(二十七)竞价

url(r‘^bid/$‘, bid.BidView.as_view()),

"""竞价"""
from app01 import models
from rest_framework.generics import ListAPIView, CreateAPIView
from rest_framework import serializers

class BidModelSerializer(serializers.ModelSerializer):
    status_text = serializers.CharField(source=‘get_status_display‘, read_only=True)
    username = serializers.CharField(source=‘user.nickname‘, read_only=True)

    class Meta:
        model = models.BidRecord
        fields = [‘id‘, ‘price‘, ‘item‘, ‘status_text‘, ‘username‘]



# 竞价    GET: http://www.xxx.com/deposit/?item_id=1
# 提交竞价 POST: http://www.xxx.com/deposit/
class BidView(ListAPIView):
    queryset = models.BidRecord.objects.all().order_by(‘-id‘)
    serializer_class = BidModelSerializer

    def get_queryset(self):
        """
        获取传过来的值
        :return:
        """
        item_id = self.request.query_params.get(‘item_id‘)
        return self.queryset.filter(item_id=item_id)

    def get(self,request, *args, **kwargs):
        """
        页面两部分 上面的部分 加价，下面的部分是价格列表
        :param request:
        :param args:
        :param kwargs:
        :return:
        """
        response = super().get(request, *args, **kwargs)
        item_id = self.request.query_params.get(‘item_id‘)
        item_obj = models.AuctionItem.objects.filter(id=item_id).first()

        # 起拍价 item_obj.start_price
        # 出价记录最高价
        #   ① 倒序 取第一个      或者
        #   ② 当前单品的所有出价记录 models.BidRecord.objects.first(item_id=item_id) 在聚合一下  aggregate是取到一个值
        # models.BidRecord.objects.first(item_id=item_id).aggregate(max_price=Max(‘price‘))是个字典
        from django.db.models import Max
        max_price = models.BidRecord.objects.filter(item_id=item_id).aggregate(max_price=Max(‘price‘))[‘max_price‘]


        result = {
            ‘unit‘:item_obj.unit,
            ‘price‘:max_price or item_obj.start_price,
            ‘bit_list‘:response.data
        }
        response.data = result

        return response

"""竞价"""
from app01 import models
from rest_framework.generics import ListAPIView, CreateAPIView
from rest_framework import serializers
from rest_framework import exceptions
from django.db import transaction
from django.db.models import Max

class BidModelSerializer(serializers.ModelSerializer):
    status_text = serializers.CharField(source=‘get_status_display‘, read_only=True)
    username = serializers.CharField(source=‘user.nickname‘, read_only=True)

    class Meta:
        model = models.BidRecord
        fields = [‘id‘, ‘price‘, ‘item‘, ‘status_text‘, ‘username‘]
　　# 校验提交过来的数据
    def validate_item(self, value):
        """ 一定是在拍卖中 """
        exists = models.AuctionItem.objects.filter(id=value, status=3).exists()
        if not exists:
            raise exceptions.ValidationError(‘已拍卖完成或未开拍‘)
        return value

    def validate_price(self, value):
        # value=用户提交的价格
        # 底价/加价幅度/最高价
        item_id = self.initial_data.get(‘item‘)
        item_object = models.AuctionItem.objects.filter(id=item_id).first()
        if value <= item_object.start_price:
            raise exceptions.ValidationError(‘不能低于起拍价‘)

        div = (value - item_object.start_price) % item_object.unit
        if div:
            raise exceptions.ValidationError(‘必须按照加价幅度来竞价‘)

        max_price = models.BidRecord.objects.filter(item_id=item_id).aggregate(max_price=Max(‘price‘))[‘max_price‘]
        if not max_price:
            return value

        if max_price >= value:
            raise exceptions.ValidationError(‘已经有人出这个价了，你再涨涨‘)
        return value



# 竞价    GET: http://www.xxx.com/deposit/?item_id=1
# 提交竞价 POST: http://www.xxx.com/deposit/
class BidView(ListAPIView, CreateAPIView):
    queryset = models.BidRecord.objects.all().order_by(‘-id‘)
    serializer_class = BidModelSerializer

    def get_queryset(self):
        """
        获取传过来的值
        :return:
        """
        item_id = self.request.query_params.get(‘item_id‘)
        return self.queryset.filter(item_id=item_id)

    def get(self,request, *args, **kwargs):

        """
        页面两部分 上面的部分 加价，下面的部分是价格列表
        :param request:
        :param args:
        :param kwargs:
        :return:
        """
        response = super().get(request, *args, **kwargs)
        item_id = self.request.query_params.get(‘item_id‘)
        item_obj = models.AuctionItem.objects.filter(id=item_id).first()

        # 起拍价 item_obj.start_price
        # 出价记录最高价
        #   ① 倒序 取第一个      或者
        #   ② 当前单品的所有出价记录 models.BidRecord.objects.first(item_id=item_id) 在聚合一下  aggregate是取到一个值
        # models.BidRecord.objects.first(item_id=item_id).aggregate(max_price=Max(‘price‘))是个字典

        max_price = models.BidRecord.objects.filter(item_id=item_id).aggregate(max_price=Max(‘price‘))[‘max_price‘]


        result = {
            ‘unit‘:item_obj.unit,
            ‘price‘:max_price or item_obj.start_price,
            ‘bit_list‘:response.data
        }
        response.data = result

        return response


# 提交过来的出价 要保存
    def perform_create(self, serializer):
        with transaction.atomic():
            price = self.request.data.get(‘price‘)
            item_id = self.request.data.get(‘item‘)
            result = models.BidRecord.objects.filter(item_id=item_id).aggregate(max_price=Max(‘price‘)).select_for_update()
            max_price = result[‘max_price‘]
            if price > max_price:
                serializer.save(user=self.request.user)
            raise exceptions.ValidationError(‘已经被出价了，再涨涨.‘)