DRF框架之自定义action

Posted 2020-12-17 xiaogongjin

一、自定义action

• 使用action装饰器
• methods
  • 支持的请求方式，为一个列表，默认为[‘get‘]
• detail
  • 必传参数，
  • 要处理的是否是详情资源对象（即是否通过url路径获取主键）
  • True表示需要传递主键id，使用通过URL获取的主键对应的数据对象
  • False表示不需要传递主键id，不使用URL获取主键
• url_path
  • 指定url部分，默认为action名称
• url_name
  • 指定url的名称，默认为action名称

二、action源码

def action(methods=None, detail=None, url_path=None, url_name=None, **kwargs):
    """
    Mark a ViewSet method as a routable action.

    `@action`-decorated functions will be endowed with a `mapping` property,
    a `MethodMapper` that can be used to add additional method-based behaviors
    on the routed action.

    :param methods: A list of HTTP method names this action responds to.
                    Defaults to GET only.
    :param detail: Required. Determines whether this action applies to
                   instance/detail requests or collection/list requests.
    :param url_path: Define the URL segment for this action. Defaults to the
                     name of the method decorated.
    :param url_name: Define the internal (`reverse`) URL name for this action.
                     Defaults to the name of the method decorated with underscores
                     replaced with dashes.
    :param kwargs: Additional properties to set on the view.  This can be used
                   to override viewset-level *_classes settings, equivalent to
                   how the `@renderer_classes` etc. decorators work for function-
                   based API views.
    """
    methods = [‘get‘] if (methods is None) else methods
    methods = [method.lower() for method in methods]

    assert detail is not None, (
        "@action() missing required argument: ‘detail‘"
    )

    # name and suffix are mutually exclusive
    if ‘name‘ in kwargs and ‘suffix‘ in kwargs:
        raise TypeError("`name` and `suffix` are mutually exclusive arguments.")

    def decorator(func):
        func.mapping = MethodMapper(func, methods)

        func.detail = detail
        func.url_path = url_path if url_path else func.__name__
        func.url_name = url_name if url_name else func.__name__.replace(‘_‘, ‘-‘)

        # These kwargs will end up being passed to `ViewSet.as_view()` within
        # the router, which eventually delegates to Django‘s CBV `View`,
        # which assigns them as instance attributes for each request.
        func.kwargs = kwargs

        # Set descriptive arguments for viewsets
        if ‘name‘ not in kwargs and ‘suffix‘ not in kwargs:
            func.kwargs[‘name‘] = pretty_name(func.__name__)
        func.kwargs[‘description‘] = func.__doc__ or None

        return func
    return decorator

三、使用方法

 1.引入action

from rest_framework.decorators import action

2.定义一个序列化器类

from rest_framework import serializers
from .models import Projects


class ProjectsNamesModelSerializer(serializers.ModelSerializer):

    class Meta:
        model = Projects
        fields = (‘id‘, ‘name‘)

3.自定义action方法

使用装饰器@action()，传入methods和detail等参数值

@action(methods=[‘get‘], detail=False)
    def names(self, request):
        qs = self.filter_queryset(self.get_queryset())
        page = self.paginate_queryset(qs)
        if page:
            serializer_obj = self.get_serializer(instance=page, many=True)
            return Response(serializer_obj.data)
        serializer_obj = self.get_serializer(instance=qs, many=True)
        return Response(serializer_obj.data)

4.重写get_serializer_class方法

使用self.action可以获取到传入的action，因此可以使用if判断来满足特定条件下返回不同的序列化器类

    def get_serializer_class(self):
        if self.action == ‘names‘:
            return ProjectsNamesModelSerializer
        else:
            return self.serializer_class

5.配置路由信息

from django.contrib import admin
from django.urls import path
from projects.views import ProjectsPageSet


urlpatterns = [
    path(‘admin/‘, admin.site.urls)
    path(‘projects/names/‘, ProjectsPageSet.as_view({
        ‘get‘: ‘names‘
    }))
]

验证结果：

四、从表关联

需求：指定获取某个项目下对应的从表的id和name?

1.定义序列化器类

from rest_framework import serializers
from .models import Projects
from interfaces.models import Interfaces


class InterfacesNamesModelSerializer(serializers.ModelSerializer):

    class Meta:
        model = Interfaces
        fields = (‘id‘, ‘name‘)


class InterfacesByProjectIdModelSerializer(serializers.ModelSerializer):
    interfaces = InterfacesNamesModelSerializer(many=True, read_only=True, label=‘从表id‘, help_text=‘从表id‘)

    class Meta:
        model = Projects
        fields = (‘id‘, ‘interfaces‘)

2.自定义action方法

@action(methods=[‘get‘], detail=True)
    def interfaces(self, request, *args, **kwargs):
        qs = self.get_object()
        serializer_obj = self.get_serializer(instance=qs)
        return Response(serializer_obj.data)

3.重写get_serializer_class方法

    def get_serializer_class(self):
        if self.action == ‘interfaces‘:
            return InterfacesByProjectIdModelSerializer
        else:
            return self.serializer_class

验证结果：