flask_sqlalchemy_basemodel.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# @file     base.py
# @author   kaka_ace <xiang.ace@gmail.com>
# @date     Jun 13 2015
# @breif     
# 


import flask_sqlalchemy
from flask_sqlalchemy import (
    SQLAlchemy,
    _BoundDeclarativeMeta,
)


class ModelMeta(_BoundDeclarativeMeta):
    pass


flask_sqlalchemy._BoundDeclarativeMeta = ModelMeta


db = SQLAlchemy()


class BaseModel(db.Model):
    __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)

    @classmethod
    def get_column_name_sets(cls):
        """
        """
        return cls.__column_name_sets

    __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._column_name_sets = column_name_sets
    return obj

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