简介
与表做强关联，之后不需要再写create与update函数了
官网：https://www.django-rest-framework.org/api-guide/serializers/语法
有多种写法，局部钩子与全局钩子是一样的
class 类名(serializers.ModelSerializer)
# 固定写法，在类中再定义一个Meta
class Meta:
# 与表做强关联，左边的字段必须是model
model = models.Book
# 查询所有字段，但在显示外键时，会显示外键的字段id，并不是名。
fields = '__all__'
# 也可以使用fields指定字段，列表中进行注册
fields = ['字段名1', '字段名2', ...]
# 只读字段
read_only_fields = ['字段名1', '字段名2']
# 只写字段
write_only_fields = ['字段名1', '字段名2']
# 对字段定制限制，方法一：在Meta中定制
extra_kwargs = {'字段名': {'max_length': 8, 'error_messages': {'max_length': '不能超过8个字符'}},
'字段名': {'read_only': True}
'字段名': {'write_only': True}}
# 方法二：在Meta类外定义，且需要在Meta中的fields中进行注册，如：
name = serializers.CharField(max_length=8, error_messages={'max_length': '不能超过8个字符'})
price = serializers.CharField(max_length=8)
publish = serializers.SerializerMethodField()
def get_publish(self, obj):
# 这里的obj其实就相当于Book.publish.name中的Book
return {'name': obj.publish.name, 'phone': obj.publish.addr}
# 多对多关系的字定义
authors = serializers.SerializerMethodField()
def get_authors(self, obj):
author_list = []
for author in obj.authors.all():
author_list.append({'name': author.name, 'phone': author.phone})
return author_list
- 如下图，使用fields='__all__'后，前端获取到的是字段id号
示例
- models.py
models.py
```python
from django.db import models
# Create your models here.
class Book(models.Model):
name = models.CharField(max_length=32)
price = models.CharField(max_length=32)
# 图书与出版社外键字段，一对多
publish = models.ForeignKey(to='Publish', on_delete=models.CASCADE)
# 图书与作者外键字段，多对多
authors = models.ManyToManyField(to='Author')
@property
def publish_detail(self):
return {'name': self.publish.name, 'addr': self.publish.addr}
@property
def author_detail(self):
author_list = []
for author in self.authors.all():
author_list.append({'name': author.name, 'phone': author.phone})
return author_list
class Publish(models.Model):
name = models.CharField(max_length=32)
addr = models.CharField(max_length=64)
class Author(models.Model):
name = models.CharField(max_length=32)
phone = models.CharField(max_length=11)
使用Meta进行定义
- serializer.py
class BookModelSerializer(serializers.ModelSerializer):
class Meta:
model = models.Book
fields = ['name', 'price', 'publish_detail', 'author_detail', 'publish', 'authors']
extra_kwargs = {'name': {'max_length': 8, 'error_messages': {'max_length': '不能超过8个字符'}},
'price': {'max_length': 8},
'publish_detail': {'read_only': True}, # 此字段是在models.py中定义的
'author_detail': {'read_only': True}, # 此字段是在models.py中定义的
'publish': {'write_only': True},
'authors': {'write_only': True}}
在Meta类外进行定义
- serializer.py
class BookModelSerializer(serializers.ModelSerializer):
class Meta:
model = models.Book
fields = ['name', 'price', 'publish', 'authors', 'publish_detail', 'author_detail']
read_only_fields = ['publish_detail', 'author_detail'] # 此字段是在models.py中定义的
write_only_fields = ['publish', 'authors']
# 注意下面两个字段是写在Meta外的
name = serializers.CharField(max_length=8, error_messages={'max_length': '不能超过8个字符'})
price = serializers.CharField(max_length=8)