drf - ModelSerializers serialized

Others 2019-09-09 01:23:12 views: null

table of Contents

drf - ModelSerializers serialized

Project Preparation

Configuration settings.py

# 注册rest_framework app
INSTALLED_APPS = [
    # ...
    'rest_framework',
]

# 连接mysql数据库
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'dg_proj',
        'USER': 'root',
        'PASSWORD': '123',
        'HOST': '127.0.0.1',
        'PORT': 3306
    }
}

# 导入pymysql模块
"""
任何__init__文件
import pymysql
pymysql.install_as_MySQLdb()
"""

# 汉化
LANGUAGE_CODE = 'zh-hans'
TIME_ZONE = 'Asia/Shanghai'
USE_I18N = True
USE_L10N = True
USE_TZ = False

# 配置静态文件路径以及媒体文件路径
STATIC_URL = '/static/'
STATICFILES_DIRS = (
    os.path.join(BASE_DIR, 'static'),
)

MEDIA_URL = '/media/'
MEDIA_ROOT = os.path.join(BASE_DIR, 'media')

routing

Primary route urls.py

from django.conf.urls import url, include
from django.contib import admin
from django.views import serve
from django.conf import settings

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^api/', include('api.urls')),
    url(r'^media/(?P<path>.*)', serve, {'document_root': settings.MEDIA_ROOT}),
]

Sub routing api / urls.py

from django.conf.urls import url
from . import views
urlpatterns = [
    url(r'^books/$', views.BookAPIView.as_view()),
    url(r'^books/(?P<pk>\d+)/$', views.BookAPIView.as_view()),
]

Multi-table design

Table relationship analysis

"""
Book表:
    name, price, img, publish(关联Publish表), authors(关联Author表), is_delete, create_time

Publish表:
    name, address, is_delete, create_time
    
Author表:
    name, age, is_delete, create_time
    
AuthorDetail表:
    mobile, author(关联Author表), is_delete, create_time
    
因为每个字段都有is_delete, create_time这两个字段,所以我们可以设置一个基表,其他的表继承基表
BaseModel表:
    is_delete, create_time
"""

Table diagram:

Creating models

Base table utils / models.py

from django.db import models

class BaseModel(models.Model):
    is_delete = models.BooleanField(default=False)
    create_time = models.DateTimeField(auto_now_add=True, null=True)
    
    class Meta:
        # 抽象表, 不会完成数据库迁移
        abstract = True

Model layer api / models.py

from django.db import models
from utils.models import BaseModel
"""
relate_name: 从表在查主表时,可以通过relate_name进行查询,无需再进行反向查询(表名小写_set)
db_constraint: 设为False表示断开表关系
on_delete: 默认为CASCSADE, 表示主表进行删除操作时进行级联删除
           DO_NOTHING, 表示主表进行删除时, 不进行任何操作
           SET_NULL, 表示主表进行删除时, 该字段设为null, 此时null要设为True
           SET_DEFAULT, 表示主表进行删除时, 该字段设为默认值, 此时default要进行设置
           
           注意: on_delete操作, 从表删除时,主表不会有任何变化
db_table: 设置建表是的表名, 不采用默认表名
verbose_name: 在admin中进行操作时, 反馈到前台表或者字段的名字
"""

# Create your models here.
class Book(BaseModel):
    name = models.CharField(max_length=64)
    price = models.DecimalField(max_digits=6, decimal_places=2)
    img = models.ImageField(upload_to='icon', default='icon/default.png')
    publish = models.ForeignKey(to='Publish',
                                null=True,
                                related_name='books',
                                db_constraint=False,
                                on_delete=models.DO_NOTHING
                                # on_delete=models.SET_NULL, null=True
                                # on_delete=models.SET_DEFAULT, default=1
                                )
    authors = models.ManyToManyField(to='Author',
                                     related_name='authors',
                                     db_constraint=False
                                     )
    # 自定义model类的方法，完成插拔式跨表查询，默认在校验时为read_only
    @property
    def publish_info(self):
        return {'name': self.publish.name, 'address': self.publish.address}
    
    @property
    def author_info(self):
        author_list = []
        
        for author in self.authors.all():
            detail = AuthorDetail.objects.filter(author_id=self.author.id)
            author_list.append({
                'name': author.name,
                'age': author.age,
                # 注意点：当author.detail为空时，就直接不走这一步了
                # 'mobile': author.detail.mobile
                'mobile': '未知' if not detail else author.detail.mobile
            })
            
        return author_list
        

    class Meta:
        db_table = "books"
        verbose_name = '书籍'
        verbose_name_plural = verbose_name

    def __str__(self):
        return self.name


class Author(BaseModel):
    name = models.CharField(max_length=64)
    age = models.IntegerField()

    @property
    def mobile(self):
        return self.detail.mobile
    
    class Meta:
        db_table = 'author'
        verbose_name = '作者'
        verbose_name_plural = verbose_name

    def __str__(self):
        return self.name


class AuthorDetail(BaseModel):
    mobile = models.CharField(max_length=11)
    author = models.OneToOneField(to='Author',
                                  null=True,
                                  related_name='detail',
                                  db_constraint=False,
                                  on_delete=models.CASCADE
                                  )
    class Meta:
        db_table = 'detail'
        verbose_name = '作者详情'
        verbose_name_plural = verbose_name

    def __str__(self):
        return f"{self.author.name}的详情"


class Publish(BaseModel):
    name = models.CharField(max_length=64)
    address = models.CharField(max_length=128)

    class Meta:
        db_table = 'publish'
        verbose_name = '出版社'
        verbose_name_plural = verbose_name

    def __str__(self):
        return self.name

Model serialization

Inherited from rest_framework.serializerstheModelSerializer

  1. Provided ModelSerializer custom classes in class Meta

    binding model class model serialization

    fields specified by the field sequence of pluggable manner

  2. Model class, by model table in Method property and then plug in the fields from even fields of the table defined in the query,

  3. If a foreign key field even complete table query, using the sequence of depth

    eg：publish = PublishModelSerializer()

Custom model serialization api / serializers.py

from rest_framework import serializers
from . import models

# 序列化深度
class PublishModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = models.Publish
        fields = ('name', 'address')
        
# 序列化深度
class AuthorModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = models.Author
        fields = ('name', 'age', 'mobile')
        
class BookModelSerializer(serializers.ModelSerializer):
    # 正向序列化深度
    publish = PublishModelSerializer()
    authors = AuthorModelSerializer(many=True)
    
    """了解：
    在ModelSerializer中不建议使用，如何书写了必须在fields中声明使用
        p_n = serializers.SerializerMethodField()
        def get_p_n(self, obj: models.Book):
            return obj.publish.name
    """
    class Meta:
        # 绑定序列化的模型类
        model = models.Book
        # 插拔字段
        fields = ('name', 'price', 'img', 'publish', 'authors', 'publish_info', 'author_info')
        
        """了解：
        fields = "__all__" ：拿出所有字段
        exclude = ('id', 'is_delete')：除了这些字段，其它字段全部拿出来
        depth = 1 ：跨表查询的深度（展示外键的所有字段）
        """

Use view api / views.py

from rest_framework.views import APIView
from utils.response import APIResponse
from . import models, serializers

class BookAPIView(APIView):
    def get(self, request, *args, **kwargs):
        # 单取
        pk = kwargs.get('pk')
        if pk:
            book_obj = models.Book.objects.filter(pk=pk, is_delete=False).first()
            if not book_obj:
                return APIResponse(1, 'pk有误')
            
            book_ser = serializers.BookModelSerializer(book_obj)
            return APIResponse(0, 'ok', results=book_ser.data)
        book_obj_list = models.Book.objects.filter(is_delete=False).all()
        if not book_obj_list:
            return APIResponse(1,'没有数据')
        book_ser = serializers.BookModelSerializer(book_obj_list, many=True)
        return APIResponse(0,'ok',results=book_ser.data)

Model deserialization

Inherited from rest_framework.serializerstheModelSerializer

  1. Provided ModelSerializer custom classes in class Meta

    models: Binding deserialized relevant model class

    fields: Plug fields specify deserialization

    extra_kwargs: definition of system rules check field

  2. Custom validation rules can be complex local and global hook hooks completion field

  3. No need to override create and update the added modification, ModelSerializer class has helped us achieve

Custom Model deserialization api / serializers.py

from rest_framework import serializers
from . import models

class BookModelDeserializer(serializers.ModelSerializer):
    # 自定义的校验字段，一定要插入到fields中
    re_name = serializers.CharField(
        min_length=3, 
        required=True, 
        error_messages={
            'min_length': '太短了',
            'required': '不能为空'
        }
    )
    class Meta:
        model = models.Book
        fields = ('name', 're_name', 'price', 'publish', 'authors')
        extra_kwargs = {
            'name':{
                'min_length': 3,
                'error_messages': {
                    'min_length': '太短了',
                    'required': '不能为空'
                }
            },
            # 有默认值的字段会默认required为False，在反序列化中就不会进行校验
            'publish':{
                'required': True,
                'error_messages':{
                    'required': '不能为空'
                }
            },
            'authors':{
                'required': True,
                'error_messages':{
                    'required': '不能为空'
                }
            }
        }
        
        # 自定义校验规则
        # 局部钩子
        def validate_name(self, value):
            if 'sb' in value:
                raise serializers.ValidationError('书名包含敏感词汇')
            return value
        
        def validate(self, attr):
            name = attr.get('name')
            re_name = attr.get('re_name')
            publish = attr.get('publish')
            if name != re_name:
                raise serializers.ValidationError(
                    {'re_name': '两次书名不一致'}
                )
            if models.Book.objects.filter(name=name, publish=publish):
                raise serializers.ValidationError(
                    {'book': '书籍已存在'}
                )
                
            return attr

Use view api / views.py

from rest_framework.views import APIView
from utils.response import APIResponse
from . import models, serializers

class BookAPIView(APIView):
    def post(self, request, *args, **kwargs):
        book_ser = serializers.BookModelDeserializer(data=request.data)
        if book_ser.is_valid():
            book_obj = book_ser.save()
            results = serializers.BookModelDeserializer(book_obj).data
            return APIResponse(0, 'ok', results=results)
        else:
            return APIResponse(1, '添加失败', resultes=book_ser.errors)

Model serializer (serialization and deserialization Integration *****)

Sub routing api / urls.py

from django.conf.urls import url
from . import views
urlpatterns = [
    url(r'^v2/books/$', views.BookV2APIView.as_view()),
    url(r'^v2/books/(?P<pk>.*)/$', views.BookV2APIView.as_view()),
]

Custom serializer api / serializers.py

from rest_framework import serializers
from . import models

class BookV2ModelSerializer(serializers.ModelSerializer):
    re_name = serializers.CharField(
        min_length=3, 
        required=True, 
        write_only=True,  # 只参与反序列化
        error_messages={
            'min_length': '太短了',
            'required': '不能为空'
        }
    )
    
    class Meta:
        model = models.Book
        fields = ('name', 're_name', 'price', 'img', 'publish', 'publish_info', 'authors', 'authors_info')
         extra_kwargs = {
            'name':{
                'min_length': 3,
                'error_messages': {
                    'min_length': '太短了',
                    'required': '不能为空'
                }
            },
            # 有默认值的字段会默认required为False，在反序列化中如果不传值不会进行校验，但是如果传值就会进行校验
            'publish':{
                'required': True,
                'write_only': True,
                'error_messages':{
                    'required': '不能为空'
                }
            },
            'authors':{
                'required': True,
                'write_only': True,
                'error_messages':{
                    'required': '不能为空'
                }
            },
        }
            
        # 自定义校验规则
        # 局部钩子
        def validate_name(self, value):
            if 'sb' in value:
                raise serializers.ValidationError('书名包含敏感词汇')
            return value
        
        def validate(self, attr):
            name = attr.get('name')
            re_name = attr.get('re_name')
            publish = attr.get('publish')
            if name != re_name:
                raise serializers.ValidationError(
                    {'re_name': '两次书名不一致'}
                )
            if models.Book.objects.filter(name=name, publish=publish):
                raise serializers.ValidationError(
                    {'book': '书籍已存在'}
                )
                
            return attr

Use view api / views.py

class BookV2APIView(APIView):
    def get(self, request, *args, **kwargs):
        pk = request.get('pk')
        # 单取
        if pk:
            book_obj = models.Book.objects.filter(is_delete=False, pk=pk).first()
            if not pk:
                return APIResponse(1, 'pk有误')
            book_ser = serializers.BookV2ModelSerializer(book_obj)
            return APIResponse(0, 'ok', results=book_ser.data)

        # 群取
        book_obj_list = models.Book.objects.filter(is_delete=False).all()
        if not book_obj_list:
            return APIResponse(1, '没有数据')
        book_ser = serializers.BookV2ModelSerializer(book_obj_list, many=True)
        return APIResponse(0, 'ok', results=book_ser.data)

    # 增加一个
    def post(self, request, *args, **kwargs):
        book_ser = serializers.BookV2ModelSerializer(data=request.data)
        if book_ser.is_valid():
            book_obj = book_ser.save()
            results = serializers.BookV2ModelSerializer(book_obj).data
            return APIResponse(0, 'ok', results=results)
        else:
            return APIResponse(1, '添加失败', results=book_ser.errors)

    # 局部修改一个
    def patch(self, request, *args, **kwargs):
        pk = request.get('pk')

        if not pk:
            return APIResponse(1, 'pk有误')

        try:
            book_obj = models.Book.objects.get(is_delete=False, pk=pk)
        except:
            return APIResponse(1, 'pk不存在')

        book_ser = serializers.BookV2ModelSerializer(instance=book_obj, data=request.data, partial=True)
        if book_ser.is_valid():
            book_obj = book_ser.save()
            results = serializers.BookV2ModelSerializer(book_obj)
            return APIResponse(0, 'ok', results=results)
        else:
            return APIResponse(1, '修改失败', results=book_ser.errors)

        # 整体修改一个

    def put(self, request, *args, **kwargs):
        pk = request.get('pk')

        if not pk:
            return APIResponse(1, 'pk有误')

        try:
            book_obj = models.Book.objects.get(is_delete=False, pk=pk)
        except:
            return APIResponse(1, 'pk不存在')

        book_ser = serializers.BookV2ModelSerializer(instance=book_obj, data=request.data)
        if book_ser.is_valid():
            book_obj = book_ser.save()
            results = serializers.BookV2ModelSerializer(book_obj)
            return APIResponse(0, 'ok', results=results)
        else:
            return APIResponse(1, '修改失败', results=book_ser.errors)

    # 删除
    def delete(self, request, *args, **kwargs):
        # 单删 /books/(pk)/
        # 群删 /books/  数据包携带 pks => request.data
        pk = request.get('pk')
        if pk:
            pks = [pk, ]
        else:
            pks = request.data.get('pk')

        if not pks:
            return APIResponse(1, 'pk有误')
        book_obj_list = models.Book.objects.filter(is_delete=False, pk__in=pks)
        if not book_obj_list.update(is_delete=True):
            return APIResponse(1, '删除失败')
        return APIResponse(0, '删除成功')

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