Cal Leeming [Simplicity Media Ltd]

"""Modified get_or_create(), to *reduce* the chance of IntegrityError exceptions, and raises ObjectNotReady when the collision is detected.

cal.leeming [at] simplicitymedialtd.co.uk
"""

from django.db import models

from django.db import IntegrityError
from django.db import DatabaseError

class ObjectNotReady(Exception):
    pass

class ExtendedManager( models.Manager ):
    # 28th april 2011:
    # please note, it is best to use UNSIGNED INTEGERS, else you will get very VERY
    # strange problems with it saying there is a duplicate key when there isn't lol.
    # reason being, if you put in an integer above the maximum signed INT, django
    # auto down converts it, which is fucking retarded. and the lookup afterwards in
    # this logic, does things properly.. so it ends up failing.
    # see ticket: http://code.djangoproject.com/ticket/15923

    def get_or_create(self, *args, **kwargs):
        created = None
        try:
            return super(ExtendedManager, self).get_or_create(*args, **kwargs)

        except IntegrityError, e:
            # Ensure the error code matches 1062 (duplicate entry)
            if not e.args[0] == 1062:
                raise e

            try:
                _obj = self.get(**kwargs)
            except self.model.DoesNotExist:
                res = self.filter(**kwargs).all()
                if res.count() == 1:
                    _obj = res[0]

                else:
                    raise ObjectNotReady, "Object busy or not yet ready: %s" % ( e )

            return (_obj, False)