课程后台接口修订

路由：course/urls.py

router.register('categories', views.CourseCategoryViewSet, 'categories')  # 分类
router.register('free', views.CourseViewSet, 'free')  # 课程

视图：course/views.py

from rest_framework.viewsets import GenericViewSet
from rest_framework.mixins import ListModelMixin
from . import models, serializers
# 课程分类群查
class CourseCategoryViewSet(GenericViewSet, ListModelMixin):
    queryset = models.CourseCategory.objects.filter(is_delete=False, is_show=True).all()
    serializer_class = serializers.CourseCategorySerializer

# 课程群查

# 分页组件：基础分页(采用)、偏移分页、游标分页(了解)
from . import pagination

# 过滤组件：搜索功能、排序功能
from rest_framework.filters import SearchFilter, OrderingFilter

# django-filter插件：分类功能
from django_filters.rest_framework import DjangoFilterBackend
from .filters import CourseFilterSet

# 前台携带所有过滤规则的请求url：
# http://127.0.0.1:8000/course/free/?page=1&page_size=10&search=python&ordering=-price&min_price=30&count=1
class CourseViewSet(GenericViewSet, ListModelMixin):
    queryset = models.Course.objects.filter(is_delete=False, is_show=True).all()
    serializer_class = serializers.CourseSerializer

    # 分页组件
    pagination_class = pagination.PageNumberPagination

    # 过滤组件：实际开发，有多个过滤条件时，要把优先级高的放在前面
    filter_backends = [SearchFilter, OrderingFilter, DjangoFilterBackend]

    # 参与搜索的字段
    search_fields = ['name', 'id', 'brief']

    # 允许排序的字段
    ordering_fields = ['id', 'price', 'students']

    # 过滤类：分类过滤、区间过滤
    filter_class = CourseFilterSet

分类区间过滤：filters.py

# django-filter插件 过滤类
from django_filters.filterset import FilterSet
from . import models
from django_filters import filters
class CourseFilterSet(FilterSet):
    # 区间过滤：field_name关联的Model字段；lookup_expr设置规则；gt是大于，gte是大于等于；
    min_price = filters.NumberFilter(field_name='price', lookup_expr='gte')
    max_price = filters.NumberFilter(field_name='price', lookup_expr='lte')
    class Meta:
        model = models.Course
        # 如果过滤条件仅仅就是Model已有的字段，方式一更好
        # 但是方式二可以自定义过滤字段
        fields = ['course_category', 'min_price', 'max_price']

分页：paginations.py

from rest_framework.pagination import PageNumberPagination as DrfPageNumberPagination

class PageNumberPagination(DrfPageNumberPagination):
    # 默认一页显示的条数
    page_size = 2
    # url中携带页码的key
    page_query_param = 'page'
    # url中用户携带自定义一页条数的key
    page_size_query_param = 'page_size'
    # 用户最大可自定义一页的条数
    max_page_size = 10

模型：course/models.py

class Course(BaseModel):
    # ...
    
    @property
    def course_type_name(self):
        return self.get_course_type_display()

    @property
    def level_name(self):
        return self.get_level_display()

    @property
    def status_name(self):
        return self.get_status_display()


    # 连表序列化字段
    @property
    def section_list(self):
        # 检索所以章节所以课时，返回前4课时，不足4课时全部返回
        temp_section_list = []

        for chapter in self.coursechapters.all():
            for section in chapter.coursesections.all():
                temp_section_list.append({
                    'name': section.name,
                    'section_link': section.section_link,
                    'duration': section.duration,
                    'free_trail': section.free_trail,
                })
                if len(temp_section_list) >= 4:
                    return temp_section_list  # 最多4条

        return temp_section_list  # 不足4条
    
    
class Teacher(BaseModel):
    # ...
    @property
    def role_name(self):
        return self.get_role_display()

序列化：course/serializers.py

from rest_framework import serializers
from . import models
class CourseCategorySerializer(serializers.ModelSerializer):
    class Meta:
        model = models.CourseCategory
        fields = ('id', 'name')


# 子序列化
class TeacherSerializer(serializers.ModelSerializer):
    class Meta:
        model = models.Teacher
        fields = ('name', 'role_name', 'title', 'signature', 'image', 'brief')


class CourseSerializer(serializers.ModelSerializer):
    teacher = TeacherSerializer(many=False)

    class Meta:
        model = models.Course
        fields = (
            'id',
            'name',
            'course_img',
            'brief',
            'attachment_path',
            'pub_sections',
            'price',
            'students',
            'period',
            'sections',
            'course_type_name',
            'level_name',
            'status_name',
            'teacher',
            'section_list',
        )