在django开发中，使用drf序列化好友列表

摘要：本文中讨论的好友列表模型设计如下聊天用户聊天用户好友分组好友分组，备注信息，备注信息添加好友时间更新分组时间好友来源即和互为好友，在数据库中只会保存一条记录，这样节省磁盘空间。

本文中讨论的好友列表模型设计如下：

user_id = models.ForeignKey(ChatUserInfo, to_field="chat_id", on_delete=models.DO_NOTHING, db_index=True,     help_text="聊天用户id")
friend_id = models.ForeignKey(ChatUserInfo, to_field="chat_id", related_name="friend", on_delete=models.DO_NOTHING, db_index=True, help_text="聊天用户id")
user_group = models.ForeignKey(ChatGroupType, to_field="flag", on_delete=models.CASCADE, help_text="好友分组")
friend_group = models.ForeignKey(ChatGroupType, to_field="flag", related_name="friend_group", on_delete=models.CASCADE, help_text="好友分组")
user_label = models.CharField(max_length=64，help_text="备注信息")
friend_label = models.CharField(max_length=64，help_text="备注信息")
create_time = models.DateTimeField("添加好友时间", auto_now_add=True)
update_time = models.DateTimeField("更新分组时间", auto_now=True)
resource = models.ForeignKey(ChatFriendResource, to_field="origin", on_delete=models.DO_NOTHING, help_text="好友来源")

即A和B互为好友，在数据库中只会保存一条记录，这样节省磁盘空间。

对于这样的模型，当前端需要展示当前用户的好友列表时，序列化方式如下：

views.py:
def get(self, request, *args, **kwargs):
    """
    聊天-好友列表
    :param request:
    :param args:
    :param kwargs:
    :return:
    """
    try:
        chat_id = request.query_params.get("chat_id", "")
        # chat_id = request.user.user.chat_id  # 添加用户认证后再使用request.user
        chat_user = models.ChatUserInfo.objects.get(chat_id=int(chat_id))
    except ValueError:
        return Response(dict(msg="请输入用户id"), status=status.HTTP_400_BAD_REQUEST)
    except models.ChatUserInfo.DoesNotExist:
        return Response(dict(msg="用户不存在"), status=status.HTTP_400_BAD_REQUEST)

    # 好友列表
    user_friends = models.ChatFriendList.objects.filter(Q(user_id=chat_id) | Q(friend_id=chat_id))
    ser = serializer.FriendSerializer(instance=user_friends, many=True, context={"chat_user": chat_user})

    friends = []
    for data in ser.data:
        friend_dict = OrderedDict()
        if data["user_id"] == int(chat_id):
            friend_dict["friend_id"] = data["friend_id"]
            friend_dict["friend_avatar"] = data["friend_avatar"]
        if data["friend_id"] == int(chat_id):
            friend_dict["friend_id"] = data["user_id"]
            friend_dict["friend_avatar"] = data["user_avatar"]
        friend_dict["friend_name"] = data["friend_name"]
        friend_dict["friend_area"] = data["friend_area"]
        friend_dict["friend_status"] = data["friend_status"]
        friend_dict["friend_label"] = data["friend_label"]
        friend_dict["friend_resource"] = data["friend_resource"]
        friends.append(friend_dict)
    logger.debug("data:%s", ser.data)
    return Response(dict(msg="OK", data=friends), status=status.HTTP_200_OK)

serializer.py:
class FriendSerializer(serializers.Serializer):
    """
    序列化-好友列表-好友信息  ChatFriendList
    """
    # 用户id
    # friend_id = serializers.SerializerMethodField(method_name="get_id")
    user_id = serializers.IntegerField(source="user.chat_id")
    friend_id = serializers.IntegerField(source="friend.chat_id")
    # 用户昵称
    friend_name = serializers.SerializerMethodField(method_name="get_name")
    # 用户头像
    # friend_avatar = serializers.SerializerMethodField(method_name="get_avatar")
    user_avatar = serializers.ImageField(source="user.user.avatar")
    friend_avatar = serializers.ImageField(source="friend.user.avatar")
    # 用户地区
    friend_area = serializers.SerializerMethodField(method_name="get_area")
    # 用户状态
    friend_status = serializers.SerializerMethodField(method_name="get_status")
    # 用户备注
    friend_label = serializers.SerializerMethodField(method_name="get_label")
    # 用户来源
    friend_resource = serializers.CharField(source="resource")

    def get_id(self, obj):
        """
        获取好友id
        :param obj:
        :return:
        """
        if obj.user.chat_id == self.context["chat_user"].chat_id:
            # user_id是当前用户
            return obj.friend.chat_id
        return obj.user.chat_id

    def get_name(self, obj):
        """
        获取好友昵称
        :param obj:
        :return:
        """
        if obj.user.chat_id == self.context["chat_user"].chat_id:
            # user_id是当前用户
            return obj.friend.user.nickname
        return obj.user.user.nickname

    def get_avatar(self, obj):
        """
        获取好友头像
        :param obj:
        :return:
        """
        if obj.user.chat_id == self.context["chat_user"].chat_id:
            # user_id是当前用户
            return obj.friend.user.avatar
        return obj.user.user.avatar

    def get_area(self, obj):
        """
        获取好友地区
        :param obj:
        :return:
        """
        if obj.user.chat_id == self.context["chat_user"].chat_id:
            # user_id是当前用户
            return obj.friend.area
        return obj.user.area

    def get_status(self, obj):
        """
        获取好友状态
        :param obj:
        :return:
        """
        if obj.user.chat_id == self.context["chat_user"].chat_id:
            # user_id是当前用户
            return obj.friend.status
        return obj.user.status

    def get_label(self, obj):
        """
        获取好友备注
        :param obj:
        :return:
        """
        if obj.user.chat_id == self.context["chat_user"].chat_id:
            # user_id是当前用户
            return obj.friend_label
        return obj.user_label

    def create(self, validated_data):
        pass

    def update(self, instance, validated_data):
        pass

上面的序列化主要使用了serializers.ImageField 和 serializers.SerializerMethodField，如有错误之处，欢迎交流指正！