Code source de 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.translation import gettext_lazy as _

from .mixins import CheckFieldDefaultMixin

__all__ = ['HStoreField']

[docs]class HStoreField(CheckFieldDefaultMixin, Field): empty_strings_allowed = False description = _('Map of strings to strings/nulls') default_error_messages = { 'not_a_string': _('The value of "%(key)s" is not a string or null.'), } _default_hint = ('dict', '{}') def db_type(self, connection): return 'hstore' def get_transform(self, name): transform = super().get_transform(name) if transform: return transform return KeyTransformFactory(name) def validate(self, value, model_instance): super().validate(value, model_instance) for key, val in value.items(): if not isinstance(val, str) and val is not None: raise exceptions.ValidationError( self.error_messages['not_a_string'], code='not_a_string', params={'key': key}, ) def to_python(self, value): if isinstance(value, str): value = json.loads(value) return value def value_to_string(self, obj): return json.dumps(self.value_from_object(obj)) def formfield(self, **kwargs): return super().formfield(**{ 'form_class': forms.HStoreField, **kwargs, }) def get_prep_value(self, value): value = super().get_prep_value(value) if isinstance(value, dict): prep_value = {} for key, val in value.items(): key = str(key) if val is not None: val = str(val) prep_value[key] = val value = prep_value if isinstance(value, list): value = [str(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().__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: 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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