Django REST framework+Vue 打造生鲜超市（十二）
十三、首页、商品数量、缓存和限速功能开发
13.1.轮播图接口实现
首先把pycharm环境改成本地的，vue中local_host也改成本地
（1）goods/serializer
class BannerSerializer(serializers.ModelSerializer): '''
轮播图
'''
class Meta:
model = Banner
fields = "__all__"
（2）goods/views.py
class BannerViewset(mixins.ListModelMixin, viewsets.GenericViewSet): """
首页轮播图
"""
queryset = Banner.objects.all().order_by("index")
serializer_class = BannerSerializer
（3）url
# 配置首页轮播图的urlrouter.register(r'banners', BannerViewset, base_name="banners")
在后台添加首页轮播图图片
13.2.新品接口功能开发
在设计Goods model时候有一个字段is_new
is_new = models.BooleanField("是否新品",default=False)实现这个接口只要在goods/filters/GoodsFilter里面添加一个过滤就可以了
class Meta: model = Goods
fields = ['pricemin', 'pricemax','is_hot','is_new']
在后台设置几个商品 is_new
13.3.首页商品分类显示功能
首先是大类，然后里面有
- 商品商标（多个）
- 大类下的二级类
- 广告商品
- 所有商品
（1）goods/serializers.py
class BrandSerializer(serializers.ModelSerializer): '''
大类下面的宣传商标
'''
class Meta:
model = GoodsCategoryBrand
fields = "__all__"
class IndexCategorySerializer(serializers.ModelSerializer):
#某个大类的商标，可以有多个商标，一对多的关系
brands = BrandSerializer(many=True)
# good有一个外键category，但这个外键指向的是三级类，直接反向通过外键category（三级类），取某个大类下面的商品是取不出来的
goods = serializers.SerializerMethodField()
# 在parent_category字段中定义的related_name="sub_cat"
# 取二级商品分类
sub_cat = CategorySerializer2(many=True)
# 广告商品
ad_goods = serializers.SerializerMethodField()
def get_ad_goods(self, obj):
goods_json = {}
ad_goods = IndexAd.objects.filter(category_id=obj.id, )
if ad_goods:
#取到这个商品Queryset[0]
good_ins = ad_goods[0].goods
#在serializer里面调用serializer的话，就要添加一个参数context（上下文request）,嵌套serializer必须加
# serializer返回的时候一定要加 “.data” ，这样才是json数据
goods_json = GoodsSerializer(good_ins, many=False, context={'request': self.context['request']}).data
return goods_json
#自定义获取方法
def get_goods(self, obj):
# 将这个商品相关父类子类等都可以进行匹配
all_goods = Goods.objects.filter(Q(category_id=obj.id) | Q(category__parent_category_id=obj.id) | Q(
category__parent_category__parent_category_id=obj.id))
goods_serializer = GoodsSerializer(all_goods, many=True, context={'request': self.context['request']})
return goods_serializer.data
class Meta:
model = GoodsCategory
fields = "__all__"
（2）goods/views.py
class IndexCategoryViewset(mixins.ListModelMixin, viewsets.GenericViewSet): """
首页商品分类数据
"""
# 获取is_tab=True（导航栏）里面的分类下的商品数据
queryset = GoodsCategory.objects.filter(is_tab=True, name__in=["生鲜食品", "酒水饮料"])
serializer_class = IndexCategorySerializer
（3）url
# 首页系列商品展示urlrouter.register(r'indexgoods', IndexCategoryViewset, base_name="indexgoods")
13.4.商品点击数和收藏数
（1）点击数GoodsListViewSet其中继承了mixins.RetrieveModelMixin（获取商品详情）
源码
class RetrieveModelMixin(object): """
Retrieve a model instance.
"""
def retrieve(self, request, *args, **kwargs):
instance = self.get_object()
serializer = self.get_serializer(instance)
return Response(serializer.data)
我们只要重写他的retrieve方法就可以了
goods/views
#商品点击数 + 1 def retrieve(self, request, *args, **kwargs):
instance = self.get_object()
instance.click_num += 1
instance.save()
serializer = self.get_serializer(instance)
return Response(serializer.data)
class GoodsListViewSet(mixins.ListModelMixin, mixins.RetrieveModelMixin,viewsets.GenericViewSet): '''
list:
商品列表，分页，搜索，过滤，排序
retrieve:
获取商品详情
'''
# authentication_classes = (TokenAuthentication,)
#这里必须要定义一个默认的排序,否则会报错
queryset = Goods.objects.all().order_by('id')
# 分页
pagination_class = GoodsPagination
#序列化
serializer_class = GoodsSerializer
filter_backends = (DjangoFilterBackend,filters.SearchFilter,filters.OrderingFilter)
# 设置filter的类为我们自定义的类
#过滤
filter_class = GoodsFilter
#搜索
search_fields = ('name', 'goods_brief', 'goods_desc')
#排序
ordering_fields = ('sold_num', 'shop_price')
#商品点击数 + 1
def retrieve(self, request, *args, **kwargs):
instance = self.get_object()
instance.click_num += 1
instance.save()
serializer = self.get_serializer(instance)
return Response(serializer.data)
（2）收藏数
前面已经写了UserFavViewset，其中继承了mixins.CreateModelMixin,添加收藏实际就是创建数据库
这里重写它的perform_create方法就可以了
user_operation/view.py
# 用户收藏的商品数量+1 def perform_create(self, serializer):
instance = serializer.save()
# 这里instance相当于UserFav model，通过它找到goods
goods = instance.goods
goods.fav_num += 1
goods.save()
class UserFavViewset(viewsets.GenericViewSet, mixins.ListModelMixin, mixins.CreateModelMixin, mixins.DestroyModelMixin):
'''
用户收藏
'''
#permission是用来做权限判断的
# IsAuthenticated：必须登录用户；IsOwnerOrReadOnly：必须是当前登录的用户
permission_classes = (IsAuthenticated,IsOwnerOrReadOnly)
#auth使用来做用户认证的
authentication_classes = (JSONWebTokenAuthentication,SessionAuthentication)
#搜索的字段
lookup_field = 'goods_id'
#动态选择serializer
def get_serializer_class(self):
if self.action == "list":
return UserFavDetailSerializer
elif self.action == "create":
return UserFavSerializer
return UserFavSerializer
def get_queryset(self):
#只能查看当前登录用户的收藏，不会获取所有用户的收藏
return UserFav.objects.filter(user=self.request.user)
# 用户收藏的商品数量+1
def perform_create(self, serializer):
instance = serializer.save()
# 这里instance相当于UserFav model，通过它找到goods
goods = instance.goods
goods.fav_num += 1
goods.save()
（3）用信号量实现
delete和create的时候django model都会发送一个信号量出来，用信号量的方式代码分离性更好
收藏数+1和-1
（1）user_operation/signal.py
# users_operation/signals.pyfrom django.db.models.signals import post_save,post_delete
from django.dispatch import receiver
from user_operation.models import UserFav
# post_save:接收信号的方式
#sender: 接收信号的model
@receiver(post_save, sender=UserFav)
def create_UserFav(sender, instance=None, created=False, **kwargs):
# 是否新建，因为update的时候也会进行post_save
if created:
goods = instance.goods
goods.fav_num += 1
goods.save()
@receiver(post_delete, sender=UserFav)
def delete_UserFav(sender, instance=None, created=False, **kwargs):
goods = instance.goods
goods.fav_num -= 1
goods.save()
（2）user_operation/apps.py
from django.apps import AppConfigclass UserOperationConfig(AppConfig):
name = 'user_operation'
verbose_name = "操作管理"
def ready(self):
import user_operation.signals
13.5.商品库存和销量修改
库存数量
商品库存数量的行为：
- 新增商品到购物车
- 修改购物车数量
- 删除购物车记录
trade/views.py
# 库存数-1 def perform_create(self, serializer):
shop_cart = serializer.save()
goods = shop_cart.goods
goods.goods_num -= shop_cart.nums
goods.save()
# 库存数+1
def perform_destroy(self, instance):
goods = instance.goods
goods.goods_num += instance.nums
goods.save()
instance.delete()
# 更新库存,修改可能是增加页可能是减少
def perform_update(self, serializer):
#首先获取修改之前的库存数量
existed_record = ShoppingCart.objects.get(id=serializer.instance.id)
existed_nums = existed_record.nums
# 先保存之前的数据existed_nums
saved_record = serializer.save()
#变化的数量
nums = saved_record.nums-existed_nums
goods = saved_record.goods
goods.goods_num -= nums
goods.save()
class ShoppingCartViewset(viewsets.ModelViewSet):
"""
购物车功能
list:
获取购物车详情
create：
加入购物车
delete：
删除购物记录
"""
permission_classes = (IsAuthenticated, IsOwnerOrReadOnly)
authentication_classes = (JSONWebTokenAuthentication, SessionAuthentication)
serializer_class = ShopCartSerializer
#商品的id
lookup_field = "goods_id"
def get_serializer_class(self):
if self.action == 'list':
return ShopCartDetailSerializer
else:
return ShopCartSerializer
#获取购物车列表
def get_queryset(self):
return ShoppingCart.objects.filter(user=self.request.user)
# 库存数-1
def perform_create(self, serializer):
shop_cart = serializer.save()
goods = shop_cart.goods
goods.goods_num -= shop_cart.nums
goods.save()
# 库存数+1
def perform_destroy(self, instance):
goods = instance.goods
goods.goods_num += instance.nums
goods.save()
instance.delete()
# 更新库存,修改可能是增加页可能是减少
def perform_update(self, serializer):
#首先获取修改之前的库存数量
existed_record = ShoppingCart.objects.get(id=serializer.instance.id)
existed_nums = existed_record.nums
# 先保存之前的数据existed_nums
saved_record = serializer.save()
#变化的数量
nums = saved_record.nums-existed_nums
goods = saved_record.goods
goods.goods_num -= nums
goods.save()
商品销量
商品的销量只有在支付成功后才会 +1
trade/views.py
for order_good in order_goods: goods = order_good.goods
goods.sold_num += order_good.goods_num
goods.save()
class AlipayView(APIView):
def get(self, request):
"""
处理支付宝的return_url返回
"""
processed_dict = {}
# 1. 获取GET中参数
for key, value in request.GET.items():
processed_dict[key] = value
# 2. 取出sign
sign = processed_dict.pop("sign", None)
# 3. 生成ALipay对象
alipay = AliPay(
app,
app_notify_url="http://47.93.198.159:8000/alipay/return/",
app_private_key_path=private_key_path,
alipay_public_key_path=ali_pub_key_path, # 支付宝的公钥，验证支付宝回传消息使用，不是你自己的公钥,
debug=True, # 默认False,
return_url="http://47.93.198.159:8000/alipay/return/"
)
verify_re = alipay.verify(processed_dict, sign)
# 这里可以不做操作。因为不管发不发return url。notify url都会修改订单状态。
if verify_re is True:
order_sn = processed_dict.get('out_trade_no', None)
trade_no = processed_dict.get('trade_no', None)
trade_status = processed_dict.get('trade_status', None)
existed_orders = OrderInfo.objects.filter(order_sn=order_sn)
for existed_order in existed_orders:
existed_order.pay_status = trade_status
existed_order.trade_no = trade_no
existed_order.pay_time = datetime.now()
existed_order.save()
response = redirect("/index/#/app/home/member/order")
return response
else:
response = redirect("index")
return response
def post(self, request):
"""
处理支付宝的notify_url
"""
#存放post里面所有的数据
processed_dict = {}
#取出post里面的数据
for key, value in request.POST.items():
processed_dict[key] = value
#把signpop掉，文档有说明
sign = processed_dict.pop("sign", None)
#生成一个Alipay对象
alipay = AliPay(
app,
app_notify_url="http://47.93.198.159:8000/alipay/return/",
app_private_key_path=private_key_path,
alipay_public_key_path=ali_pub_key_path, # 支付宝的公钥，验证支付宝回传消息使用，不是你自己的公钥,
debug=True, # 默认False,
return_url="http://47.93.198.159:8000/alipay/return/"
)
#进行验证
verify_re = alipay.verify(processed_dict, sign)
# 如果验签成功
if verify_re is True:
#商户网站唯一订单号
order_sn = processed_dict.get('out_trade_no', None)
#支付宝系统交易流水号
trade_no = processed_dict.get('trade_no', None)
#交易状态
trade_status = processed_dict.get('trade_status', None)
# 查询数据库中订单记录
existed_orders = OrderInfo.objects.filter(order_sn=order_sn)
for existed_order in existed_orders:
# 订单商品项
order_goods = existed_order.goods.all()
# 商品销量增加订单中数值
for order_good in order_goods:
goods = order_good.goods
goods.sold_num += order_good.goods_num
goods.save()
# 更新订单状态
existed_order.pay_status = trade_status
existed_order.trade_no = trade_no
existed_order.pay_time = datetime.now()
existed_order.save()
#需要返回一个'success'给支付宝，如果不返回，支付宝会一直发送订单支付成功的消息
return Response("success")
13.6.drf的缓存设置
为了加速网站的访问速度，将一些数据放到缓存当中，取数据的时候首先去缓存中去，然后再去数据库中取
我们用drf的一个扩展来实现缓存，github上面的使用说明：http://chibisov.github.io/drf-extensions/docs/#caching
（1）安装
pip install drf-extensions（2）使用方法
导入
from rest_framework_extensions.cache.mixins import CacheResponseMixin在GoodsListViewSet中添加缓存功能
#CacheResponseMixin一定要放在第一个位置class GoodsListViewSet(CacheResponseMixin,mixins.ListModelMixin, mixins.RetrieveModelMixin,viewsets.GenericViewSet):
设置过期时间，settings里面
#缓存配置REST_FRAMEWORK_EXTENSIONS = {
'DEFAULT_CACHE_RESPONSE_TIMEOUT': 5 #5s过期，时间自己可以随便设定
}
这个缓存使用的是内存，每次重启之后就会失效
13.7.drf配置redis缓存
使用django-redis第三方库：http://django-redis-chs.readthedocs.io/zh_CN/latest/#id8 （文档说明）
（1）安装
pip install django-redis（2）settings
# redis缓存CACHES = {
"default": {
"BACKEND": "django_redis.cache.RedisCache",
"LOCATION": "redis://127.0.0.1:6379",
"OPTIONS": {
"CLIENT_CLASS": "django_redis.client.DefaultClient",
}
}
}
13.8.drf的throttle设置api的访问速率
为了防止爬虫对服务器造成的重大压力，对数据进行访问速率限制就显得非常的重要了
官网使用说明：http://www.django-rest-framework.org/api-guide/throttling/
（1）settings中配置
REST_FRAMEWORK = { #限速设置
'DEFAULT_THROTTLE_CLASSES': (
'rest_framework.throttling.AnonRateThrottle', #未登陆用户
'rest_framework.throttling.UserRateThrottle' #登陆用户
),
'DEFAULT_THROTTLE_RATES': {
'anon': '3/minute', #每分钟可以请求两次
'user': '5/minute' #每分钟可以请求五次
}
}
（2）goods/views.py中使用
from rest_framework.throttling import UserRateThrottle,AnonRateThrottleclass GoodsListViewSet(CacheResponseMixin,mixins.ListModelMixin, mixins.RetrieveModelMixin,viewsets.GenericViewSet):
.
.
throttle_classes = (UserRateThrottle, AnonRateThrottle)
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