base_model.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# 
#  @file     model/model/base.py
#  @author   kaka_ace <xiang.ace@gmail.com>
#  @date     
#  @brief   
#


from sqlalchemy.ext.declarative import (
    declarative_base,
    DeclarativeMeta,
)

from sqlalchemy.orm import aliased
from sqlalchemy import or_


class ModelMeta(DeclarativeMeta):
    def __new__(cls, name, bases, d):
        return DeclarativeMeta.__new__(cls, name, bases, d)

    def __init__(self, name, bases, d):
        DeclarativeMeta.__init__(self, name, bases, d)


_Base = declarative_base(metaclass=ModelMeta)


class BaseModel(_Base):
    __abstract__ = True

    _column_name_sets = NotImplemented

    def get_py_dict(self):
        """
        """
        return dict((column_name, getattr(self, column_name, None)) for column_name in self._column_name_sets)

    def set_py_dict(self, data, check_key_sets=None):
        """

        :param: data: dict of data
        :param : check_key_sets: check nullable key sets, the structure should be set()

        """
        if check_key_sets is not None:
            if isinstance(check_key_sets, list):
                check_key_sets = set(check_key_sets)

            key_sets = set(dict().keys())
            if not check_key_sets.issubset(key_sets):
                raise KeyError(
                    "check_key_sets not match for data keys(not subset) check_key_sets {0} vs key_sets {1}".format(
                        check_key_sets, key_sets
                    )
                )

        for k, v in data.items():
            if k in self._column_name_sets:
                setattr(self, k, v)

    @classmethod
    def check_py_dict_integrity(cls, data):
        """
        set Column Attribute from Python Dict
        this output should not be printed
        """
        key_sets = set(data.keys())
        return cls._column_name_sets.issubset(key_sets)

    @classmethod
    def is_py_dict_key_in_column_sets(cls, data):
        """
        set Column Attribute from Python Dict
        this output should not be printed
        可能有空集
        """
        key_sets = set(data.keys())
        return key_sets.issubset(cls._column_name_sets)

    @classmethod
    def get_attributes_sets(cls):
        """

        """
        return cls._column_name_sets

    @classmethod
    def get_table_name_prefix(cls):
        return cls._table_name_prefix

    or_ = or_

    __str__ = lambda self: str(self.get_py_dict())
    __repr__ = lambda self: repr(self.get_py_dict())


def modelmeta__new__(cls, name, bases, namespace, **kwds):
    column_name_sets = set()
    for k, v in namespace.items():
        if getattr(v, '__class__', None) is None:
            continue
        if v.__class__.__name__ == 'Column':
            column_name_sets.add(k)

    # obj = type.__new__(cls, name, bases, dict(namespace))
    obj = DeclarativeMeta.__new__(cls, name, bases, dict(namespace))
    # update set
    if obj._column_name_sets is NotImplemented:
        obj._column_name_sets = column_name_sets
    else:
        obj._column_name_sets.update(column_name_sets)
    return obj


# modify BaseModel' metatype ModelMeta' __new__ definition
setattr(ModelMeta, '__new__', modelmeta__new__)