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pip install django==2.1.7
pip install djangorestframework
settings配置文件中注册rest_framework
INSTALLED_APPS = [
...............
'rest_framework',
]
APIView与View的区别:
不管是View还是APIView最开始调用的都是as_view()方法
APIView继承了View, 并且执行了View中的as_view()方法,最后把view返回了,用csrf_exempt()方法包裹后去掉了csrf的认证
那我们看看View中的as_view()方法做了什么~
在View中的as_view方法返回了view函数,而view函数执行了self.dispatch()方法,而这里的dispatch方法是APIView中的方法
我们去initialize_request中看下把什么赋值给了request,并且赋值给了self.request, 也就是我们在视图中用的request.xxx到底是什么
我们看到,这个方法返回的是Request这个类的实例对象~~我们注意我们看下这个Request类中的第一个参数request,这是django中旧的request
这个Request类把原来的request赋值给了self._request, 也就是说以后_request是我们老的request,新的request是我们这个Request类。那我们继承APIView之后请求来的数据都在哪呢
我们用了rest_framework框架以后,我们的request是重新封装的Request类,request.query_params 存放的是我们get请求的参数,request.data 存放的是我们所有的数据,包括post请求的以及put,patch请求,相比原来的django的request,我们现在的request更加精简,清晰了。
from django.db import models
__all__ = ['Book', 'Publisher', 'Author']
class Book(models.Model):
title = models.CharField(max_length=32)
CHOICES = (
(1, 'Python'),
(2, 'Linux'),
(3, 'Go')
)
category = models.IntegerField(choices=CHOICES)
pub_time = models.DateField()
publisher = models.ForeignKey(to = 'Publisher', on_delete=models.CASCADE)
authors = models.ManyToManyField(to = 'Author')
class Publisher(models.Model):
title = models.CharField(max_length=32)
class Author(models.Model):
name = models.CharField(max_length=32)
在app目录下创建serializers.py文件
from rest_framework import serializers
from .models import Book
class PublisherSerializer(serializers.Serializer):
id = serializers.IntegerField()
title = serializers.CharField(max_length=32)
class AutherSerializer(serializers.Serializer):
id = serializers.IntegerField()
name = serializers.CharField(max_length=32)
class BookSerializer(serializers.Serializer):
id = serializers.IntegerField(required=False) # required=False 指明反序时(前端提交数据过来)不做校验
title = serializers.CharField(max_length=32)
pub_time = serializers.DateField()
category = serializers.CharField(source='get_category_display', read_only=True)
# 外键关系的序列化是嵌套的序列化对象;内部通过外键关系的id找到publisher对象,再使用PublisherSerializer(publisher对象)
publisher = PublisherSerializer(read_only=True) # 嵌套序列化器
authors = AutherSerializer(many=True, read_only=True) # 多对多关系需要加上参数:many = True
# read_only:指明该字段只做序列化,反序列化时不走该字段;那么反序列化时就必须重新指定字段名
# write_only:指明该字段只做反序列化
post_category = serializers.IntegerField(write_only=True)
publisher_id = serializers.IntegerField(write_only=True)
author_list = serializers.ListField(write_only=True)
def create(self, validated_data):
# validated_data 校验通过的数据
# 通过ORM操作给Book表添加数据
# print(validated_data)
# {'title': 'Die Hard', 'pub_time': datetime.date(2020, 1, 12), 'post_category': 1, 'publisher_id': 1, 'author_list': [1, 2]}
book_obj = Book.objects.create(
title=validated_data['title'],
pub_time=validated_data['pub_time'],
category=validated_data['post_category'],
publisher_id=validated_data['publisher_id']
)
book_obj.authors.add(*validated_data['author_list'])
return book_obj
def update(self, instance, validated_data):
# instance为需要更新的对象
instance.title = validated_data.get('title', instance.title)
instance.pub_time = validated_data.get('pub_time', instance.pub_time)
instance.category = validated_data.get('post_category', instance.category)
instance.publisher_id = validated_data.get('publisher_id', instance.publisher_id)
if validated_data.get('author_list'):
instance.authors.set(validated_data['author_list'])
instance.save()
return instance
# 参数校验,与Django中的form校验一样
def validate_title(self, value):
# 单个字段校验;value就是title的值
if 'python' not in value.lower():
raise serializers.ValidationError('标题必须包含python')
return value
def validate(self, attrs):
# 多个字段校验;attrs是个字典,包含前端传递过来的所有字段
if 'python' in attrs['title'].lower() and attrs['post_category'] == 1:
return attrs
raise serializers.ValidationError('参数错误')
自定义数据校验:
def my_validate(value):
if '敏感信息' in value.lower():
raise serializers.ValidationError('some message')
return value
class BookSerializer(serializers.Serializer):
id = serializers.IntegerField(required=False) # required=False 指明反序时(前端提交数据过来)不做校验
title = serializers.CharField(max_length=32, validators = [my_validate,])
............................
validate做数据校验错误返回的key问题:
def validate(self, attrs):
password = attrs.get('password')
re_password = attrs.pop('re_password')
print(password, re_password)
if password != re_password:
raise serializers.ValidationError('两次密码不一致')
return attrs
校验如有错误,报错的格式如下:
{
"status": 1,
"message": {
"non_field_errors": [
"两次密码不一致"
]
}
}
message的key为non_field_errors,传递到前端不方便处理,可以自定义一个key
raise serializers.ValidationError({'password': '两次密码不一致'})
报错格式如下:
{
"status": 1,
"message": {
"password": [
"两次密码不一致"
]
}
}
class BookView(APIView):
def get(self, request):
book_queryset = Book.objects.all()
ser_obj = BookSerializer(book_queryset, many = True)
return Response(ser_obj.data)
def post(self, request):
book_obj = request.data
# print(book_obj, type(book_obj))
ser_obj = BookSerializer(data = book_obj)
if ser_obj.is_valid():
# ser_obj.save()使用该方法时,序列化器中必须实例create()方法
ser_obj.save()
return Response(ser_obj.validated_data)
return Response(ser_obj.errors)
class BookEditView(APIView):
def get(self, request, id):
book_obj = Book.objects.filter(id = id).first()
ser_obj = BookSerializer(book_obj)
return Response(ser_obj.data)
def put(self, request, id):
book_obj = Book.objects.filter(id=id).first()
# partial=True 指明为部分字段做校验,即传入什么字段就校验什么字段,其他字段不做校验
ser_obj = BookSerializer(instance = book_obj, data = request.data, partial = True)
if ser_obj.is_valid():
ser_obj.save()
return Response(ser_obj.validated_data)
return Response(ser_obj.errors)
使用serializers.Serializer方法序列化时注意以下几点:
1:正序与反序字段不一致
2:字段中的参数 required=False 指明反序时(前端提交数据过来)不做数据校验
3:read_only=True 参数指明该字段只做序列化,反序列化时不走该字段;那么反序列化时就必须重新指定字段名
4:write_only 参数指明该字段只用做反序列化
5:序列化器中必须实现create()与update()方法,分别对应创建与更新
6:前端提交的参数校验与Django中的form表单校验数据一样
# 只修改了book表的序列化器,其他文件不动
class BookSerializer(serializers.ModelSerializer):
class Meta:
model = Book
fields = '__all__'
序列化后的数据如下:
外键关联的字段只显示了id,添加一个depth参数
class BookSerializer(serializers.ModelSerializer):
class Meta:
model = Book
fields = '__all__'
depth = 1
序列化后的数据如下:
depth=1,意为找到一层关联的数据,即找到publisher关联表,如果publisher中有还有关联的表,不会再往下去找。
注意:
class BookSerializer(serializers.ModelSerializer):
class Meta:
model = Book
fields = '__all__'
# exclude = ['id']
# depth = 1 # 注意: depth会让所有的外键关系字段变成read_only=True
extra_kwargs = {
'publisher': {'write_only': True},
'authors': {'write_only': True},
}
# 重写正序字段
publisher_info = serializers.SerializerMethodField(read_only=True)
# SerializerMethodField是一个方法字段,即需要一个方法的返回值再赋给该字段
authors_info = serializers.SerializerMethodField(read_only=True)
def get_publisher_info(self, obj):
publisher_obj = obj.publisher
print(publisher_obj)
return {'id': publisher_obj.id, 'title': publisher_obj.title}
def get_authors_info(self, obj):
authors_queryset = obj.authors.all()
return [{'id': author.id, 'name': author.name} for author in authors_queryset]
外键关联的字段正序使用的是publisher_info与authors_info,那么反序还是使用的publisher与authors字段。字段的校验与上面的一样。
这里所说的自定义序列字段可以另一张表中的字段,也可以自定要序列化的字段,也可以是外键关联的字段。
这种字段可以使用serializers.SerializerMethodField方法写在序列化器中
也可以在模型类中定义方法
1:写在序列化器中
class BookSerializer(serializers.ModelSerializer):
publisher = serializers.SerializerMethodField()
def get_publisher(self, obj):
return obj.publisher.name
class Meta:
model = Book
fields = ['name', 'price', 'publisher']
注意:使用serializers.SerializerMethodField方法时,在fields列表中必须写上该字段,如上面代码中的publisher。如果fields列表中没有指定publiser字段,会报如下异常:
The field 'publisher' was declared on serializer BookSerializer, but has not been included in the 'fields' option.
2:写在模型类中
class Book(BaseModel):
name = models.CharField(max_length=64)
price = models.DecimalField(max_digits=5, decimal_places=2)
img = models.ImageField(upload_to='img', default='img/default.jpg')
publisher = models.ForeignKey(to='Publisher', on_delete=models.CASCADE)
authors = models.ManyToManyField(to='Author')
class Meta:
db_table = 'gin_book'
def __str__(self):
return self.name
@property
def publisher_name(self): # 定义成一个方法属性,方法名与属性名不能重复
return self.publisher.name
序列化类中的fields列表,可以指定publisher_name;不指定也不报异常
class BookSerializer(serializers.ModelSerializer):
class Meta:
model = Book
fields = ['name', 'price', 'publisher_name'] # 不指定publisher_name字段不会抛异常
使用该方法时反序列化如下:
class BookSerializer(serializers.ModelSerializer):
class Meta:
model = Book
fields = ['name', 'price', 'publisher_name', 'img', 'author_list', 'publisher', 'authors']
extra_kwargs = {
'publisher': {'write_only': True},
'authors': {'write_only': True},
'name': {
'required': True,
'min_length': 3,
'error_messages': {
'required': '必填项',
'min_length': '至少3个字符'
}
}
}
视图类:
class BooksView(APIView):
def get(self, request):
queryset = Book.objects.filter(is_delete = False)
serializer = BookSerializer(queryset, many = True)
return Response(serializer.data)
def post(self, request):
ser_obj = BookSerializer(data = request.data)
ser_obj.is_valid(raise_exception=True) # 当校验失败会马上终止当前视图方法,抛出异常给前台
book_obj = ser_obj.save()
return Response({'status': 0, 'message': 'OK', 'result': BookSerializer(book_obj).data})
模型类如下:
class Book(BaseModel):
name = models.CharField(max_length=64)
price = models.DecimalField(max_digits=5, decimal_places=2)
img = models.ImageField(upload_to='img', default='img/default.jpg')
publisher = models.ForeignKey(to='Publisher', on_delete=models.CASCADE)
authors = models.ManyToManyField(to='Author')
class Meta:
db_table = 'gin_book'
def __str__(self):
return self.name
class Publisher(BaseModel):
name = models.CharField(max_length=64)
address = models.CharField(max_length=64)
class Meta:
db_table = 'gin_publisher'
def __str__(self):
return self.name
需求:Book表序列化时,也要序列化Pulisher表中指定的字段
class PublisherSerializer(serializers.ModelSerializer):
class Meta:
model = Publisher
fields = ['name', 'address']
class BookSerializer(serializers.ModelSerializer):
# 自定义连表深度 - 子序列化方式
publisher = PublisherSerializer()
class Meta:
model = Book
fields = ['name', 'price', 'publisher']
序列化器如下:
class BookSerializer(serializers.ModelSerializer):
class Meta:
model = Book
fields = ['name', 'price', 'publisher_name', 'img', 'author_list', 'publisher', 'authors']
extra_kwargs = {
'publisher': {'write_only': True},
'authors': {'write_only'
版权声明:本文来源CSDN,感谢博主原创文章,遵循 CC 4.0 by-sa 版权协议,转载请附上原文出处链接和本声明。
原文链接:https://blog.csdn.net/pcn01/article/details/103952474
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发表于 2021-06-14 00:27:52
- 阅读 ( 839 )
- 分类:Go
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