DRF(七)

一.准备工作:

1.主路由:

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^api/', include('api.urls')),
]

2.api路由:

from django.conf.urls import url
from . import views

urlpatterns = [
    url(r'^cars/$', views.CarModelViewSet.as_view({
        'get': 'list',
        'post': 'create'
    })),
    url(r'^cars/(?P<pk>.*)/$', views.CarModelViewSet.as_view({
        'get': 'retrieve',
        'put': 'update',
        'patch': 'partial_update',
        'delete': 'destroy'
    })),
]

3.setting.py:

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'api.apps.ApiConfig',

    'rest_framework',

]

4.models:

from django.db import models


class BaseModel(models.Model):
    is_delete = models.BooleanField(default=0)
    create_time = models.DateTimeField(auto_now_add=True)
    class Meta:
        abstract = True

class Car(BaseModel):
    name = models.CharField(max_length=32)
    price = models.DecimalField(max_digits=5, decimal_places=2)
    brand = models.ForeignKey('Brand', db_constraint=False, on_delete=models.DO_NOTHING, related_name='cars')

    @property
    def brand_name(self):
        return self.brand.name

    class Meta:
        db_table = 'old_boy_car'
        verbose_name = '汽车'
        verbose_name_plural = verbose_name
    def __str__(self):
        return self.name

class Brand(BaseModel):
    name = models.CharField(max_length=16)
    class Meta:
        db_table = 'old_boy_brand'
        verbose_name = '品牌'
        verbose_name_plural = verbose_name
    def __str__(self):
        return self.name

5.视图类:

class CarModelViewSet(ModelViewSet):
    queryset = models.Car.objects.filter(is_delete=False)
    serializer_class = serializers.CarModelSerializer

    def destroy(self, request, *args, **kwargs):
        pk = kwargs.get('pk')
        try:
            car_obj = models.Car.objects.get(pk=pk, is_delete=False)
            car_obj.is_delete = True
            car_obj.save()
            return Response({
                'status': 0,
                'msg': '删除成功'
            })
        except:
            return Response({
                'status': 1,
                'msg': '删除失败'
            })

   def list(self, request, *args, **kwargs):
       response = super().list(request, *args, **kwargs)
       return Response({
              'status': 0,
               'msg': 'ok',
              'results': response.data
       }) 

二.路由组件 (写前面信息'cars'即可,有名分组自动补全pk):

from . import views
from rest_framework.routers import SimpleRouter
# 初始化路由对象
router = SimpleRouter()

# 注册各种接口路由
router.register('cars', views.CarModelViewSet, base_name='car')
# router.register('brands', views.BrandModelViewSet, base_name='brand')

urlpatterns = [   ]
urlpatterns.extend(router.urls)

三.搜索组件

主要是利用mixins.ListModelMixin类找到queryset,进而进行搜索,过滤,排序等操作

在filters.py文件中有SearchFilter和OrderingFilter两个类:

class SearchFilter(BaseFilterBackend):
    # The URL query parameter used for the search.
    search_param = api_settings.SEARCH_PARAM   默认是search
    template = 'rest_framework/filters/search.html'
    lookup_prefixes = {
        '^': 'istartswith',
        '=': 'iexact',
        '@': 'search',
        '$': 'iregex',
    }
    search_title = _('Search')
    search_description = _('A search term.')

需要两个参数:

    def filter_queryset(self, request, queryset, view):
        search_fields = self.get_search_fields(view, request)
        search_terms = self.get_search_terms(request)

视图类中自定义写法:

    from rest_framework.filters import SearchFilter, OrderingFilter

    # 搜索组件
    # 接口：/cars/?search=秦  ||  /cars/?search=1  在name和price两个字段中模糊搜索
    filter_backends = [SearchFilter]
    # 默认模糊查询，等价$，以什么开头^，精确匹配=，@？？
    search_fields = ['name', 'price']

四.排序组件(支持倒序)

    filter_backends = [SearchFilter, OrderingFilter]
    ordering_fields = ['pk', 'price']

   # 接口： api/cars/?search=1&ordering=-pk

五.筛选组件

安装:

pip install django-filter

配置:

INSTALLED_APPS = [
    ...
    'django_filters',  # 需要注册应用，
]

全局(也可以设置局部):
REST_FRAMEWORK = {
    ...
    'DEFAULT_FILTER_BACKENDS': ('django_filters.rest_framework.DjangoFilterBackend',)
}

视图类中:

   from .filtersets import CarFilterSet

    # 筛选(分类、区间)
    filter_backends = [SearchFilter, OrderingFilter, DjangoFilterBackend]
    # 分类：一般都是可以分组的字段
    # filter_fields = ['brand']
    # 区间，也可以包含分类，提倡 筛选 就采用该方式
    filter_class = CarFilterSet

区间类:

from django_filters.rest_framework import FilterSet
from django_filters import filters
from . import models
class CarFilterSet(FilterSet):
    min_price = filters.NumberFilter(field_name='price', lookup_expr='gte')
    max_price = filters.NumberFilter(field_name='price', lookup_expr='lte')
    class Meta:
        model = models.Car
        # brand还是实现分类
        # min_price，max_price可以定义区间
        fields = ['brand', 'min_price', 'max_price']

六.分页组件

视图分页:

 # 分页
    # 普通分页（最常用）
    # pagination_class = pagination.CarPageNumberPagination
    # 偏移分页
    # pagination_class = pagination.CarLimitOffsetPagination
    # 加密分页
    pagination_class = pagination.CarCursorPagination

自定义pagination.py:

from rest_framework.pagination import PageNumberPagination
# 普通分页
class CarPageNumberPagination(PageNumberPagination):
    # 默认一页的条数
    page_size = 3
    # 用户可以自定义选择一页的条数，但最多显示5条
    page_size_query_param = 'page_size'
    max_page_size = 5
    # 默认条数访问 /cars/?page=页面号
    #       eg：/cars/?page=1
    # 自定义条数访问 /cars/?page=页面号&page_size=一页的条数
    #       eg：/cars/?page=1&page_size=5


from rest_framework.pagination import LimitOffsetPagination
# 偏移分页
class CarLimitOffsetPagination(LimitOffsetPagination):
    # 默认一页的条数
    default_limit = 3
    # limit控制一页显示的条数，offset控制偏移的条数(从头开始计数)
    limit_query_param = 'limit'
    offset_query_param = 'offset'
    # 限制limit可以设置的最大显示条数
    max_limit = 5
    # 接口 /cars/?limit=一页的条数&offset=偏移的条数
    #       eg：/cars/?limit=5&offset=2  # 显示3~7条



from rest_framework.pagination import CursorPagination
# 加密分页
class CarCursorPagination(CursorPagination):
    # 默认一页的条数
    page_size = 3
    # 用户可以自定义选择一页的条数，但最多显示5条
    page_size_query_param = 'page_size'
    max_page_size = 5
    # 默认排序规则
    ordering = 'pk'
    # 采用默认排序访问 /cars/?cursor=加密串
    #       eg：/cars/?cursor=cD0z
    # 结合视图类实现OrderingFilter自定义排序规则
    #  /cars/?cursor=加密串&ordering=排序字段
    #       eg：/cars/?cursor=cD0z&ordering=-price

七.异常处理

配置:

# drf配置
REST_FRAMEWORK = {
    'EXCEPTION_HANDLER': 'api.exception.exception_handler'
}

自定义exception:

# rest_framework.views 下的 exception_handler 处理了所有 drf可控范围内的异常
from rest_framework.views import exception_handler as drf_exception_handler
# drf的异常还是交给 drf_exception_handler，我们只需要处理 drf未处理的异常

from rest_framework.response import Response

# 自定义异常句柄的原因：要通过 logging 记录异常日志
def exception_handler(exc, context):
    response = drf_exception_handler(exc, context)

    if response is None:
        # drf处理不了的异常
        return Response({
            'exception': '服务器异常',
        }, status=500)

    response.exception = True
    return response

八.接口文档(yapi)