Safe Input: Take that, idiot user!
A Python module to enquire user input safely.
Whenever you ask a user for specific input, there is a good chance he/she messes it up.
Enter a number between 1 and 5: SePhEn
>>> Traceback (most recent call last):
>>> File "<project>", line 99, in <module>
>>> ValueError: invalid literal for int() with base 10: 'SePhEn'
>>>
Hey dude, your program doesn't work. I thought you were a hacker.
So you have to make sure that no input can crash your code.
With each project I pursued one of two policies:
- re-invent the wheel
- don't give a crap
And with each project I thought: Wouldn't it be clever to have something reusable? Well, here we are.
Enquire keeps asking for input until the user gets it right.
Use Enquire when user input is limited to specific values, like choosing options or entering an integer.
- Input without validation
- Input for further processing
Python 3.6+
Copy the file enquire.py to an appropriate folder.
Enquire is used quite like input with extra steps:
- Ask for a number with
Enquire.number(). Returns an integer. - Ask for a string with
Enquire.letter(). Returns a lowercase string. - Add specification about allowed numbers / letters.
- Add a default value returned upon empty entry.
Input is non-case-sensitive.
Returned strings are always lowercase.
from enquire import Enquire
enq = Enquire()
# a number within limits
number_from_user = enq.number("Enter a number between 1 and 5: ", allowed="1_5")
# a number within limits and with a default return value
number_from_user = enq.number("Enter 1-10, default is 5: ", allowed="1_10", default=5)
# a letter from a specific set
letter_from_user = enq.letter("Enter one of these: W T F: ", allowed="w,t,f")
# one out of a set of options
option_from_user = enq.letter("Type (Play|Pause|Skip|Quit): ", allowed="play,pause,skip,quit")
Add string parameter allowed to specify allowed input.
Specifications are non-case-sensitive.
Specify a range of numbers or consecutive letters by a string of lower and upper limits, separated by an underscore.
Default is allowed="0_9" for numbers and allowed="a_z" for letters.
Define a set of valid entries by comma separated values inside a string.
Example for numbers: allowed="2,4,6,8"
Example for letters: allowed="a,b,x,y"
Example for options: allowed="option1, option2, option3"
I just figured out that there's a thing called PyPI with a truckload of professional grade modules for safe input.
Well, this is mine.
Keep coding!