302 lines
9.6 KiB
Python
302 lines
9.6 KiB
Python
# postgresql/json.py
|
|
# Copyright (C) 2005-2017 the SQLAlchemy authors and contributors
|
|
# <see AUTHORS file>
|
|
#
|
|
# This module is part of SQLAlchemy and is released under
|
|
# the MIT License: http://www.opensource.org/licenses/mit-license.php
|
|
from __future__ import absolute_import
|
|
|
|
import json
|
|
import collections
|
|
|
|
from .base import ischema_names, colspecs
|
|
from ... import types as sqltypes
|
|
from ...sql import operators
|
|
from ...sql import elements
|
|
from ... import util
|
|
|
|
__all__ = ('JSON', 'JSONB')
|
|
|
|
idx_precedence = operators._PRECEDENCE[operators.json_getitem_op]
|
|
|
|
ASTEXT = operators.custom_op(
|
|
"->>", precedence=idx_precedence, natural_self_precedent=True,
|
|
eager_grouping=True
|
|
)
|
|
|
|
JSONPATH_ASTEXT = operators.custom_op(
|
|
"#>>", precedence=idx_precedence, natural_self_precedent=True,
|
|
eager_grouping=True
|
|
)
|
|
|
|
|
|
HAS_KEY = operators.custom_op(
|
|
"?", precedence=idx_precedence, natural_self_precedent=True,
|
|
eager_grouping=True
|
|
)
|
|
|
|
HAS_ALL = operators.custom_op(
|
|
"?&", precedence=idx_precedence, natural_self_precedent=True,
|
|
eager_grouping=True
|
|
)
|
|
|
|
HAS_ANY = operators.custom_op(
|
|
"?|", precedence=idx_precedence, natural_self_precedent=True,
|
|
eager_grouping=True
|
|
)
|
|
|
|
CONTAINS = operators.custom_op(
|
|
"@>", precedence=idx_precedence, natural_self_precedent=True,
|
|
eager_grouping=True
|
|
)
|
|
|
|
CONTAINED_BY = operators.custom_op(
|
|
"<@", precedence=idx_precedence, natural_self_precedent=True,
|
|
eager_grouping=True
|
|
)
|
|
|
|
|
|
class JSONPathType(sqltypes.JSON.JSONPathType):
|
|
def bind_processor(self, dialect):
|
|
super_proc = self.string_bind_processor(dialect)
|
|
|
|
def process(value):
|
|
assert isinstance(value, collections.Sequence)
|
|
tokens = [util.text_type(elem)for elem in value]
|
|
value = "{%s}" % (", ".join(tokens))
|
|
if super_proc:
|
|
value = super_proc(value)
|
|
return value
|
|
|
|
return process
|
|
|
|
def literal_processor(self, dialect):
|
|
super_proc = self.string_literal_processor(dialect)
|
|
|
|
def process(value):
|
|
assert isinstance(value, collections.Sequence)
|
|
tokens = [util.text_type(elem)for elem in value]
|
|
value = "{%s}" % (", ".join(tokens))
|
|
if super_proc:
|
|
value = super_proc(value)
|
|
return value
|
|
|
|
return process
|
|
|
|
colspecs[sqltypes.JSON.JSONPathType] = JSONPathType
|
|
|
|
|
|
class JSON(sqltypes.JSON):
|
|
"""Represent the PostgreSQL JSON type.
|
|
|
|
This type is a specialization of the Core-level :class:`.types.JSON`
|
|
type. Be sure to read the documentation for :class:`.types.JSON` for
|
|
important tips regarding treatment of NULL values and ORM use.
|
|
|
|
.. versionchanged:: 1.1 :class:`.postgresql.JSON` is now a PostgreSQL-
|
|
specific specialization of the new :class:`.types.JSON` type.
|
|
|
|
The operators provided by the PostgreSQL version of :class:`.JSON`
|
|
include:
|
|
|
|
* Index operations (the ``->`` operator)::
|
|
|
|
data_table.c.data['some key']
|
|
|
|
data_table.c.data[5]
|
|
|
|
|
|
* Index operations returning text (the ``->>`` operator)::
|
|
|
|
data_table.c.data['some key'].astext == 'some value'
|
|
|
|
* Index operations with CAST
|
|
(equivalent to ``CAST(col ->> ['some key'] AS <type>)``)::
|
|
|
|
data_table.c.data['some key'].astext.cast(Integer) == 5
|
|
|
|
* Path index operations (the ``#>`` operator)::
|
|
|
|
data_table.c.data[('key_1', 'key_2', 5, ..., 'key_n')]
|
|
|
|
* Path index operations returning text (the ``#>>`` operator)::
|
|
|
|
data_table.c.data[('key_1', 'key_2', 5, ..., 'key_n')].astext == \
|
|
'some value'
|
|
|
|
.. versionchanged:: 1.1 The :meth:`.ColumnElement.cast` operator on
|
|
JSON objects now requires that the :attr:`.JSON.Comparator.astext`
|
|
modifier be called explicitly, if the cast works only from a textual
|
|
string.
|
|
|
|
Index operations return an expression object whose type defaults to
|
|
:class:`.JSON` by default, so that further JSON-oriented instructions
|
|
may be called upon the result type.
|
|
|
|
Custom serializers and deserializers are specified at the dialect level,
|
|
that is using :func:`.create_engine`. The reason for this is that when
|
|
using psycopg2, the DBAPI only allows serializers at the per-cursor
|
|
or per-connection level. E.g.::
|
|
|
|
engine = create_engine("postgresql://scott:tiger@localhost/test",
|
|
json_serializer=my_serialize_fn,
|
|
json_deserializer=my_deserialize_fn
|
|
)
|
|
|
|
When using the psycopg2 dialect, the json_deserializer is registered
|
|
against the database using ``psycopg2.extras.register_default_json``.
|
|
|
|
.. seealso::
|
|
|
|
:class:`.types.JSON` - Core level JSON type
|
|
|
|
:class:`.JSONB`
|
|
|
|
"""
|
|
|
|
astext_type = sqltypes.Text()
|
|
|
|
def __init__(self, none_as_null=False, astext_type=None):
|
|
"""Construct a :class:`.JSON` type.
|
|
|
|
:param none_as_null: if True, persist the value ``None`` as a
|
|
SQL NULL value, not the JSON encoding of ``null``. Note that
|
|
when this flag is False, the :func:`.null` construct can still
|
|
be used to persist a NULL value::
|
|
|
|
from sqlalchemy import null
|
|
conn.execute(table.insert(), data=null())
|
|
|
|
.. versionchanged:: 0.9.8 - Added ``none_as_null``, and :func:`.null`
|
|
is now supported in order to persist a NULL value.
|
|
|
|
.. seealso::
|
|
|
|
:attr:`.JSON.NULL`
|
|
|
|
:param astext_type: the type to use for the
|
|
:attr:`.JSON.Comparator.astext`
|
|
accessor on indexed attributes. Defaults to :class:`.types.Text`.
|
|
|
|
.. versionadded:: 1.1
|
|
|
|
"""
|
|
super(JSON, self).__init__(none_as_null=none_as_null)
|
|
if astext_type is not None:
|
|
self.astext_type = astext_type
|
|
|
|
class Comparator(sqltypes.JSON.Comparator):
|
|
"""Define comparison operations for :class:`.JSON`."""
|
|
|
|
@property
|
|
def astext(self):
|
|
"""On an indexed expression, use the "astext" (e.g. "->>")
|
|
conversion when rendered in SQL.
|
|
|
|
E.g.::
|
|
|
|
select([data_table.c.data['some key'].astext])
|
|
|
|
.. seealso::
|
|
|
|
:meth:`.ColumnElement.cast`
|
|
|
|
"""
|
|
|
|
if isinstance(self.expr.right.type, sqltypes.JSON.JSONPathType):
|
|
return self.expr.left.operate(
|
|
JSONPATH_ASTEXT,
|
|
self.expr.right, result_type=self.type.astext_type)
|
|
else:
|
|
return self.expr.left.operate(
|
|
ASTEXT, self.expr.right, result_type=self.type.astext_type)
|
|
|
|
comparator_factory = Comparator
|
|
|
|
|
|
colspecs[sqltypes.JSON] = JSON
|
|
ischema_names['json'] = JSON
|
|
|
|
|
|
class JSONB(JSON):
|
|
"""Represent the PostgreSQL JSONB type.
|
|
|
|
The :class:`.JSONB` type stores arbitrary JSONB format data, e.g.::
|
|
|
|
data_table = Table('data_table', metadata,
|
|
Column('id', Integer, primary_key=True),
|
|
Column('data', JSONB)
|
|
)
|
|
|
|
with engine.connect() as conn:
|
|
conn.execute(
|
|
data_table.insert(),
|
|
data = {"key1": "value1", "key2": "value2"}
|
|
)
|
|
|
|
The :class:`.JSONB` type includes all operations provided by
|
|
:class:`.JSON`, including the same behaviors for indexing operations.
|
|
It also adds additional operators specific to JSONB, including
|
|
:meth:`.JSONB.Comparator.has_key`, :meth:`.JSONB.Comparator.has_all`,
|
|
:meth:`.JSONB.Comparator.has_any`, :meth:`.JSONB.Comparator.contains`,
|
|
and :meth:`.JSONB.Comparator.contained_by`.
|
|
|
|
Like the :class:`.JSON` type, the :class:`.JSONB` type does not detect
|
|
in-place changes when used with the ORM, unless the
|
|
:mod:`sqlalchemy.ext.mutable` extension is used.
|
|
|
|
Custom serializers and deserializers
|
|
are shared with the :class:`.JSON` class, using the ``json_serializer``
|
|
and ``json_deserializer`` keyword arguments. These must be specified
|
|
at the dialect level using :func:`.create_engine`. When using
|
|
psycopg2, the serializers are associated with the jsonb type using
|
|
``psycopg2.extras.register_default_jsonb`` on a per-connection basis,
|
|
in the same way that ``psycopg2.extras.register_default_json`` is used
|
|
to register these handlers with the json type.
|
|
|
|
.. versionadded:: 0.9.7
|
|
|
|
.. seealso::
|
|
|
|
:class:`.JSON`
|
|
|
|
"""
|
|
|
|
__visit_name__ = 'JSONB'
|
|
|
|
class Comparator(JSON.Comparator):
|
|
"""Define comparison operations for :class:`.JSON`."""
|
|
|
|
def has_key(self, other):
|
|
"""Boolean expression. Test for presence of a key. Note that the
|
|
key may be a SQLA expression.
|
|
"""
|
|
return self.operate(HAS_KEY, other, result_type=sqltypes.Boolean)
|
|
|
|
def has_all(self, other):
|
|
"""Boolean expression. Test for presence of all keys in jsonb
|
|
"""
|
|
return self.operate(HAS_ALL, other, result_type=sqltypes.Boolean)
|
|
|
|
def has_any(self, other):
|
|
"""Boolean expression. Test for presence of any key in jsonb
|
|
"""
|
|
return self.operate(HAS_ANY, other, result_type=sqltypes.Boolean)
|
|
|
|
def contains(self, other, **kwargs):
|
|
"""Boolean expression. Test if keys (or array) are a superset
|
|
of/contained the keys of the argument jsonb expression.
|
|
"""
|
|
return self.operate(CONTAINS, other, result_type=sqltypes.Boolean)
|
|
|
|
def contained_by(self, other):
|
|
"""Boolean expression. Test if keys are a proper subset of the
|
|
keys of the argument jsonb expression.
|
|
"""
|
|
return self.operate(
|
|
CONTAINED_BY, other, result_type=sqltypes.Boolean)
|
|
|
|
comparator_factory = Comparator
|
|
|
|
ischema_names['jsonb'] = JSONB
|