Source code for django.contrib.postgres.fields.hstore

import json

from django.contrib.postgres import forms, lookups
from django.contrib.postgres.fields.array import ArrayField
from django.core import exceptions
from django.db.models import Field, TextField, Transform
from django.utils import six
from django.utils.encoding import force_text
from django.utils.translation import ugettext_lazy as _

__all__ = ['HStoreField']

[docs]class HStoreField(Field): empty_strings_allowed = False description = _('Map of strings to strings') default_error_messages = { 'not_a_string': _('The value of "%(key)s" is not a string.'), } def db_type(self, connection): return 'hstore' def get_transform(self, name): transform = super(HStoreField, self).get_transform(name) if transform: return transform return KeyTransformFactory(name) def validate(self, value, model_instance): super(HStoreField, self).validate(value, model_instance) for key, val in value.items(): if not isinstance(val, six.string_types): raise exceptions.ValidationError( self.error_messages['not_a_string'], code='not_a_string', params={'key': key}, ) def to_python(self, value): if isinstance(value, six.string_types): value = json.loads(value) return value def value_to_string(self, obj): return json.dumps(self.value_from_object(obj)) def formfield(self, **kwargs): defaults = { 'form_class': forms.HStoreField, } defaults.update(kwargs) return super(HStoreField, self).formfield(**defaults) def get_prep_value(self, value): value = super(HStoreField, self).get_prep_value(value) if isinstance(value, dict): prep_value = {} for key, val in value.items(): key = force_text(key) if val is not None: val = force_text(val) prep_value[key] = val value = prep_value if isinstance(value, list): value = [force_text(item) for item in value] return value
HStoreField.register_lookup(lookups.DataContains) HStoreField.register_lookup(lookups.ContainedBy) HStoreField.register_lookup(lookups.HasKey) HStoreField.register_lookup(lookups.HasKeys) HStoreField.register_lookup(lookups.HasAnyKeys) class KeyTransform(Transform): output_field = TextField() def __init__(self, key_name, *args, **kwargs): super(KeyTransform, self).__init__(*args, **kwargs) self.key_name = key_name def as_sql(self, compiler, connection): lhs, params = compiler.compile(self.lhs) return "(%s -> '%s')" % (lhs, self.key_name), params class KeyTransformFactory(object): def __init__(self, key_name): self.key_name = key_name def __call__(self, *args, **kwargs): return KeyTransform(self.key_name, *args, **kwargs) @HStoreField.register_lookup class KeysTransform(Transform): lookup_name = 'keys' function = 'akeys' output_field = ArrayField(TextField()) @HStoreField.register_lookup class ValuesTransform(Transform): lookup_name = 'values' function = 'avals' output_field = ArrayField(TextField())
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