• Language: en

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

import json

from psycopg2.extras import Json

from django.contrib.postgres import forms, lookups
from django.core import exceptions
from django.db.models import (
    Field, TextField, Transform, lookups as builtin_lookups,
)
from django.utils.translation import gettext_lazy as _

from .mixins import CheckFieldDefaultMixin

__all__ = ['JSONField']


class JsonAdapter(Json):
    """
    Customized psycopg2.extras.Json to allow for a custom encoder.
    """
    def __init__(self, adapted, dumps=None, encoder=None):
        self.encoder = encoder
        super().__init__(adapted, dumps=dumps)

    def dumps(self, obj):
        options = {'cls': self.encoder} if self.encoder else {}
        return json.dumps(obj, **options)


[docs]class JSONField(CheckFieldDefaultMixin, Field): empty_strings_allowed = False description = _('A JSON object') default_error_messages = { 'invalid': _("Value must be valid JSON."), } _default_hint = ('dict', '{}') def __init__(self, verbose_name=None, name=None, encoder=None, **kwargs): if encoder and not callable(encoder): raise ValueError("The encoder parameter must be a callable object.") self.encoder = encoder super().__init__(verbose_name, name, **kwargs) def db_type(self, connection): return 'jsonb' def deconstruct(self): name, path, args, kwargs = super().deconstruct() if self.encoder is not None: kwargs['encoder'] = self.encoder return name, path, args, kwargs def get_transform(self, name): transform = super().get_transform(name) if transform: return transform return KeyTransformFactory(name) def get_prep_value(self, value): if value is not None: return JsonAdapter(value, encoder=self.encoder) return value def validate(self, value, model_instance): super().validate(value, model_instance) options = {'cls': self.encoder} if self.encoder else {} try: json.dumps(value, **options) except TypeError: raise exceptions.ValidationError( self.error_messages['invalid'], code='invalid', params={'value': value}, ) def value_to_string(self, obj): return self.value_from_object(obj) def formfield(self, **kwargs): defaults = {'form_class': forms.JSONField} defaults.update(kwargs) return super().formfield(**defaults)
JSONField.register_lookup(lookups.DataContains) JSONField.register_lookup(lookups.ContainedBy) JSONField.register_lookup(lookups.HasKey) JSONField.register_lookup(lookups.HasKeys) JSONField.register_lookup(lookups.HasAnyKeys) class KeyTransform(Transform): operator = '->' nested_operator = '#>' def __init__(self, key_name, *args, **kwargs): super().__init__(*args, **kwargs) self.key_name = key_name def as_sql(self, compiler, connection): key_transforms = [self.key_name] previous = self.lhs while isinstance(previous, KeyTransform): key_transforms.insert(0, previous.key_name) previous = previous.lhs lhs, params = compiler.compile(previous) if len(key_transforms) > 1: return "(%s %s %%s)" % (lhs, self.nested_operator), [key_transforms] + params try: int(self.key_name) except ValueError: lookup = "'%s'" % self.key_name else: lookup = "%s" % self.key_name return "(%s %s %s)" % (lhs, self.operator, lookup), params class KeyTextTransform(KeyTransform): operator = '->>' nested_operator = '#>>' output_field = TextField() class KeyTransformTextLookupMixin: """ Mixin for combining with a lookup expecting a text lhs from a JSONField key lookup. Make use of the ->> operator instead of casting key values to text and performing the lookup on the resulting representation. """ def __init__(self, key_transform, *args, **kwargs): assert isinstance(key_transform, KeyTransform) key_text_transform = KeyTextTransform( key_transform.key_name, *key_transform.source_expressions, **key_transform.extra ) super().__init__(key_text_transform, *args, **kwargs) class KeyTransformIExact(KeyTransformTextLookupMixin, builtin_lookups.IExact): pass class KeyTransformIContains(KeyTransformTextLookupMixin, builtin_lookups.IContains): pass class KeyTransformStartsWith(KeyTransformTextLookupMixin, builtin_lookups.StartsWith): pass class KeyTransformIStartsWith(KeyTransformTextLookupMixin, builtin_lookups.IStartsWith): pass class KeyTransformEndsWith(KeyTransformTextLookupMixin, builtin_lookups.EndsWith): pass class KeyTransformIEndsWith(KeyTransformTextLookupMixin, builtin_lookups.IEndsWith): pass class KeyTransformRegex(KeyTransformTextLookupMixin, builtin_lookups.Regex): pass class KeyTransformIRegex(KeyTransformTextLookupMixin, builtin_lookups.IRegex): pass KeyTransform.register_lookup(KeyTransformIExact) KeyTransform.register_lookup(KeyTransformIContains) KeyTransform.register_lookup(KeyTransformStartsWith) KeyTransform.register_lookup(KeyTransformIStartsWith) KeyTransform.register_lookup(KeyTransformEndsWith) KeyTransform.register_lookup(KeyTransformIEndsWith) KeyTransform.register_lookup(KeyTransformRegex) KeyTransform.register_lookup(KeyTransformIRegex) class KeyTransformFactory: def __init__(self, key_name): self.key_name = key_name def __call__(self, *args, **kwargs): return KeyTransform(self.key_name, *args, **kwargs)
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