105 lines
2.9 KiB
Python
105 lines
2.9 KiB
Python
import json
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from django.contrib.postgres import forms, lookups
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from django.contrib.postgres.fields.array import ArrayField
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from django.core import exceptions
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from django.db.models import Field, TextField, Transform
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from django.utils import six
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from django.utils.translation import ugettext_lazy as _
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__all__ = ['HStoreField']
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class HStoreField(Field):
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empty_strings_allowed = False
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description = _('Map of strings to strings')
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default_error_messages = {
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'not_a_string': _('The value of "%(key)s" is not a string.'),
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}
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def db_type(self, connection):
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return 'hstore'
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def get_transform(self, name):
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transform = super(HStoreField, self).get_transform(name)
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if transform:
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return transform
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return KeyTransformFactory(name)
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def validate(self, value, model_instance):
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super(HStoreField, self).validate(value, model_instance)
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for key, val in value.items():
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if not isinstance(val, six.string_types):
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raise exceptions.ValidationError(
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self.error_messages['not_a_string'],
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code='not_a_string',
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params={'key': key},
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)
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def to_python(self, value):
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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 value_to_string(self, obj):
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value = self._get_val_from_obj(obj)
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return json.dumps(value)
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def formfield(self, **kwargs):
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defaults = {
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'form_class': forms.HStoreField,
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}
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defaults.update(kwargs)
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return super(HStoreField, self).formfield(**defaults)
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HStoreField.register_lookup(lookups.DataContains)
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HStoreField.register_lookup(lookups.ContainedBy)
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@HStoreField.register_lookup
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class HasKeyLookup(lookups.PostgresSimpleLookup):
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lookup_name = 'has_key'
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operator = '?'
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@HStoreField.register_lookup
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class HasKeysLookup(lookups.PostgresSimpleLookup):
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lookup_name = 'has_keys'
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operator = '?&'
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class KeyTransform(Transform):
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output_field = TextField()
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def __init__(self, key_name, *args, **kwargs):
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super(KeyTransform, self).__init__(*args, **kwargs)
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self.key_name = key_name
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def as_sql(self, compiler, connection):
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lhs, params = compiler.compile(self.lhs)
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return "(%s -> '%s')" % (lhs, self.key_name), params
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class KeyTransformFactory(object):
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def __init__(self, key_name):
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self.key_name = key_name
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def __call__(self, *args, **kwargs):
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return KeyTransform(self.key_name, *args, **kwargs)
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@HStoreField.register_lookup
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class KeysTransform(lookups.FunctionTransform):
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lookup_name = 'keys'
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function = 'akeys'
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output_field = ArrayField(TextField())
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@HStoreField.register_lookup
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class ValuesTransform(lookups.FunctionTransform):
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lookup_name = 'values'
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function = 'avals'
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output_field = ArrayField(TextField())
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