DRF序列化和反序列化——基本使用

from rest_framework import serializers

class BookInfo(models.Model):
    """书籍信息模型"""
    name = models.CharField(max_length=20, verbose_name='名称') #图书名称
    pub_date = models.DateField(verbose_name='发布日期') #发布日期
    readcount = models.IntegerField(default=0, verbose_name='阅读量') #阅读量
    commentcount = models.IntegerField(default=0, verbose_name='评论量') #评论量

    class Meta:
        db_table = 'bookinfo' # 指明数据库表名
        verbose_name = '图书'  # 在admin站点中显示的名称
        verbose_name_plural = verbose_name  # 显示的复数名称

    def __str__(self):
        """定义每个数据对象的显示信息"""
        return self.name

class BookInfoSerializer(serializers.Serializer):
    """BookInfo序列化器"""
    id = serializers.IntegerField(label='ID')
    name = serializers.CharField(label='名称')
    pub_date = serializers.DateField(label='发布日期')
    readcount = serializers.IntegerField(label='阅读量')
    commentcount = serializers.IntegerField(label='评论量')

Serializer(instance=None, data=empty, **kwarg)

class BookView(View):

    def get(self, request, *args, **kwargs):
        book_id = request.GET.get('id')
        obj = BookInfo.objects.get(id=book_id)
        data = BookInfoSerializer(obj).data     # 序列化并获取数据

        return JsonResponse(data)

http://127.0.0.1:8000/book?id=1     # 查询id为1的书籍信息

class BookView(View):

    def get(self, request, *args, **kwargs):
        book_id = request.GET.get('id', '')
        if book_id:     # 前端如果传入id，那么查询一条数据
            obj = BookInfo.objects.get(id=book_id)
            data = BookInfoSerializer(obj).data
            return JsonResponse(data)
        else:           # 前端如果没有传入id，那么返回所有数据
            objs = BookInfo.objects.all()
            data = BookInfoSerializer(objs, many=True).data		# 获取多条数据
            return JsonResponse(data, safe=False)

http://127.0.0.1:8000/book

class BookInfoSerializer(serializers.Serializer):
    """BookInfo序列化器"""
    id = serializers.IntegerField(label='ID', read_only=True)       # 只序列化
    name = serializers.CharField(label='名称', max_length=10)        # 书籍名称最多10字符
    pub_date = serializers.DateField(label='发布日期')
    readcount = serializers.IntegerField(label='阅读量', min_value=0, required=False)   # 最小值0，不是必传参数
    commentcount = serializers.IntegerField(label='评论量', min_value=0, required=False)  # 最小值0，不是必传参数

    def create(self, validated_data):
        """序列化器对象的save()方法会调用create"""

        # 使用ORM的create()方法向数据库增加一条数据
        return BookInfo.objects.create(**validated_data)

    def update(self, instance, validated_data):
        """序列化器对象的save()方法会调用update"""
        instance.name = validated_data.get('name', instance.name)       # 如果前端没有传递这个书籍，那么就获取原来的值
        instance.pub_date = validated_data.get('pub_date', instance.pub_date)

        instance.save()
        return instance

class BookView(View):
    """书籍视图"""
    def get(self, request, *args, **kwargs):
        """查询一个或者整个列表"""
        book_id = request.GET.get('id', '')
        if book_id:     # 前端如果传入id，那么查询一条数据
            try:
                obj = BookInfo.objects.get(id=book_id)
            except BookInfo.DoesNotExist:
                return JsonResponse({}, status=404)
            else:
                data = BookInfoSerializer(obj).data
                return JsonResponse(data)
        else:           # 前端如果没有传入id，那么返回所有数据
            objs = BookInfo.objects.all()
            data = BookInfoSerializer(objs, many=True).data
            return JsonResponse(data, safe=False)
        

    def post(self, request, *args, **kwargs):
        """新增书籍"""
        json_data = json.loads(request.body)
        pub_date = json_data.get('pub_date')
        name = json_data.get('name')
        # 反序列化
        obj = BookInfoSerializer(data={"name":name, "pub_date": pub_date, "readcount": 0, "commentcount": 0})
        # 使用is_valid()进行验证
        if obj.is_valid():
            # 使用save进行保存
            obj.save()
            return JsonResponse(obj.data)
        else:
            # 序列化器对象的errors属性获取字典形式的错误信息
            return JsonResponse(data=obj.errors, status=400)


    def put(self, request, *args, **kwargs):
        """修改书籍信息"""
        book_id = request.GET.get('id')
        json_data = json.loads(request.body)
        pub_date = json_data.get('pub_date')
        name = json_data.get('name')
        try:
            obj = BookInfo.objects.get(id=book_id)
        except BookInfo.DoesNotExist:
            return JsonResponse({}, status=404)
        else:
            ser = BookInfoSerializer(instance=obj, data={"name": name, "pub_date": pub_date})
            if ser.is_valid():
            # 使用save进行保存
                ser.save()
                return JsonResponse(ser.data)
            else:
            # 序列化器对象的errors属性获取字典形式的错误信息
                return JsonResponse(data=ser.errors, status=400)

    
    def delete(self, request, *args, **kwargs):
        """删除一本书籍，删除和序列化器没有关系"""
        id = request.GET.get('id')
        try:
            obj = BookInfo.objects.get(id=id)
        except:
            return JsonResponse({}, status=404)
        else:
            obj.delete()
        return JsonResponse({},status=204)