djangorestframework

 

1、安装

pip install djangorestframework

Serializers and ModelSerializer

首先我们要定义一些序列化程序。我们创建一个名为 tutorial/quickstart/serializers.py的文件，来用作我们的数据表示。

# by gaoxin
from rest_framework import serializers
from .models import Book


class PublisherSerializer(serializers.Serializer):
    id = serializers.IntegerField()
    title = serializers.CharField(max_length=32)


class AuthorSerializer(serializers.Serializer):
    id = serializers.IntegerField()
    name = serializers.CharField(max_length=32)


book_obj = {
        "title": "Alex的使用教程",
        "w_category": 1,
        "pub_time": "2018-10-09",
        "publisher_id": 1,
        "author_list": [1, 2]
    }


data = {
    "title": "Alex的使用教程2"
}

# 验证器：为某些字段设置额外的验证  
# 权重信息大于钩子，就是先验证该条件
def my_validate(value):
    if "敏感信息" in value.lower():
        raise serializers.ValidationError("不能含有敏感信息")
    else:
        return value


# class BookSerializer(serializers.Serializer):
#     required=False  设置是收数据是该字段可以为空
#     id = serializers.IntegerField(required=False)
#     validators=[my_validate]  验证器：为该字段设置额外的验证函数
#     title = serializers.CharField(max_length=32, validators=[my_validate])
#     CHOICES = ((1, "Python"), (2, "Go"), (3, "Linux"))
#     source="get_category_display"  获取数字所对应的值  read_only=True  设置为只用于发送数据，不用于验证信息
#     category = serializers.ChoiceField(choices=CHOICES, source="get_category_display", read_only=True)
#     write_only=True  接受信息验证时使用该字段，前段传数据时key要用w_category
#     w_category = serializers.ChoiceField(choices=CHOICES, write_only=True)
#     pub_time = serializers.DateField()
#
#     publisher = PublisherSerializer(read_only=True)
#     publisher_id = serializers.IntegerField(write_only=True)
#     author = AuthorSerializer(many=True, read_only=True)
#     author_list = serializers.ListField(write_only=True)
#
#      post 创建数据时需要重构该方法
#     def create(self, validated_data):
#         book = Book.objects.create(title=validated_data["title"], category=validated_data["w_category"],
#                                 pub_time=validated_data["pub_time"], publisher_id=validated_data["publisher_id"])
#         book.author.add(*validated_data["author_list"])
#         return book
#
#       put 更新数据时需要重构该方法
#     def update(self, instance, validated_data):
#         instance.title = validated_data.get("title", instance.title)
#         instance.category = validated_data.get("category", instance.category)
#         instance.pub_time = validated_data.get("pub_time", instance.pub_time)
#         instance.publisher_id = validated_data.get("publisher_id", instance.publisher_id)
#          多对多数据时的方法
#         if validated_data.get("author_list"):
#             instance.author.set(validated_data["author_list"])
#         instance.save()
#         return instance
#            
#       局部钩子函数为title字段设置额外的验证要求    
#     def validate_title(self, value):
#         if "python" not in value.lower():
#             raise serializers.ValidationError("标题必须含有python")
#         return value
#
#      全局钩子
#     def validate(self, attrs):
#         if attrs["w_category"] == 1 and attrs["publisher_id"] == 1:
#             return attrs
#         else:
#             raise serializers.ValidationError("分类以及标题不符合要求")


class BookSerializer(serializers.ModelSerializer):
    # 根据相应的get_...方法执行只获取我们想要的数据
    category_display = serializers.SerializerMethodField(read_only=True)
    publisher_info = serializers.SerializerMethodField(read_only=True)
    authors = serializers.SerializerMethodField(read_only=True)

    def get_category_display(self, obj):
        return obj.get_category_display()

    def get_authors(self, obj):
        authors_query_set = obj.author.all()
        return [{"id": author_obj.id, "name": author_obj.name} for author_obj in authors_query_set]

    def get_publisher_info(self, obj):
        # obj 是我们序列化的每个Book对象
        publisher_obj = obj.publisher
        return {"id": publisher_obj.id, "title": publisher_obj.title}

    class Meta:
        model = Book
        # fields = ["id", "title", "pub_time"]
        fields = "__all__"
        # depth = 1 根据外键关系只向下找一层  depth = 2 向下找二层 
        # depth = 1   这种是获取所有字段
        # read_only=True 结合下面的"write_only": True 原来显示的字段不展示，只显示需要的数据
        extra_kwargs = {"category": {"write_only": True}, "publisher": {"write_only": True},
                        "author": {"write_only": True}}

Serializer以及ModelSerializer区别(常用的)