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1.轮播图

轮播图没东西 因为之前涉及了model 所以直接使用ListModelMixin就好了 Serializer也是获得所有即可。

代码：

# models.pyclass GoodsImage(models.Model):    """    商品轮播图    """    goods = models.ForeignKey(Goods, verbose_name=u'商品', related_name = 'images', on_delete=models.CASCADE)    image = models.ImageField(upload_to='', verbose_name=u'图片', null=True, blank=True)    index = models.IntegerField(default=0, verbose_name=u'轮播顺序')    add_time = models.DateTimeField(default=datetime.now, verbose_name=u'添加时间')    class Meta:        verbose_name = u'商品图片'        verbose_name_plural = verbose_name    def __str__(self):        return self.goods.name# views.pyfrom .models import Bannerfrom .serializers import  BannerSerializerclass BannerViewset(mixins.ListModelMixin, viewsets.GenericViewSet):    """    获取轮播图列表    """    queryset = Banner.objects.all().order_by("index")    serializer_class = BannerSerializer# serializers.pyfrom goods.models import Bannerclass BannerSerializer(serializers.ModelSerializer):    class Meta:        model = Banner        fields = "__all__"# urls.pyfrom goods.views import BannerViewsetrouter.register('banners', BannerViewset, base_name='banners')

这样轮播图就完成了

2.新品功能开发;

因为新品是goods（model）中的一个字段名 所以只需要将过滤条件增加一个就可以了

# 之前写的那个fitlers.py 在fields中增加一个‘is_new’元素即可# encoding:utf-8import django_filtersfrom django.db.models import Qfrom .models import Goodsclass GoodsFilter(django_filters.rest_framework.FilterSet):    """    商品的过滤类    """    pricemin = django_filters.NumberFilter(field_name='shop_price', lookup_expr='gte', help_text="最低价格")    pricemax = django_filters.NumberFilter(field_name='shop_price', lookup_expr='lte')    # 获取相应类别下的所有商品    top_category = django_filters.NumberFilter(method='top_category_filter')    # 这是全部匹配    name = django_filters.CharFilter(field_name='name')# 这是部分匹配 不分大小写#     name = django_filters.CharFilter(field_name='name', lookup_expr='icontains')    def top_category_filter(self, queryset, name, value):        return queryset.filter(Q(category_id = value) | Q(category__parent_category_id = value) | Q(category__parent_category__parent_category_id = value))    class Meta:        model = Goods#  ------------------------------------------------------> 这里        fields = ['pricemin','pricemax', 'name', 'is_hot', 'is_new']

3. 商品分类显示

主页的这部分

这里面涉及了很多内容 多层级的1对多的关系 

先做商品类型的展示，就是图片左下角的那些

class IndexCategorySerializer(serializers.ModelSerializer):    class Meta:        model = GoodsCategory        fields = "__all__"

首先先做品牌展示 利用商品类别来方向选择对应类别的品牌

在model中我们添加related_name参数，这样方便做反向选择

# models.py/class GoodsCategoryBrand# Django2.0以上需要增加on_delete参数 针对外键    category = models.ForeignKey(GoodsCategory, related_name="brands", null=True, blank=True, verbose_name=u'商品类目', on_delete=models.CASCADE)

这样在goods_category中就可以反向拿到brand(品牌)了

然后我们在写一个brand的Serializer 然后嵌套到IndexSerializer中

这里有一个要明确 indexSerializer是包含上面截的整张图的所有信息。所以 相关的Serializer都会嵌套进去 统一返回给前端

# Serializers.pyclass BannerSerializer(serializers.ModelSerializer):    class Meta:        model = Banner        fields = "__all__"class IndexCategorySerializer(serializers.ModelSerializer):    brands = BrandSerializer(many=True)    class Meta:        model = GoodsCategory        fields = "__all__"

为什么不能直接用goods的Serializer。

goods中确实有一个外键指向我们的category。为什么不能反向取。

>因为商品选择哪个类别的时候，往往选择的是最小的类别。(第三类)

获取商品：

外键指向的第三类。而我们要拿到第一类别的数据。直接使用goods的Serializer取不出来。

自定义商品（取相应类别的商品，使用自定义函数Serializer字段）

class IndexCategorySerializer(serializers.ModelSerializer):    brands = BrandSerializer(many=True)    goods = serializers.SerializerMethodField()    def get_goods(self, obj):        all_goods = Goods.objects.filter(Q(category_id = obj.id) | Q(category__parent_category_id = obj.id) | Q(category__parent_category__parent_category_id = obj.id))        goods_serializer = GoodsSerializer(all_goods, many=True)        return goods_serializer.data

获取二类商品类别，利用之前做过的那个GategorySerializer2

class IndexCategorySerializer(serializers.ModelSerializer):    brands = BrandSerializer(many=True)    goods = serializers.SerializerMethodField()    sub_cat = CategorySerializer2(many=True)# 这是之前做的class CategorySerializer2(serializers.ModelSerializer):    sub_cat = CategorySerializer3(many=True)    class Meta:        model = GoodsCategory        fields = "__all__"

最后搞右边的那7张图片

先去建model

class IndexAd(models.Model):    """    首页类别标签右边展示的七个商品广告    """    category = models.ForeignKey(GoodsCategory, on_delete=models.CASCADE, related_name='category', verbose_name="商品类目")    goods = models.ForeignKey(Goods, on_delete=models.CASCADE, related_name='goods')    class Meta:        verbose_name = '首页广告'        verbose_name_plural = verbose_name    def __str__(self):        return self.goods.name

然后在IndexCategorySerializer中增加这些广告

from goods.models import IndexAdclass IndexCategorySerializer(serializers.ModelSerializer):    brands = BrandSerializer(many=True)    goods = serializers.SerializerMethodField()    sub_cat = CategorySerializer2(many=True)    ad_goods = serializers.SerializerMethodField()    def get_ad_goods(self, obj):        goods_json = {}        ad_goods = IndexAd.objects.filter(category_id = obj.id)        if ad_goods:            goods_ins = ad_goods[0].goods            goods_json = GoodsSerializer(goods_ins, many=False).data        return goods_json

这时候输出到前端的img路径是不包含url地址的。 因为我们在Serializer中嵌套了serializer 并且还自定义了序列化方法。 这样的形式默认是不会加上url的 所以我们需要在嵌套的Serializer中加上context参数

def get_ad_goods(self, obj):        goods_json = {}        ad_goods = IndexAd.objects.filter(category_id = obj.id)        if ad_goods:            goods_ins = ad_goods[0].goods# --------------------------------------------------------------> 这里            goods_json = GoodsSerializer(goods_ins, many=False, context={'request': self.context['request']}).data        return goods_json

这样输出到前端的图片路径就是包含URL域名的了。 帖完整的Serializer代码

from goods.models import Goods, GoodsCategory, GoodsImage, Banner, GoodsCategoryBrand, IndexAdfrom django.db.models import Qclass IndexCategorySerializer(serializers.ModelSerializer):    brands = BrandSerializer(many=True)    goods = serializers.SerializerMethodField()    sub_cat = CategorySerializer2(many=True)    ad_goods = serializers.SerializerMethodField()    def get_ad_goods(self, obj):        goods_json = {}        ad_goods = IndexAd.objects.filter(category_id = obj.id)        if ad_goods:            goods_ins = ad_goods[0].goods            goods_json = GoodsSerializer(goods_ins, many=False, context={'request': self.context['request']}).data        return goods_json    def get_goods(self, obj):        all_goods = Goods.objects.filter(Q(category_id = obj.id) | Q(category__parent_category_id = obj.id) | Q(category__parent_category__parent_category_id = obj.id))        goods_serializer = GoodsSerializer(all_goods, many=True, context={'request': self.context['request']})        return goods_serializer.data    class Meta:        model = GoodsCategory        fields = "__all__"

然后我们来写view

class IndexCategoryViewset(mixins.ListModelMixin, viewsets.GenericViewSet):    """    首页商品分类数据    """# 限定了是否是用于导航 并且限定了两类商品（正式环境是不限定商品类型）    queryset = GoodsCategory.objects.filter(is_tab=True, name__in=["生鲜食品","酒水饮料"])    serializer_class = IndexCategorySerializer

urls.py:

#主页商品系列数据router.register('indexgoods', IndexCategoryViewset, base_name='indexgoods')

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