Trying to make a captcha field for forms - django

Question

I'm trying to create a custom captcha field for a form, and it seems to be working alright except for the fact that when the code is supposed to pick a random captcha to return to the end-user for them to solve, it returns a ValueError: too many values to unpack (expected 2). I think this is because the list isn't being randomised and python is selecting the entire list to use as the user's captcha. How can I fix this issue?
class CaptchaField(IntegerField):
widget = CaptchaInput
error_msgs = { 'incorrect': _('Captcha incorrect- try again'), }
def __init__(self):
captcha_array = (
('What is the product of fifteen and four?', 60),
('What is four plus four?', 8),
('What is nine times one?', 9),
('How many letters are in the word orange?', 6),
('What is the sum of ten and two?', 12),
('What is the difference of eighty-four and nineteen?', 65),
('How many letters are in the word forest?', 6),
('How many letter are in the word apple?', 5),
('If there are four palm trees and one dies, how many are alive?', 3),
('What is four divided by two?', 2),
('How many letters are in the name of the capital of France?', 5),
)
captcha = random.choice(captcha_array)
for (a,b) in captcha:
return a
def validate(self, value):
for (a,b) in captcha:
if value == b:
return value
else:
raise ValidationError(self.error_msgs['incorrect'], code = 'incorrect')

Answer 1

captcha = random.choice(captcha_array) returns a tuple (i.e. ('What is the product of fifteen and four?', 60)). If you only want to return a string 'What is the product of fifteen and four?' you can just do return captcha[0].
Otherwise your loop will raise ValueError:
for (a,b) in captcha:
return a
captcha being a tuple will supply only 1 value, not two - first string, then number, to the loop. To unpack values like you do captcha has to be an iterable of tuples (list, dict, ...).
Also, do you expect captcha do be accessible later in validate? If so you need to save captcha in self.