Convert array of strings to a single integer

December 9, 2022

I am trying to create a "permissions" system where I can store all the permissions a user has. Currently, all the permissions of a user are stored as an array inside the database:

[
    'role.users.view',
    'role.users.manage',
    'role.users.delete'
    ...
]

However, the more permissions I create, the bigger the size of the database becomes. As a result, I would like to be able to store all this array as an unique string/integer/identifier which allows me to efficiently transform the array above into a single integer – let’s say the array of strings above becomes the number 1290481294. My initial thought would have been to construct an integer based on whether the permission is on/off – resulting in an integer like 10101010101 – but this number would also become ridiculously long; so I’m trying to find a more efficient approach to this.

I am completely sure there is already an existing technique for this, but I don’t really know how it is called or where I can document myself upon the subject.

tl;dr: I am trying to convert the array of strings above into a single, as-short-as-possible integer.

>Solution :

If you’re working with Python you could use this.

all_permissions = [ # List of all permissions (prefarably unique)
    'role.users.view',
    'role.users.manage',
    'role.users.delete'
]

permission_flag = 1
permission_flags = {}
for permission in all_permissions: # Initiate flags
    permission_flags[permission] = permission_flag
    permission_flag *= 2

all_permissions = [] # Clear all_permissions, we don't need it anymore
permissions = [ # Old user permissions
    'role.users.view',
    'role.users.delete',
    'role.users.delete'
]

permission_identifier = 0
for permission in permissions:
    permission_identifier |= permission_flags[permission] # Bitwise or

print(permission_identifier)

Ouput:

This is correct, because: 2^0 + 2^2 = 1 + 4 = 5