目錄
數據准備
model.py文件
定義兩個表Car表和Brand表，其中Car中的brand字段外鍵關聯Brand表
from django.db import models
class BaseModel(models.Model):
is_delete = models.BooleanField(default=False)
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 = '汽車'
verbose_name_plural = verbose_name
def __str__(self):
return self.name
class Brand(BaseModel):
name = models.CharField(max_length=32)
class Meta:
db_table = 'old_boy_brand'
verbose_name = '品牌'
verbose_name_plural = verbose_name
def __str__(self):
return self.name
新建的serializer.py文件
brand字段只參與反序列化，brand_name只參與序列化
from rest_framework.serializers import ModelSerializer
from . import models
class CarModelSerializer(ModelSerializer):
class Meta:
model = models.Car
fields = ('name','price','brand','brand_name')
extra_kwargs = {
"brand":{
'write_only':True
},
'brand_name':{
'read_only':True
},
}
分類篩選 filter_fields
views.py文件
from rest_framework.viewsets import ModelViewSet
from . import models, serializer
from django_filters.rest_framework import DjangoFilterBackend
class CarModelViewSet(ModelViewSet):
queryset = models.Car.objects.filter(is_delete=False)
serializer_class = serializer.CarModelSerializer
filter_backends = [DjangoFilterBackend]
# 分類: 一般都是可以分組的字段
filter_fields = ['brand']
# 按品牌brand分類，url鏈接：/car/?brand=1
區間篩選 filter_class
新建的 filterset.py
max_price與min_price是用於參與區間分類，不寫也可以僅做分類同 filter_fields效果一樣
from django_filters import FilterSet,filters
from . import models
class CarFilterSet(FilterSet):
max_price = filters.NumberFilter(field_name='price',lookup_expr='lte')
min_price = filters.NumberFilter(field_name='price',lookup_expr='gte')
class Meta:
model = models.Car
# brand 還是實現分類
fields = ['brand','max_price','min_price']
views.py文件
from rest_framework.viewsets import ModelViewSet
from . import models, serializer
from django_filters.rest_framework import DjangoFilterBackend
from .filterset import CarFilterSet
class CarModelViewSet(ModelViewSet):
queryset = models.Car.objects.filter(is_delete=False)
serializer_class = serializer.CarModelSerializer
filter_backends = [DjangoFilterBackend]
filter_class = CarFilterSet
# url鏈接：/car/?max_price=100 價格不超過100
# url鏈接：/car/?min_price=10 價格不低於10
# url鏈接：/car/?brand=1&min_price=10&max_price=100 品牌brand為1且價格在[10,100]內的汽車
DjangoFilterBackend部分源碼解析
1. 在DjangoFilterBackend組件中先調用filter_queryset方法中
def filter_queryset(self, request, queryset, view):
filterset = self.get_filterset(request, queryset, view) # 獲取篩選條件
# 如果filterset為None，表示沒有篩選條件
if filterset is None:
return queryset
# 無效的篩選條件處理
if not filterset.is_valid() and self.raise_exception:
raise utils.translate_validation(filterset.errors)
return filterset.qs
2. 調用get_filterset方法獲取filterset
def get_filterset(self, request, queryset, view):
filterset_class = self.get_filterset_class(view, queryset) # 獲取篩選類
if filterset_class is None:
return None
kwargs = self.get_filterset_kwargs(request, queryset, view)
return filterset_class(**kwargs)
3.調用get_filterset_class方法獲取filterset_class
def get_filterset_class(self, view, queryset=None):
"""
Return the `FilterSet` class used to filter the queryset.
"""
filterset_class = getattr(view, 'filterset_class', None)
filterset_fields = getattr(view, 'filterset_fields', None)
# 將filter_class映射給filterset_class
if filterset_class is None and hasattr(view, 'filter_class'):
utils.deprecate(
"`%s.filter_class` attribute should be renamed `filterset_class`."
% view.__class__.__name__)
filterset_class = getattr(view, 'filter_class', None)
# 將filter_fields映射給filterset_fields
if filterset_fields is None and hasattr(view, 'filter_fields'):
utils.deprecate(
"`%s.filter_fields` attribute should be renamed `filterset_fields`."
% view.__class__.__name__)
filterset_fields = getattr(view, 'filter_fields', None)
# 有filterset_class時執行，filterset_class定義的是一個類
if filterset_class:
filterset_model = filterset_class._meta.model
# FilterSets do not need to specify a Meta class
if filterset_model and queryset is not None:
assert issubclass(queryset.model, filterset_model), \
'FilterSet model %s does not match queryset model %s' % \
(filterset_model, queryset.model)
return filterset_class
# 有filterset_fields時執行
if filterset_fields and queryset is not None:
MetaBase = getattr(self.filterset_base, 'Meta', object)
class AutoFilterSet(self.filterset_base):
class Meta(MetaBase):
model = queryset.model
fields = filterset_fields
return AutoFilterSet
return None