登录验证中间件middleware.py

from django.http import HttpResponseRedirect
from django.urls import reverse
from django.utils.deprecation import MiddlewareMixin
import re

from user.models import User


class LoginStatusMiddleware(MiddlewareMixin):

    def process_request(self, request):
        user_id = request.session.get('user_id')
        if user_id:
            user = User.objects.filter(pk=user_id).first()
            request.user = user
        # 过滤不需要验证的URL
        not_need_check = ['/user/register/',
                          '/user/login/',
                          '/goods/index/',
                          '/media/.*',
                          '/goods/detail/.*',
                          '/carts/add_cart/',
                          '/carts/carts/']
        path = request.path
        for not_check in not_need_check:
            if re.match(not_check, path):
                return None
        user_id = request.session.get('user_id')
        if not user_id:
            return HttpResponseRedirect(reverse('user:login'))
        user = User.objects.filter(pk=user_id).first()
        if not user:
            return HttpResponseRedirect(reverse('user:login'))
        # 获取到user，则设置全局用户对象
        request.user = user
        return None

添加商品到session的views.py

from django.http import JsonResponse
from django.shortcuts import render

from goods.models import Goods


def carts(request):
    if request.method == 'GET':
        return render(request, 'cart.html')


def add_cart(request):
    if request.method == 'POST':
        # 保存到session中
        # 1.获取前端ajax提交的商品goods_id，商品数量nums
        # 2.组装存储到session中的数据结构
        # [ [goods_id, nums, is_select], [goods_id, nums, is_select]...]
        # 3.如果加入到session中的商品已经存在于session中，则更新nums字段
        goods_id = int(request.POST.get('goods_id'))
        nums = int(request.POST.get('nums'))
        # 组装存储的结构，[商品id值， 商品数量， 商品选择状态]
        goods_list = [int(goods_id), int(nums), 1]
        # 判断session中是否保存了购物车数据， {'goods': [[goods_id, nums, 1], [goods_id, nums, 1]]
        session_goods = request.session.get('goods')
        if session_goods:
            # 修改
            flag = False
            for goods in session_goods:
                # goods为 [goods_id, nums, is_select]
                if goods[0] == goods_id:
                    goods[1] += nums
                    flag = True
            # 添加
            if not flag:
                session_goods.append(goods_list)
            request.session['goods'] = session_goods
            # session中保存的商品的个数
            goods_count = len(session_goods)
        else:
            # 第一次添加商品到session中时，保存键值对
            # 键为goods, 值为 [ [goods_id, nums, is_select] ]
            request.session['goods'] = [goods_list]
            goods_count = 1
        return JsonResponse({'code': 200, 'msg': '请求成功', 'goods_count': goods_count})

    if request.method == 'GET':
        session_goods = request.session.get('goods')
        if session_goods:
            goods_count = len(session_goods)
        else:
            goods_count = 0
        return JsonResponse({'goods_count': goods_count})

商品详情页

{% extends 'base_main.html' %}

{% block title %}
天天生鲜-商品详情
{% endblock %}

{% block pagename %}
商品详情
{% endblock %}

{% block search %}
    <div class="search_bar clearfix">
        <a href="{% url 'goods:index' %}" class="logo fl"><img src="/static/images/logo.png"></a>
        <div class="search_con fl">
            <input type="text" class="input_text fl" name="" placeholder="搜索商品">
            <input type="button" class="input_btn fr" name="" value="搜索">
        </div>
        <div class="guest_cart fr">
            <a href="{% url 'carts:cart' %}" class="cart_name fl">我的购物车</a>
            <div class="goods_count fl" id="show_count">0</div>
        </div>
    </div>
{% endblock %}

{% block content %}

    <div class="navbar_con">
        <div class="navbar clearfix">
            <div class="subnav_con fl">
                <h1>全部商品分类</h1> 
                <span></span>           
                <ul class="subnav">
                    <li><a href="#" class="fruit">新鲜水果</a></li>
                    <li><a href="#" class="seafood">海鲜水产</a></li>
                    <li><a href="#" class="meet">猪牛羊肉</a></li>
                    <li><a href="#" class="egg">禽类蛋品</a></li>
                    <li><a href="#" class="vegetables">新鲜蔬菜</a></li>
                    <li><a href="#" class="ice">速冻食品</a></li>
                </ul>
            </div>
            <ul class="navlist fl">
                <li><a href="{% url 'goods:index' %}">首页</a></li>
                <li class="interval">|</li>
                <li><a href="">手机生鲜</a></li>
                <li class="interval">|</li>
                <li><a href="">抽奖</a></li>
            </ul>
        </div>
    </div>

    <div class="breadcrumb">
        <a href="#">全部分类</a>
        <span>></span>
        <a href="#">{{ category }}</a>
        <span>></span>
        <a href="#">商品详情</a>
    </div>

    <div class="goods_detail_con clearfix">
        <div class="goods_detail_pic fl"><img src="/media/{{ goods.goods_front_image }}"></div>

        <div class="goods_detail_list fr">
            <h3>{{ goods.name }}</h3>
            <p>{{ goods.goods_brief }}</p>
            <div class="prize_bar">
                <span class="show_pirze">¥<em id="price">{{ goods.shop_price }}</em></span>
                <span class="show_unit">单  位：500g</span>
            </div>
            <div class="goods_num clearfix">
                {% csrf_token %}
                <div class="num_name fl">数 量：</div>
                <div class="num_add fl">
                    <input style="display: none" id="goods_num" value="{{ goods.goods_nums }}">
                    <input type="text" class="num_show fl" id="num" value="1">
                    <a href="javascript:;" class="add fr" id="add">+</a>
                    <a href="javascript:;" class="minus fr" id="minus">-</a>
                </div> 
            </div>
            <div class="total">总价：<em><span id="total"></span>元</em></div>
            <div class="operate_btn">
                <a href="javascript:;" class="buy_btn">立即购买</a>
                <a href="javascript:;" class="add_cart" onclick="add_to_cart({{ goods.id }})">加入购物车</a>
            </div>
        </div>
    </div>

    <div class="main_wrap clearfix">
        <div class="l_wrap fl clearfix">
            <div class="new_goods">
                <h3>新品推荐</h3>
                <ul>
                    <li>
                        <a href="#"><img src="/static/images/goods/goods001.jpg"></a>
                        <h4><a href="#">进口柠檬</a></h4>
                        <div class="prize">￥3.90</div>
                    </li>
                    <li>
                        <a href="#"><img src="/static/images/goods/goods002.jpg"></a>
                        <h4><a href="#">玫瑰香葡萄</a></h4>
                        <div class="prize">￥16.80</div>
                    </li>
                </ul>
            </div>
        </div>

        <div class="r_wrap fr clearfix">
            <ul class="detail_tab clearfix">
                <li class="active">商品介绍</li>
                <li>评论</li>
            </ul>

            <div class="tab_content">
                <dl>
                    <dt>商品详情：</dt>
                    <dd>{{ goods.goods_desc | safe }}</dd>
                </dl>
            </div>

        </div>
    </div>


    <div class="add_jump"></div>

{% endblock %}

{% block js2 %}

    <script type="text/javascript" src="/static/js/jquery-2.1.4.min.js"></script>
    <script type="text/javascript">
        var goods_num = $('#goods_num').val()
        function total(){
            $('#total').text(parseInt($('#num').val()) * parseInt($('#price').text()))
        }
        total()
        $('#total').text(parseInt($('#num').val()) * parseInt($('#price').text()))
        $('#add').on('click', function () {
            var num = parseInt($('#num').val())
            if(num < goods_num){
                $('#num').val(num + 1)
                total()
            }
        })
        $('#minus').on('click', function () {
            var num = parseInt($('#num').val())
            if(num > 1){
                $('#num').val(num - 1)
                total()
            }
        })
        $('#num').change(function () {
            var num = $('#num').val()
            if(parseInt(num) > 0 && num != '' && parseInt(num) <= goods_num){
                total()
            }else{
                alert('数量必须大于0且少于库存')
                $('#num').val(1)
                total()
            }
        })

        function add_to_cart(id) {
            var nums = $('#num').val();
            var csrf = $('input[name="csrfmiddlewaretoken"]').val();
            $.ajax({
                url: '/carts/add_cart/',
                data: {
                    'goods_id': id,
                    'nums': nums,
                },
                type: 'POST',
                dataType: 'JSON',
                headers: {'X-CSRFToken': csrf},
                success: function (data) {
                    if(data.code == 200){
                        $('#show_count').text(data.goods_count)
                    }
                },
                error: function (data) {
                    alert('失败')
                }

            })
        }

        $(function () {
            $.ajax({
                url: '/carts/add_cart/',
                type: 'GET',
                dataType: 'JSON',
                success: function (data) {
                    $('#show_count').text(data.goods_count)
                },
                error: function (data) {
                    alert('失败')
                }
            })
        })
    </script>
    
{% endblock %}