_permission',
 'auth.delete_user',
 'contenttypes.add_contenttype',
 'contenttypes.change_contenttype',
 'contenttypes.delete_contenttype',
 'resources.add_idc',
 'resources.change_idc',
 'resources.delete_idc',
 'sessions.add_session',
 'sessions.change_session',
 'sessions.delete_session'}

In [20]: user.groups.all()
Out[20]: <QuerySet []>

Group Permission

• group permission管理逻辑与user permission管理一致，group中使用permissions字段做
  权限管理

group.permissions.set([permission_list])#设置权限
group.permissions.add(permission, permission, …)#添加权限
group.permissions.remove(permission, permission, …)#删除权限
group.permissions.clear()#情况权限

• 练习

In [40]: group = Group.objects.get(name='51reboot')#取出一个组
In [41]: group.permissions.all()#列出组所有权限
Out[41]: <QuerySet [<Permission: admin | log entry | Can add log entry>, <Permission: admin | log entry | Can change log entry>, <Permission: admin | log entry | Can delete log entry>, <Permission: auth | group | Can add group>, <Permission: auth | group | Can change group>, <Permission: auth | group | Can delete group>, <Permission: auth | permission | Can add permission>, <Permission: auth | permission | Can change permission>, <Permission: auth | permission | Can delete permission>, <Permission: auth | user | Can add user>, <Permission: auth | user | Can change user>, <Permission: auth | user | Can delete user>, <Permission: contenttypes | content type | Can add content type>, <Permission: contenttypes | content type | Can change content type>, <Permission: contenttypes | content type | Can delete content type>, <Permission: resources | idc | Can add idc>, <Permission: resources | idc | Can change idc>, <Permission: resources | idc | Can delete idc>, <Permission: sessions | session | Can add session>, <Permission: sessions | session | Can change session>, '...(remaining elements truncated)...']>

In [42]: permission = Permission.objects.get(id=20)#先取出一个权限（Can change idc）

In [43]: group.permissions.remove(permission)#从组里删除这个权限

In [44]: group.permissions.all()#再次查看权限
Out[44]: <QuerySet [<Permission: admin | log entry | Can add log entry>, <Permission: admin | log entry | Can change log entry>, <Permission: admin | log entry | Can delete log entry>, <Permission: auth | group | Can add group>, <Permission: auth | group | Can change group>, <Permission: auth | group | Can delete group>, <Permission: auth | permission | Can add permission>, <Permission: auth | permission | Can change permission>, <Permission: auth | permission | Can delete permission>, <Permission: auth | user | Can add user>, <Permission: auth | user | Can change user>, <Permission: auth | user | Can delete user>, <Permission: contenttypes | content type | Can add content type>, <Permission: contenttypes | content type | Can change content type>, <Permission: contenttypes | content type | Can delete content type>, <Permission: resources | idc | Can add idc>, <Permission: resources | idc | Can delete idc>, <Permission: sessions | session | Can add session>, <Permission: sessions | session | Can change session>, <Permission: sessions | session | Can delete session>]>

In [45]: group.permissions.add(permission)添加权限

In [46]: group.permissions.all()#再次查看权限
Out[46]: <QuerySet [<Permission: admin | log entry | Can add log entry>, <Permission: admin | log entry | Can change log entry>, <Permission: admin | log entry | Can delete log entry>, <Permission: auth | group | Can add group>, <Permission: auth | group | Can change group>, <Permission: auth | group | Can delete group>, <Permission: auth | permission | Can add permission>, <Permission: auth | permission | Can change permission>, <Permission: auth | permission | Can delete permission>, <Permission: auth | user | Can add user>, <Permission: auth | user | Can change user>, <Permission: auth | user | Can delete user>, <Permission: contenttypes | content type | Can add content type>, <Permission: contenttypes | content type | Can change content type>, <Permission: contenttypes | content type | Can delete content type>, <Permission: resources | idc | Can add idc>, <Permission: resources | idc | Can change idc>, <Permission: resources | idc | Can delete idc>, <Permission: sessions | session | Can add session>, <Permission: sessions | session | Can change session>, '...(remaining elements truncated)...']>

In [48]: group.permissions.set([permission])#设置权限，会清空之前的所有权限，传入一个权限列表

In [49]: group.permissions.all()#再次查看权限
Out[49]: <QuerySet [<Permission: resources | idc | Can change idc>]>

In [50]: group.permissions.clear()#清空所有权限

In [51]: group.permissions.all()#再次查看权限
Out[51]: <QuerySet []>

权限验证-普通视图

• 在视图中验证权限—— permission_required，
• 当业务逻辑中涉及到权限检查时，decorator能够分离权限验证和核心的业务逻辑，使代码更
  简洁，逻辑更清晰。permission的decorator为permission_required

from django.contrib.auth.decorators import login_required, permission_required
@login_required
@permission_required(’dashboard.view_server')
def my_view(request,*args,**kwargs):

权限验证-类视图

from django.utils.decorators import method_decorator
from django.contrib.auth.decorators import login_required, permission_required
class ServerView(TemplateView):
    @method_decorator(login_required)
    @method_decorator(permission_required(“dashboard.view_server”)
    def get(self, request, *args, **kwargs):
    ...

权限验证-view代码中验证

if not request.user.has_perm(’dashboard.view_server')
    return HttpResponse('Forbidden')

权限验证-模板中验证

• 验证是否有登陆

{% if user.is_authenticated %}
    <p>Welcome, {{ user.username }}. Thanks for logging in.</p>
{% else %}
    <p>Welcome, new user. Please log in.</p>
{% endif %}

• 验证是否有权限

{% if perms.dashboard.view_server %}
有权限
{% endif %}

PermissionRequiredMixin

from django.contrib.auth.mixins import PermissionRequiredMixin
class IndexView(LoginRequiredMixin,PermissionRequiredMixin,TemplateView):
    template_name = 'index.html'

自定义PermissionRequiredMixin

创建仅限

• 在模型的 Meta 类中定制权限

class Meta:
    permissions = (
    ("modify_user_status", "修改用户状态"),
    ("modify_user_passwd", "修改用户密码"),
    )

• 直接创建权限

from resources.models import Idc
from django.contrib.auth.models import Group, Permission
from django.contrib.contenttypes.models import ContentType
content_type = ContentType.objects.get_for_model(Idc)
permission = Permission.objects.create(codename='can_view',
name='Can view Idc',
content_type=content_type)