django使用auth模块进行身份认证

https://docs.djangoproject.com/zh-hans/2.0/topics/auth/default/#authentication-in-web-requests

django认证模型系统是django自带，默认配置文件在settings.py文件当中。这个项目在INSTALLED_APPS setting里面由两个部分组成，分别是：

1. 'django.contrib.auth' 包含了认证框架的核心模块, 是默认的模型。
2. 'django.contrib.contenttypes' 是django的内容类型系统, 这个会允许你连接你创建的模型。

这是你的中间件配置:

1. SessionMiddleware manages sessions across requests.
2. AuthenticationMiddleware associates users with requests using sessions.

一、创建超级用户

$ python manage.py createsuperuser --username=joe --email=joe@example.com

更改密码

from django.contrib.auth.models import User
u = User.objects.get(username='john')
u.set_password('new password')
u.save()

# 这里的User是django默认创建的用户表，如果用到自己定义的表，这里需要更改，更改后的表含有User表所有的方法。

检查密码

auth 提供的一个检查密码是否正确的方法，需要提供当前请求用户的密码。
密码正确返回True，否则返回False。
用法：

ok = user_obj.check_password('密码')

或者

ok = request.user.check_password(raw_password='原密码')

一个简单的修改密码功能的事例：

@login_required
def set_password(request):
    user = request.user
    err_msg = ''
    if request.method == 'POST':
        old_password = request.POST.get('old_password', '')
        new_password = request.POST.get('new_password', '')
        repeat_password = request.POST.get('repeat_password', '')
        # 检查旧密码是否正确
        if user.check_password(old_password):
            if not new_password:
                err_msg = '新密码不能为空'
            elif new_password != repeat_password:
                err_msg = '两次密码不一致'
            else:
                user.set_password(new_password)
                user.save()
                return redirect("/login/")
        else:
            err_msg = '原密码输入错误'
    content = {
        'err_msg': err_msg,
    }
    return render(request, 'set_password.html', content)

修改密码示例

验证用户

from django.contrib.auth import authenticate
user = authenticate(username='john', password='secret')
if user is not None:
    # 验证通过
    # A backend authenticated the credentials
else:
    # 验证失败
    # No backend authenticated the credentials

request is an optional HttpRequest which is passed on the authenticate() method of the authentication backends.

 Changed in Django 1.11:

The optional request argument was added.

权限和认证

User objects have two many-to-many fields: groups and user_permissions. User objects can access their related objects in the same way as any other Django model:

myuser.groups.set([group_list])
myuser.groups.add(group, group, ...)
myuser.groups.remove(group, group, ...)
myuser.groups.clear()
myuser.user_permissions.set([permission_list])
myuser.user_permissions.add(permission, permission, ...)
myuser.user_permissions.remove(permission, permission, ...)
myuser.user_permissions.clear()


from django.contrib.auth.models import User

u = User.objects.get(username='john')
u.groups.add()
或
u = User.objects.get(username='john')
u.user_permissions.add()

默认权限

假设我创建了一个app名称叫做foo,model名称叫做Bar，测试你所拥有的基本权限方法如下：

add: user.has_perm('foo.add_bar')
change: user.has_perm('foo.change_bar')
delete: user.has_perm('foo.delete_bar')

权限缓存

from django.contrib.auth.models import Permission, User
from django.contrib.contenttypes.models import ContentType
from django.shortcuts import get_object_or_404

from myapp.models import BlogPost

def user_gains_perms(request, user_id):
    user = get_object_or_404(User, pk=user_id)
    # any permission check will cache the current set of permissions
    user.has_perm('myapp.change_blogpost')

    content_type = ContentType.objects.get_for_model(BlogPost)
    permission = Permission.objects.get(
        codename='change_blogpost',
        content_type=content_type,
    )
    user.user_permissions.add(permission)

    # Checking the cached permission set
    user.has_perm('myapp.change_blogpost')  # False

    # Request new instance of User
    # Be aware that user.refresh_from_db() won't clear the cache.
    user = get_object_or_404(User, pk=user_id)

    # Permission cache is repopulated from the database
    user.has_perm('myapp.change_blogpost')  # True

    ...

Web 请求的认证

django使用session中间件来验证request objects，如果用户验证没有通过，这个实例会被设置成AnonymousUser。


if request.user.is_authenticated: # Do something for authenticated users. ... else: # Do something for anonymous users. ...

如何使用authenticate()和login():

from django.contrib.auth import authenticate, login

def my_view(request):
    username = request.POST['username']
    password = request.POST['password']
    user = authenticate(request, username=username, password=password)
    if user is not None:
        login(request, user)
        # Redirect to a success page.
        ...
    else:
        # Return an 'invalid login' error message.
        ...

用户如何登出

from django.contrib.auth import logout

def logout_view(request):
    logout(request)
    # Redirect to a success page.

Limiting access to logged-in users

from django.conf import settings
from django.shortcuts import redirect

def my_view(request):
    if not request.user.is_authenticated:
        return redirect('%s?next=%s' % (settings.LOGIN_URL, request.path))
    # ...

或者返回一个错误页面

from django.shortcuts import render

def my_view(request):
    if not request.user.is_authenticated:
        return render(request, 'myapp/login_error.html')
    # ...

login_required 装饰器

使用方法如下

from django.contrib.auth.decorators import login_required

@login_required
def my_view(request):
    ...

登陆成功后默认会跳转到/accounts/login/目录，如果需要使用自定义目录，需要添加在settings.py文件LOGIN_URL 参数。

测试登陆用户，验证用户是否存在email字段

from django.shortcuts import redirect

def my_view(request):
    if not request.user.email.endswith('@example.com'):
        return redirect('/login/?next=%s' % request.path)
    # ...

user_passes_test(test_func, login_url=None, redirect_field_name='next')[source]¶

As a shortcut, you can use the convenient user_passes_test decorator which performs a redirect when the callable returns False:

from django.contrib.auth.decorators import user_passes_test

def email_check(user):
    return user.email.endswith('@example.com')

@user_passes_test(email_check)
def my_view(request):

permission_required 装饰器

permission_required(perm, login_url=None, raise_exception=False)[source]

from django.contrib.auth.decorators import permission_required

@permission_required('polls.can_vote')
def my_view(request):
    ...

就好像has_perm方法一样，permission_requierd使用方法为<app label>.<permission codename>

注意permission_required()仍然需要login_url字段。作为login_required的装饰，login_url默认设置的为settings.LOGIN_URL，也就是settings.py文件当中的LOGIN_URL参数。

如果raise_exception字段抛出，这个装饰会抛出PermissionDenied，403 Forbidden，而不是跳转的login页面。如果你想要在异常抛出前再给你的用户登陆，你可以加上login_required()

from django.contrib.auth.decorators import login_required, permission_required

@login_required
@permission_required('polls.can_vote', raise_exception=True)
def my_view(request):

Session invalidation on password change

如果用户认证的model从 AbstractBaseUser 或者从get_session_auth_hash()方法实现，通过这些，认证缓存会通过hash方法实现，在AbstractBaseUser例子中，如果你想要更改密码并且不退出登陆，使用update_session_auth_hash()方法。

from django.contrib.auth import update_session_auth_hash

def password_change(request):
    if request.method == 'POST':
        form = PasswordChangeForm(user=request.user, data=request.POST)
        if form.is_valid():
            form.save()
            update_session_auth_hash(request, form.user)
    else:
        ...

 如何扩展自带的auth_user表

1. 新建一个表， 一对一关联上面的auth_user表

2. 继承的方式

from django.contrib.auth.models import AbstractUser
        
class UserInfo(AbstractUser):
    phone = models.CharField(max_length=11)
    addr = models.CharField(max_length=128)
    相当于对默认的auth_user表做了扩展， 并且代替auth_user

注意：
在settings.py中一定要加
AUTH_USER_MODEL = 'app名.类名'

https://docs.djangoproject.com/zh-hans/2.0/topics/auth/default/#authentication-in-web-requests