广告小程序后端开发（16.优惠券系统：原理流程图，奖品实验数据，生成二维码）

业务需求：在一个广告小程序内发许多其他的小程序的优惠券。

1.原理流程图

2.奖品（优惠券）实验数据

1.修改apps/ad/models.py中的Prize表类

class Prize(models.Model):
    """奖品"""
    title = models.CharField(max_length=15, null=True, blank=True, verbose_name='标题', help_text='最多15字')
    url=models.CharField(max_length=200, null=True, blank=True, verbose_name='小程序url')
    area = models.ForeignKey(Area, null=True, blank=True, verbose_name="地区", on_delete=models.CASCADE)
    get_num=models.IntegerField(default=0,verbose_name='被领取数')
    price = models.IntegerField(default=0, verbose_name='所需积分')
    all_num=models.IntegerField(default=0,verbose_name='发布数')
    is_out=models.BooleanField(default=False,verbose_name='是否已售罄')
    desc = models.TextField(default='', max_length=400, verbose_name='描述', help_text='最多400字')
    usage = models.TextField(default='', max_length=200, verbose_name='使用方式', help_text='最多200字')
    image = models.ImageField(max_length=200, default='', upload_to='prizeimg/', verbose_name='奖品图片')
    end_time = models.DateTimeField(default=datetime.now, verbose_name='过期时间')
    add_time = models.DateTimeField(default=datetime.now, verbose_name='添加时间')

    class Meta:
        verbose_name = "奖品"
        verbose_name_plural = verbose_name

    def __str__(self):
        return self.title

    def image_url(self):
        return mark_safe('<img src="/media/{0}" class="field_img">'.format(self.image))

    image_url.short_description = '奖品图片'

执行数据更新命令：

python manage.py makemigrations
python manage.py migrate

2.修改apps/ad/adminx.py中的PrizeAdmin

class PrizeAdmin(object):
    list_display = ["title", "get_num","is_out","url","price","area", "all_num", "desc","usage","end_time","image_url","add_time"]
    list_filter = ["title", "get_num","is_out","url", "price", "area","all_num", "desc","usage","end_time","add_time"]
    search_fields = ["title", "get_num", "price", "all_num", "desc","usage"]

3.通过xadmin后台，直接向奖品表Prize中填入一些实验

3.生成图片二维码

1.从网上下载14张（这个数目可以自定义的），然后放到gg/static/下新建目录2下，这些图片用于生成二维码的背景图：

 

2.安装myqr

pip install myqr

3.修改apps/user_operation/models.py中的GetPrize表类：

class GetPrize(models.Model):
    """兑奖表"""
    user = models.ForeignKey(UserProfile, verbose_name="用户", on_delete=models.CASCADE)
    prize=models.ForeignKey(Prize, verbose_name="奖品", on_delete=models.CASCADE)
    title = models.CharField(max_length=15, null=True, blank=True, verbose_name='标题', help_text='最多15字')
    status = models.CharField(choices=(("0", "未使用"), ("1", "已使用")),default="0",max_length=6, verbose_name="使用状态")
    twoimg=models.ImageField(max_length=200, default='', upload_to='twoimg/', verbose_name='二维码')
    end_time = models.DateTimeField(default=datetime.now, verbose_name='过期时间')
    add_time = models.DateTimeField(default=datetime.now, verbose_name="添加时间")

    class Meta:
        verbose_name = "兑奖表"
        verbose_name_plural = verbose_name

    def __str__(self):
        return self.prize.title

    def image_url(self):
        return mark_safe('<img src="/media/{0}" class="field_img">'.format(self.twoimg))

    image_url.short_description = '二维码'

执行数据更新命令：

python manage.py makemigrations
python manage.py migrate

4.在apps/user_operation/views.py中新建BuyUseJiFen类：

#……
from users.models import UserProfile
from .serializers import MessageModelSerializer,GetPrizeModelSerializer
from .models import Message,GetPrize
from ad.models import Prize
from MyQR import myqr
import os,random
from gg.settings import BASE_DIR

#……


class BuyUseJiFen(APIView):
    """购买积分商品,生成二维码，控制每个用户领取一次"""
    renderer_classes = [JSONRenderer]  # 渲染器

    def get(self,request):
        token = request.GET.get('token')
        user = UserProfile.objects.filter(token=token).first()
        prizeid=request.GET.get('prizeid')
        if user and prizeid:
            prizeid_int = int(prizeid)
            prize = Prize.objects.filter(id=prizeid_int).first()
            if prize.get_num>=prize.all_num:
                # 如果奖品的领取数大于等于发布数，则返回已售罄
                prize.is_out=True
                prize.save()
                return HttpResponse('403')
            else:
                # 兑奖表，查看用户是否已经领取过了这个优惠券，如果已经领取过了则返回已经领取过了
                p=GetPrize.objects.filter(user=user,prize=prize).first()
                if p:
                    # 已经领取过了
                    return HttpResponse('404')
                else:
                    # 用户未领取
                    # 扣除对应积分
                    if (user.jifen - prize.price)>=0:
                        user.jifen = user.jifen - prize.price
                        user.save()
                        # 制作二维码
                        two_name=str(user.id)+'and'+prizeid+'.png'#生成二维码文件名
                        b = os.path.join(BASE_DIR, 'static/2/' + str(random.randint(1, 14)) + '.jpg')#背景图片路径
                        c_dir = os.path.join(BASE_DIR, 'media/twoimg')#生成二维码的存放目录
                        user_openid=user.open_id
                        url=prize.url+"?pid="+prizeid+"&oid="+user_openid
                        myqr.run(words=url,version=5,level='H',picture=b,colorized=True,save_dir=c_dir,save_name=two_name)
                        # 生成兑奖表记录
                        new_getprize=GetPrize()
                        new_getprize.user=user
                        new_getprize.prize=prize
                        new_getprize.title=prize.title
                        new_getprize.end_time=prize.end_time
                        new_getprize.twoimg='twoimg/'+two_name
                        new_getprize.save()
                        # 奖品被领取数+1
                        prize.is_out = False
                        prize.get_num += 1
                        prize.save()
                        msg = Message()
                        msg.user = user
                        msg.content = "您成功领取了 奖品：" +prize.title
                        msg.save()
                        return HttpResponse('200')
                    else:
                        # 积分不足
                        return HttpResponse('405')
        else:
            return HttpResponse('参数不足')

5.在apps/user_operation/urls.py内配置路由：

from django.urls import path
from .views import GetMessage,ReadMessage,DelMessage,BuyUseJiFen

urlpatterns = [
    path('getmessage/',GetMessage.as_view()),
    path('readmessage/',ReadMessage.as_view()),
    path('delmessage/',DelMessage.as_view()),
    path('buyusejifen/',BuyUseJiFen.as_view()),
]