RestrictedPython 3.4.2

print

To support the print statement in restricted code, we supply a _print_ object (note that it’s a factory, e.g. a class or a callable, from which the restricted machinery will create the object):

>>> from RestrictedPython.PrintCollector import PrintCollector
>>> _print_ = PrintCollector

>>> src = '''
... print "Hello World!"
... '''
>>> code = compile_restricted(src, '<string>', 'exec')
>>> exec(code)

As you can see, the text doesn’t appear on stdout. The print collector collects it. We can have access to the text using the printed variable, though:

>>> src = '''
... print "Hello World!"
... result = printed
... '''
>>> code = compile_restricted(src, '<string>', 'exec')
>>> exec(code)

>>> result
'Hello World!\n'

Built-ins

By supplying a different __builtins__ dictionary, we can rule out unsafe operations, such as opening files:

>>> from RestrictedPython.Guards import safe_builtins
>>> restricted_globals = dict(__builtins__ = safe_builtins)

>>> src = '''
... open('/etc/passwd')
... '''
>>> code = compile_restricted(src, '<string>', 'exec')
>>> exec(code) in restricted_globals
Traceback (most recent call last):
  ...
NameError: name 'open' is not defined

Guards

Here’s an example of a write guard that never lets restricted code modify (assign, delete an attribute or item) except dictionaries and lists:

>>> from RestrictedPython.Guards import full_write_guard
>>> _write_ = full_write_guard
>>> _getattr_ = getattr

>>> class BikeShed(object):
...     colour = 'green'
...
>>> shed = BikeShed()

Normally accessing attriutes works as expected, because we’re using the standard getattr function for the _getattr_ guard:

>>> src = '''
... print shed.colour
... result = printed
... '''
>>> code = compile_restricted(src, '<string>', 'exec')
>>> exec(code)

>>> result
'green\n'

However, changing an attribute doesn’t work:

>>> src = '''
... shed.colour = 'red'
... '''
>>> code = compile_restricted(src, '<string>', 'exec')
>>> exec(code)
Traceback (most recent call last):
  ...
TypeError: attribute-less object (assign or del)

As said, this particular write guard (full_write_guard) will allow restricted code to modify lists and dictionaries:

>>> fibonacci = [1, 1, 2, 3, 4]
>>> transl = dict(one=1, two=2, tres=3)
>>> src = '''
... # correct mistake in list
... fibonacci[-1] = 5
... # one item doesn't belong
... del transl['tres']
... '''
>>> code = compile_restricted(src, '<string>', 'exec')
>>> exec(code)

>>> fibonacci
[1, 1, 2, 3, 5]
>>> sorted(transl.keys())
['one', 'two']

3.4.2 (2007/07/28)

• Changed homepage URL to the CheeseShop site

• Greatly improved README.txt

3.4.1 (2007/06/23)

• Fixed Collector/#2295 (Zope 2, PythonScripts)

3.4.0 (2007/06/04)

• RestrictedPython now has its own release cycle as a separate egg.

• Synchronized with RestrictedPython from Zope 2 tree.

3.2.0 (2006/01/05)

• Corresponds to the verison of the RestrictedPython package shipped as part of the Zope 3.2.0 release.

• No changes from 3.1.0.

3.1.0 (2005/10/03)

• Corresponds to the verison of the RestrictedPython package shipped as part of the Zope 3.1.0 release.

• Removed unused fossil module, ‘SafeMapping’.

• Replaced use of deprecated ‘whrandom’ module with ‘random’ (aliased to ‘whrandom’ for backward compatibility).

3.0.0 (2004/11/07)

• Corresponds to the verison of the RestrictedPython package shipped as part of the Zope X3.0.0 release.