fget=Bulbs 类属性初始化时参数的范围是什么？
比如我在写的时候：
from bulbs.model import Node, Relationship
from bulbs.property import String
class foobar(Node)
element_type = "foobar"
fget_property = String(fget=some_method)
some_method正确定义 fget_property 应该得到什么？它应该对其他类属性执行一些操作，还是它也可以是类实例所喜欢的关系的函数，例如调用的东西self.outV(some_relation)？
这里的值fget应该是返回计算值的方法名称。方法名称应该引用在您的 Bulbs Model 类中定义的方法，并且该方法应该没有参数。
fget每次创建/更新/保存元素到数据库时都会调用该方法。
见https://github.com/espeed/bulbs/blob/master/bulbs/model.py#L347
Bulbs 使用 Python 元类将fget函数设置为您正在定义的Python （ 不要与 Bulbs 数据库混淆，例如在您的示例中）。propertyModel classPropertyString
请参阅 Python 类属性（小“p”）与 Bulbs 数据库属性（大“P”）...
以下是您定义fget的灯泡的设置方式：Model
class ModelMeta(type):
"""Metaclass used to set database Property definitions on Models."""
def __init__(cls, name, base, namespace):
"""Store Property instance definitions on the class as a dictionary."""
# Get inherited Properties
cls._properties = cls._get_initial_properties()
# Add new Properties
cls._register_properties(namespace)
### ...other class methods snipped for brevity... ###
def _initialize_property(cls, key, property_instance):
"""
Set the Model class attribute based on the Property definition.
:param key: Class attribute key
:type key: str
:param property_instance: Property instance
:type property_instance bulbs.property.Property
"""
if property_instance.fget:
fget = getattr(cls, property_instance.fget)
# TODO: implement fset and fdel (maybe)
fset = None
fdel = None
property_value = property(fget, fset, fdel)
else:
property_value = None
setattr(cls, key, property_value)
见https://github.com/espeed/bulbs/blob/master/bulbs/model.py#L97
有关元类如何在 Python 中工作的概述，请参阅：
更新：这是使用fget方法的模型声明的完整工作示例...
# people.py
from bulbs.model import Node, Relationship
from bulbs.property import String, Integer, DateTime
from bulbs.utils import current_datetime
class Person(Node):
element_type = "person"
name = String(nullable=False)
age = Integer("calc_age")
def calc_age(self):
"""A pointless method that calculates a hard-coded age."""
age = 2014 - 1977
return age
class Knows(Relationship):
label = "knows"
timestamp = DateTime(default=current_datetime, nullable=False)
这是一个完整的工作示例，说明如何使用它......
>>> from bulbs.rexster import Graph
>>> from people import Person, Knows
>>> g = Graph()
>>> g.add_proxy("people", Person)
>>> g.add_proxy("knows", Knows)
>>> james = g.people.create(name="James")
>>> julie = g.people.create(name="Julie")
>>> knows = g.knows.create(james, julie)
>>> print james.age
37
>>> print knows.timestamp
2014-08-04 21:28:31