Usage of ast.

[Vincent Vande Vyvre]

Le 27/02/17 à 14:09, Chris Angelico a écrit :
> On Mon, Feb 27, 2017 at 11:57 PM, Vincent Vande Vyvre
> <vincent.vande.vyvre at telenet.be> wrote:
>> I've this strange error:
>>
>> Python 3.4.3 (default, Nov 17 2016, 01:08:31)
>> [GCC 4.8.4] on linux
>> Type "help", "copyright", "credits" or "license" for more information.
>>>>> import ast
>>>>> l = "print('hello world')"
>>>>> ast.literal_eval(l)
>> Traceback (most recent call last):
>>    File "<stdin>", line 1, in <module>
>>    File "/usr/lib/python3.4/ast.py", line 84, in literal_eval
>>      return _convert(node_or_string)
>>    File "/usr/lib/python3.4/ast.py", line 83, in _convert
>>      raise ValueError('malformed node or string: ' + repr(node))
>> ValueError: malformed node or string: <_ast.Call object at 0x7fcf955871d0>
>>
>>
>> Is it an import question ?
> The message is a little confusing, but the error comes from the fact
> that literal_eval permits a very few legal operations, and calling a
> function isn't one of them. So when you try to evaluate the "literal"
> that you've given it, you get back an error saying that a Call is
> 'malformed'. More accurate would be to say that it's not permitted.
>
> ChrisA

OK, it's coherent with the secure execution.


Thanks


Vincent