Django field and helpers for validating an Australian post code, and
retrieving the locality and State of a given post code.

Uses Australia Post published post code data to check the validity of an
entered post code.


INSTALLATION: 
~~~~~~~~~~~~~

Firstly, add 'aupostcodes' to your INSTALLED_APPS in settings.py. This is
because two tables are used to store the data against which postcodes are
validated.

Next, run ./manage.py syncdb to create the required tables.

Finally, run:

    ./manage.py loaddata <PATH_TO_APP>/aupostcodes/fixtures/postcodes.json

I've avoided using initial_data.json, as there's no need to reload the
fixture every time syncdb is done.


USAGE: 
~~~~~~

The simplest usage is through aupostcodes.fields.AUPostCodeField as so:

    from django.db import models 
    from aupostcodes.fields import AUPostCodeField
    
    class UserProfile(models.Model):
        ...
        postcode = AUPostCodeField()

Or, to use the form field directly:

    from django import forms
    from aupostcodes.fields import AUPostCodeFormField
    
    class RegistrationForm(forms.Form):
        ...
        postcode = AUPostCodeFormField()

Both will ensure appropriate validation. If you see that ostensibly valid
post codes are being invalidated, you probably haven't loaded the post codes
fixture correctly (see `installation`).

At this stage, the python type of the value returned by an AUPostCodeField is
unicode, not AUPostCode. For this reason, if you wish to use the post code to
determine locality or state, you will need to fetch it from the db yourself,
for instance:

    postcode = AUPostCode.objects.get(postcode=form.cleaned_data['postcode'])
    states = postcode.states
    if len(states) == 1 and states[0] == 'NSW':
        print "Howdy neighbour"

I'll probably fix this at some stage.