基于rest_framework的ModelViewSet类编写登录视图和认证视图
背景：看了博主一抹浅笑的rest_framework认证模板，发现登录视图函数是基于APIView类封装。
优化：使用ModelViewSet类通过重写create方法编写登录函数。
环境：既然接触到rest_framework的使用，相信已经搭建好相关环境了。
1 建立模型
编写模型类
# models.py
from django.db import models
class User(models.Model):
username = models.CharField(verbose_name='用户名称',unique=True,max_length=16)
password = models.CharField(verbose_name='登陆密码',max_length=16)
class Token(models.Model):
username = models.CharField(verbose_name='用户名称',unique=True,max_length=16)
token = models.CharField(verbose_name='验证密钥',max_length=32)
生成迁移文件
python manage.py makemigrations
迁移数据模型
python manage.py migrate
2 确定需要重写的方法
查看ModelViewSet类源码
'''
class ModelViewSet(mixins.CreateModelMixin,
mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
mixins.DestroyModelMixin,
mixins.ListModelMixin,
GenericViewSet):
"""
A viewset that provides default `create()`, `retrieve()`, `update()`,
`partial_update()`, `destroy()` and `list()` actions.
"""
pass
'''
最终目的是往Token模型对应的表添加数据，所以得选择CreateModelMixin模型的源码查看。
'''
class CreateModelMixin:
"""
Create a model instance.
"""
def create(self, request, *args, **kwargs):
serializer = self.get_serializer(data=request.data)
serializer.is_valid(raise_exception=True)
self.perform_create(serializer)
headers = self.get_success_headers(serializer.data)
return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
def perform_create(self, serializer):
serializer.save()
def get_success_headers(self, data):
try:
return {'Location': str(data[api_settings.URL_FIELD_NAME])}
except (TypeError, KeyError):
return {}
'''
查看得知，CreateModelMixin类下的create方法调用了serializer类的save方法创建数据。继续查看save方法。
通过serializers.ModelSerializer定位到serializers.py文件，搜索'def save('定位到以下内容。
'''
def save(self, **kwargs):
assert hasattr(self, '_errors'), (
'You must call `.is_valid()` before calling `.save()`.'
)
assert not self.errors, (
'You cannot call `.save()` on a serializer with invalid data.'
)
# Guard against incorrect use of `serializer.save(commit=False)`
assert 'commit' not in kwargs, (
"'commit' is not a valid keyword argument to the 'save()' method. "
"If you need to access data before committing to the database then "
"inspect 'serializer.validated_data' instead. "
"You can also pass additional keyword arguments to 'save()' if you "
"need to set extra attributes on the saved model instance. "
"For example: 'serializer.save(owner=request.user)'.'"
)
assert not hasattr(self, '_data'), (
"You cannot call `.save()` after accessing `serializer.data`."
"If you need to access data before committing to the database then "
"inspect 'serializer.validated_data' instead. "
)
validated_data = {**self.validated_data, **kwargs}
if self.instance is not None:
self.instance = self.update(self.instance, validated_data)
assert self.instance is not None, (
'`update()` did not return an object instance.'
)
else:
self.instance = self.create(validated_data)
assert self.instance is not None, (
'`create()` did not return an object instance.'
)
'''
看最后这个if……else……语句中的self.instance = self.create(validated_data)。
说明这里调用了create方法，返回一个模型对象。于是查看ModelSerializer类的create方法。
'''
def create(self, validated_data):
"""
We have a bit of extra checking around this in order to provide
descriptive messages when something goes wrong, but this method is
essentially just:
return ExampleModel.objects.create(**validated_data)
If there are many to many fields present on the instance then they
cannot be set until the model is instantiated, in which case the
implementation is like so:
example_relationship = validated_data.pop('example_relationship')
instance = ExampleModel.objects.create(**validated_data)
instance.example_relationship = example_relationship
return instance
The default implementation also does not handle nested relationships.
If you want to support writable nested relationships you'll need
to write an explicit `.create()` method.
"""
raise_errors_on_nested_writes('create', self, validated_data)
ModelClass = self.Meta.model
# Remove many-to-many relationships from validated_data.
# They are not valid arguments to the default `.create()` method,
# as they require that the instance has already been saved.
info = model_meta.get_field_info(ModelClass)
many_to_many = {}
for field_name, relation_info in info.relations.items():
if relation_info.to_many and (field_name in validated_data):
many_to_many[field_name] = validated_data.pop(field_name)
try:
instance = ModelClass._default_manager.create(**validated_data)
except TypeError:
tb = traceback.format_exc()
msg = (
'Got a `TypeError` when calling `%s.%s.create()`. '
'This may be because you have a writable field on the '
'serializer class that is not a valid argument to '
'`%s.%s.create()`. You may need to make the field '
'read-only, or override the %s.create() method to handle '
'this correctly.\nOriginal exception was:\n %s' %
(
ModelClass.__name__,
ModelClass._default_manager.name,
ModelClass.__name__,
ModelClass._default_manager.name,
self.__class__.__name__,
tb
)
)
raise TypeError(msg)
# Save many-to-many relationships after the instance is created.
if many_to_many:
for field_name, value in many_to_many.items():
field = getattr(instance, field_name)
field.set(value)
return instance
'''
这逻辑我是没看懂，但是通过print、type、dir函数可以确定
接收对象validated_data是一个字典，
返回对象instance是一个模型对象。
于是可以把源码cv过来，简单测试是否能够通。
import time
import hashlib
from rest_framework import status
from rest_framework import serializers
from rest_framework.response import Response
from rest_framework.viewsets import ModelViewSet
from myapp import models as myapp_models
class TokenSerializer(serializers.ModelSerializer):
class Meta:
model = myapp_models.Token
fields = '__all__'
def create(self,validated_data):
######################################
query_obj = myapp_models.Token.objects.update_or_create(
username=validated_data['username'],
defaults={"username":validated_data['username'],"token":validated_data['token']})[0]
print(query_obj)
return query_obj
#------------------------------------#
class LoginView(ModelViewSet):
queryset = myapp_models.Token.objects.all()
serializer_class = TokenSerializer
def create(self, request, *args, **kwargs):
serializer = self.get_serializer(data=request.data)
serializer.is_valid(raise_exception=True)
self.perform_create(serializer)
headers = self.get_success_headers(serializer.data)
return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
3 重写create方法
3.1 编写登录逻辑
TokenSerializer
1.获取username和password。
2.验证username、password匹配性。
3.匹配错误：更新或创建模型中username对应的token为空字符串，返回模型对象。
4.匹配正确：通过md5加密生成token,更新或创建模型中username对应的token为密钥。
ModelViewSet
1.根据username查询token值。
2.将username、token值设置到session会话。
import time
import hashlib
from rest_framework import status
from rest_framework import serializers
from rest_framework.response import Response
from rest_framework.viewsets import ModelViewSet
from myapp import models as myapp_models
class TokenSerializer(serializers.ModelSerializer):
class Meta:
model = myapp_models.Token
fields = '__all__'
def create(self,validated_data):
######################################
user_obj = myapp_models.User.objects.filter(
username=validated_data['username'],
password=validated_data['token'])
user_dict = validated_data
user_dict['token'] = ''
if not user_obj.exists():
query_obj = myapp_models.Token.objects.update_or_create(
username=user_dict['username'],
defaults={"username":user_dict['username'],"token":user_dict['token']})[0]
return query_obj
validated_data['token'] = hashlib.md5(
''.format(time.time(),''.join(validated_data.values())).encode()).hexdigest()
query_obj = myapp_models.Token.objects.update_or_create(
username=validated_data['username'],
defaults={"username":validated_data['username'],"token":validated_data['token']})[0]
print(query_obj)
return query_obj
#------------------------------------#
class LoginView(ModelViewSet):
queryset = myapp_models.Token.objects.all()
serializer_class = TokenSerializer
def create(self, request, *args, **kwargs):
serializer = self.get_serializer(data=request.data)
serializer.is_valid(raise_exception=True)
self.perform_create(serializer)
headers = self.get_success_headers(serializer.data)
######################################
token_obj = myapp_models.Token.objects.filter(
username=request.POST.get('username')).first()
if token_obj.token == '':
request.session['username'] = token_obj.username
request.session['token'] = token_obj.token
return Response('检查输入的账户和密码')
request.session['username'] = token_obj.username
request.session['token'] = token_obj.token
#------------------------------------#
return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
3.2 编写认证逻辑
1.从session中获取username，token。
2.判断username，token是否不存在、或token是否为空字符串。
3.判断正确：抛出异常。
4.判断错误：范围username和模型对象组成的元组。
from rest_framework import exceptions
from rest_framework.authentication import BaseAuthentication
from myapp import models as myapp_models
class Authentication(BaseAuthentication):
def authenticate(self,request):
######################################
username = request._request.session.get('username','')
token = request._request.session.get('token','')
token_obj = myapp_models.Token.objects.filter(
username=username,token=token)
if not token_obj.exists or token_obj.first().token == '':
raise exceptions.AuthenticationFailed('认证失败')
return (token_obj.first().username,token_obj.first())
#------------------------------------#
3.3 添加路由
path('login/',myapp_views.LoginView.as_view({
'post':'create'}),name='login')
