条件搜索

如果某个API需要传递一些条件进行搜索，其实就在是URL后面通过GET传参即可，例如：

/api/users?age=19&category=12

在drf中也有相应组件可以支持条件搜索。

自定义Filter

自定义filter后，需要在view视图类中定义filter_backeds类变量，django会自动读取循环filter_backeds中的filter类并执行实例化对象的filter_query方法。（get，put，delete，patch都会执行，post不会）

# urls.pyfrom django.urls import path
from app01 import viewsurlpatterns = [path('api/users/', views.UserView.as_view({"get": "list", "post": "create"})),path('api/users/<int:pk>/', views.UserView.as_view({"get": "retrieve", "put": "update", "patch": "partial_update", "delete": "destroy"})),
]

# views.pyfrom rest_framework import serializers
from rest_framework.viewsets import ModelViewSet
from rest_framework.filters import BaseFilterBackend
from app01 import modelsclass UserModelSerializer(serializers.ModelSerializer):level_text = serializers.CharField(source="get_level_display",read_only=True)extra = serializers.SerializerMethodField(read_only=True)class Meta:model = models.UserInfofields = ["username", "age", "email", "level_text", "extra"]def get_extra(self, obj):return 666class Filter1(BaseFilterBackend):def filter_queryset(self, request, queryset, view):age = request.query_params.get('age')if not age:return querysetreturn queryset.filter(age=age)class Filter2(BaseFilterBackend):def filter_queryset(self, request, queryset, view):user_id = request.query_params.get('id')if not user_id:return querysetreturn queryset.filter(id__gt=user_id)class UserView(ModelViewSet):filter_backends = [Filter1, Filter2]queryset = models.UserInfo.objects.all()serializer_class = UserModelSerializerdef perform_create(self, serializer):""" 序列化：对请求的数据校验成功后，执行保存。"""serializer.save(depart_id=1, password="123")

第三方Filter

在drf开发中有一个常用的第三方过滤器：DjangoFilterBackend。

pip install django-filter

注册app：

INSTALLED_APPS = [...'django_filters',...
]

视图配置和应用（示例1）：

最简单应用：

可以通过下载，django-filter组件，引入django_filter.rest_framework import DjangoFilterBancked。

在view视图类中定义filter_banckeds=[DjangoFilterBancked]，和filterset_fields=[“id”,“name”,“age”]。

# views.py
from rest_framework import serializers
from rest_framework.viewsets import ModelViewSet
from django_filters.rest_framework import DjangoFilterBackend
from app01 import modelsclass UserModelSerializer(serializers.ModelSerializer):level_text = serializers.CharField(source="get_level_display",read_only=True)extra = serializers.SerializerMethodField(read_only=True)class Meta:model = models.UserInfofields = ["username", "age", "email", "level_text", "extra"]def get_extra(self, obj):return 666class UserView(ModelViewSet):filter_backends = [DjangoFilterBackend, ]filterset_fields = ["id", "age", "email"]queryset = models.UserInfo.objects.all()serializer_class = UserModelSerializerdef perform_create(self, serializer):""" 序列化：对请求的数据校验成功后，执行保存。"""serializer.save(depart_id=1, password="123")

视图配置和应用（示例2）：

还可以通过定义类变量filterset_class来定义更复杂的查询变量条件,

flilter类应该继承FilterSet，（类的构建类似于MoldeForm）

from rest_framework import serializers
from rest_framework.viewsets import ModelViewSet
from django_filters.rest_framework import DjangoFilterBackend
from django_filters import FilterSet, filters
from app01 import modelsclass UserModelSerializer(serializers.ModelSerializer):level_text = serializers.CharField(source="get_level_display",read_only=True)depart_title = serializers.CharField(source="depart.title",read_only=True)extra = serializers.SerializerMethodField(read_only=True)class Meta:model = models.UserInfofields = ["id", "username", "age", "email", "level_text", "extra", "depart_title"]def get_extra(self, obj):return 666class MyFilterSet(FilterSet):depart = filters.CharFilter(field_name="depart__title", lookup_expr="exact")min_id = filters.NumberFilter(field_name='id', lookup_expr='gte')class Meta:model = models.UserInfofields = ["min_id", "depart"]class UserView(ModelViewSet):filter_backends = [DjangoFilterBackend, ]filterset_class = MyFilterSetqueryset = models.UserInfo.objects.all()serializer_class = UserModelSerializerdef perform_create(self, serializer):""" 序列化：对请求的数据校验成功后，执行保存。"""serializer.save(depart_id=1, password="123")

视图配置和应用（示例3）：

• 构建filter类的字段：

  NumberFilter，CharFilter，BooleanFilter，MultipleChoiceFilter，BaseInFilter，NumericRangeFilter，OrderingFilter，

  还可以通过CharFilter使用自定义搜索的方法。

• lookup_expr过滤条件：

  'exact': _(''),
  'iexact': _(''),'contains': _('contains'),
  'icontains': _('contains'),
  'startswith': _('starts with'),
  'istartswith': _('starts with'),
  'endswith': _('ends with'),  
  'iendswith': _('ends with'),'gt': _('is greater than'),
  'gte': _('is greater than or equal to'),
  'lt': _('is less than'),
  'lte': _('is less than or equal to'),'in': _('is in'),
  'range': _('is in range'),
  'isnull': _(''),'regex': _('matches regex'),
  'iregex': _('matches regex'),
  

from rest_framework import serializers
from rest_framework.viewsets import ModelViewSet
from django_filters.rest_framework import DjangoFilterBackend, OrderingFilter
from django_filters import FilterSet, filters
from app01 import modelsclass UserModelSerializer(serializers.ModelSerializer):level_text = serializers.CharField(source="get_level_display",read_only=True)depart_title = serializers.CharField(source="depart.title",read_only=True)extra = serializers.SerializerMethodField(read_only=True)class Meta:model = models.UserInfofields = ["id", "username", "age", "email", "level_text", "extra", "depart_title"]def get_extra(self, obj):return 666class MyFilterSet(FilterSet):# /api/users/?min_id=2  -> id>=2min_id = filters.NumberFilter(field_name='id', lookup_expr='gte')# /api/users/?name=wupeiqi  -> not ( username=wupeiqi )name = filters.CharFilter(field_name="username", lookup_expr="exact", exclude=True)# /api/users/?depart=xx     -> depart__title like %xx%depart = filters.CharFilter(field_name="depart__title", lookup_expr="contains")# /api/users/?token=true      -> "token" IS NULL# /api/users/?token=false     -> "token" IS NOT NULLtoken = filters.BooleanFilter(field_name="token", lookup_expr="isnull")# /api/users/?email=xx     -> email like xx%email = filters.CharFilter(field_name="email", lookup_expr="startswith")# /api/users/?level=2&level=1   -> "level" = 1 OR "level" = 2（必须的是存在的数据，否则报错-->内部有校验机制）# level = filters.AllValuesMultipleFilter(field_name="level", lookup_expr="exact")level = filters.MultipleChoiceFilter(field_name="level", lookup_expr="exact", choices=models.UserInfo.level_choices)# /api/users/?age=18,20     -> age in [18,20]age = filters.BaseInFilter(field_name='age', lookup_expr="in")# /api/users/?range_id_max=10&range_id_min=1    -> id BETWEEN 1 AND 10range_id = filters.NumericRangeFilter(field_name='id', lookup_expr='range')# /api/users/?ordering=id     -> order by id asc# /api/users/?ordering=-id     -> order by id desc# /api/users/?ordering=age     -> order by age asc# /api/users/?ordering=-age     -> order by age descordering = filters.OrderingFilter(fields=["id", "age"])# /api/users/?size=1     -> limit 1（自定义搜索）size = filters.CharFilter(method='filter_size', distinct=False, required=False)class Meta:model = models.UserInfofields = ["id", "min_id", "name", "depart", "email", "level", "age", 'range_id', "size", "ordering"]def filter_size(self, queryset, name, value):int_value = int(value)return queryset[0:int_value]class UserView(ModelViewSet):filter_backends = [DjangoFilterBackend, ]filterset_class = MyFilterSetqueryset = models.UserInfo.objects.all()serializer_class = UserModelSerializerdef perform_create(self, serializer):""" 序列化：对请求的数据校验成功后，执行保存。"""serializer.save(depart_id=1, password="123")

lookup_expr有很多常见选择：

'exact': _(''),
'iexact': _(''),'contains': _('contains'),
'icontains': _('contains'),
'startswith': _('starts with'),
'istartswith': _('starts with'),
'endswith': _('ends with'),  
'iendswith': _('ends with'),'gt': _('is greater than'),
'gte': _('is greater than or equal to'),
'lt': _('is less than'),
'lte': _('is less than or equal to'),'in': _('is in'),
'range': _('is in range'),
'isnull': _(''),'regex': _('matches regex'),
'iregex': _('matches regex'),

全局配置和应用：

# settings.py 全局配置REST_FRAMEWORK = {'DEFAULT_FILTER_BACKENDS': ['django_filters.rest_framework.DjangoFilterBackend',]
}

内置Filter

drf源码中内置了2个filter，分别是：

• OrderingFilter，支持排序。

  from rest_framework import serializers
  from rest_framework.viewsets import ModelViewSet
  from app01 import models
  from rest_framework.filters import OrderingFilterclass UserModelSerializer(serializers.ModelSerializer):level_text = serializers.CharField(source="get_level_display",read_only=True)depart_title = serializers.CharField(source="depart.title",read_only=True)extra = serializers.SerializerMethodField(read_only=True)class Meta:model = models.UserInfofields = ["id", "username", "age", "email", "level_text", "extra", "depart_title"]def get_extra(self, obj):return 666class UserView(ModelViewSet):filter_backends = [OrderingFilter, ]# ?order=id# ?order=-id# ?order=ageordering_fields = ["id", "age"]queryset = models.UserInfo.objects.all()serializer_class = UserModelSerializerdef perform_create(self, serializer):""" 序列化：对请求的数据校验成功后，执行保存。"""serializer.save(depart_id=1, password="123")
  

• SearchFilter，支持模糊搜索。

  from rest_framework import serializers
  from rest_framework.viewsets import ModelViewSet
  from app01 import models
  from rest_framework.filters import SearchFilterclass UserModelSerializer(serializers.ModelSerializer):level_text = serializers.CharField(source="get_level_display",read_only=True)depart_title = serializers.CharField(source="depart.title",read_only=True)extra = serializers.SerializerMethodField(read_only=True)class Meta:model = models.UserInfofields = ["id", "username", "age", "email", "level_text", "extra", "depart_title"]def get_extra(self, obj):return 666class UserView(ModelViewSet):# ?search=DP%Tfilter_backends = [SearchFilter, ]search_fields = ["id", "username", "age"]queryset = models.UserInfo.objects.all()serializer_class = UserModelSerializerdef perform_create(self, serializer):""" 序列化：对请求的数据校验成功后，执行保存。"""serializer.save(depart_id=1, password="123")

  "app01_userinfo"."id" LIKE %DPT% ESCAPE '\' 
  OR 
  "app01_userinfo"."username" LIKE %DPT% ESCAPE '\' 
  OR 
  "app01_userinfo"."age" LIKE %DPT% ESCAPE '\'
  

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