如何在Python中安全评估urlencode字典？

Question

I should communicate with an online service that sends me the following data urlencoded:

data_to_process = {...}
args = {'args0': data_to_process, 'action': 'save'}

result = urllib2.urlopen(..., urllib.urlencode(args), ...)

The main data of interest is stored in the data_to_process dictionary. I would like to get back the original dictionary that's supposed to contain only string, numeric and boolean values. How can you achieve this?

I've tried

eval(dict_str,{'__builtins__': None})

but this fails for False values (and who knows what else).

thanks for any ideas!

Answer 1

Use ast.literal_eval :

>>> from ast import literal_eval
>>> test = repr({"ham": True, 42: "spam", "foo": "bar"})
>>> test
"{42: 'spam', 'foo': 'bar', 'ham': True}"
>>> literal_eval(test)
{42: 'spam', 'foo': 'bar', 'ham': True}

Answer 2

Are you sure that the service isn't sending you JSON? In which case you can parse it using the built-in json.loads() function (since Python 2.6).