用于App Engine的Python中的克隆和Expando类对象

Question

在Google App Engine上使用Python时克隆（复制）Expando类对象的好方法是什么？

我碰到一些代码来了这里，但除非我错了，它不expando属性工作：Copy an entity in Google App Engine datastore in Python without knowing property names at 'compile' time

谢谢！

Answer 1

这里是Nick's function的修订版，其中包括动态属性：

def clone_entity(e, **extra_args): 
    """Clones an entity, adding or overriding constructor attributes. 

    The cloned entity will have exactly the same property values as the original 
    entity, except where overridden. By default it will have no parent entity or 
    key name, unless supplied. 

    Args: 
    e: The entity to clone 
    extra_args: Keyword arguments to override from the cloned entity and pass 
     to the constructor. 
    Returns: 
    A cloned, possibly modified, copy of entity e. 
    """ 
    klass = e.__class__ 
    props = dict((k, v.__get__(e, klass)) for k, v in klass.properties().iteritems()) 
    props.update(dict([(k, getattr(e, k)) for k in e.dynamic_properties()])) 
    props.update(extra_args) 
    return klass(**props)