Generate a Unique String in Python/Django

Question

What I want is to generate a string(key) of size 5 for my users on my website. More like a BBM PIN.

The key will contain numbers and uppercase English letters:

• AU1B7
• Y56AX
• M0K7A

How can I also be at rest about the uniqueness of the strings even if I generate them in millions?

In the most pythonic way possible, how can I do this?

Answer 1

My favourite is

import uuid  uuid.uuid4().hex[:6].upper() 

If you using django you can set the unique constrain on this field in order to make sure it is unique. https://docs.djangoproject.com/en/dev/ref/models/fields/#django.db.models.Field.unique

Answer 2

From 3.6 You can use secrets module to generate nice random strings. https://docs.python.org/3/library/secrets.html#module-secrets

import secrets
print(secrets.token_hex(5))

Answer 3

A more secure and shorter way of doing is using Django's crypto module.

from django.utils.crypto import get_random_string
code = get_random_string(5)

get_random_string() function returns a securely generated random string, uses secrets module under the hood.

You can also pass allowed_chars:

from django.utils.crypto import get_random_string
import string

code = get_random_string(5, allowed_chars=string.ascii_uppercase + string.digits)