Bastion — Restricting access to objects¶Deprecated since version 2.6:
Deprecated since version 2.6: The Bastion module has been removed in Python 3.0.
Changed in version 2.3:
Changed in version 2.3: Disabled module.
Note
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 in bastion.py for the details. Overriding the default
BastionClass will rarely be required.
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 the repr() of the BastionClass
instance.