day02---模型类序列化器

一时失言乱红尘 2022-12-08 15:45 141阅读 0赞

## 一：模型类序列化器的定义和基本使用： ##

1：demo测试：

from rest_framework import serializers
    # serializers.ModelSerializer : 模型类序列化器基类
    from models import BookInfo
    class BooInfoModelSerialisers(serializers.ModelSerializer):
        class Meta:
            # 1: 声明当前序列化器针对的模型类
            model = BookInfo
            # 2: 声明参与序列化/反序列化的模型类字段
            fields = "__all__" # 所有字段

2：测试运行：

>>> from books.serializers import *
    >>> from books.models import *
    >>> book = BookInfo.objects.get(pk=1)
    >>> book
    <BookInfo: 射雕英雄传>
    >>> bs = BooInfoModelSerialisers(instance=book)
    >>> bs.data
    {
        'image': None, 'bread': 12, 'btitle': '射雕英雄传', 'bcomment': 34, 'is_delete': False, 'bpub_date': '1980-05-01', 'id': 1}

3：注意的事情：  
3.1：**all** 的范围：除了主键字段会映射，其余隐藏字段：如外键字段，不会主动映射。  
3.2： 查看序列化哪些内容：直接调用一下序列化器对象：

>>> BooInfoModelSerialisers()
    BooInfoModelSerialisers():
        id = IntegerField(label='ID', read_only=True)
        btitle = CharField(label='名称', max_length=20)
        bpub_date = DateField(label='发布日期')
        bread = IntegerField(label='阅读量', max_value=2147483647, min_value=-2147483648, required=False)
        bcomment = IntegerField(label='评论量', max_value=2147483647, min_value=-2147483648, required=False)
        is_delete = BooleanField(label='逻辑删除', required=False)
        image = ImageField(allow_null=True, label='图片', max_length=100, required=False)

3.3：显示的声明哪些字段需要被序列化/反序列化：fields = \[\]

class BooInfoModelSerialisers(serializers.ModelSerializer):
        class Meta:
            # 1: 声明当前序列化器针对的模型类
            model = BookInfo
            # 2: 声明参与序列化/反序列化的模型类字段
            # fields = "__all__" # 所有字段
            fields = ['btitle', 'bread']

BooInfoModelSerialisers():
        btitle = CharField(label='名称', max_length=20)
        bread = IntegerField(label='阅读量', max_value=2147483647, min_value=-2147483648, required=False)

3.4:除了。。。以外的字段都拿过来。。：exclude = \[\]

exclude = ['btitle', 'bread']

>>> from books.serializers import *
    >>> BooInfoModelSerialisers()
    BooInfoModelSerialisers():
        id = IntegerField(label='ID', read_only=True)
        bpub_date = DateField(label='发布日期')
        bcomment = IntegerField(label='评论量', max_value=2147483647, min_value=-2147483648, required=False)
        is_delete = BooleanField(label='逻辑删除', required=False)
        image = ImageField(allow_null=True, label='图片', max_length=100, required=False)

3.5: 修改映射过来的约束条件：`extra_kwargs = {"bread": {"min_value" : 0}}`

class BooInfoModelSerialisers(serializers.ModelSerializer):
    
    
        class Meta:
            # 1: 声明当前序列化器针对的模型类
            model = BookInfo
            # 2: 声明参与序列化/反序列化的模型类字段
            fields = "__all__" # 所有字段
            extra_kwargs = {
        "bcomment": {
        "min_value": 0}}

>>> from books.serializers import * 
    >>> BooInfoModelSerialisers()
    BooInfoModelSerialisers():
        id = IntegerField(label='ID', read_only=True)
        btitle = CharField(label='名称', max_length=20)
        bpub_date = DateField(label='发布日期')
        bread = IntegerField(label='阅读量', max_value=2147483647, min_value=-2147483648, required=False)
        bcomment = IntegerField(label='评论量', max_value=2147483647, min_value=0, required=False)
        is_delete = BooleanField(label='逻辑删除', required=False)
        image = ImageField(allow_null=True, label='图片', max_length=100, required=False)

3.6:设置read\_only 的方法： read\_only\_fields = \[\]  
id 只参与序列化，不参与反序列化。

## 二：利用模型类序列化器进行新建和修改 ##

1： 测试新建：

>>> from books.serializers import *
    >>> from books.models import *
    >>> book_info = {
        "btitle": "胡子猎战", "bpub_date": "1999-10-1"}
    >>> bs = BooInfoModelSerialisers(data = book_info)
    >>> bs.is_valid()
    True
    >>> bs.save()
    <BookInfo: 胡子猎战>

2：测试修改：

>>> book = BookInfo.objects.get(pk =6)
    >>> book_info = {
        "btitle": "山纹列传"}
    >>> bs = BooInfoModelSerialisers(instance= book, data= book_info, partial=True)
    >>> bs.is_valid()
    True
    >>> bs.save()
    <BookInfo: 山纹列传>