• Luffy项目
• 一、轮播图接口加缓存
  • 1、轮播图接口修改
  • 2、双写一致性
• 二、课程前端页面
• 三、课程功能表分析

Luffy项目

一、轮播图接口加缓存

• 为什么要加入缓存
  • 首页访问频率很高，如果同时有很多人来访问主页就会，mysql效率就会变低，如果将热点数据加入缓存，就可以很好的提高项目效率
• 逻辑：
  • 当用户访问主页时，先去缓存中查找，如果没有，就把数据添加至缓存中，以后再有用户访问时，就会直接从redis中拿出数据展示

1、轮播图接口修改

Views.py----》：轮播图功能代码修改

# 重写list请求，用于满足result规范
    def list(self, request, *args, **kwargs):
        # 当收到请求时，首先会判断redis中是否有该数据
        banner_list = cache.get('banner_list')
        # 如果缓存中存在，直接将数据返回（缓存中获取）
        if banner_list:
            return APIResponse(data=banner_list)
        # 如果没有，走数据库查询，然后将数据添加到缓存，以后在访问该接口，直接从缓冲中获取
        # 调用父类list方法，接收返回值
        res = super().list(request, *args, **kwargs)
        # 将热点数据添加缓存
        cache.set('banner_list', res.data)
        # 使用自己封装的response对象返回数据
        return APIResponse(data=res.data)

2、双写一致性

• 什么是双写一致性：
  • 指硬盘中的数据（mysql）和内存中的数据（redis）不一致，这样用户访问的时候，就会出现内容不真实
• 如何解决：
  • 修改数据库，删除缓存
  • 修改数据，更新缓存
  • 定时更新缓存（实时性差）

首页轮播图缓存定时更新：

# 在celery中写入定时任务，到规定时间后更新缓存中的数据
	 # 导入定时需要的模块
    from datetime import timedelta
    from celery.schedules import crontab
    # 指定时区
    app.conf.timezone = 'Asia/Shanghai'
    # 是否使用UTC
    app.conf.enable_utc = False
    # celery的配置文件
    # 任务的定时配置
    app.conf.beat_schedule = {
        'banner_updata': {  # 配置执行函数的别名
            'task': 'celery_task.task.redis_up',  # 导入任务的位置
            # 'schedule': timedelta(seconds=1),  # 时间对象
            'schedule': crontab(hour=8, day_of_week=1),  # 每周一早八点
            # 'schedule': crontab(hour=9, minute=43),  # 每天9点43
            # 'args': ('18888888', '6666'),  # 配置执行函数需要的参数
        },

    }

====================================================================
# 定时更新缓存  task.py
    @app.task()
    def redis_up():
        # 数据库中查询数据
        banner_list = Banner.objects.filter(is_delete=False, is_show=True).order_by('orders').all()
        # 将查询到的数据序列化
        ser = BannerSerializer(instance=banner_list, many=True)
        # 将数据加入缓存
        cache.get('banner_list', ser.data)
        return True
    
    
=====================================================================

# 第二步：启动worker，启动beat

二、课程前端页面

课程页面分析:

# 免费课，实战课，轻课
	-不要钱的，免费的
    -实战课：python面向对象  39.9 
    -线下课程完整版的视频   19999
    
    
    
    
# 课程列表页数据
	1 新建3个页面组件
        FreeCourserView  # 免费课程
        ActualCourserView  # 实战课
        LightCourseView  # 轻课
    2 配置路由
        {
            path: '/free-course',
            name: 'free',
            component: FreeCourserView
        },
        {
            path: '/actual-course',
            name: 'actual-course',
            component: ActualCourserView
        },
        {
            path: '/light-course',
            name: 'light-course',
            component: LightCourseView
        },
	3 复制代码
    

课程页面代码：

<template>
  <div class="course">
    <Header></Header>
    <div class="main">
      <!-- 筛选条件 -->
      <div class="condition">
        <ul class="cate-list">
          <li class="title">课程分类:</li>
          <li class="this">全部</li>
          <li>Python</li>
          <li>Linux运维</li>
          <li>Python进阶</li>
          <li>开发工具</li>
          <li>Go语言</li>
          <li>机器学习</li>
          <li>技术生涯</li>
        </ul>

        <div class="ordering">
          <ul>
            <li class="title">筛&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;选:</li>
            <li class="default this">默认</li>
            <li class="hot">人气</li>
            <li class="price">价格</li>
          </ul>
          <p class="condition-result">共21个课程</p>
        </div>

      </div>
      <!-- 课程列表 -->
      <div class="course-list">
        <div class="course-item">
          <div class="course-image">
            <img src="@/assets/img/course-cover.jpeg" alt="">
          </div>
          <div class="course-info">
            <h3>Python开发21天入门 <span><img src="@/assets/img/avatar1.svg" alt="">100人已加入学习</span></h3>
            <p class="teather-info">Alex 金角大王 老男孩Python教学总监 <span>共154课时/更新完成</span></p>
            <ul class="lesson-list">
              <li><span class="lesson-title">01 | 第1节：初识编码</span> <span class="free">免费</span></li>
              <li><span class="lesson-title">01 | 第1节：初识编码初识编码</span> <span class="free">免费</span></li>
              <li><span class="lesson-title">01 | 第1节：初识编码</span></li>
              <li><span class="lesson-title">01 | 第1节：初识编码初识编码</span></li>
            </ul>
            <div class="pay-box">
              <span class="discount-type">限时免费</span>
              <span class="discount-price">￥0.00元</span>
              <span class="original-price">原价：9.00元</span>
              <span class="buy-now">立即购买</span>
            </div>
          </div>
        </div>
        <div class="course-item">
          <div class="course-image">
            <img src="@/assets/img/course-cover.jpeg" alt="">
          </div>
          <div class="course-info">
            <h3>Python开发21天入门 <span><img src="@/assets/img/avatar1.svg" alt="">100人已加入学习</span></h3>
            <p class="teather-info">Alex 金角大王 老男孩Python教学总监 <span>共154课时/更新完成</span></p>
            <ul class="lesson-list">
              <li><span class="lesson-title">01 | 第1节：初识编码</span> <span class="free">免费</span></li>
              <li><span class="lesson-title">01 | 第1节：初识编码初识编码</span> <span class="free">免费</span></li>
              <li><span class="lesson-title">01 | 第1节：初识编码</span></li>
              <li><span class="lesson-title">01 | 第1节：初识编码初识编码</span></li>
            </ul>
            <div class="pay-box">
              <span class="discount-type">限时免费</span>
              <span class="discount-price">￥0.00元</span>
              <span class="original-price">原价：9.00元</span>
              <span class="buy-now">立即购买</span>
            </div>
          </div>
        </div>
        <div class="course-item">
          <div class="course-image">
            <img src="@/assets/img/course-cover.jpeg" alt="">
          </div>
          <div class="course-info">
            <h3>Python开发21天入门 <span><img src="@/assets/img/avatar1.svg" alt="">100人已加入学习</span></h3>
            <p class="teather-info">Alex 金角大王 老男孩Python教学总监 <span>共154课时/更新完成</span></p>
            <ul class="lesson-list">
              <li><span class="lesson-title">01 | 第1节：初识编码</span> <span class="free">免费</span></li>
              <li><span class="lesson-title">01 | 第1节：初识编码初识编码</span> <span class="free">免费</span></li>
              <li><span class="lesson-title">01 | 第1节：初识编码</span></li>
              <li><span class="lesson-title">01 | 第1节：初识编码初识编码</span></li>
            </ul>
            <div class="pay-box">
              <span class="discount-type">限时免费</span>
              <span class="discount-price">￥0.00元</span>
              <span class="original-price">原价：9.00元</span>
              <span class="buy-now">立即购买</span>
            </div>
          </div>
        </div>
        <div class="course-item">
          <div class="course-image">
            <img src="@/assets/img/course-cover.jpeg" alt="">
          </div>
          <div class="course-info">
            <h3>Python开发21天入门 <span><img src="@/assets/img/avatar1.svg" alt="">100人已加入学习</span></h3>
            <p class="teather-info">Alex 金角大王 老男孩Python教学总监 <span>共154课时/更新完成</span></p>
            <ul class="lesson-list">
              <li><span class="lesson-title">01 | 第1节：初识编码</span> <span class="free">免费</span></li>
              <li><span class="lesson-title">01 | 第1节：初识编码初识编码</span> <span class="free">免费</span></li>
              <li><span class="lesson-title">01 | 第1节：初识编码</span></li>
              <li><span class="lesson-title">01 | 第1节：初识编码初识编码</span></li>
            </ul>
            <div class="pay-box">
              <span class="discount-type">限时免费</span>
              <span class="discount-price">￥0.00元</span>
              <span class="original-price">原价：9.00元</span>
              <span class="buy-now">立即购买</span>
            </div>
          </div>
        </div>
      </div>
    </div>
    <Footer></Footer>
  </div>
</template>

<script>
import Header from "@/components/Header"
import Footer from "@/components/Footer"

export default {
  name: "Course",
  data() {
    return {
      category: 0,
    }
  },
  components: {
    Header,
    Footer,
  }
}
</script>

<style scoped>
.course {
  background: #f6f6f6;
}

.course .main {
  width: 1100px;
  margin: 35px auto 0;
}

.course .condition {
  margin-bottom: 35px;
  padding: 25px 30px 25px 20px;
  background: #fff;
  border-radius: 4px;
  box-shadow: 0 2px 4px 0 #f0f0f0;
}

.course .cate-list {
  border-bottom: 1px solid #333;
  border-bottom-color: rgba(51, 51, 51, .05);
  padding-bottom: 18px;
  margin-bottom: 17px;
}

.course .cate-list::after {
  content: "";
  display: block;
  clear: both;
}

.course .cate-list li {
  float: left;
  font-size: 16px;
  padding: 6px 15px;
  line-height: 16px;
  margin-left: 14px;
  position: relative;
  transition: all .3s ease;
  cursor: pointer;
  color: #4a4a4a;
  border: 1px solid transparent; /* transparent 透明 */
}

.course .cate-list .title {
  color: #888;
  margin-left: 0;
  letter-spacing: .36px;
  padding: 0;
  line-height: 28px;
}

.course .cate-list .this {
  color: #ffc210;
  border: 1px solid #ffc210 !important;
  border-radius: 30px;
}

.course .ordering::after {
  content: "";
  display: block;
  clear: both;
}

.course .ordering ul {
  float: left;
}

.course .ordering ul::after {
  content: "";
  display: block;
  clear: both;
}

.course .ordering .condition-result {
  float: right;
  font-size: 14px;
  color: #9b9b9b;
  line-height: 28px;
}

.course .ordering ul li {
  float: left;
  padding: 6px 15px;
  line-height: 16px;
  margin-left: 14px;
  position: relative;
  transition: all .3s ease;
  cursor: pointer;
  color: #4a4a4a;
}

.course .ordering .title {
  font-size: 16px;
  color: #888;
  letter-spacing: .36px;
  margin-left: 0;
  padding: 0;
  line-height: 28px;
}

.course .ordering .this {
  color: #ffc210;
}

.course .ordering .price {
  position: relative;
}

.course .ordering .price::before,
.course .ordering .price::after {
  cursor: pointer;
  content: "";
  display: block;
  width: 0px;
  height: 0px;
  border: 5px solid transparent;
  position: absolute;
  right: 0;
}

.course .ordering .price::before {
  border-bottom: 5px solid #aaa;
  margin-bottom: 2px;
  top: 2px;
}

.course .ordering .price::after {
  border-top: 5px solid #aaa;
  bottom: 2px;
}

.course .course-item:hover {
  box-shadow: 4px 6px 16px rgba(0, 0, 0, .5);
}

.course .course-item {
  width: 1100px;
  background: #fff;
  padding: 20px 30px 20px 20px;
  margin-bottom: 35px;
  border-radius: 2px;
  cursor: pointer;
  box-shadow: 2px 3px 16px rgba(0, 0, 0, .1);
  /* css3.0 过渡动画 hover 事件操作 */
  transition: all .2s ease;
}

.course .course-item::after {
  content: "";
  display: block;
  clear: both;
}

/* 顶级元素 父级元素  当前元素{} */
.course .course-item .course-image {
  float: left;
  width: 423px;
  height: 210px;
  margin-right: 30px;
}

.course .course-item .course-image img {
  width: 100%;
}

.course .course-item .course-info {
  float: left;
  width: 596px;
}

.course-item .course-info h3 {
  font-size: 26px;
  color: #333;
  font-weight: normal;
  margin-bottom: 8px;
}

.course-item .course-info h3 span {
  font-size: 14px;
  color: #9b9b9b;
  float: right;
  margin-top: 14px;
}

.course-item .course-info h3 span img {
  width: 11px;
  height: auto;
  margin-right: 7px;
}

.course-item .course-info .teather-info {
  font-size: 14px;
  color: #9b9b9b;
  margin-bottom: 14px;
  padding-bottom: 14px;
  border-bottom: 1px solid #333;
  border-bottom-color: rgba(51, 51, 51, .05);
}

.course-item .course-info .teather-info span {
  float: right;
}

.course-item .lesson-list::after {
  content: "";
  display: block;
  clear: both;
}

.course-item .lesson-list li {
  float: left;
  width: 44%;
  font-size: 14px;
  color: #666;
  padding-left: 22px;
  /* background: url("路径") 是否平铺 x轴位置 y轴位置 */
  background: url("/src/assets/img/play-icon-gray.svg") no-repeat left 4px;
  margin-bottom: 15px;
}

.course-item .lesson-list li .lesson-title {
  /* 以下3句，文本内容过多，会自动隐藏，并显示省略符号 */
  text-overflow: ellipsis;
  overflow: hidden;
  white-space: nowrap;
  display: inline-block;
  max-width: 200px;
}

.course-item .lesson-list li:hover {
  background-image: url("/src/assets/img/play-icon-yellow.svg");
  color: #ffc210;
}

.course-item .lesson-list li .free {
  width: 34px;
  height: 20px;
  color: #fd7b4d;
  vertical-align: super;
  margin-left: 10px;
  border: 1px solid #fd7b4d;
  border-radius: 2px;
  text-align: center;
  font-size: 13px;
  white-space: nowrap;
}

.course-item .lesson-list li:hover .free {
  color: #ffc210;
  border-color: #ffc210;
}

.course-item .pay-box::after {
  content: "";
  display: block;
  clear: both;
}

.course-item .pay-box .discount-type {
  padding: 6px 10px;
  font-size: 16px;
  color: #fff;
  text-align: center;
  margin-right: 8px;
  background: #fa6240;
  border: 1px solid #fa6240;
  border-radius: 10px 0 10px 0;
  float: left;
}

.course-item .pay-box .discount-price {
  font-size: 24px;
  color: #fa6240;
  float: left;
}

.course-item .pay-box .original-price {
  text-decoration: line-through;
  font-size: 14px;
  color: #9b9b9b;
  margin-left: 10px;
  float: left;
  margin-top: 10px;
}

.course-item .pay-box .buy-now {
  width: 120px;
  height: 38px;
  background: transparent;
  color: #fa6240;
  font-size: 16px;
  border: 1px solid #fd7b4d;
  border-radius: 3px;
  transition: all .2s ease-in-out;
  float: right;
  text-align: center;
  line-height: 38px;
}

.course-item .pay-box .buy-now:hover {
  color: #fff;
  background: #ffc210;
  border: 1px solid #ffc210;
}
</style>

三、课程功能表分析

表分析：

# 轻课 实战课 免费课    需要几个表
	-所有课程使用一个表  通过类型区分，但是可能出现字段不一样，数据量越来越多，导致表查询速度慢
    -一种课程一个表
    
    
# 实战课线---》分析出5张表
	-课程分类表  一个分类下有多个课程跟课程一对多
	-实战课表  一个实战课，会有多个章节，跟章节一对多
    -章节表   一个章节下有多个课时，章节和课时一对多
    -课时表
    -老师表   跟实战课一对多
    
    
    -正常课程 有评论，需要建立评论表，评论板块没写，这个表就不写了

表迁移：

from django.db import models
from utils.common_model import BaseModel


# Create your models here.
# 5张：课程分类，实战课，章节，课时，老师表


# 课程分类表
class CourseCategory(BaseModel):
    """分类"""
    name = models.CharField(max_length=64, unique=True, verbose_name="分类名称")

    class Meta:
        db_table = "luffy_course_category"
        verbose_name = "分类"
        verbose_name_plural = verbose_name

    def __str__(self):
        return "%s" % self.name


# 实战课表
class Course(BaseModel):
    """课程"""
    course_type = (
        (0, '付费'),
        (1, 'VIP专享'),
        (2, '学位课程')
    )
    level_choices = (
        (0, '初级'),
        (1, '中级'),
        (2, '高级'),
    )
    status_choices = (
        (0, '上线'),
        (1, '下线'),
        (2, '预上线'),
    )
    name = models.CharField(max_length=128, verbose_name="课程名称")
    course_img = models.ImageField(upload_to="courses", max_length=255, verbose_name="封面图片", blank=True, null=True)
    course_type = models.SmallIntegerField(choices=course_type, default=0, verbose_name="付费类型")
    brief = models.TextField(max_length=2048, verbose_name="详情介绍", null=True, blank=True)
    level = models.SmallIntegerField(choices=level_choices, default=0, verbose_name="难度等级")
    pub_date = models.DateField(verbose_name="发布日期", auto_now_add=True)
    period = models.IntegerField(verbose_name="建议学习周期(day)", default=7)
    attachment_path = models.FileField(upload_to="attachment", max_length=128, verbose_name="课件路径", blank=True,null=True)
    status = models.SmallIntegerField(choices=status_choices, default=0, verbose_name="课程状态")

    students = models.IntegerField(verbose_name="学习人数", default=0) # 跟用户表做关联，优化字段

    sections = models.IntegerField(verbose_name="总课时数量", default=0)
    pub_sections = models.IntegerField(verbose_name="课时更新数量", default=0)
    price = models.DecimalField(max_digits=6, decimal_places=2, verbose_name="课程原价", default=0)

    # on_delete 级联删除，出了级联删除外，还有 很多其他的，暂时先不讲
    teacher = models.ForeignKey("Teacher", on_delete=models.DO_NOTHING, null=True, blank=True, verbose_name="授课老师")
    course_category = models.ForeignKey("CourseCategory", on_delete=models.SET_NULL, db_constraint=False, null=True,blank=True, verbose_name="课程分类")
    class Meta:
        db_table = "luffy_course"
        verbose_name = "课程"
        verbose_name_plural = "课程"

    def __str__(self):
        return "%s" % self.name


# 章节表
class CourseChapter(BaseModel):
    """章节"""
    # 章节跟课程一对多，关联字段写在多的一方
    # related_name 暂时先不讲
    course = models.ForeignKey("Course", related_name='coursechapters', on_delete=models.CASCADE, verbose_name="课程名称")
    chapter = models.SmallIntegerField(verbose_name="第几章", default=1)
    name = models.CharField(max_length=128, verbose_name="章节标题")
    summary = models.TextField(verbose_name="章节介绍", blank=True, null=True)
    pub_date = models.DateField(verbose_name="发布日期", auto_now_add=True)

    class Meta:
        db_table = "luffy_course_chapter"
        verbose_name = "章节"
        verbose_name_plural = verbose_name

    def __str__(self):
        return "%s:(第%s章)%s" % (self.course, self.chapter, self.name)


# 课时表
class CourseSection(BaseModel):
    """课时"""
    section_type_choices = (
        (0, '文档'),
        (1, '练习'),
        (2, '视频')
    )
    # 课时跟章节一对多，关联写段写在多的一方
    chapter = models.ForeignKey("CourseChapter", related_name='coursesections', on_delete=models.CASCADE,verbose_name="课程章节")
    name = models.CharField(max_length=128, verbose_name="课时标题")
    orders = models.PositiveSmallIntegerField(verbose_name="课时排序")
    section_type = models.SmallIntegerField(default=2, choices=section_type_choices, verbose_name="课时种类")
    section_link = models.CharField(max_length=255, blank=True, null=True, verbose_name="课时链接",help_text="若是video，填vid,若是文档，填link")
    duration = models.CharField(verbose_name="视频时长", blank=True, null=True, max_length=32)  # 仅在前端展示使用
    pub_date = models.DateTimeField(verbose_name="发布时间", auto_now_add=True)
    free_trail = models.BooleanField(verbose_name="是否可试看", default=False)

    class Meta:
        db_table = "luffy_course_section"
        verbose_name = "课时"
        verbose_name_plural = verbose_name

    def __str__(self):
        return "%s-%s" % (self.chapter, self.name)


# 老师表
class Teacher(BaseModel):
    """导师"""
    role_choices = (
        (0, '讲师'),
        (1, '导师'),
        (2, '班主任'),
    )
    name = models.CharField(max_length=32, verbose_name="导师名")
    role = models.SmallIntegerField(choices=role_choices, default=0, verbose_name="导师身份")
    title = models.CharField(max_length=64, verbose_name="职位、职称")
    signature = models.CharField(max_length=255, verbose_name="导师签名", help_text="导师签名", blank=True, null=True)
    image = models.ImageField(upload_to="teacher", null=True, verbose_name="导师封面")
    brief = models.TextField(max_length=1024, verbose_name="导师描述")

    class Meta:
        db_table = "luffy_teacher"
        verbose_name = "导师"
        verbose_name_plural = verbose_name

    def __str__(self):
        return "%s" % self.name