shortuuid 1.0.3

A generator library for concise, unambiguous and URL-safe UUIDs.

shortuuid is a simple python library that generates concise, unambiguous, URL-safe UUIDs.

Often, one needs to use non-sequential IDs in places where users will see them, but the IDs must be as concise and easy to use as possible. shortuuid solves this problem by generating uuids using Python’s built-in uuid module and then translating them to base57 using lowercase and uppercase letters and digits, and removing similar-looking characters such as l, 1, I, O and 0.

Installation

To install shortuuid you need:

• Python 2.5 or later in the 2.x line (earlier than 2.6 not tested), or any 3.x.

If you have the dependencies, you have multiple options of installation:

• With pip (preferred), do pip install shortuuid.

• With setuptools, do easy_install shortuuid.

• To install the source, download it from https://github.com/stochastic-technologies/shortuuid and do python setup.py install.

Usage

To use shortuuid, just import it in your project like so:

>>> import shortuuid

You can then generate a short UUID:

>>> shortuuid.uuid()
'vytxeTZskVKR7C7WgdSP3d'

If you prefer a version 5 UUID, you can pass a name (DNS or URL) to the call and it will be used as a namespace (uuid.NAMESPACE_DNS or uuid.NAMESPACE_URL) for the resulting UUID:

>>> shortuuid.uuid(name="example.com")
'wpsWLdLt9nscn2jbTD3uxe'
>>> shortuuid.uuid(name="http://example.com")
'c8sh5y9hdSMS6zVnrvf53T'

You can also generate a cryptographically secure random string (using os.urandom(), internally) with:

>>> shortuuid.ShortUUID().random(length=22)
'RaF56o2r58hTKT7AYS9doj'

To see the alphabet that is being used to generate new UUIDs:

>>> shortuuid.get_alphabet()
'23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'

If you want to use your own alphabet to generate UUIDs, use set_alphabet():

>>> shortuuid.set_alphabet("aaaaabcdefgh1230123")
>>> shortuuid.uuid()
'0agee20aa1hehebcagddhedddc0d2chhab3b'

shortuuid will automatically sort and remove duplicates from your alphabet to ensure consistency:

>>> shortuuid.get_alphabet()
'0123abcdefgh'

If the default 22 digits are too long for you, you can get shorter IDs by just truncating the string to the desired length. The IDs won’t be universally unique any longer, but the probability of a collision will still be very low.

To serialize existing UUIDs, use encode() and decode():

>>> import uuid ; u = uuid.uuid4() ; u
UUID('6ca4f0f8-2508-4bac-b8f1-5d1e3da2247a')
>>> s = shortuuid.encode(u) ; s
'cu8Eo9RyrUsV4MXEiDZpLM'
>>> shortuuid.decode(s) == u
True
>>> short = s[:7] ; short
'cu8Eo9R'
>>> h = shortuuid.decode(short)
UUID('00000000-0000-0000-0000-00b8c0b9f952')
>>> shortuuid.decode(shortuuid.encode(h)) == h
True

Class-based usage

If you need to have various alphabets per-thread, you can use the ShortUUID class, like so:

>>> su = shortuuid.ShortUUID(alphabet="01345678")
>>> su.uuid()
'034636353306816784480643806546503818874456'
>>> su.get_alphabet()
'01345678'
>>> su.set_alphabet("21345687654123456")
>>> su.get_alphabet()
'12345678'

Command-line usage

shortuuid provides a simple way to generate a short UUID in a terminal:

$ python3 -m shortuuid
fZpeF6gcskHbSpTgpQCkcJ

(Replace python3 with py if you are using Windows)

Django field

shortuuid includes a Django field that generates random short UUIDs by default, for your convenience:

from shortuuid.django_fields import ShortUUIDField

class MyModel(models.Model):
    # A primary key ID of length 16 and a short alphabet.
    id = ShortUUIDField(length=16, alphabet="abcdefg1234", primary_key=True)
    # A short UUID of length 22 and the default alphabet.
    api_key = ShortUUIDField()

The field is the same as the CharField, with max_length replaced with length, an alphabet argument added and the default argument removed. Everything else is exactly the same, e.g. index, help_text, etc.

Compatibility note

Versions of ShortUUID prior to 1.0.0 generated UUIDs with their MSB last, i.e. reversed. This was later fixed, but if you have some UUIDs stored as a string with the old method, you need to pass legacy=True to decode() when converting your strings back to UUIDs.

That option will go away in the future, so you will want to convert your UUIDs to strings using the new method. This can be done like so:

>>> new_uuid_str = encode(decode(old_uuid_str, legacy=True))

License

shortuuid is distributed under the BSD license.