psycopg2/lib/extensions.py

"""psycopg extensions to the DBAPI-2.0

This module holds all the extensions to the DBAPI-2.0 provided by psycopg.

- `connection` -- the new-type inheritable connection class
- `cursor` -- the new-type inheritable cursor class
- `adapt()` -- exposes the PEP-246_ compatible adapting mechanism used
  by psycopg to adapt Python types to PostgreSQL ones
  
.. _PEP-246: http://www.python.org/peps/pep-0246.html
"""
# psycopg/extensions.py - DBAPI-2.0 extensions specific to psycopg
#
# Copyright (C) 2003-2004 Federico Di Gregorio  <fog@debian.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY
# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
# for more details.

from _psycopg import UNICODE, INTEGER, LONGINTEGER, BOOLEAN, FLOAT
from _psycopg import TIME, DATE, INTERVAL

from _psycopg import Boolean, QuotedString, AsIs
try:
    from _psycopg import DateFromMx, TimeFromMx, TimestampFromMx
    from _psycopg import IntervalFromMx
except:
    pass
try:
    from _psycopg import DateFromPy, TimeFromPy, TimestampFromPy
    from _psycopg import IntervalFromPy
except:
    pass

from _psycopg import adapt, adapters, encodings, connection, cursor
from _psycopg import string_types, binary_types, new_type, register_type
from _psycopg import ISQLQuote

from _psycopg import QueryCanceledError, TransactionRollbackError

"""Isolation level values."""
ISOLATION_LEVEL_AUTOCOMMIT     = 0
ISOLATION_LEVEL_READ_COMMITTED = 1 
ISOLATION_LEVEL_SERIALIZABLE   = 2

# PostgreSQL maps the the other standard values to already defined levels
ISOLATION_LEVEL_REPEATABLE_READ  = ISOLATION_LEVEL_SERIALIZABLE
ISOLATION_LEVEL_READ_UNCOMMITTED = ISOLATION_LEVEL_READ_COMMITTED

"""psycopg connection status values."""
STATUS_SETUP    = 0
STATUS_READY    = 1
STATUS_BEGIN    = 2
STATUS_SYNC     = 3
STATUS_ASYNC    = 4

# This is a usefull mnemonic to check if the connection is in a transaction
STATUS_IN_TRANSACTION = STATUS_BEGIN

"""Backend transaction status values."""
TRANSACTION_STATUS_IDLE    = 0
TRANSACTION_STATUS_ACTIVE  = 1
TRANSACTION_STATUS_INTRANS = 2
TRANSACTION_STATUS_INERROR = 3
TRANSACTION_STATUS_UNKNOWN = 4

def register_adapter(typ, callable):
    """Register 'callable' as an ISQLQuote adapter for type 'typ'."""
    adapters[(typ, ISQLQuote)] = callable


# The SQL_IN class is the official adapter for tuples starting from 2.0.6.
class SQL_IN(object):
    """Adapt any iterable to an SQL quotable object."""
    
    def __init__(self, seq):
        self._seq = seq

    def prepare(self, conn):
        self._conn = conn
    
    def getquoted(self):
        # this is the important line: note how every object in the
        # list is adapted and then how getquoted() is called on it
        pobjs = [adapt(o) for o in self._seq]
        for obj in pobjs:
            if hasattr(obj, 'prepare'):
                obj.prepare(self._conn)
        qobjs = [str(o.getquoted()) for o in pobjs]
        return '(' + ', '.join(qobjs) + ')'

    __str__ = getquoted

register_adapter(tuple, SQL_IN)


__all__ = [ k for k in locals().keys() if not k.startswith('_') ]