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from __future__ import unicode_literals
import json
from django.db import models
from django.utils.encoding import force_text
from django.utils import six
from django.utils.encoding import python_2_unicode_compatible
@python_2_unicode_compatible
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 __str__(self):
return '%s%s' % (force_text(self.first), force_text(self.second))
def __eq__(self, other):
if isinstance(other, self.__class__):
return self.first == other.first and self.second == other.second
return False
class SmallField(six.with_metaclass(models.SubfieldBase, 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.
"""
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, connection):
return six.text_type(value)
def get_prep_lookup(self, lookup_type, value):
if lookup_type == 'exact':
return force_text(value)
if lookup_type == 'in':
return [force_text(v) for v in value]
if lookup_type == 'isnull':
return []
raise TypeError('Invalid lookup type: %r' % lookup_type)
class SmallerField(SmallField):
pass
class JSONField(six.with_metaclass(models.SubfieldBase, models.TextField)):
description = ("JSONField automatically serializes and deserializes values to "
"and from JSON.")
def to_python(self, value):
if not value:
return None
if isinstance(value, six.string_types):
value = json.loads(value)
return value
def get_db_prep_save(self, value, connection):
if value is None:
return None
return json.dumps(value)
class CustomTypedField(models.TextField):
def db_type(self, connection):
return 'custom_field'
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