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75 lines
2.1 KiB
Python
75 lines
2.1 KiB
Python
from __future__ import unicode_literals
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import json
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from django.db import models
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from django.utils.encoding import force_text
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from django.utils import six
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from django.utils.encoding import python_2_unicode_compatible
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@python_2_unicode_compatible
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class Small(object):
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"""
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A simple class to show that non-trivial Python objects can be used as
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attributes.
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"""
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def __init__(self, first, second):
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self.first, self.second = first, second
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def __str__(self):
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return '%s%s' % (force_text(self.first), force_text(self.second))
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class SmallField(six.with_metaclass(models.SubfieldBase, models.Field)):
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"""
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Turns the "Small" class into a Django field. Because of the similarities
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with normal character fields and the fact that Small.__unicode__ does
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something sensible, we don't need to implement a lot here.
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"""
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def __init__(self, *args, **kwargs):
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kwargs['max_length'] = 2
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super(SmallField, self).__init__(*args, **kwargs)
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def get_internal_type(self):
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return 'CharField'
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def to_python(self, value):
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if isinstance(value, Small):
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return value
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return Small(value[0], value[1])
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def get_db_prep_save(self, value, connection):
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return six.text_type(value)
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def get_prep_lookup(self, lookup_type, value):
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if lookup_type == 'exact':
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return force_text(value)
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if lookup_type == 'in':
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return [force_text(v) for v in value]
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if lookup_type == 'isnull':
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return []
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raise TypeError('Invalid lookup type: %r' % lookup_type)
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class SmallerField(SmallField):
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pass
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class JSONField(six.with_metaclass(models.SubfieldBase, models.TextField)):
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description = ("JSONField automatically serializes and desializes values to "
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"and from JSON.")
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def to_python(self, value):
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if not value:
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return None
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if isinstance(value, six.string_types):
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value = json.loads(value)
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return value
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def get_db_prep_save(self, value, connection):
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if value is None:
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return None
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return json.dumps(value)
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