Current File : //proc/thread-self/root/opt/alt/python37/lib64/python3.7/site-packages/psycopg2/extras.py
"""Miscellaneous goodies for psycopg2
This module is a generic place used to hold little helper functions
and classes until a better place in the distribution is found.
"""
# psycopg/extras.py - miscellaneous extra goodies for psycopg
#
# Copyright (C) 2003-2019 Federico Di Gregorio <fog@debian.org>
#
# psycopg2 is free software: you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# In addition, as a special exception, the copyright holders give
# permission to link this program with the OpenSSL library (or with
# modified versions of OpenSSL that use the same license as OpenSSL),
# and distribute linked combinations including the two.
#
# You must obey the GNU Lesser General Public License in all respects for
# all of the code used other than OpenSSL.
#
# psycopg2 is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
# License for more details.
import os as _os
import time as _time
import re as _re
from collections import namedtuple, OrderedDict
import logging as _logging
import psycopg2
from psycopg2 import extensions as _ext
from .extensions import cursor as _cursor
from .extensions import connection as _connection
from .extensions import adapt as _A, quote_ident
from .compat import PY2, PY3, lru_cache
from psycopg2._psycopg import ( # noqa
REPLICATION_PHYSICAL, REPLICATION_LOGICAL,
ReplicationConnection as _replicationConnection,
ReplicationCursor as _replicationCursor,
ReplicationMessage)
# expose the json adaptation stuff into the module
from psycopg2._json import ( # noqa
json, Json, register_json, register_default_json, register_default_jsonb)
# Expose range-related objects
from psycopg2._range import ( # noqa
Range, NumericRange, DateRange, DateTimeRange, DateTimeTZRange,
register_range, RangeAdapter, RangeCaster)
# Expose ipaddress-related objects
from psycopg2._ipaddress import register_ipaddress # noqa
class DictCursorBase(_cursor):
"""Base class for all dict-like cursors."""
def __init__(self, *args, **kwargs):
if 'row_factory' in kwargs:
row_factory = kwargs['row_factory']
del kwargs['row_factory']
else:
raise NotImplementedError(
"DictCursorBase can't be instantiated without a row factory.")
super(DictCursorBase, self).__init__(*args, **kwargs)
self._query_executed = False
self._prefetch = False
self.row_factory = row_factory
def fetchone(self):
if self._prefetch:
res = super(DictCursorBase, self).fetchone()
if self._query_executed:
self._build_index()
if not self._prefetch:
res = super(DictCursorBase, self).fetchone()
return res
def fetchmany(self, size=None):
if self._prefetch:
res = super(DictCursorBase, self).fetchmany(size)
if self._query_executed:
self._build_index()
if not self._prefetch:
res = super(DictCursorBase, self).fetchmany(size)
return res
def fetchall(self):
if self._prefetch:
res = super(DictCursorBase, self).fetchall()
if self._query_executed:
self._build_index()
if not self._prefetch:
res = super(DictCursorBase, self).fetchall()
return res
def __iter__(self):
try:
if self._prefetch:
res = super(DictCursorBase, self).__iter__()
first = next(res)
if self._query_executed:
self._build_index()
if not self._prefetch:
res = super(DictCursorBase, self).__iter__()
first = next(res)
yield first
while True:
yield next(res)
except StopIteration:
return
class DictConnection(_connection):
"""A connection that uses `DictCursor` automatically."""
def cursor(self, *args, **kwargs):
kwargs.setdefault('cursor_factory', DictCursor)
return super(DictConnection, self).cursor(*args, **kwargs)
class DictCursor(DictCursorBase):
"""A cursor that keeps a list of column name -> index mappings."""
def __init__(self, *args, **kwargs):
kwargs['row_factory'] = DictRow
super(DictCursor, self).__init__(*args, **kwargs)
self._prefetch = True
def execute(self, query, vars=None):
self.index = OrderedDict()
self._query_executed = True
return super(DictCursor, self).execute(query, vars)
def callproc(self, procname, vars=None):
self.index = OrderedDict()
self._query_executed = True
return super(DictCursor, self).callproc(procname, vars)
def _build_index(self):
if self._query_executed and self.description:
for i in range(len(self.description)):
self.index[self.description[i][0]] = i
self._query_executed = False
class DictRow(list):
"""A row object that allow by-column-name access to data."""
__slots__ = ('_index',)
def __init__(self, cursor):
self._index = cursor.index
self[:] = [None] * len(cursor.description)
def __getitem__(self, x):
if not isinstance(x, (int, slice)):
x = self._index[x]
return super(DictRow, self).__getitem__(x)
def __setitem__(self, x, v):
if not isinstance(x, (int, slice)):
x = self._index[x]
super(DictRow, self).__setitem__(x, v)
def items(self):
g = super(DictRow, self).__getitem__
return ((n, g(self._index[n])) for n in self._index)
def keys(self):
return iter(self._index)
def values(self):
g = super(DictRow, self).__getitem__
return (g(self._index[n]) for n in self._index)
def get(self, x, default=None):
try:
return self[x]
except Exception:
return default
def copy(self):
return OrderedDict(self.items())
def __contains__(self, x):
return x in self._index
def __getstate__(self):
return self[:], self._index.copy()
def __setstate__(self, data):
self[:] = data[0]
self._index = data[1]
if PY2:
iterkeys = keys
itervalues = values
iteritems = items
has_key = __contains__
def keys(self):
return list(self.iterkeys())
def values(self):
return tuple(self.itervalues())
def items(self):
return list(self.iteritems())
class RealDictConnection(_connection):
"""A connection that uses `RealDictCursor` automatically."""
def cursor(self, *args, **kwargs):
kwargs.setdefault('cursor_factory', RealDictCursor)
return super(RealDictConnection, self).cursor(*args, **kwargs)
class RealDictCursor(DictCursorBase):
"""A cursor that uses a real dict as the base type for rows.
Note that this cursor is extremely specialized and does not allow
the normal access (using integer indices) to fetched data. If you need
to access database rows both as a dictionary and a list, then use
the generic `DictCursor` instead of `!RealDictCursor`.
"""
def __init__(self, *args, **kwargs):
kwargs['row_factory'] = RealDictRow
super(RealDictCursor, self).__init__(*args, **kwargs)
def execute(self, query, vars=None):
self.column_mapping = []
self._query_executed = True
return super(RealDictCursor, self).execute(query, vars)
def callproc(self, procname, vars=None):
self.column_mapping = []
self._query_executed = True
return super(RealDictCursor, self).callproc(procname, vars)
def _build_index(self):
if self._query_executed and self.description:
self.column_mapping = [d[0] for d in self.description]
self._query_executed = False
class RealDictRow(OrderedDict):
"""A `!dict` subclass representing a data record."""
def __init__(self, *args, **kwargs):
if args and isinstance(args[0], _cursor):
cursor = args[0]
args = args[1:]
else:
cursor = None
super(RealDictRow, self).__init__(*args, **kwargs)
if cursor is not None:
# Required for named cursors
if cursor.description and not cursor.column_mapping:
cursor._build_index()
# Store the cols mapping in the dict itself until the row is fully
# populated, so we don't need to add attributes to the class
# (hence keeping its maintenance, special pickle support, etc.)
self[RealDictRow] = cursor.column_mapping
def __setitem__(self, key, value):
if RealDictRow in self:
# We are in the row building phase
mapping = self[RealDictRow]
super(RealDictRow, self).__setitem__(mapping[key], value)
if key == len(mapping) - 1:
# Row building finished
del self[RealDictRow]
return
super(RealDictRow, self).__setitem__(key, value)
class NamedTupleConnection(_connection):
"""A connection that uses `NamedTupleCursor` automatically."""
def cursor(self, *args, **kwargs):
kwargs.setdefault('cursor_factory', NamedTupleCursor)
return super(NamedTupleConnection, self).cursor(*args, **kwargs)
class NamedTupleCursor(_cursor):
"""A cursor that generates results as `~collections.namedtuple`.
`!fetch*()` methods will return named tuples instead of regular tuples, so
their elements can be accessed both as regular numeric items as well as
attributes.
>>> nt_cur = conn.cursor(cursor_factory=psycopg2.extras.NamedTupleCursor)
>>> rec = nt_cur.fetchone()
>>> rec
Record(id=1, num=100, data="abc'def")
>>> rec[1]
100
>>> rec.data
"abc'def"
"""
Record = None
MAX_CACHE = 1024
def execute(self, query, vars=None):
self.Record = None
return super(NamedTupleCursor, self).execute(query, vars)
def executemany(self, query, vars):
self.Record = None
return super(NamedTupleCursor, self).executemany(query, vars)
def callproc(self, procname, vars=None):
self.Record = None
return super(NamedTupleCursor, self).callproc(procname, vars)
def fetchone(self):
t = super(NamedTupleCursor, self).fetchone()
if t is not None:
nt = self.Record
if nt is None:
nt = self.Record = self._make_nt()
return nt._make(t)
def fetchmany(self, size=None):
ts = super(NamedTupleCursor, self).fetchmany(size)
nt = self.Record
if nt is None:
nt = self.Record = self._make_nt()
return list(map(nt._make, ts))
def fetchall(self):
ts = super(NamedTupleCursor, self).fetchall()
nt = self.Record
if nt is None:
nt = self.Record = self._make_nt()
return list(map(nt._make, ts))
def __iter__(self):
try:
it = super(NamedTupleCursor, self).__iter__()
t = next(it)
nt = self.Record
if nt is None:
nt = self.Record = self._make_nt()
yield nt._make(t)
while True:
yield nt._make(next(it))
except StopIteration:
return
# ascii except alnum and underscore
_re_clean = _re.compile(
'[' + _re.escape(' !"#$%&\'()*+,-./:;<=>?@[\\]^`{|}~') + ']')
def _make_nt(self):
key = tuple(d[0] for d in self.description) if self.description else ()
return self._cached_make_nt(key)
@classmethod
def _do_make_nt(cls, key):
fields = []
for s in key:
s = cls._re_clean.sub('_', s)
# Python identifier cannot start with numbers, namedtuple fields
# cannot start with underscore. So...
if s[0] == '_' or '0' <= s[0] <= '9':
s = 'f' + s
fields.append(s)
nt = namedtuple("Record", fields)
return nt
@lru_cache(512)
def _cached_make_nt(cls, key):
return cls._do_make_nt(key)
# Exposed for testability, and if someone wants to monkeypatch to tweak
# the cache size.
NamedTupleCursor._cached_make_nt = classmethod(_cached_make_nt)
class LoggingConnection(_connection):
"""A connection that logs all queries to a file or logger__ object.
.. __: https://docs.python.org/library/logging.html
"""
def initialize(self, logobj):
"""Initialize the connection to log to `!logobj`.
The `!logobj` parameter can be an open file object or a Logger
instance from the standard logging module.
"""
self._logobj = logobj
if _logging and isinstance(logobj, _logging.Logger):
self.log = self._logtologger
else:
self.log = self._logtofile
def filter(self, msg, curs):
"""Filter the query before logging it.
This is the method to overwrite to filter unwanted queries out of the
log or to add some extra data to the output. The default implementation
just does nothing.
"""
return msg
def _logtofile(self, msg, curs):
msg = self.filter(msg, curs)
if msg:
if PY3 and isinstance(msg, bytes):
msg = msg.decode(_ext.encodings[self.encoding], 'replace')
self._logobj.write(msg + _os.linesep)
def _logtologger(self, msg, curs):
msg = self.filter(msg, curs)
if msg:
self._logobj.debug(msg)
def _check(self):
if not hasattr(self, '_logobj'):
raise self.ProgrammingError(
"LoggingConnection object has not been initialize()d")
def cursor(self, *args, **kwargs):
self._check()
kwargs.setdefault('cursor_factory', LoggingCursor)
return super(LoggingConnection, self).cursor(*args, **kwargs)
class LoggingCursor(_cursor):
"""A cursor that logs queries using its connection logging facilities."""
def execute(self, query, vars=None):
try:
return super(LoggingCursor, self).execute(query, vars)
finally:
self.connection.log(self.query, self)
def callproc(self, procname, vars=None):
try:
return super(LoggingCursor, self).callproc(procname, vars)
finally:
self.connection.log(self.query, self)
class MinTimeLoggingConnection(LoggingConnection):
"""A connection that logs queries based on execution time.
This is just an example of how to sub-class `LoggingConnection` to
provide some extra filtering for the logged queries. Both the
`initialize()` and `filter()` methods are overwritten to make sure
that only queries executing for more than ``mintime`` ms are logged.
Note that this connection uses the specialized cursor
`MinTimeLoggingCursor`.
"""
def initialize(self, logobj, mintime=0):
LoggingConnection.initialize(self, logobj)
self._mintime = mintime
def filter(self, msg, curs):
t = (_time.time() - curs.timestamp) * 1000
if t > self._mintime:
if PY3 and isinstance(msg, bytes):
msg = msg.decode(_ext.encodings[self.encoding], 'replace')
return msg + _os.linesep + " (execution time: %d ms)" % t
def cursor(self, *args, **kwargs):
kwargs.setdefault('cursor_factory', MinTimeLoggingCursor)
return LoggingConnection.cursor(self, *args, **kwargs)
class MinTimeLoggingCursor(LoggingCursor):
"""The cursor sub-class companion to `MinTimeLoggingConnection`."""
def execute(self, query, vars=None):
self.timestamp = _time.time()
return LoggingCursor.execute(self, query, vars)
def callproc(self, procname, vars=None):
self.timestamp = _time.time()
return LoggingCursor.callproc(self, procname, vars)
class LogicalReplicationConnection(_replicationConnection):
def __init__(self, *args, **kwargs):
kwargs['replication_type'] = REPLICATION_LOGICAL
super(LogicalReplicationConnection, self).__init__(*args, **kwargs)
class PhysicalReplicationConnection(_replicationConnection):
def __init__(self, *args, **kwargs):
kwargs['replication_type'] = REPLICATION_PHYSICAL
super(PhysicalReplicationConnection, self).__init__(*args, **kwargs)
class StopReplication(Exception):
"""
Exception used to break out of the endless loop in
`~ReplicationCursor.consume_stream()`.
Subclass of `~exceptions.Exception`. Intentionally *not* inherited from
`~psycopg2.Error` as occurrence of this exception does not indicate an
error.
"""
pass
class ReplicationCursor(_replicationCursor):
"""A cursor used for communication on replication connections."""
def create_replication_slot(self, slot_name, slot_type=None, output_plugin=None):
"""Create streaming replication slot."""
command = "CREATE_REPLICATION_SLOT %s " % quote_ident(slot_name, self)
if slot_type is None:
slot_type = self.connection.replication_type
if slot_type == REPLICATION_LOGICAL:
if output_plugin is None:
raise psycopg2.ProgrammingError(
"output plugin name is required to create "
"logical replication slot")
command += "LOGICAL %s" % quote_ident(output_plugin, self)
elif slot_type == REPLICATION_PHYSICAL:
if output_plugin is not None:
raise psycopg2.ProgrammingError(
"cannot specify output plugin name when creating "
"physical replication slot")
command += "PHYSICAL"
else:
raise psycopg2.ProgrammingError(
"unrecognized replication type: %s" % repr(slot_type))
self.execute(command)
def drop_replication_slot(self, slot_name):
"""Drop streaming replication slot."""
command = "DROP_REPLICATION_SLOT %s" % quote_ident(slot_name, self)
self.execute(command)
def start_replication(
self, slot_name=None, slot_type=None, start_lsn=0,
timeline=0, options=None, decode=False, status_interval=10):
"""Start replication stream."""
command = "START_REPLICATION "
if slot_type is None:
slot_type = self.connection.replication_type
if slot_type == REPLICATION_LOGICAL:
if slot_name:
command += "SLOT %s " % quote_ident(slot_name, self)
else:
raise psycopg2.ProgrammingError(
"slot name is required for logical replication")
command += "LOGICAL "
elif slot_type == REPLICATION_PHYSICAL:
if slot_name:
command += "SLOT %s " % quote_ident(slot_name, self)
# don't add "PHYSICAL", before 9.4 it was just START_REPLICATION XXX/XXX
else:
raise psycopg2.ProgrammingError(
"unrecognized replication type: %s" % repr(slot_type))
if type(start_lsn) is str:
lsn = start_lsn.split('/')
lsn = "%X/%08X" % (int(lsn[0], 16), int(lsn[1], 16))
else:
lsn = "%X/%08X" % ((start_lsn >> 32) & 0xFFFFFFFF,
start_lsn & 0xFFFFFFFF)
command += lsn
if timeline != 0:
if slot_type == REPLICATION_LOGICAL:
raise psycopg2.ProgrammingError(
"cannot specify timeline for logical replication")
command += " TIMELINE %d" % timeline
if options:
if slot_type == REPLICATION_PHYSICAL:
raise psycopg2.ProgrammingError(
"cannot specify output plugin options for physical replication")
command += " ("
for k, v in options.items():
if not command.endswith('('):
command += ", "
command += "%s %s" % (quote_ident(k, self), _A(str(v)))
command += ")"
self.start_replication_expert(
command, decode=decode, status_interval=status_interval)
# allows replication cursors to be used in select.select() directly
def fileno(self):
return self.connection.fileno()
# a dbtype and adapter for Python UUID type
class UUID_adapter(object):
"""Adapt Python's uuid.UUID__ type to PostgreSQL's uuid__.
.. __: https://docs.python.org/library/uuid.html
.. __: https://www.postgresql.org/docs/current/static/datatype-uuid.html
"""
def __init__(self, uuid):
self._uuid = uuid
def __conform__(self, proto):
if proto is _ext.ISQLQuote:
return self
def getquoted(self):
return ("'%s'::uuid" % self._uuid).encode('utf8')
def __str__(self):
return "'%s'::uuid" % self._uuid
def register_uuid(oids=None, conn_or_curs=None):
"""Create the UUID type and an uuid.UUID adapter.
:param oids: oid for the PostgreSQL :sql:`uuid` type, or 2-items sequence
with oids of the type and the array. If not specified, use PostgreSQL
standard oids.
:param conn_or_curs: where to register the typecaster. If not specified,
register it globally.
"""
import uuid
if not oids:
oid1 = 2950
oid2 = 2951
elif isinstance(oids, (list, tuple)):
oid1, oid2 = oids
else:
oid1 = oids
oid2 = 2951
_ext.UUID = _ext.new_type((oid1, ), "UUID",
lambda data, cursor: data and uuid.UUID(data) or None)
_ext.UUIDARRAY = _ext.new_array_type((oid2,), "UUID[]", _ext.UUID)
_ext.register_type(_ext.UUID, conn_or_curs)
_ext.register_type(_ext.UUIDARRAY, conn_or_curs)
_ext.register_adapter(uuid.UUID, UUID_adapter)
return _ext.UUID
# a type, dbtype and adapter for PostgreSQL inet type
class Inet(object):
"""Wrap a string to allow for correct SQL-quoting of inet values.
Note that this adapter does NOT check the passed value to make
sure it really is an inet-compatible address but DOES call adapt()
on it to make sure it is impossible to execute an SQL-injection
by passing an evil value to the initializer.
"""
def __init__(self, addr):
self.addr = addr
def __repr__(self):
return "%s(%r)" % (self.__class__.__name__, self.addr)
def prepare(self, conn):
self._conn = conn
def getquoted(self):
obj = _A(self.addr)
if hasattr(obj, 'prepare'):
obj.prepare(self._conn)
return obj.getquoted() + b"::inet"
def __conform__(self, proto):
if proto is _ext.ISQLQuote:
return self
def __str__(self):
return str(self.addr)
def register_inet(oid=None, conn_or_curs=None):
"""Create the INET type and an Inet adapter.
:param oid: oid for the PostgreSQL :sql:`inet` type, or 2-items sequence
with oids of the type and the array. If not specified, use PostgreSQL
standard oids.
:param conn_or_curs: where to register the typecaster. If not specified,
register it globally.
"""
import warnings
warnings.warn(
"the inet adapter is deprecated, it's not very useful",
DeprecationWarning)
if not oid:
oid1 = 869
oid2 = 1041
elif isinstance(oid, (list, tuple)):
oid1, oid2 = oid
else:
oid1 = oid
oid2 = 1041
_ext.INET = _ext.new_type((oid1, ), "INET",
lambda data, cursor: data and Inet(data) or None)
_ext.INETARRAY = _ext.new_array_type((oid2, ), "INETARRAY", _ext.INET)
_ext.register_type(_ext.INET, conn_or_curs)
_ext.register_type(_ext.INETARRAY, conn_or_curs)
return _ext.INET
def wait_select(conn):
"""Wait until a connection or cursor has data available.
The function is an example of a wait callback to be registered with
`~psycopg2.extensions.set_wait_callback()`. This function uses
:py:func:`~select.select()` to wait for data to become available, and
therefore is able to handle/receive SIGINT/KeyboardInterrupt.
"""
import select
from psycopg2.extensions import POLL_OK, POLL_READ, POLL_WRITE
while True:
try:
state = conn.poll()
if state == POLL_OK:
break
elif state == POLL_READ:
select.select([conn.fileno()], [], [])
elif state == POLL_WRITE:
select.select([], [conn.fileno()], [])
else:
raise conn.OperationalError("bad state from poll: %s" % state)
except KeyboardInterrupt:
conn.cancel()
# the loop will be broken by a server error
continue
def _solve_conn_curs(conn_or_curs):
"""Return the connection and a DBAPI cursor from a connection or cursor."""
if conn_or_curs is None:
raise psycopg2.ProgrammingError("no connection or cursor provided")
if hasattr(conn_or_curs, 'execute'):
conn = conn_or_curs.connection
curs = conn.cursor(cursor_factory=_cursor)
else:
conn = conn_or_curs
curs = conn.cursor(cursor_factory=_cursor)
return conn, curs
class HstoreAdapter(object):
"""Adapt a Python dict to the hstore syntax."""
def __init__(self, wrapped):
self.wrapped = wrapped
def prepare(self, conn):
self.conn = conn
# use an old-style getquoted implementation if required
if conn.info.server_version < 90000:
self.getquoted = self._getquoted_8
def _getquoted_8(self):
"""Use the operators available in PG pre-9.0."""
if not self.wrapped:
return b"''::hstore"
adapt = _ext.adapt
rv = []
for k, v in self.wrapped.items():
k = adapt(k)
k.prepare(self.conn)
k = k.getquoted()
if v is not None:
v = adapt(v)
v.prepare(self.conn)
v = v.getquoted()
else:
v = b'NULL'
# XXX this b'ing is painfully inefficient!
rv.append(b"(" + k + b" => " + v + b")")
return b"(" + b'||'.join(rv) + b")"
def _getquoted_9(self):
"""Use the hstore(text[], text[]) function."""
if not self.wrapped:
return b"''::hstore"
k = _ext.adapt(list(self.wrapped.keys()))
k.prepare(self.conn)
v = _ext.adapt(list(self.wrapped.values()))
v.prepare(self.conn)
return b"hstore(" + k.getquoted() + b", " + v.getquoted() + b")"
getquoted = _getquoted_9
_re_hstore = _re.compile(r"""
# hstore key:
# a string of normal or escaped chars
"((?: [^"\\] | \\. )*)"
\s*=>\s* # hstore value
(?:
NULL # the value can be null - not catched
# or a quoted string like the key
| "((?: [^"\\] | \\. )*)"
)
(?:\s*,\s*|$) # pairs separated by comma or end of string.
""", _re.VERBOSE)
@classmethod
def parse(self, s, cur, _bsdec=_re.compile(r"\\(.)")):
"""Parse an hstore representation in a Python string.
The hstore is represented as something like::
"a"=>"1", "b"=>"2"
with backslash-escaped strings.
"""
if s is None:
return None
rv = {}
start = 0
for m in self._re_hstore.finditer(s):
if m is None or m.start() != start:
raise psycopg2.InterfaceError(
"error parsing hstore pair at char %d" % start)
k = _bsdec.sub(r'\1', m.group(1))
v = m.group(2)
if v is not None:
v = _bsdec.sub(r'\1', v)
rv[k] = v
start = m.end()
if start < len(s):
raise psycopg2.InterfaceError(
"error parsing hstore: unparsed data after char %d" % start)
return rv
@classmethod
def parse_unicode(self, s, cur):
"""Parse an hstore returning unicode keys and values."""
if s is None:
return None
s = s.decode(_ext.encodings[cur.connection.encoding])
return self.parse(s, cur)
@classmethod
def get_oids(self, conn_or_curs):
"""Return the lists of OID of the hstore and hstore[] types.
"""
conn, curs = _solve_conn_curs(conn_or_curs)
# Store the transaction status of the connection to revert it after use
conn_status = conn.status
# column typarray not available before PG 8.3
typarray = conn.info.server_version >= 80300 and "typarray" or "NULL"
rv0, rv1 = [], []
# get the oid for the hstore
curs.execute("""\
SELECT t.oid, %s
FROM pg_type t JOIN pg_namespace ns
ON typnamespace = ns.oid
WHERE typname = 'hstore';
""" % typarray)
for oids in curs:
rv0.append(oids[0])
rv1.append(oids[1])
# revert the status of the connection as before the command
if (conn_status != _ext.STATUS_IN_TRANSACTION
and not conn.autocommit):
conn.rollback()
return tuple(rv0), tuple(rv1)
def register_hstore(conn_or_curs, globally=False, unicode=False,
oid=None, array_oid=None):
r"""Register adapter and typecaster for `!dict`\-\ |hstore| conversions.
:param conn_or_curs: a connection or cursor: the typecaster will be
registered only on this object unless *globally* is set to `!True`
:param globally: register the adapter globally, not only on *conn_or_curs*
:param unicode: if `!True`, keys and values returned from the database
will be `!unicode` instead of `!str`. The option is not available on
Python 3
:param oid: the OID of the |hstore| type if known. If not, it will be
queried on *conn_or_curs*.
:param array_oid: the OID of the |hstore| array type if known. If not, it
will be queried on *conn_or_curs*.
The connection or cursor passed to the function will be used to query the
database and look for the OID of the |hstore| type (which may be different
across databases). If querying is not desirable (e.g. with
:ref:`asynchronous connections <async-support>`) you may specify it in the
*oid* parameter, which can be found using a query such as :sql:`SELECT
'hstore'::regtype::oid`. Analogously you can obtain a value for *array_oid*
using a query such as :sql:`SELECT 'hstore[]'::regtype::oid`.
Note that, when passing a dictionary from Python to the database, both
strings and unicode keys and values are supported. Dictionaries returned
from the database have keys/values according to the *unicode* parameter.
The |hstore| contrib module must be already installed in the database
(executing the ``hstore.sql`` script in your ``contrib`` directory).
Raise `~psycopg2.ProgrammingError` if the type is not found.
"""
if oid is None:
oid = HstoreAdapter.get_oids(conn_or_curs)
if oid is None or not oid[0]:
raise psycopg2.ProgrammingError(
"hstore type not found in the database. "
"please install it from your 'contrib/hstore.sql' file")
else:
array_oid = oid[1]
oid = oid[0]
if isinstance(oid, int):
oid = (oid,)
if array_oid is not None:
if isinstance(array_oid, int):
array_oid = (array_oid,)
else:
array_oid = tuple([x for x in array_oid if x])
# create and register the typecaster
if PY2 and unicode:
cast = HstoreAdapter.parse_unicode
else:
cast = HstoreAdapter.parse
HSTORE = _ext.new_type(oid, "HSTORE", cast)
_ext.register_type(HSTORE, not globally and conn_or_curs or None)
_ext.register_adapter(dict, HstoreAdapter)
if array_oid:
HSTOREARRAY = _ext.new_array_type(array_oid, "HSTOREARRAY", HSTORE)
_ext.register_type(HSTOREARRAY, not globally and conn_or_curs or None)
class CompositeCaster(object):
"""Helps conversion of a PostgreSQL composite type into a Python object.
The class is usually created by the `register_composite()` function.
You may want to create and register manually instances of the class if
querying the database at registration time is not desirable (such as when
using an :ref:`asynchronous connections <async-support>`).
"""
def __init__(self, name, oid, attrs, array_oid=None, schema=None):
self.name = name
self.schema = schema
self.oid = oid
self.array_oid = array_oid
self.attnames = [a[0] for a in attrs]
self.atttypes = [a[1] for a in attrs]
self._create_type(name, self.attnames)
self.typecaster = _ext.new_type((oid,), name, self.parse)
if array_oid:
self.array_typecaster = _ext.new_array_type(
(array_oid,), "%sARRAY" % name, self.typecaster)
else:
self.array_typecaster = None
def parse(self, s, curs):
if s is None:
return None
tokens = self.tokenize(s)
if len(tokens) != len(self.atttypes):
raise psycopg2.DataError(
"expecting %d components for the type %s, %d found instead" %
(len(self.atttypes), self.name, len(tokens)))
values = [curs.cast(oid, token)
for oid, token in zip(self.atttypes, tokens)]
return self.make(values)
def make(self, values):
"""Return a new Python object representing the data being casted.
*values* is the list of attributes, already casted into their Python
representation.
You can subclass this method to :ref:`customize the composite cast
<custom-composite>`.
"""
return self._ctor(values)
_re_tokenize = _re.compile(r"""
\(? ([,)]) # an empty token, representing NULL
| \(? " ((?: [^"] | "")*) " [,)] # or a quoted string
| \(? ([^",)]+) [,)] # or an unquoted string
""", _re.VERBOSE)
_re_undouble = _re.compile(r'(["\\])\1')
@classmethod
def tokenize(self, s):
rv = []
for m in self._re_tokenize.finditer(s):
if m is None:
raise psycopg2.InterfaceError("can't parse type: %r" % s)
if m.group(1) is not None:
rv.append(None)
elif m.group(2) is not None:
rv.append(self._re_undouble.sub(r"\1", m.group(2)))
else:
rv.append(m.group(3))
return rv
def _create_type(self, name, attnames):
self.type = namedtuple(name, attnames)
self._ctor = self.type._make
@classmethod
def _from_db(self, name, conn_or_curs):
"""Return a `CompositeCaster` instance for the type *name*.
Raise `ProgrammingError` if the type is not found.
"""
conn, curs = _solve_conn_curs(conn_or_curs)
# Store the transaction status of the connection to revert it after use
conn_status = conn.status
# Use the correct schema
if '.' in name:
schema, tname = name.split('.', 1)
else:
tname = name
schema = 'public'
# column typarray not available before PG 8.3
typarray = conn.info.server_version >= 80300 and "typarray" or "NULL"
# get the type oid and attributes
curs.execute("""\
SELECT t.oid, %s, attname, atttypid
FROM pg_type t
JOIN pg_namespace ns ON typnamespace = ns.oid
JOIN pg_attribute a ON attrelid = typrelid
WHERE typname = %%s AND nspname = %%s
AND attnum > 0 AND NOT attisdropped
ORDER BY attnum;
""" % typarray, (tname, schema))
recs = curs.fetchall()
# revert the status of the connection as before the command
if (conn_status != _ext.STATUS_IN_TRANSACTION
and not conn.autocommit):
conn.rollback()
if not recs:
raise psycopg2.ProgrammingError(
"PostgreSQL type '%s' not found" % name)
type_oid = recs[0][0]
array_oid = recs[0][1]
type_attrs = [(r[2], r[3]) for r in recs]
return self(tname, type_oid, type_attrs,
array_oid=array_oid, schema=schema)
def register_composite(name, conn_or_curs, globally=False, factory=None):
"""Register a typecaster to convert a composite type into a tuple.
:param name: the name of a PostgreSQL composite type, e.g. created using
the |CREATE TYPE|_ command
:param conn_or_curs: a connection or cursor used to find the type oid and
components; the typecaster is registered in a scope limited to this
object, unless *globally* is set to `!True`
:param globally: if `!False` (default) register the typecaster only on
*conn_or_curs*, otherwise register it globally
:param factory: if specified it should be a `CompositeCaster` subclass: use
it to :ref:`customize how to cast composite types <custom-composite>`
:return: the registered `CompositeCaster` or *factory* instance
responsible for the conversion
"""
if factory is None:
factory = CompositeCaster
caster = factory._from_db(name, conn_or_curs)
_ext.register_type(caster.typecaster, not globally and conn_or_curs or None)
if caster.array_typecaster is not None:
_ext.register_type(
caster.array_typecaster, not globally and conn_or_curs or None)
return caster
def _paginate(seq, page_size):
"""Consume an iterable and return it in chunks.
Every chunk is at most `page_size`. Never return an empty chunk.
"""
page = []
it = iter(seq)
while True:
try:
for i in range(page_size):
page.append(next(it))
yield page
page = []
except StopIteration:
if page:
yield page
return
def execute_batch(cur, sql, argslist, page_size=100):
r"""Execute groups of statements in fewer server roundtrips.
Execute *sql* several times, against all parameters set (sequences or
mappings) found in *argslist*.
The function is semantically similar to
.. parsed-literal::
*cur*\.\ `~cursor.executemany`\ (\ *sql*\ , *argslist*\ )
but has a different implementation: Psycopg will join the statements into
fewer multi-statement commands, each one containing at most *page_size*
statements, resulting in a reduced number of server roundtrips.
After the execution of the function the `cursor.rowcount` property will
**not** contain a total result.
"""
for page in _paginate(argslist, page_size=page_size):
sqls = [cur.mogrify(sql, args) for args in page]
cur.execute(b";".join(sqls))
def execute_values(cur, sql, argslist, template=None, page_size=100, fetch=False):
'''Execute a statement using :sql:`VALUES` with a sequence of parameters.
:param cur: the cursor to use to execute the query.
:param sql: the query to execute. It must contain a single ``%s``
placeholder, which will be replaced by a `VALUES list`__.
Example: ``"INSERT INTO mytable (id, f1, f2) VALUES %s"``.
:param argslist: sequence of sequences or dictionaries with the arguments
to send to the query. The type and content must be consistent with
*template*.
:param template: the snippet to merge to every item in *argslist* to
compose the query.
- If the *argslist* items are sequences it should contain positional
placeholders (e.g. ``"(%s, %s, %s)"``, or ``"(%s, %s, 42)``" if there
are constants value...).
- If the *argslist* items are mappings it should contain named
placeholders (e.g. ``"(%(id)s, %(f1)s, 42)"``).
If not specified, assume the arguments are sequence and use a simple
positional template (i.e. ``(%s, %s, ...)``), with the number of
placeholders sniffed by the first element in *argslist*.
:param page_size: maximum number of *argslist* items to include in every
statement. If there are more items the function will execute more than
one statement.
:param fetch: if `!True` return the query results into a list (like in a
`~cursor.fetchall()`). Useful for queries with :sql:`RETURNING`
clause.
.. __: https://www.postgresql.org/docs/current/static/queries-values.html
After the execution of the function the `cursor.rowcount` property will
**not** contain a total result.
While :sql:`INSERT` is an obvious candidate for this function it is
possible to use it with other statements, for example::
>>> cur.execute(
... "create table test (id int primary key, v1 int, v2 int)")
>>> execute_values(cur,
... "INSERT INTO test (id, v1, v2) VALUES %s",
... [(1, 2, 3), (4, 5, 6), (7, 8, 9)])
>>> execute_values(cur,
... """UPDATE test SET v1 = data.v1 FROM (VALUES %s) AS data (id, v1)
... WHERE test.id = data.id""",
... [(1, 20), (4, 50)])
>>> cur.execute("select * from test order by id")
>>> cur.fetchall()
[(1, 20, 3), (4, 50, 6), (7, 8, 9)])
'''
from psycopg2.sql import Composable
if isinstance(sql, Composable):
sql = sql.as_string(cur)
# we can't just use sql % vals because vals is bytes: if sql is bytes
# there will be some decoding error because of stupid codec used, and Py3
# doesn't implement % on bytes.
if not isinstance(sql, bytes):
sql = sql.encode(_ext.encodings[cur.connection.encoding])
pre, post = _split_sql(sql)
result = [] if fetch else None
for page in _paginate(argslist, page_size=page_size):
if template is None:
template = b'(' + b','.join([b'%s'] * len(page[0])) + b')'
parts = pre[:]
for args in page:
parts.append(cur.mogrify(template, args))
parts.append(b',')
parts[-1:] = post
cur.execute(b''.join(parts))
if fetch:
result.extend(cur.fetchall())
return result
def _split_sql(sql):
"""Split *sql* on a single ``%s`` placeholder.
Split on the %s, perform %% replacement and return pre, post lists of
snippets.
"""
curr = pre = []
post = []
tokens = _re.split(br'(%.)', sql)
for token in tokens:
if len(token) != 2 or token[:1] != b'%':
curr.append(token)
continue
if token[1:] == b's':
if curr is pre:
curr = post
else:
raise ValueError(
"the query contains more than one '%s' placeholder")
elif token[1:] == b'%':
curr.append(b'%')
else:
raise ValueError("unsupported format character: '%s'"
% token[1:].decode('ascii', 'replace'))
if curr is pre:
raise ValueError("the query doesn't contain any '%s' placeholder")
return pre, post
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