2.关于redis缓存购物车及结算中心-shoppingcar篇

shoppingcar.py
"""这是一个关于redis购物车的模块"""
import json
from rest_framework.views import APIView
from rest_framework.response import Response
from api import models
from mysite import settings
from django_redis import get_redis_connection
from utils.response import BaseResponse

USER_ID = 1    # 模拟用户


class ShoppingCarViewSet(APIView):
    # 类下的全局变量
    conn = get_redis_connection("default")

    def post(self, request, *args, **kwargs):
        """
        将课程添加到购物车
        :param request:
        :param args:
        :param kwargs:
        :return:
        """
        ret = BaseResponse()
        try:
            # 1.获取用户提交的课程id和价格策略id
            course_id = int(request.data.get("courseid"))
            policy_id = int(request.data.get("policyid"))
            # 2.获取专题课程信息
            course = models.Course.objects.get(id=course_id)
            # 3.获取该课程相关的所有价格策略
            price_policy_list = course.price_policy.all()
            price_policy_dict = {}
            for item in price_policy_list:
                price_policy_dict[item.id] = {
                    "period": item.valid_period,
                    "period_display": item.get_valid_period_display(),
                    "price": item.price,
                }
            # 4.判断用户提交的价格策略是否合法
            if policy_id not in price_policy_dict:
                # 价格策略不合法
                ret.code = 1001
                ret.error = "价格异常"
                return Response(ret.dict)
            # 5.将购物信息添加到redis中
            car_key = settings.SHOPPING_CAR_KEY % (USER_ID, course_id)
            car_dict = {
                "title": course.name,
                "img": course.course_img,
                "default_policy": policy_id,
                "policy": json.dumps(price_policy_dict)
            }
            self.conn.hmset(car_key, car_dict)
            ret.data = "添加成功"
        except Exception as e:
            ret.code = 1002
            ret.error = "获取购物车失败"
        return Response(ret.dict)

    def delete(self, request, *args, **kwargs):
        """
        删除购物车中课程
        :param request:
        :param args:
        :param kwargs:
        :return:
        """
        ret = BaseResponse()
        try:
            course_id_list = request.data.get("courseids")
            key_list = [settings.SHOPPING_CAR_KEY % (USER_ID, course_id) for course_id in course_id_list]
            self.conn.delete(*key_list)
        except Exception as e:
            ret.code = 1001
            ret.error = "删除失败"
        return Response(ret.dict)

    def patch(self, request, *args, **kwargs):
        """
        修改课程的价格策略
        :param request:
        :param args:
        :param kwargs:
        :return:
        """
        ret = BaseResponse()
        try:
            # 1.获取价格策略和课程id
            course_id = request.data.get("courseid")
            policy_id = request.data.get("policyid")
            # 2.拼接课程的key
            key = settings.SHOPPING_CAR_KEY % (USER_ID, course_id)
            if not self.conn.exists(key):
                ret.code = 1001
                ret.error = "购物车中不存在此课程"
                return Response(ret.dict)
            # 3.redis中获取所有的价格策略
            policy_dict = json.loads(str(self.conn.hget(key, "policy"), encoding="utf-8"))
            if policy_id not in policy_dict:
                ret.code = 1002
                ret.data = "价格策略不合法"
                return Response(ret.dict)
            # 4.在购物车中修改该课程默认价格策略
            self.conn.hset(key, "default_policy", policy_id)
            ret.data = "修改成功"
        except Exception as e:
            ret.code = 1003
            ret.error = "修改失败"
        return Response(ret.dict)

    def get(self, request, *args, **kwargs):
        """
        查看购物车中所有的商品
        :param request:
        :param args:
        :param kwargs:
        :return:
        """
        ret = BaseResponse()
        try:
            key_match = settings.SHOPPING_CAR_KEY % (USER_ID, "*")
            course_list = []

            for key in self.conn.scan_iter(key_match, count=10):
                info = {
                    "title": self.conn.hget(key, "title").decode("utf-8"),
                    "img": self.conn.hget(key, "img").decode("utf-8"),
                    "policy": json.loads(self.conn.hget(key, "policy").decode("utf-8")),
                    "default_policy": self.conn.hget(key, "default_policy").decode("utf-8"),
                }
                course_list.append(info)
            ret.data = course_list
        except Exception as e:
            ret.code = 1002
            ret.error = "获取失败"
        return Response(ret.dict)