[Django]-Generating a non-sequential ID/PK for a Django Model

There is built-in Django way to achieve what you want. Add a field to the model of “custom page” with primary_key=True and default= name of key generation function, like this:

class CustomPage(models.Model):
    ...
    mykey = models.CharField(max_length=6, primary_key=True, default=pkgen)
    ...

Now, for every model instance page, page.pk becomes an alias for page.mykey, which is being auto-assigned with the string returned by your function pkgen() at the moment of creation of that instance.
Fast&dirty implementation:

def pkgen():
    from base64 import b32encode
    from hashlib import sha1
    from random import random
    rude = ('lol',)
    bad_pk = True
    while bad_pk:
        pk = b32encode(sha1(str(random())).digest()).lower()[:6]
        bad_pk = False
        for rw in rude:
            if pk.find(rw) >= 0: bad_pk = True
    return pk

The probability of two pages getting identical primary keys is very low (assuming random() is random enough), and there are no concurrency issues. And, of couse, this method is easilly extensible by slicing more chars from encoded string.

Django now includes an UUIDField type, so you don’t need any custom code or the external package Srikanth Chundi suggested. This implementation uses HEX strings with dashes, so the text is pretty child-safe, other than 1337 expressions like abad1d3a 🙂

You would use it like this to alias pk to the uuid field as a primary key:

import uuid
from django.db import models

class MyModel(models.Model):
    uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    # other fields

Note, however, that when you’re routing to this view in urls.py, you need a different regex as mentioned here, e.g.:

urlpatterns = [
    url(r'mymodel/(?P<pk>[^/]+)/$', MyModelDetailView.as_view(),
        name='mymodel'),
]

May be you need to look at Python UUID, it can generate random lengthy characters. But you can slice it and use the number of characters you want with little check to make sure it’s unique even after slicing.

UUIDField snippet may help you if you don’t want to take pain of generating UUID yourself.

Also have a look at this blog post

Oli: If you’re worried about spelling out rude words, you can always compare/search your UUIDField for them, using the django profanity filter, and skip any UUIDs that might be triggery.

This is what I ended up using UUID.

import uuid 

from django.db import models
from django.contrib.auth.models import User


class SluggedModel(models.Model):
    slug = models.SlugField(primary_key=True, unique=True, editable=False, blank=True)

    def save(self, *args, **kwargs):
        if not self.slug:
            uuid.uuid4().hex[:16]    # can vary up to 32 chars in length
        super(SluggedModel, self).save(*args, **kwargs)

    class Meta:
        abstract = True

Looking at the above answers, here is what I am using now.

import uuid

from django.db import models
from django.utils.http import int_to_base36


ID_LENGTH = 9


def id_gen() -> str:
    """Generates random string whose length is `ID_LENGTH`"""
    return int_to_base36(uuid.uuid4().int)[:ID_LENGTH]


class BaseModel(models.Model):
    """Django abstract model whose primary key is a random string"""
    id = models.CharField(max_length=ID_LENGTH, primary_key=True, default=id_gen, editable=False)

    class Meta:
        abstract = True


class CustomPage(BaseModel):
    ...