I found a "maybe" way... but I don't know if it's good idea... the
"propertyProxy" instances have a field called "descriptor" which the
"InstrumentedAttribute" don't have... so I can always do this:
--------------------------------------------------
def getProperties4(cls):
properties = list()
for varKey in vars(cls):
varVal = getattr(cls, varKey)
try:
if "descriptor" in vars(varVal):
if isinstance(getattr(varVal, "descriptor"),
property):
properties.append(varKey)
except TypeError:
pass
print("Properties found: '%s'" % properties)
return properties
--------------------------------------------------
That works...
Properties found: '['id', password', 'userName']'
...but I don't really know what I'm exactly touching here... (and how
"dangerous"... or correct it may be)
2010/12/21 Hector Blanco <[email protected]>:
> First of all, thank you for replying.
>
> I don't really know if I understood your idea.
>
> I dug a bit more in the User class (not the instance, but what it
> would be self.__class__) and the problem is that both "password" and
> "_password" have a "__get__":
>
>
> I changed the getProperties method a bit, to introspect the __class__ thing:
>
> def getProperties(cls):
> properties = list()
>
> for varName in vars(cls):
> log.debug("Studying prop '%s' of type: %s" %(varName,
> type(getattr(cls, varName))))
> if varName == "password" or varName == "_password":
> valTmp = getattr(cls, varName)
> print(" \t Has %s a __get()__? %s" % (varName,
> getattr(valTmp, "__get__")))
> print(" \t Contents of %s" % varName)
> for key, val in valTmp.__dict__.iteritems():
> print(" \t\t %s: %s" % (key, val))
>
> return None
> #return properties
>
> ----- And it outputs this (showing only the password thing:) ---------
>
> Studying prop '_password' of type: <class
> 'sqlalchemy.orm.attributes.InstrumentedAttribute'>
> Has _password a __get()__? <bound method
> InstrumentedAttribute.__get__ of
>
> <sqlalchemy.orm.attributes.InstrumentedAttribute object at 0xa26e46c>>
> Contents of _password
> parententity: Mapper|User|users
> __doc__: None
> impl: <sqlalchemy.orm.attributes.ScalarAttributeImpl object
> at 0xa3d758c>
> key: _password
> comparator: <sqlalchemy.orm.properties.Comparator object at
> 0xa26e44c>
> Studying prop 'password' of type: <class
> 'sqlalchemy.orm.attributes.propertyProxy'>
> Has password a __get()__? <bound method propertyProxy.__get__ of
> <sqlalchemy.orm.attributes.propertyProxy
> object at 0xa26eacc>>
> Contents of password
> _comparator: <function comparator at 0xa269bc4>
> key: password
> descriptor: <property object at 0xa25ef7c>
> _parententity: Mapper|User|users
> user_prop: <property object at 0xa25ef7c>
> __doc__: Get password
> impl: <sqlalchemy.orm.attributes._ProxyImpl object at
> 0xa26eaec>
>
> ------------------
>
> I have also tried to check isinstance(getattr(cls, varName),
> sqlalchemy.orm.attributes.InstrumentedAttribute) (even though it may
> not be the best option, but...) and the problem is that both
> "password" and "_password" happen to be InstrumentedAttributes
> (propertyProxy extends from InstrumentedAttribute).
>
> I've seen in the "attributes.py" file an "is_instrumented" method...
> Maybe I could get the vars of an instance (not the class, no... an
> instance) which would give me:
> (["_sa_instance_state", "_id", "_userName", "_password"]),
> then check if these variables are instrumented ("_sa_instance_state"
> isn't) and then check if the class has the attributes ["id",
> "userName" and "password"] but in order to do that I need to remove
> the first character of the attribute name (to get "userName" from
> "_userName") and that seems it's going to mess up with the
> performance...
>
> Thank you!
>
> 2010/12/20 Michael Bayer <[email protected]>:
>>
>> On Dec 20, 2010, at 7:30 PM, Hector Blanco wrote:
>>
>>> Hello all!
>>>
>>> I have an application running under Python2.6 and the classes are set
>>> up with properties (in a Python2.4 style, though).
> [ . . . ]
>>> So here's the question:
>>> Is there any way to get the properties of a class mapped with SqlAlchemy?
>>
>> I'd look at the object to see if it has a __get__() method, since that's
>> what defines a "descriptor" in Python, not just isinstance(x, property).
>> duck typing
>>
>>
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>>
>
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