Django里rest_framework的视图组件ModelViewSet进行优化视图

使用视图组件进行接口优化

1. 使用视图组件的generics进行接口逻辑优化

   1. 导入ModelViewSet

      from rest_framework.viewsets import ModelViewSet
      

   2. 定义序列化类

      class BookSerializer(serializers.ModelSerializer):
        	class Meta:
            	model = 指定模型类
              fields = (指定验证字段)
              extra_kwargs = {"field_name":{"write_only":True}}
      

   3. 导入序列化类

      from .app_serializers import BookSerializer
      

   4. 定义视图类

      # 如果你的类只需要get和post方法你继承generics.ListCreateAPIView就可以了
      class BookView(ModelViewSet):
        	# queryset和serializer_class是固定的写法
        	# 指定queryset
        	queryset = BookInfo.objects.all()
          # 指定序列化类
          serializer_class = BookSerializer
      

GET获取全部数据和POST新增一条数据案列GET获取一条数据和PUT修改一条数据和DELETE删除一条数据

1. 建立url

    re_path(r"^books/$", BookView.as_view({
        "get": "list",
        "post": "create"
    })),
   
    re_path(r"^books/(?P\d+)/$", BookView.as_view({
        "get": "retrieve",
        "put": "update",
        "delete": "destroy"
    }))
   

2. 正则不取名叫pk会报一个Expected view BookFilterView to be called with a URL keyword argument named “pk”.的错误
   

3. 建立model

   from django.db import models
   
   from datetime import datetime
   # from django.contrib.auth.models import AbstractUser
   
   
   class AuthorInfo(models.Model):
       name = models.CharField(max_length=32, verbose_name="作者名称")
       age = models.IntegerField(verbose_name="作者年龄")
   
       class Meta:
           db_table = "db_author_info"
           verbose_name = "作者信息"
           verbose_name_plural = verbose_name
   
       def __str__(self):
           return self.name
   
   
   class PublishInfo(models.Model):
       name = models.CharField(max_length=32, verbose_name="出版社名称")
       city = models.CharField(max_length=32, verbose_name="出版社所在城市")
       email = models.EmailField(verbose_name="出版社邮箱")
   
       class Meta:
           db_table = "db_publish_info"
           verbose_name = "出版社信息"
           verbose_name_plural = verbose_name
   
       def __str__(self):
           return self.name
   
   
   class BookInfo(models.Model):
       title = models.CharField(max_length=32, verbose_name="书名")
       publishDate = models.DateField(default=datetime.now, verbose_name="出版日期")
   
       # max_digits小数位加整数位多少长度 decimal_places小数位长度为2
       price = models.DecimalField(max_digits=5, decimal_places=2, verbose_name="图书价格")
       publish = models.ForeignKey(PublishInfo, related_name="book", related_query_name="book_query", on_delete=models.CASCADE, verbose_name="出版社")
       # ManyToManyField多对多
       authors = models.ManyToManyField(AuthorInfo, verbose_name="图书作者")
   
       class Meta:
           db_table = "db_book_info"
           verbose_name = "图书信息"
           verbose_name_plural = verbose_name
   
       def __str__(self):
           return self.title
   
   

4. 导入ModelViewSet

    from rest_framework.viewsets import ModelViewSet
   

5. 定义序列化类

   from.models import BookInfo
   # 第一步: 导入模块
   from rest_framework import serializers
   
   class BookSerializer(serializers.ModelSerializer):
       class Meta:
           # 指定    要操作的模型类
           model = BookInfo
   
           # 指定序列化的字段
           fields = (
               "title",
               "price",
               "publishDate",
               "publish",
               "authors",
               "author_list",
               "publish_name",
               "publish_city"
           )
   
           # 指定那些字段是只写的
           # write_only只写的 (只写的 前端发送数据时要写它, 后端返回数据时没有它)
           extra_kwargs = {
               "publish": {"write_only": True},
               "authors": {"write_only": True}
           }
   
       # 自定义的字段
       # read_only只读的 (只读的 前端发送数据时不用写它, 后端返回数据时有它)
       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 = []
   
           for author in book_obj.authors.all():
               authors.append(author.name)
           return authors
   

6. 导入序列化类

   from .app_serializers import BookSerializer
   

7. 定义视图类

   from rest_framework.viewsets import ModelViewSet
   
   from .models import BookInfo, PublishInfo, AuthorInfo
   from .app_serializers import BookSerializer
   
   class BookView(ModelViewSet):
       # queryset和serializer_class是固定的写法
       # 告诉它quertset是谁
       queryset = BookInfo.objects.all()
    
       # 告诉它序列化的类
       serializer_class = BookSerializer
   

8. postman的GET请求所有数据
   

9. postman的POST请求所有数据
   

10. postman的GET请求获取一条数据
    

11. postman的PUT请求修改一条数据
    

12. postman的DELETE请求删除一条数据
    

viewset源码剖析

• Django程序启动, 开始初始化, 读取url.py, 读取settings, 读取视图类
• 执行as_views(), BookView没有, 需要到父类(ModelViewSet)中找
• ModelViewSet继承了mixin的几个Modelmixin和GenericViewSet, 显然ModelMixin也没有, 只有GenericViewSet中有
• GenericViewSet没有任何代码, 只继承了ViewSetMixin和generics, GenericAPIView
• 继续去ViewSetMixin中查找, 找到了as_view类方法, 在重新封装view函数的过程中, 有一个self.action_map = actions
• 这个actions就是我们给as_view()传递的从参数
• 绑定url和视图函数(actions)之间的映射关系
• 等待用户请求
• 接受到用户请求, 根据url找到视图函数
• 执行视图函数的dispatch方法(因为视图函数的返回值是: return self.dispatch())
• dispatch分发请求, 查找到视图类的五个方法中的某个
• 开始执行, 比如post请求, 返回: self.create(), 视图类本身没有, 则会到父类中查找
• 最后在CreateModelMixin中查找
• 执行create()方法, 获取queryset和serializer_class
• 返回数据

这就是viewset优化方案, 整个优化方案最重要的地方就是url.py中我们传入的参数, 然后对参数进行映射关系绑定