Hi.
I use sqlalchemy 1.0.17, thanks for you great library :)
I have such code:
class FlagsMixin(object):
@hybrid_method
def exist_flag(self, flag):
if not self.flags or not flag:
return False
return self.flags & flag == flag
@exist_flag.expression
def exist_flag(self, flag):
return and_(flag != 0, self.flags != 0, self.flags.op('&')(flag) != 0)
class SomeModel(Base, FlagsMixin, AnyOtherClass):
# class attrs and methods
In case of optimization, I want to create sqlalchemy-free class, which
contains all methods and attributes of class. So, i wrote that code:
@staticmethod
def _get_sa_free_class(klass, with_mro=False):
sa_free_cls = getattr(klass, '__sa_free_cls', None)
if sa_free_cls is None:
items = {}
klasses = [klass] if not with_mro else klass.__mro__
for k in klasses:
for name, val in k.__dict__.items():
if name not in items and name not in ['__mapper__', '__dict__',
'__class__', '_sa_class_manager', 'query', 'metadata']:
if isinstance(val, InstrumentedAttribute):
items[name] = None
else:
items[name] = val
for method_name in ('exist_flag', ):
items[method_name] = getattr(klass, method_name)
sa_free_cls = type('Unbound' + klass.__name__, (object, ), dict(items))
sa_free_cls._sa_free = True
sa_free_cls.__init__ = klass._sa_class_manager.original_init.im_func
setattr(klass, '__sa_free_cls', sa_free_cls)
return sa_free_cls
Result class should has `exist_flag()` method, and it has to be used always
with `func` attribute of hybrid_property, neither `expr` (as I want to have
SQLA-free class).
As you can see, I want to ensure `exist_flag()` method existence in result
`klass` object, and if method called with `with_mro=False`.
But, of course, such a way can't allow this, because of descriptor logic -
return `expr` if instance not specified:
klass.exist_flag(1)
<sqlalchemy.sql.elements.BooleanClauseList object at 0x7f2a79b835d0>
Also, I tried to use this versions with same result - AttributeError(''):
klass.exist_flag.func
klass.exist_flag.__class__.func
...
AttributeError: 'function' object has no attribute 'func'
Is there any way to get `func` attribute of hybrid_method?
And also, maybe sqlalchemy already has some alternative to get
sqla-free-class?
Thank you again.
Anton.
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SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
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