摘要：本文中討論的好友列表模型設計如下聊天用戶聊天用戶好友分組好友分組，備注信息，備注信息添加好友時間更新分組時間好友來源即和互為好友，在數據庫中只會保存一條記錄，這樣節省磁盤空間。

本文中討論的好友列表模型設計如下：

user_id = models.ForeignKey(ChatUserInfo, to_field="chat_id", on_delete=models.DO_NOTHING, db_index=True,     help_text="聊天用戶id")
friend_id = models.ForeignKey(ChatUserInfo, to_field="chat_id", related_name="friend", on_delete=models.DO_NOTHING, db_index=True, help_text="聊天用戶id")
user_group = models.ForeignKey(ChatGroupType, to_field="flag", on_delete=models.CASCADE, help_text="好友分組")
friend_group = models.ForeignKey(ChatGroupType, to_field="flag", related_name="friend_group", on_delete=models.CASCADE, help_text="好友分組")
user_label = models.CharField(max_length=64，help_text="備注信息")
friend_label = models.CharField(max_length=64，help_text="備注信息")
create_time = models.DateTimeField("添加好友時間", auto_now_add=True)
update_time = models.DateTimeField("更新分組時間", auto_now=True)
resource = models.ForeignKey(ChatFriendResource, to_field="origin", on_delete=models.DO_NOTHING, help_text="好友來源")

即A和B互為好友，在數據庫中只會保存一條記錄，這樣節省磁盤空間。

對于這樣的模型，當前端需要展示當前用戶的好友列表時，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  # 添加用戶認證后再使用request.user
        chat_user = models.ChatUserInfo.objects.get(chat_id=int(chat_id))
    except ValueError:
        return Response(dict(msg="請輸入用戶id"), status=status.HTTP_400_BAD_REQUEST)
    except models.ChatUserInfo.DoesNotExist:
        return Response(dict(msg="用戶不存在"), 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
    """
    # 用戶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")
    # 用戶昵稱
    friend_name = serializers.SerializerMethodField(method_name="get_name")
    # 用戶頭像
    # friend_avatar = serializers.SerializerMethodField(method_name="get_avatar")
    user_avatar = serializers.ImageField(source="user.user.avatar")
    friend_avatar = serializers.ImageField(source="friend.user.avatar")
    # 用戶地區
    friend_area = serializers.SerializerMethodField(method_name="get_area")
    # 用戶狀態
    friend_status = serializers.SerializerMethodField(method_name="get_status")
    # 用戶備注
    friend_label = serializers.SerializerMethodField(method_name="get_label")
    # 用戶來源
    friend_resource = serializers.CharField(source="resource")

    def get_id(self, obj):
        """
        獲取好友id
        :param obj:
        :return:
        """
        if obj.user.chat_id == self.context["chat_user"].chat_id:
            # user_id是當前用戶
            return obj.friend.chat_id
        return obj.user.chat_id

    def get_name(self, obj):
        """
        獲取好友昵稱
        :param obj:
        :return:
        """
        if obj.user.chat_id == self.context["chat_user"].chat_id:
            # user_id是當前用戶
            return obj.friend.user.nickname
        return obj.user.user.nickname

    def get_avatar(self, obj):
        """
        獲取好友頭像
        :param obj:
        :return:
        """
        if obj.user.chat_id == self.context["chat_user"].chat_id:
            # user_id是當前用戶
            return obj.friend.user.avatar
        return obj.user.user.avatar

    def get_area(self, obj):
        """
        獲取好友地區
        :param obj:
        :return:
        """
        if obj.user.chat_id == self.context["chat_user"].chat_id:
            # user_id是當前用戶
            return obj.friend.area
        return obj.user.area

    def get_status(self, obj):
        """
        獲取好友狀態
        :param obj:
        :return:
        """
        if obj.user.chat_id == self.context["chat_user"].chat_id:
            # user_id是當前用戶
            return obj.friend.status
        return obj.user.status

    def get_label(self, obj):
        """
        獲取好友備注
        :param obj:
        :return:
        """
        if obj.user.chat_id == self.context["chat_user"].chat_id:
            # user_id是當前用戶
            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，如有錯誤之處，歡迎交流指正！