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"""
psycopg client-side binding cursors
"""
# Copyright (C) 2022 The Psycopg Team
from typing import Optional, Tuple, TYPE_CHECKING
from functools import partial
from ._queries import PostgresQuery, PostgresClientQuery
from . import pq
from . import adapt
from . import errors as e
from .abc import ConnectionType, Query, Params
from .rows import Row
from .cursor import BaseCursor, Cursor
from ._preparing import Prepare
from .cursor_async import AsyncCursor
if TYPE_CHECKING:
from typing import Any # noqa: F401
from .connection import Connection # noqa: F401
from .connection_async import AsyncConnection # noqa: F401
TEXT = pq.Format.TEXT
BINARY = pq.Format.BINARY
class ClientCursorMixin(BaseCursor[ConnectionType, Row]):
def mogrify(self, query: Query, params: Optional[Params] = None) -> str:
"""
Return the query and parameters merged.
Parameters are adapted and merged to the query the same way that
`!execute()` would do.
"""
self._tx = adapt.Transformer(self)
pgq = self._convert_query(query, params)
return pgq.query.decode(self._tx.encoding)
def _execute_send(
self,
query: PostgresQuery,
*,
force_extended: bool = False,
binary: Optional[bool] = None,
) -> None:
if binary is None:
fmt = self.format
else:
fmt = BINARY if binary else TEXT
if fmt == BINARY:
raise e.NotSupportedError(
"client-side cursors don't support binary results"
)
self._query = query
if self._conn._pipeline:
# In pipeline mode always use PQsendQueryParams - see #314
# Multiple statements in the same query are not allowed anyway.
self._conn._pipeline.command_queue.append(
partial(self._pgconn.send_query_params, query.query, None)
)
elif force_extended:
self._pgconn.send_query_params(query.query, None)
else:
# If we can, let's use simple query protocol,
# as it can execute more than one statement in a single query.
self._pgconn.send_query(query.query)
def _convert_query(
self, query: Query, params: Optional[Params] = None
) -> PostgresQuery:
pgq = PostgresClientQuery(self._tx)
pgq.convert(query, params)
return pgq
def _get_prepared(
self, pgq: PostgresQuery, prepare: Optional[bool] = None
) -> Tuple[Prepare, bytes]:
return (Prepare.NO, b"")
class ClientCursor(ClientCursorMixin["Connection[Any]", Row], Cursor[Row]):
__module__ = "psycopg"
class AsyncClientCursor(
ClientCursorMixin["AsyncConnection[Any]", Row], AsyncCursor[Row]
):
__module__ = "psycopg"