11.6 交易记录

1.业务逻辑

image.png

这两个条件应该是或者（or）的关系

2.获取鱼漂列表

# select * from drift where requester_id = ? or gifter_id = ?
    # order by create_time desc
    drifts = Drift.query.filter(
        or_(Drift.requester_id == current_user.id,
            Drift.gifter_id == current_user.id))\
        .order_by(desc(Drift.create_time)).all()

3.Drift ViewModel 编写

Drift ViewModel需要适应当前用户是赠送者和当前用户是索要者两个情况

image.png

class DriftCollection:

    def __init__(self, drifts, current_user_id):
        self.data = []

        self.data = self._parse(drifts, current_user_id)

    def _parse(self, drifts, current_user_id):
        return [DriftViewModel(drift, current_user_id).data for drift in drifts]


class DriftViewModel:

    def __init__(self, drift, current_user_id):
        self.data = {}

        self.data = self._parse(drift, current_user_id)

    @staticmethod
    def requester_or_gifter(drift, current_user_id):
        # 不建议将current_user耦合进DriftViewModel，破坏了封装性，难以扩展，所以当做参数从外部传入
        return 'requester' if current_user_id == drift.requester_id else 'gifter'

    def _parse(self, drift, current_user_id):
        you_are = DriftViewModel.requester_or_gifter(drift, current_user_id)
        # pending_status 设计到了4*2=8种状态，这个状态的判断应该在PendingStatus完成
        pending_status = PendingStatus.pending_str(drift.pending, you_are)
        r = {
            'drift_id': drift.id,
            'you_are': you_are,
            'book_title': drift.book_title,
            'book_author': drift.book_author,
            'book_img': drift.book_img,
            'date': drift.create_datetime.strftime('%Y-%m-%d'),
            'operator': drift.requester_nickname if you_are != 'requester' \
                else drift.gifter_nickname,
            'message': drift.message,
            'address': drift.address,
            'status_str': pending_status,
            'recipient_name': drift.recipient_name,
            'mobile': drift.mobile,
            'status': drift.pending
        }

        return r

enums.py

class PendingStatus(Enum):
    Waiting = 1
    Success = 2
    Reject = 3
    Redraw = 4

    @classmethod
    def pending_str(cls, status, key):
        key_map = {
            cls.Waiting.value: {
                'requester': '等待对方邮寄',
                'gifter': '等待你邮寄'
            },
            cls.Reject.value: {
                'requester': '对方已拒绝',
                'gifter': '你已拒绝'
            },
            cls.Redraw.value: {
                'requester': '你已撤销',
                'gifter': '对方已撤销'
            },
            cls.Success.value: {
                'requester': '对方已邮寄',
                'gifter': '你已邮寄，交易完成'
            }
        }
        return key_map[status][key]

对比三种ViewModel

1.BookViewModel将单体和集合分开，单体定义实例属性，清晰明了（最推荐） 2.MyTrade 将单体作为字典融合在集合类里面，代码少，灵活性高，但是不易扩展（最不推荐） 3.DriftViewModel 将单体和集合分开，单体使用字典。坚固了前两中的优点，但是可读性下降（也不是特别推荐）