30.2. Bastion
— Restricting access to objects¶
2.6 版后已移除: The Bastion
module has been removed in Python 3.
在 2.3 版更改: Disabled module.
注解
The documentation has been left in place to help in reading old code that uses the module.
According to the dictionary, a bastion is “a fortified area or position”, or
“something that is considered a stronghold.” It’s a suitable name for this
module, which provides a way to forbid access to certain attributes of an
object. It must always be used with the rexec
module, in order to allow
restricted-mode programs access to certain safe attributes of an object, while
denying access to other, unsafe attributes.
-
Bastion.
Bastion
(object[, filter[, name[, class]]])¶ Protect the object object, returning a bastion for the object. Any attempt to access one of the object’s attributes will have to be approved by the filter function; if the access is denied an
AttributeError
exception will be raised.If present, filter must be a function that accepts a string containing an attribute name, and returns true if access to that attribute will be permitted; if filter returns false, the access is denied. The default filter denies access to any function beginning with an underscore (
'_'
). The bastion’s string representation will be<Bastion for name>
if a value for name is provided; otherwise,repr(object)
will be used.class, if present, should be a subclass of
BastionClass
; see the code inbastion.py
for the details. Overriding the defaultBastionClass
will rarely be required.
-
class
Bastion.
BastionClass
(getfunc, name)¶ Class which actually implements bastion objects. This is the default class used by
Bastion()
. The getfunc parameter is a function which returns the value of an attribute which should be exposed to the restricted execution environment when called with the name of the attribute as the only parameter. name is used to construct therepr()
of theBastionClass
instance.