Returning an instance of StringUUID in to_python breaks Django's prefetch_related when a UUIDField is set to primary_key=True - the code expects a string, not an instance.

I started work on Python 3 support today, since I'm trying to port an app of mine that uses django-uuidfield. You can see the beginnings of my work at https://github.com/dominicrodger/django-uuidfield/compare/py3.

I'm mostly there, there are two outstanding issues:

1. There's one failing test that I'd appreciate some help with if anyone's got any Python 3/Django/Postgres experience - test_raises_exception throws a psycopg2.DataError at the moment), but it did require switching the tests out from using django-nose to using the default Django test runner, since django-nose doesn't support Python 3 (see https://github.com/jbalogh/django-nose/pull/103). I'm not sure django-nose gets us a lot - it seems to run all the tests twice (I get 10 tests run, even though there are only 5 tests - if I add a simple failing test, I get 12 tests run, 2 failed), and the normal Django runner correctly runs 5 tests.
2. I'm not quite sure what the purpose of smart_unicode in to_python - the tests don't seem to hit it. I'm guessing just using django.utils.smart_text is the right approach if smart_unicode is still needed.

I've run the unit tests on Python 2.6, 2.7 and with Django 1.4.5 and 1.5.1 (as you'll see from my changes to tox.ini).

Does this approach look reasonable? If so, I'll tidy it up, figure out the Postgres issue and send a pull request.

I started from dominicrodger's PR, and did:

• rebase against master
• added additional required fixes for python3
• updated tox. added .travis.yml, and coveralls

Note: I was not able to use runtests.py (it is not used by tox/.travis.yml) - perhaps that one should be removed? (in favour of the setup.py test).

Note: seems some tests are missing, in particular, these methods are not covered at all:

• value_to_string
• formfield

and a test using uuid version1 should probably exist as well.

UUIDField now returns a StringUUID object. The json encoder has no idea what to do with that, it's not in any of the JSON encoding rules, so it just throws an error.

Not returning a StringUUID from to_python works, but ideally we'd make StringUUID work in JSON. I could define a custom JSON encoder, but ideally I'd rather make StringUUID just work with JSON so I don't have to.

Created two models with a UUIDField(primary_key=True,hyphenate=True,auto=True) fields. One model has a foreign key to the other model.

Fixture fields contain UUIDs with hyphens.

Problem 1: loaddata loads the UUIDs into the database with hyphens removed

Problem 2: generic.edit.CreateView fails due to a foreign key problem - the form is submitted with a hyphenated UUID, this appears to fail since it is stored without hyphens in the database

I would like to modify UUIDField to return a UUID with hyphens in it. I don't mind how it is stored (in fact, using the Postgres type, it is stored with hyphens in the database). How about an option groups=True that sets max_length to 36 and uses uuid.UUID instead of StringUUID?

The following code will trigger the problem with PostgreSQL backend:

SomeModel.objects.get(uuid="invalid_uuid")

An example traceback:

/.../lib/python2.7/site-packages/django/db/backends/utils.pyc in execute(self, sql, params)
     63                 return self.cursor.execute(sql)
     64             else:
---> 65                 return self.cursor.execute(sql, params)
     66 
     67     def executemany(self, sql, param_list):

DataError: invalid input syntax for uuid: "invalid_uuid"
LINE 1: ... "some_model" WHERE "some_model"."uuid" = 'invalid_u...
                                                     ^

PostgreSQL has a UUID type and throws an error with badly formatted UUID. However, it is not the expected behavior of an API. When user provides an invalid UUID, the API in most cases is expected to return 404, instead of 500 caused by this uncaught exception.

The problem lies in method get_db_prep_value. If the provided UUID is not valid, the method should return an arbitrary valid UUID that matches nothing in the database.

I don't know why it's failing with this error. the way I am using it looks legit to me. https://gist.github.com/pazooki/b3ee2937c72bd0fa679f#file-traceback

import psycopg2 alone does not load the extras module: in cases where the latter was not previously loaded as a side effect of other code, the following psycopg2.extras.register_uuid() fails with an AttributeError, leading to other errors later due to the UUID type not being registered in psycopg2.

import psycopg2.extras fixes this.

I'm using django-uuidfield together with django-rest-framework to develop a RESTful API. Whenever I try to use the UUIDField, Django throws me this error:

TypeError at (...)
UUID('a00fef915e284f6d9d9af8b0500234b7') is not JSON serializable

I believe the UUIDField lacks a method which can serialize it to JSON using python's JSON encoder and decoder.

Here's the stack trace:

Traceback:
File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py" in get_response
  137.                 response = response.render()
File "/usr/local/lib/python2.7/dist-packages/django/template/response.py" in render
  103.             self.content = self.rendered_content
File "/usr/local/lib/python2.7/dist-packages/rest_framework/response.py" in rendered_content
  63.         ret = renderer.render(self.data, media_type, context)
File "/usr/local/lib/python2.7/dist-packages/rest_framework/renderers.py" in render
  606.         context = self.get_context(data, accepted_media_type, renderer_context)
File "/usr/local/lib/python2.7/dist-packages/rest_framework/renderers.py" in get_context
  556.         raw_data_post_form = self.get_raw_data_form(view, 'POST', request)
File "/usr/local/lib/python2.7/dist-packages/rest_framework/renderers.py" in get_raw_data_form
  506.                 content = renderer.render(serializer.data, accepted, context)
File "/usr/local/lib/python2.7/dist-packages/rest_framework/renderers.py" in render
  87.             indent=indent, ensure_ascii=self.ensure_ascii
File "/usr/lib/python2.7/json/__init__.py" in dumps
  250.         sort_keys=sort_keys, **kw).encode(obj)
File "/usr/lib/python2.7/json/encoder.py" in encode
  209.             chunks = list(chunks)
File "/usr/lib/python2.7/json/encoder.py" in _iterencode
  434.             for chunk in _iterencode_dict(o, _current_indent_level):
File "/usr/lib/python2.7/json/encoder.py" in _iterencode_dict
  408.                 for chunk in chunks:
File "/usr/lib/python2.7/json/encoder.py" in _iterencode
  442.             o = _default(o)
File "/usr/local/lib/python2.7/dist-packages/rest_framework/utils/encoders.py" in default
  58.         return super(JSONEncoder, self).default(o)
File "/usr/lib/python2.7/json/encoder.py" in default
  184.         raise TypeError(repr(o) + " is not JSON serializable")

Exception Type: TypeError at /api/Participants/
Exception Value: UUID('a00fef915e284f6d9d9af8b0500234b7') is not JSON serializable

The default uuid version is uuid4(), which generates a UUID of length 36. However, the default max_length used is 32, and no easy option is provided to customize this length.

You should increase the default length to 36 or higher, and provide max_length as a customizable option.

File "C:\Users\mgerd\AppData\Local\Programs\Python\Python36-32\lib\site-packages\uuidfield_init_.py", line 8, in from .fields import UUIDField File "C:\Users\mgerd\AppData\Local\Programs\Python\Python36-32\lib\site-packages\uuidfield\fields.py", line 4, in from django.db.models import Field, SubfieldBase ImportError: cannot import name 'SubfieldBase' how do i fix it?

Django 1.8 dropped SubFieldBase

I don't have a pull request for you as I'm using the field in a slightly different way that isn't reusable but here's what I did. You'll probably want to do some checks to maintain backwards compatibility as this will break old versions.

I removed the import of SubfieldBase and the following line in the class:

# __metaclass__ = SubfieldBase

and added the class method:

def from_db_value(self, value, expression, connection, context):
    if value is None:
        return value
    return self.get_db_prep_value(value)

I haven't tested this either.

Hi, David!

I'd like to use django-uuidfield in my project that uses Python 3.4 and Django 1.7.

Version 0.5.0 doesn't work, but all the necessary fixes are already in master branch.

Due to my project specifics, I cannot use Git dependency, only PyPI version.

Could you, please, release a new version of django-uuidfield? :) It's been a year since 0.5.0 already