• 4.2
  • dev
  • Documentation version: 3.2

Source code for django.db.models.fields.json

import json

from django import forms
from django.core import checks, exceptions
from django.db import NotSupportedError, connections, router
from django.db.models import lookups
from django.db.models.lookups import PostgresOperatorLookup, Transform
from django.utils.translation import gettext_lazy as _

from . import Field
from .mixins import CheckFieldDefaultMixin

__all__ = ['JSONField']


[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, decoder=None, **kwargs, ): if encoder and not callable(encoder): raise ValueError('The encoder parameter must be a callable object.') if decoder and not callable(decoder): raise ValueError('The decoder parameter must be a callable object.') self.encoder = encoder self.decoder = decoder super().__init__(verbose_name, name, **kwargs) def check(self, **kwargs): errors = super().check(**kwargs) databases = kwargs.get('databases') or [] errors.extend(self._check_supported(databases)) return errors def _check_supported(self, databases): errors = [] for db in databases: if not router.allow_migrate_model(db, self.model): continue connection = connections[db] if ( self.model._meta.required_db_vendor and self.model._meta.required_db_vendor != connection.vendor ): continue if not ( 'supports_json_field' in self.model._meta.required_db_features or connection.features.supports_json_field ): errors.append( checks.Error( '%s does not support JSONFields.' % connection.display_name, obj=self.model, id='fields.E180', ) ) return errors def deconstruct(self): name, path, args, kwargs = super().deconstruct() if self.encoder is not None: kwargs['encoder'] = self.encoder if self.decoder is not None: kwargs['decoder'] = self.decoder return name, path, args, kwargs def from_db_value(self, value, expression, connection): if value is None: return value # Some backends (SQLite at least) extract non-string values in their # SQL datatypes. if isinstance(expression, KeyTransform) and not isinstance(value, str): return value try: return json.loads(value, cls=self.decoder) except json.JSONDecodeError: return value def get_internal_type(self): return 'JSONField' def get_prep_value(self, value): if value is None: return value return json.dumps(value, cls=self.encoder) 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) try: json.dumps(value, cls=self.encoder) 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): return super().formfield(**{ 'form_class': forms.JSONField, 'encoder': self.encoder, 'decoder': self.decoder, **kwargs, })
def compile_json_path(key_transforms, include_root=True): path = ['$'] if include_root else [] for key_transform in key_transforms: try: num = int(key_transform) except ValueError: # non-integer path.append('.') path.append(json.dumps(key_transform)) else: path.append('[%s]' % num) return ''.join(path) class DataContains(PostgresOperatorLookup): lookup_name = 'contains' postgres_operator = '@>' def as_sql(self, compiler, connection): if not connection.features.supports_json_field_contains: raise NotSupportedError( 'contains lookup is not supported on this database backend.' ) lhs, lhs_params = self.process_lhs(compiler, connection) rhs, rhs_params = self.process_rhs(compiler, connection) params = tuple(lhs_params) + tuple(rhs_params) return 'JSON_CONTAINS(%s, %s)' % (lhs, rhs), params class ContainedBy(PostgresOperatorLookup): lookup_name = 'contained_by' postgres_operator = '<@' def as_sql(self, compiler, connection): if not connection.features.supports_json_field_contains: raise NotSupportedError( 'contained_by lookup is not supported on this database backend.' ) lhs, lhs_params = self.process_lhs(compiler, connection) rhs, rhs_params = self.process_rhs(compiler, connection) params = tuple(rhs_params) + tuple(lhs_params) return 'JSON_CONTAINS(%s, %s)' % (rhs, lhs), params class HasKeyLookup(PostgresOperatorLookup): logical_operator = None def as_sql(self, compiler, connection, template=None): # Process JSON path from the left-hand side. if isinstance(self.lhs, KeyTransform): lhs, lhs_params, lhs_key_transforms = self.lhs.preprocess_lhs(compiler, connection) lhs_json_path = compile_json_path(lhs_key_transforms) else: lhs, lhs_params = self.process_lhs(compiler, connection) lhs_json_path = '$' sql = template % lhs # Process JSON path from the right-hand side. rhs = self.rhs rhs_params = [] if not isinstance(rhs, (list, tuple)): rhs = [rhs] for key in rhs: if isinstance(key, KeyTransform): *_, rhs_key_transforms = key.preprocess_lhs(compiler, connection) else: rhs_key_transforms = [key] rhs_params.append('%s%s' % ( lhs_json_path, compile_json_path(rhs_key_transforms, include_root=False), )) # Add condition for each key. if self.logical_operator: sql = '(%s)' % self.logical_operator.join([sql] * len(rhs_params)) return sql, tuple(lhs_params) + tuple(rhs_params) def as_mysql(self, compiler, connection): return self.as_sql(compiler, connection, template="JSON_CONTAINS_PATH(%s, 'one', %%s)") def as_oracle(self, compiler, connection): sql, params = self.as_sql(compiler, connection, template="JSON_EXISTS(%s, '%%s')") # Add paths directly into SQL because path expressions cannot be passed # as bind variables on Oracle. return sql % tuple(params), [] def as_postgresql(self, compiler, connection): if isinstance(self.rhs, KeyTransform): *_, rhs_key_transforms = self.rhs.preprocess_lhs(compiler, connection) for key in rhs_key_transforms[:-1]: self.lhs = KeyTransform(key, self.lhs) self.rhs = rhs_key_transforms[-1] return super().as_postgresql(compiler, connection) def as_sqlite(self, compiler, connection): return self.as_sql(compiler, connection, template='JSON_TYPE(%s, %%s) IS NOT NULL') class HasKey(HasKeyLookup): lookup_name = 'has_key' postgres_operator = '?' prepare_rhs = False class HasKeys(HasKeyLookup): lookup_name = 'has_keys' postgres_operator = '?&' logical_operator = ' AND ' def get_prep_lookup(self): return [str(item) for item in self.rhs] class HasAnyKeys(HasKeys): lookup_name = 'has_any_keys' postgres_operator = '?|' logical_operator = ' OR ' class JSONExact(lookups.Exact): can_use_none_as_rhs = True def process_lhs(self, compiler, connection): lhs, lhs_params = super().process_lhs(compiler, connection) if connection.vendor == 'sqlite': rhs, rhs_params = super().process_rhs(compiler, connection) if rhs == '%s' and rhs_params == [None]: # Use JSON_TYPE instead of JSON_EXTRACT for NULLs. lhs = "JSON_TYPE(%s, '$')" % lhs return lhs, lhs_params def process_rhs(self, compiler, connection): rhs, rhs_params = super().process_rhs(compiler, connection) # Treat None lookup values as null. if rhs == '%s' and rhs_params == [None]: rhs_params = ['null'] if connection.vendor == 'mysql': func = ["JSON_EXTRACT(%s, '$')"] * len(rhs_params) rhs = rhs % tuple(func) return rhs, rhs_params JSONField.register_lookup(DataContains) JSONField.register_lookup(ContainedBy) JSONField.register_lookup(HasKey) JSONField.register_lookup(HasKeys) JSONField.register_lookup(HasAnyKeys) JSONField.register_lookup(JSONExact) class KeyTransform(Transform): postgres_operator = '->' postgres_nested_operator = '#>' def __init__(self, key_name, *args, **kwargs): super().__init__(*args, **kwargs) self.key_name = str(key_name) def preprocess_lhs(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 connection.vendor == 'oracle': # Escape string-formatting. key_transforms = [key.replace('%', '%%') for key in key_transforms] return lhs, params, key_transforms def as_mysql(self, compiler, connection): lhs, params, key_transforms = self.preprocess_lhs(compiler, connection) json_path = compile_json_path(key_transforms) return 'JSON_EXTRACT(%s, %%s)' % lhs, tuple(params) + (json_path,) def as_oracle(self, compiler, connection): lhs, params, key_transforms = self.preprocess_lhs(compiler, connection) json_path = compile_json_path(key_transforms) return ( "COALESCE(JSON_QUERY(%s, '%s'), JSON_VALUE(%s, '%s'))" % ((lhs, json_path) * 2) ), tuple(params) * 2 def as_postgresql(self, compiler, connection): lhs, params, key_transforms = self.preprocess_lhs(compiler, connection) if len(key_transforms) > 1: sql = '(%s %s %%s)' % (lhs, self.postgres_nested_operator) return sql, tuple(params) + (key_transforms,) try: lookup = int(self.key_name) except ValueError: lookup = self.key_name return '(%s %s %%s)' % (lhs, self.postgres_operator), tuple(params) + (lookup,) def as_sqlite(self, compiler, connection): lhs, params, key_transforms = self.preprocess_lhs(compiler, connection) json_path = compile_json_path(key_transforms) return 'JSON_EXTRACT(%s, %%s)' % lhs, tuple(params) + (json_path,) class KeyTextTransform(KeyTransform): postgres_operator = '->>' postgres_nested_operator = '#>>' class KeyTransformTextLookupMixin: """ Mixin for combining with a lookup expecting a text lhs from a JSONField key lookup. On PostgreSQL, 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): if not isinstance(key_transform, KeyTransform): raise TypeError( 'Transform should be an instance of KeyTransform in order to ' 'use this lookup.' ) key_text_transform = KeyTextTransform( key_transform.key_name, *key_transform.source_expressions, **key_transform.extra, ) super().__init__(key_text_transform, *args, **kwargs) class CaseInsensitiveMixin: """ Mixin to allow case-insensitive comparison of JSON values on MySQL. MySQL handles strings used in JSON context using the utf8mb4_bin collation. Because utf8mb4_bin is a binary collation, comparison of JSON values is case-sensitive. """ def process_lhs(self, compiler, connection): lhs, lhs_params = super().process_lhs(compiler, connection) if connection.vendor == 'mysql': return 'LOWER(%s)' % lhs, lhs_params return lhs, lhs_params def process_rhs(self, compiler, connection): rhs, rhs_params = super().process_rhs(compiler, connection) if connection.vendor == 'mysql': return 'LOWER(%s)' % rhs, rhs_params return rhs, rhs_params class KeyTransformIsNull(lookups.IsNull): # key__isnull=False is the same as has_key='key' def as_oracle(self, compiler, connection): sql, params = HasKey( self.lhs.lhs, self.lhs.key_name, ).as_oracle(compiler, connection) if not self.rhs: return sql, params # Column doesn't have a key or IS NULL. lhs, lhs_params, _ = self.lhs.preprocess_lhs(compiler, connection) return '(NOT %s OR %s IS NULL)' % (sql, lhs), tuple(params) + tuple(lhs_params) def as_sqlite(self, compiler, connection): template = 'JSON_TYPE(%s, %%s) IS NULL' if not self.rhs: template = 'JSON_TYPE(%s, %%s) IS NOT NULL' return HasKey(self.lhs.lhs, self.lhs.key_name).as_sql( compiler, connection, template=template, ) class KeyTransformIn(lookups.In): def resolve_expression_parameter(self, compiler, connection, sql, param): sql, params = super().resolve_expression_parameter( compiler, connection, sql, param, ) if ( not hasattr(param, 'as_sql') and not connection.features.has_native_json_field ): if connection.vendor == 'oracle': value = json.loads(param) sql = "%s(JSON_OBJECT('value' VALUE %%s FORMAT JSON), '$.value')" if isinstance(value, (list, dict)): sql = sql % 'JSON_QUERY' else: sql = sql % 'JSON_VALUE' elif connection.vendor in {'sqlite', 'mysql'}: sql = "JSON_EXTRACT(%s, '$')" if connection.vendor == 'mysql' and connection.mysql_is_mariadb: sql = 'JSON_UNQUOTE(%s)' % sql return sql, params class KeyTransformExact(JSONExact): def process_lhs(self, compiler, connection): lhs, lhs_params = super().process_lhs(compiler, connection) if connection.vendor == 'sqlite': rhs, rhs_params = super().process_rhs(compiler, connection) if rhs == '%s' and rhs_params == ['null']: lhs, *_ = self.lhs.preprocess_lhs(compiler, connection) lhs = 'JSON_TYPE(%s, %%s)' % lhs return lhs, lhs_params def process_rhs(self, compiler, connection): if isinstance(self.rhs, KeyTransform): return super(lookups.Exact, self).process_rhs(compiler, connection) rhs, rhs_params = super().process_rhs(compiler, connection) if connection.vendor == 'oracle': func = [] sql = "%s(JSON_OBJECT('value' VALUE %%s FORMAT JSON), '$.value')" for value in rhs_params: value = json.loads(value) if isinstance(value, (list, dict)): func.append(sql % 'JSON_QUERY') else: func.append(sql % 'JSON_VALUE') rhs = rhs % tuple(func) elif connection.vendor == 'sqlite': func = ["JSON_EXTRACT(%s, '$')" if value != 'null' else '%s' for value in rhs_params] rhs = rhs % tuple(func) return rhs, rhs_params def as_oracle(self, compiler, connection): rhs, rhs_params = super().process_rhs(compiler, connection) if rhs_params == ['null']: # Field has key and it's NULL. has_key_expr = HasKey(self.lhs.lhs, self.lhs.key_name) has_key_sql, has_key_params = has_key_expr.as_oracle(compiler, connection) is_null_expr = self.lhs.get_lookup('isnull')(self.lhs, True) is_null_sql, is_null_params = is_null_expr.as_sql(compiler, connection) return ( '%s AND %s' % (has_key_sql, is_null_sql), tuple(has_key_params) + tuple(is_null_params), ) return super().as_sql(compiler, connection) class KeyTransformIExact(CaseInsensitiveMixin, KeyTransformTextLookupMixin, lookups.IExact): pass class KeyTransformIContains(CaseInsensitiveMixin, KeyTransformTextLookupMixin, lookups.IContains): pass class KeyTransformStartsWith(KeyTransformTextLookupMixin, lookups.StartsWith): pass class KeyTransformIStartsWith(CaseInsensitiveMixin, KeyTransformTextLookupMixin, lookups.IStartsWith): pass class KeyTransformEndsWith(KeyTransformTextLookupMixin, lookups.EndsWith): pass class KeyTransformIEndsWith(CaseInsensitiveMixin, KeyTransformTextLookupMixin, lookups.IEndsWith): pass class KeyTransformRegex(KeyTransformTextLookupMixin, lookups.Regex): pass class KeyTransformIRegex(CaseInsensitiveMixin, KeyTransformTextLookupMixin, lookups.IRegex): pass class KeyTransformNumericLookupMixin: def process_rhs(self, compiler, connection): rhs, rhs_params = super().process_rhs(compiler, connection) if not connection.features.has_native_json_field: rhs_params = [json.loads(value) for value in rhs_params] return rhs, rhs_params class KeyTransformLt(KeyTransformNumericLookupMixin, lookups.LessThan): pass class KeyTransformLte(KeyTransformNumericLookupMixin, lookups.LessThanOrEqual): pass class KeyTransformGt(KeyTransformNumericLookupMixin, lookups.GreaterThan): pass class KeyTransformGte(KeyTransformNumericLookupMixin, lookups.GreaterThanOrEqual): pass KeyTransform.register_lookup(KeyTransformIn) KeyTransform.register_lookup(KeyTransformExact) KeyTransform.register_lookup(KeyTransformIExact) KeyTransform.register_lookup(KeyTransformIsNull) 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) KeyTransform.register_lookup(KeyTransformLt) KeyTransform.register_lookup(KeyTransformLte) KeyTransform.register_lookup(KeyTransformGt) KeyTransform.register_lookup(KeyTransformGte) 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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