DRF也给我们提供了跟模型紧密连接的序列化器:ModelSerializer
- 它会根据模型自动生成一组字段
- 它简单的默认实现了.update()以及.create()方法
定义一个ModelSerializer序列化器
class BookSerializer(serializers.ModelSerializer):
class Meta:
model = Book
fields = "__all__"
# fields = ["id", "title", "pub_time"]
# exclude = ["user"]
# 分别是所有字段 包含某些字段 排除某些字段
外键关系的序列化
注意:当序列化类MATE中定义了depth时,这个序列化类中引用字段(外键)则自动变为只读.
class BookSerializer(serializers.ModelSerializer):
class Meta:
model = Book
fields = "__all__"
# fields = ["id", "title", "pub_time"]
# exclude = ["user"]
# 分别是所有字段 包含某些字段 排除某些字段
depth = 1
# depth 代表找嵌套关系的第几层
自定义字段
我们可以自己声明一些字段来覆盖默认字段,来进行自定制
比如我们的选择字段,默认显示的是选择的key,我们要给用户展示的是value.
class BookSerializer(serializers.ModelSerializer):
chapter = serializers.CharField(source="get_chapter_display", read_only=True)
class Meta:
model = Book
fields = "__all__"
# fields = ["id", "title", "pub_time"]
# exclude = ["user"]
# 分别是所有字段 包含某些字段 排除某些字段
depth = 1
Meta中其它关键字参数
class BookSerializer(serializers.ModelSerializer):
chapter = serializers.CharField(source="get_chapter_display", read_only=True)
class Meta:
model = Book
fields = "__all__"
# fields = ["id", "title", "pub_time"]
# exclude = ["user"]
# 分别是所有字段 包含某些字段 排除某些字段
depth = 1
read_only_fields = ["id"]
extra_kwargs = {"title": {"validators": [my_validate,]}}
post以及patch请求
由于depth会让我们外键变成只读，所以我们再定义一个序列化的类，其实只要去掉depth就可以了~~
class BookSerializer(serializers.ModelSerializer):
chapter = serializers.CharField(source="get_chapter_display", read_only=True)
class Meta:
model = Book
fields = "__all__"
# fields = ["id", "title", "pub_time"]
# exclude = ["user"]
# 分别是所有字段 包含某些字段 排除某些字段
read_only_fields = ["id"]
extra_kwargs = {"title": {"validators": [my_validate,]}}
SerializerMethodField
外键关联的对象有很多字段我们是用不到的都传给前端会有数据冗余就需要我们自己去定制序列化外键对象的哪些字段~~
class BookSerializer(serializers.ModelSerializer):
chapter = serializers.CharField(source="get_chapter_display", read_only=True)
user = serializers.SerializerMethodField()
publisher = serializers.SerializerMethodField()
def get_user(self, obj):
# obj是当前序列化的book对象
users_query_set = obj.user.all()
return [{"id": user_obj.pk, "name": user_obj.name} for user_obj in users_query_set]
def get_publisher(self, obj):
publisher_obj = obj.publisher
return {"id": publisher_obj.pk, "title": publisher_obj.title}
class Meta:
model = Book
fields = "__all__"
# fields = ["id", "title", "pub_time"]
# exclude = ["user"]
# 分别是所有字段 包含某些字段 排除某些字段
read_only_fields = ["id"]
extra_kwargs = {"title": {"validators": [my_validate,]}}
用ModelSerializer改进上面的Serializer的完整版
class BookSerializer(serializers.ModelSerializer):
dis_chapter = serializers.SerializerMethodField(read_only=True)
users = serializers.SerializerMethodField(read_only=True)
publishers = serializers.SerializerMethodField(read_only=True)
def get_users(self, obj):
# obj是当前序列化的book对象
users_query_set = obj.user.all()
return [{"id": user_obj.pk, "name": user_obj.name} for user_obj in users_query_set]
def get_publishers(self, obj):
publisher_obj = obj.publisher
return {"id": publisher_obj.pk, "title": publisher_obj.title}
def get_dis_chapter(self, obj):
return obj.get_chapter_display()
class Meta:
model = Book
# fields = "__all__"
# 字段是有序的
fields = ["id", "title","dis_chapter", "pub_time", "publishers", "users","chapter", "user", "publisher"]
# exclude = ["user"]
# 分别是所有字段 包含某些字段 排除某些字段
read_only_fields = ["id", "dis_chapter", "users", "publishers"]
extra_kwargs = {"title": {"validators": [my_validate,]}, "user": {"write_only": True}, "publisher": {"write_only": True},
"chapter": {"write_only": True}}