DRF组件的使用和接口设计

一.序列化组件的使用及接口设计

1.通过序列化组件进行get和post接口设计

　　创建models.py

from django.db import models

# Create your models here.

class Author(models.Model):
    nid = models.AutoField(primary_key=True)
    name = models.CharField(max_length=32)
    age = models.IntegerField()
    def __str__(self):
        return self.name

class Publish(models.Model):
    nid = models.AutoField(primary_key=True)
    name = models.CharField(max_length=32)
    city = models.CharField(max_length=32)
    email = models.EmailField()

    def __str__(self):
        return self.name

class Book(models.Model):
    nid = models.AutoField(primary_key=True)
    title = models.CharField(max_length=32)
    price = models.DecimalField(max_digits=5,decimal_places=2)

    publish = models.ForeignKey(to="Publish",related_name="book",related_query_name="book_query",on_delete=models.CASCADE)
    authors = models.ManyToManyField(to="Author")

　　urls.py

from django.contrib import admin
from django.urls import path,re_path,include
from app01 import views

urlpatterns = [
    path('admin/', admin.site.urls),
    path('books/', views.BookView.as_view()),
]

　　app_serializers.py

from rest_framework import serializers


# 第二步， 创建一个序列化类，字段类型不一定要跟models的字段一致
class BookSerializer(serializers.Serializer):
    # nid = serializers.CharField(max_length=32)
    title = serializers.CharField(max_length=128)
    price = serializers.DecimalField(max_digits=5, decimal_places=2)
    publish = serializers.CharField()
    # 外键字段, 显示__str__方法的返回值
    publish_name = serializers.CharField(max_length=32, read_only=True, source='publish.name')
    publish_city = serializers.CharField(max_length=32, read_only=True, source='publish.city')
    # authors = serializers.CharField(max_length=32) # book_obj.authors.all()

    # 多对多字段需要自己手动获取数据，SerializerMethodField()
    authors_list = serializers.SerializerMethodField()

    def get_authors_list(self, book_obj):
        author_list = list()

        for author in book_obj.authors.all():
            author_list.append(author.name)

        return author_list

    def create(self, validated_data):
        # {'title': 'Python666', 'price': Decimal('66.00'), 'publish': '2'}
        validated_data['publish_id'] = validated_data.pop('publish')
        book = Book.objects.create(**validated_data)

        return book

　　view.py

　　from rest_framework.views import APIView
　　from rest_framework.response import Response

　　from .models import (
　　　　Book,
　　　　Publish,
　　　　Author,
　　)
　　from .app_serializers import BookSerializer

class BookView(APIView):
    def get(self, request):
        # 第三步，获取queryset
        origin_data = Book.objects.all()

        # 第四步，开始序列化
        serialized_data = BookSerializer(origin_data, many=True)

        return Response(serialized_data.data)

    def post(self, request):

        verified_data = BookSerializer(data=request.data)

        if verified_data.is_valid():
            book = verified_data.save()
            authors = Author.objects.filter(nid__in=request.data['authors'])
            book.authors.add(*authors)
            return Response(verified_data.data)
        else:
            return Response(verified_data.errors)

总结：
　　1. serializers.Serializer无法插入数据，只能自己实现create
　　2. 字段太多，不能自动序列化

2.通过序列化组件进行get单条数据和put,delete接口设计

　　get单条数据接口设计

　　　　1. 定义url
　　　　2. 获取数据对象
　　　　3. 开始序列化：serialized_data = BookSerializer(book_obj, many=False)
　　　　4. 返回数据：serialized_data.data

　　put数据接口设计
　　　　1. 定义url
　　　　2. 获取数据对象
　　　　　　2.1 book_obj = Book.objects.get(pk=1)
　　　　3. 开始序列化（验证数据，save()）
　　　　　　3.1 verified_data = BookSerializer(instance=book_obj, many=False)
　　　　4. 验证成功写入数据库，验证失败返回错误
　　　　　　4.1 verified_data.is_valid()

　　　deltet数据接口设计

　　　　1.定义url

　　　　2.获取数据对象并删除

　　　　　　　Book.objects.get(pk=nid).delete()

　　url.py

from django.urls import re_path
from serializer import views

urlpatterns = [
    re_path(r'books/$', views.BookView.as_view()),
    re_path(r'books/(?P<pk>d+)/$', views.BookFilterView.as_view()),
]

　　app_serializers.py

from rest_framework import serializers

from .models import Book

class BookSerializer(serializers.ModelSerializer):
    class Meta:
        model = Book

        fields = ('title',
                  'price',
                  'publish',
                  'authors',
                  'author_list',
                  'publish_name',
                  'publish_city'
                  )
        extra_kwargs = {
            'publish': {'write_only': True},
            'authors': {'write_only': True}
        }

    publish_name = serializers.CharField(max_length=32, read_only=True, source='publish.name')
    publish_city = serializers.CharField(max_length=32, read_only=True, source='publish.city')

    author_list = serializers.SerializerMethodField()

    def get_author_list(self, book_obj):
        # 拿到queryset开始循环 [{}, {}, {}, {}]
        authors = list()

        for author in book_obj.authors.all():
            authors.append(author.name)

        return authors

　　view.py

from rest_framework.views import APIView
from rest_framework.response import Response

from .app_serializers import BookSerializer
from .models import (
    Book,
    Publish,
    Author,
)

class BookFilterView(APIView):
    def get(self, request, nid):
        book_obj = Book.objects.get(pk=nid)

        serialized_data = BookSerializer(book_obj, many=False)

        return Response(serialized_data.data)

    def put(self, request, nid):
        book_obj = Book.objects.get(pk=nid)

        verified_data = BookSerializer(data=request.data, instance=book_obj)

        if verified_data.is_valid():
            verified_data.save()
            return Response(verified_data.data)
        else:
            return Response(verified_data.errors)

    def delete(self, request, nid):
        book_obj = Book.objects.get(pk=nid).delete()

        return Response()