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✏️ Editing: psycopg.py

# dialects/postgresql/psycopg.py
# Copyright (C) 2005-2025 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: https://www.opensource.org/licenses/mit-license.php
# mypy: ignore-errors

r"""
.. dialect:: postgresql+psycopg
    :name: psycopg (a.k.a. psycopg 3)
    :dbapi: psycopg
    :connectstring: postgresql+psycopg://user:password@host:port/dbname[?key=value&key=value...]
    :url: https://pypi.org/project/psycopg/

``psycopg`` is the package and module name for version 3 of the ``psycopg``
database driver, formerly known as ``psycopg2``.  This driver is different
enough from its ``psycopg2`` predecessor that SQLAlchemy supports it
via a totally separate dialect; support for ``psycopg2`` is expected to remain
for as long as that package continues to function for modern Python versions,
and also remains the default dialect for the ``postgresql://`` dialect
series.

The SQLAlchemy ``psycopg`` dialect provides both a sync and an async
implementation under the same dialect name. The proper version is
selected depending on how the engine is created:

* calling :func:`_sa.create_engine` with ``postgresql+psycopg://...`` will
  automatically select the sync version, e.g.::

from sqlalchemy import create_engine

sync_engine = create_engine(
        "postgresql+psycopg://scott:tiger@localhost/test"
    )

* calling :func:`_asyncio.create_async_engine` with
  ``postgresql+psycopg://...`` will automatically select the async version,
  e.g.::

from sqlalchemy.ext.asyncio import create_async_engine

asyncio_engine = create_async_engine(
        "postgresql+psycopg://scott:tiger@localhost/test"
    )

The asyncio version of the dialect may also be specified explicitly using the
``psycopg_async`` suffix, as::

from sqlalchemy.ext.asyncio import create_async_engine

asyncio_engine = create_async_engine(
        "postgresql+psycopg_async://scott:tiger@localhost/test"
    )

.. seealso::

:ref:`postgresql_psycopg2` - The SQLAlchemy ``psycopg``
    dialect shares most of its behavior with the ``psycopg2`` dialect.
    Further documentation is available there.

Using a different Cursor class
------------------------------

One of the differences between ``psycopg`` and the older ``psycopg2``
is how bound parameters are handled: ``psycopg2`` would bind them
client side, while ``psycopg`` by default will bind them server side.

It's possible to configure ``psycopg`` to do client side binding by
specifying the ``cursor_factory`` to be ``ClientCursor`` when creating
the engine::

from psycopg import ClientCursor

client_side_engine = create_engine(
        "postgresql+psycopg://...",
        connect_args={"cursor_factory": ClientCursor},
    )

Similarly when using an async engine the ``AsyncClientCursor`` can be
specified::

from psycopg import AsyncClientCursor

client_side_engine = create_async_engine(
        "postgresql+psycopg://...",
        connect_args={"cursor_factory": AsyncClientCursor},
    )

.. seealso::

`Client-side-binding cursors <https://www.psycopg.org/psycopg3/docs/advanced/cursors.html#client-side-binding-cursors>`_

"""  # noqa
from __future__ import annotations

from collections import deque
import logging
import re
from typing import cast
from typing import TYPE_CHECKING

from . import ranges
from ._psycopg_common import _PGDialect_common_psycopg
from ._psycopg_common import _PGExecutionContext_common_psycopg
from .base import INTERVAL
from .base import PGCompiler
from .base import PGIdentifierPreparer
from .base import REGCONFIG
from .json import JSON
from .json import JSONB
from .json import JSONPathType
from .types import CITEXT
from ... import pool
from ... import util
from ...engine import AdaptedConnection
from ...sql import sqltypes
from ...util.concurrency import await_fallback
from ...util.concurrency import await_only

if TYPE_CHECKING:
    from typing import Iterable

from psycopg import AsyncConnection

logger = logging.getLogger("sqlalchemy.dialects.postgresql")

class _PGString(sqltypes.String):
    render_bind_cast = True

class _PGREGCONFIG(REGCONFIG):
    render_bind_cast = True

class _PGJSON(JSON):
    def bind_processor(self, dialect):
        return self._make_bind_processor(None, dialect._psycopg_Json)

def result_processor(self, dialect, coltype):
        return None

class _PGJSONB(JSONB):
    def bind_processor(self, dialect):
        return self._make_bind_processor(None, dialect._psycopg_Jsonb)

def result_processor(self, dialect, coltype):
        return None

class _PGJSONIntIndexType(sqltypes.JSON.JSONIntIndexType):
    __visit_name__ = "json_int_index"

render_bind_cast = True

class _PGJSONStrIndexType(sqltypes.JSON.JSONStrIndexType):
    __visit_name__ = "json_str_index"

render_bind_cast = True

class _PGJSONPathType(JSONPathType):
    pass

class _PGInterval(INTERVAL):
    render_bind_cast = True

class _PGTimeStamp(sqltypes.DateTime):
    render_bind_cast = True

class _PGDate(sqltypes.Date):
    render_bind_cast = True

class _PGTime(sqltypes.Time):
    render_bind_cast = True

class _PGInteger(sqltypes.Integer):
    render_bind_cast = True

class _PGSmallInteger(sqltypes.SmallInteger):
    render_bind_cast = True

class _PGNullType(sqltypes.NullType):
    render_bind_cast = True

class _PGBigInteger(sqltypes.BigInteger):
    render_bind_cast = True

class _PGBoolean(sqltypes.Boolean):
    render_bind_cast = True

class _PsycopgRange(ranges.AbstractSingleRangeImpl):
    def bind_processor(self, dialect):
        psycopg_Range = cast(PGDialect_psycopg, dialect)._psycopg_Range

def to_range(value):
            if isinstance(value, ranges.Range):
                value = psycopg_Range(
                    value.lower, value.upper, value.bounds, value.empty
                )
            return value

return to_range

def result_processor(self, dialect, coltype):
        def to_range(value):
            if value is not None:
                value = ranges.Range(
                    value._lower,
                    value._upper,
                    bounds=value._bounds if value._bounds else "[)",
                    empty=not value._bounds,
                )
            return value

return to_range

class _PsycopgMultiRange(ranges.AbstractMultiRangeImpl):
    def bind_processor(self, dialect):
        psycopg_Range = cast(PGDialect_psycopg, dialect)._psycopg_Range
        psycopg_Multirange = cast(
            PGDialect_psycopg, dialect
        )._psycopg_Multirange

NoneType = type(None)

def to_range(value):
            if isinstance(value, (str, NoneType, psycopg_Multirange)):
                return value

return psycopg_Multirange(
                [
                    psycopg_Range(
                        element.lower,
                        element.upper,
                        element.bounds,
                        element.empty,
                    )
                    for element in cast("Iterable[ranges.Range]", value)
                ]
            )

return to_range

def result_processor(self, dialect, coltype):
        def to_range(value):
            if value is None:
                return None
            else:
                return ranges.MultiRange(
                    ranges.Range(
                        elem._lower,
                        elem._upper,
                        bounds=elem._bounds if elem._bounds else "[)",
                        empty=not elem._bounds,
                    )
                    for elem in value
                )

return to_range

class PGExecutionContext_psycopg(_PGExecutionContext_common_psycopg):
    pass

class PGCompiler_psycopg(PGCompiler):
    pass

class PGIdentifierPreparer_psycopg(PGIdentifierPreparer):
    pass

def _log_notices(diagnostic):
    logger.info("%s: %s", diagnostic.severity, diagnostic.message_primary)

class PGDialect_psycopg(_PGDialect_common_psycopg):
    driver = "psycopg"

supports_statement_cache = True
    supports_server_side_cursors = True
    default_paramstyle = "pyformat"
    supports_sane_multi_rowcount = True

execution_ctx_cls = PGExecutionContext_psycopg
    statement_compiler = PGCompiler_psycopg
    preparer = PGIdentifierPreparer_psycopg
    psycopg_version = (0, 0)

_has_native_hstore = True
    _psycopg_adapters_map = None

colspecs = util.update_copy(
        _PGDialect_common_psycopg.colspecs,
        {
            sqltypes.String: _PGString,
            REGCONFIG: _PGREGCONFIG,
            JSON: _PGJSON,
            CITEXT: CITEXT,
            sqltypes.JSON: _PGJSON,
            JSONB: _PGJSONB,
            sqltypes.JSON.JSONPathType: _PGJSONPathType,
            sqltypes.JSON.JSONIntIndexType: _PGJSONIntIndexType,
            sqltypes.JSON.JSONStrIndexType: _PGJSONStrIndexType,
            sqltypes.Interval: _PGInterval,
            INTERVAL: _PGInterval,
            sqltypes.Date: _PGDate,
            sqltypes.DateTime: _PGTimeStamp,
            sqltypes.Time: _PGTime,
            sqltypes.Integer: _PGInteger,
            sqltypes.SmallInteger: _PGSmallInteger,
            sqltypes.BigInteger: _PGBigInteger,
            ranges.AbstractSingleRange: _PsycopgRange,
            ranges.AbstractMultiRange: _PsycopgMultiRange,
        },
    )

def __init__(self, **kwargs):
        super().__init__(**kwargs)

if self.dbapi:
            m = re.match(r"(\d+)\.(\d+)(?:\.(\d+))?", self.dbapi.__version__)
            if m:
                self.psycopg_version = tuple(
                    int(x) for x in m.group(1, 2, 3) if x is not None
                )

if self.psycopg_version < (3, 0, 2):
                raise ImportError(
                    "psycopg version 3.0.2 or higher is required."
                )

from psycopg.adapt import AdaptersMap

self._psycopg_adapters_map = adapters_map = AdaptersMap(
                self.dbapi.adapters
            )

if self._native_inet_types is False:
                import psycopg.types.string

adapters_map.register_loader(
                    "inet", psycopg.types.string.TextLoader
                )
                adapters_map.register_loader(
                    "cidr", psycopg.types.string.TextLoader
                )

if self._json_deserializer:
                from psycopg.types.json import set_json_loads

set_json_loads(self._json_deserializer, adapters_map)

if self._json_serializer:
                from psycopg.types.json import set_json_dumps

set_json_dumps(self._json_serializer, adapters_map)

def create_connect_args(self, url):
        # see https://github.com/psycopg/psycopg/issues/83
        cargs, cparams = super().create_connect_args(url)

if self._psycopg_adapters_map:
            cparams["context"] = self._psycopg_adapters_map
        if self.client_encoding is not None:
            cparams["client_encoding"] = self.client_encoding
        return cargs, cparams

def _type_info_fetch(self, connection, name):
        from psycopg.types import TypeInfo

return TypeInfo.fetch(connection.connection.driver_connection, name)

def initialize(self, connection):
        super().initialize(connection)

# PGDialect.initialize() checks server version for <= 8.2 and sets
        # this flag to False if so
        if not self.insert_returning:
            self.insert_executemany_returning = False

# HSTORE can't be registered until we have a connection so that
        # we can look up its OID, so we set up this adapter in
        # initialize()
        if self.use_native_hstore:
            info = self._type_info_fetch(connection, "hstore")
            self._has_native_hstore = info is not None
            if self._has_native_hstore:
                from psycopg.types.hstore import register_hstore

# register the adapter for connections made subsequent to
                # this one
                assert self._psycopg_adapters_map
                register_hstore(info, self._psycopg_adapters_map)

# register the adapter for this connection
                assert connection.connection
                register_hstore(info, connection.connection.driver_connection)

@classmethod
    def import_dbapi(cls):
        import psycopg

return psycopg

@classmethod
    def get_async_dialect_cls(cls, url):
        return PGDialectAsync_psycopg

@util.memoized_property
    def _isolation_lookup(self):
        return {
            "READ COMMITTED": self.dbapi.IsolationLevel.READ_COMMITTED,
            "READ UNCOMMITTED": self.dbapi.IsolationLevel.READ_UNCOMMITTED,
            "REPEATABLE READ": self.dbapi.IsolationLevel.REPEATABLE_READ,
            "SERIALIZABLE": self.dbapi.IsolationLevel.SERIALIZABLE,
        }

@util.memoized_property
    def _psycopg_Json(self):
        from psycopg.types import json

return json.Json

@util.memoized_property
    def _psycopg_Jsonb(self):
        from psycopg.types import json

return json.Jsonb

@util.memoized_property
    def _psycopg_TransactionStatus(self):
        from psycopg.pq import TransactionStatus

return TransactionStatus

@util.memoized_property
    def _psycopg_Range(self):
        from psycopg.types.range import Range

return Range

@util.memoized_property
    def _psycopg_Multirange(self):
        from psycopg.types.multirange import Multirange

return Multirange

def _do_isolation_level(self, connection, autocommit, isolation_level):
        connection.autocommit = autocommit
        connection.isolation_level = isolation_level

def get_isolation_level(self, dbapi_connection):
        status_before = dbapi_connection.info.transaction_status
        value = super().get_isolation_level(dbapi_connection)

# don't rely on psycopg providing enum symbols, compare with
        # eq/ne
        if status_before == self._psycopg_TransactionStatus.IDLE:
            dbapi_connection.rollback()
        return value

def set_isolation_level(self, dbapi_connection, level):
        if level == "AUTOCOMMIT":
            self._do_isolation_level(
                dbapi_connection, autocommit=True, isolation_level=None
            )
        else:
            self._do_isolation_level(
                dbapi_connection,
                autocommit=False,
                isolation_level=self._isolation_lookup[level],
            )

def set_readonly(self, connection, value):
        connection.read_only = value

def get_readonly(self, connection):
        return connection.read_only

def on_connect(self):
        def notices(conn):
            conn.add_notice_handler(_log_notices)

fns = [notices]

if self.isolation_level is not None:

def on_connect(conn):
                self.set_isolation_level(conn, self.isolation_level)

fns.append(on_connect)

# fns always has the notices function
        def on_connect(conn):
            for fn in fns:
                fn(conn)

return on_connect

def is_disconnect(self, e, connection, cursor):
        if isinstance(e, self.dbapi.Error) and connection is not None:
            if connection.closed or connection.broken:
                return True
        return False

def _do_prepared_twophase(self, connection, command, recover=False):
        dbapi_conn = connection.connection.dbapi_connection
        if (
            recover
            # don't rely on psycopg providing enum symbols, compare with
            # eq/ne
            or dbapi_conn.info.transaction_status
            != self._psycopg_TransactionStatus.IDLE
        ):
            dbapi_conn.rollback()
        before_autocommit = dbapi_conn.autocommit
        try:
            if not before_autocommit:
                self._do_autocommit(dbapi_conn, True)
            dbapi_conn.execute(command)
        finally:
            if not before_autocommit:
                self._do_autocommit(dbapi_conn, before_autocommit)

def do_rollback_twophase(
        self, connection, xid, is_prepared=True, recover=False
    ):
        if is_prepared:
            self._do_prepared_twophase(
                connection, f"ROLLBACK PREPARED '{xid}'", recover=recover
            )
        else:
            self.do_rollback(connection.connection)

def do_commit_twophase(
        self, connection, xid, is_prepared=True, recover=False
    ):
        if is_prepared:
            self._do_prepared_twophase(
                connection, f"COMMIT PREPARED '{xid}'", recover=recover
            )
        else:
            self.do_commit(connection.connection)

@util.memoized_property
    def _dialect_specific_select_one(self):
        return ";"

class AsyncAdapt_psycopg_cursor:
    __slots__ = ("_cursor", "await_", "_rows")

_psycopg_ExecStatus = None

def __init__(self, cursor, await_) -> None:
        self._cursor = cursor
        self.await_ = await_
        self._rows = deque()

def __getattr__(self, name):
        return getattr(self._cursor, name)

@property
    def arraysize(self):
        return self._cursor.arraysize

@arraysize.setter
    def arraysize(self, value):
        self._cursor.arraysize = value

def close(self):
        self._rows.clear()
        # Normal cursor just call _close() in a non-sync way.
        self._cursor._close()

def execute(self, query, params=None, **kw):
        result = self.await_(self._cursor.execute(query, params, **kw))
        # sqlalchemy result is not async, so need to pull all rows here
        res = self._cursor.pgresult

# don't rely on psycopg providing enum symbols, compare with
        # eq/ne
        if res and res.status == self._psycopg_ExecStatus.TUPLES_OK:
            rows = self.await_(self._cursor.fetchall())
            self._rows = deque(rows)
        return result

def executemany(self, query, params_seq):
        return self.await_(self._cursor.executemany(query, params_seq))

def __iter__(self):
        while self._rows:
            yield self._rows.popleft()

def fetchone(self):
        if self._rows:
            return self._rows.popleft()
        else:
            return None

def fetchmany(self, size=None):
        if size is None:
            size = self._cursor.arraysize

rr = self._rows
        return [rr.popleft() for _ in range(min(size, len(rr)))]

def fetchall(self):
        retval = list(self._rows)
        self._rows.clear()
        return retval

class AsyncAdapt_psycopg_ss_cursor(AsyncAdapt_psycopg_cursor):
    def execute(self, query, params=None, **kw):
        self.await_(self._cursor.execute(query, params, **kw))
        return self

def close(self):
        self.await_(self._cursor.close())

def fetchone(self):
        return self.await_(self._cursor.fetchone())

def fetchmany(self, size=0):
        return self.await_(self._cursor.fetchmany(size))

def fetchall(self):
        return self.await_(self._cursor.fetchall())

def __iter__(self):
        iterator = self._cursor.__aiter__()
        while True:
            try:
                yield self.await_(iterator.__anext__())
            except StopAsyncIteration:
                break

class AsyncAdapt_psycopg_connection(AdaptedConnection):
    _connection: AsyncConnection
    __slots__ = ()
    await_ = staticmethod(await_only)

def __init__(self, connection) -> None:
        self._connection = connection

def __getattr__(self, name):
        return getattr(self._connection, name)

def execute(self, query, params=None, **kw):
        cursor = self.await_(self._connection.execute(query, params, **kw))
        return AsyncAdapt_psycopg_cursor(cursor, self.await_)

def cursor(self, *args, **kw):
        cursor = self._connection.cursor(*args, **kw)
        if hasattr(cursor, "name"):
            return AsyncAdapt_psycopg_ss_cursor(cursor, self.await_)
        else:
            return AsyncAdapt_psycopg_cursor(cursor, self.await_)

def commit(self):
        self.await_(self._connection.commit())

def rollback(self):
        self.await_(self._connection.rollback())

def close(self):
        self.await_(self._connection.close())

@property
    def autocommit(self):
        return self._connection.autocommit

@autocommit.setter
    def autocommit(self, value):
        self.set_autocommit(value)

def set_autocommit(self, value):
        self.await_(self._connection.set_autocommit(value))

def set_isolation_level(self, value):
        self.await_(self._connection.set_isolation_level(value))

def set_read_only(self, value):
        self.await_(self._connection.set_read_only(value))

def set_deferrable(self, value):
        self.await_(self._connection.set_deferrable(value))

class AsyncAdaptFallback_psycopg_connection(AsyncAdapt_psycopg_connection):
    __slots__ = ()
    await_ = staticmethod(await_fallback)

class PsycopgAdaptDBAPI:
    def __init__(self, psycopg) -> None:
        self.psycopg = psycopg

for k, v in self.psycopg.__dict__.items():
            if k != "connect":
                self.__dict__[k] = v

def connect(self, *arg, **kw):
        async_fallback = kw.pop("async_fallback", False)
        creator_fn = kw.pop(
            "async_creator_fn", self.psycopg.AsyncConnection.connect
        )
        if util.asbool(async_fallback):
            return AsyncAdaptFallback_psycopg_connection(
                await_fallback(creator_fn(*arg, **kw))
            )
        else:
            return AsyncAdapt_psycopg_connection(
                await_only(creator_fn(*arg, **kw))
            )

class PGDialectAsync_psycopg(PGDialect_psycopg):
    is_async = True
    supports_statement_cache = True

@classmethod
    def import_dbapi(cls):
        import psycopg
        from psycopg.pq import ExecStatus

AsyncAdapt_psycopg_cursor._psycopg_ExecStatus = ExecStatus

return PsycopgAdaptDBAPI(psycopg)

@classmethod
    def get_pool_class(cls, url):
        async_fallback = url.query.get("async_fallback", False)

if util.asbool(async_fallback):
            return pool.FallbackAsyncAdaptedQueuePool
        else:
            return pool.AsyncAdaptedQueuePool

def _type_info_fetch(self, connection, name):
        from psycopg.types import TypeInfo

adapted = connection.connection
        return adapted.await_(TypeInfo.fetch(adapted.driver_connection, name))

def _do_isolation_level(self, connection, autocommit, isolation_level):
        connection.set_autocommit(autocommit)
        connection.set_isolation_level(isolation_level)

def _do_autocommit(self, connection, value):
        connection.set_autocommit(value)

def set_readonly(self, connection, value):
        connection.set_read_only(value)

def set_deferrable(self, connection, value):
        connection.set_deferrable(value)

def get_driver_connection(self, connection):
        return connection._connection

dialect = PGDialect_psycopg
dialect_async = PGDialectAsync_psycopg

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