118 lines
3.3 KiB
Python
118 lines
3.3 KiB
Python
"""
|
|
Tests for field subclassing.
|
|
"""
|
|
|
|
from django.db import models
|
|
from django.utils.encoding import force_unicode
|
|
from django.core import serializers
|
|
from django.core.exceptions import FieldError
|
|
|
|
class Small(object):
|
|
"""
|
|
A simple class to show that non-trivial Python objects can be used as
|
|
attributes.
|
|
"""
|
|
def __init__(self, first, second):
|
|
self.first, self.second = first, second
|
|
|
|
def __unicode__(self):
|
|
return u'%s%s' % (force_unicode(self.first), force_unicode(self.second))
|
|
|
|
def __str__(self):
|
|
return unicode(self).encode('utf-8')
|
|
|
|
class SmallField(models.Field):
|
|
"""
|
|
Turns the "Small" class into a Django field. Because of the similarities
|
|
with normal character fields and the fact that Small.__unicode__ does
|
|
something sensible, we don't need to implement a lot here.
|
|
"""
|
|
__metaclass__ = models.SubfieldBase
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
kwargs['max_length'] = 2
|
|
super(SmallField, self).__init__(*args, **kwargs)
|
|
|
|
def get_internal_type(self):
|
|
return 'CharField'
|
|
|
|
def to_python(self, value):
|
|
if isinstance(value, Small):
|
|
return value
|
|
return Small(value[0], value[1])
|
|
|
|
def get_db_prep_save(self, value):
|
|
return unicode(value)
|
|
|
|
def get_db_prep_lookup(self, lookup_type, value):
|
|
if lookup_type == 'exact':
|
|
return force_unicode(value)
|
|
if lookup_type == 'in':
|
|
return [force_unicode(v) for v in value]
|
|
if lookup_type == 'isnull':
|
|
return []
|
|
raise FieldError('Invalid lookup type: %r' % lookup_type)
|
|
|
|
def flatten_data(self, follow, obj=None):
|
|
return {self.attname: force_unicode(self._get_val_from_obj(obj))}
|
|
|
|
class MyModel(models.Model):
|
|
name = models.CharField(max_length=10)
|
|
data = SmallField('small field')
|
|
|
|
def __unicode__(self):
|
|
return force_unicode(self.name)
|
|
|
|
__test__ = {'API_TESTS': ur"""
|
|
# Creating a model with custom fields is done as per normal.
|
|
>>> s = Small(1, 2)
|
|
>>> print s
|
|
12
|
|
>>> m = MyModel(name='m', data=s)
|
|
>>> m.save()
|
|
|
|
# Custom fields still have normal field's attributes.
|
|
>>> m._meta.get_field('data').verbose_name
|
|
'small field'
|
|
|
|
# The m.data attribute has been initialised correctly. It's a Small object.
|
|
>>> m.data.first, m.data.second
|
|
(1, 2)
|
|
|
|
# The data loads back from the database correctly and 'data' has the right type.
|
|
>>> m1 = MyModel.objects.get(pk=m.pk)
|
|
>>> isinstance(m1.data, Small)
|
|
True
|
|
>>> print m1.data
|
|
12
|
|
|
|
# We can do normal filtering on the custom field (and will get an error when we
|
|
# use a lookup type that does not make sense).
|
|
>>> s1 = Small(1, 3)
|
|
>>> s2 = Small('a', 'b')
|
|
>>> MyModel.objects.filter(data__in=[s, s1, s2])
|
|
[<MyModel: m>]
|
|
>>> MyModel.objects.filter(data__lt=s)
|
|
Traceback (most recent call last):
|
|
...
|
|
FieldError: Invalid lookup type: 'lt'
|
|
|
|
# Serialization works, too.
|
|
>>> stream = serializers.serialize("json", MyModel.objects.all())
|
|
>>> stream
|
|
'[{"pk": 1, "model": "field_subclassing.mymodel", "fields": {"data": "12", "name": "m"}}]'
|
|
>>> obj = list(serializers.deserialize("json", stream))[0]
|
|
>>> obj.object == m
|
|
True
|
|
|
|
# Test retrieving custom field data
|
|
>>> m.delete()
|
|
>>> m1 = MyModel(name="1", data=Small(1, 2))
|
|
>>> m1.save()
|
|
>>> m2 = MyModel(name="2", data=Small(2, 3))
|
|
>>> m2.save()
|
|
>>> for m in MyModel.objects.all(): print unicode(m.data)
|
|
12
|
|
23
|
|
"""}
|