Edit File: 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> # Copyright (C) 2020-2021 The Psycopg Team # # 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 functools import 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().__init__(*args, **kwargs) self._query_executed = False self._prefetch = False self.row_factory = row_factory def fetchone(self): if self._prefetch: res = super().fetchone() if self._query_executed: self._build_index() if not self._prefetch: res = super().fetchone() return res def fetchmany(self, size=None): if self._prefetch: res = super().fetchmany(size) if self._query_executed: self._build_index() if not self._prefetch: res = super().fetchmany(size) return res def fetchall(self): if self._prefetch: res = super().fetchall() if self._query_executed: self._build_index() if not self._prefetch: res = super().fetchall() return res def __iter__(self): try: if self._prefetch: res = super().__iter__() first = next(res) if self._query_executed: self._build_index() if not self._prefetch: res = super().__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', self.cursor_factory or DictCursor) return super().cursor(*args, **kwargs) class DictCursor(DictCursorBase): """A cursor that keeps a list of column name -> index mappings__. .. __: https://docs.python.org/glossary.html#term-mapping """ def __init__(self, *args, **kwargs): kwargs['row_factory'] = DictRow super().__init__(*args, **kwargs) self._prefetch = True def execute(self, query, vars=None): self.index = OrderedDict() self._query_executed = True return super().execute(query, vars) def callproc(self, procname, vars=None): self.index = OrderedDict() self._query_executed = True return super().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().__getitem__(x) def __setitem__(self, x, v): if not isinstance(x, (int, slice)): x = self._index[x] super().__setitem__(x, v) def items(self): g = super().__getitem__ return ((n, g(self._index[n])) for n in self._index) def keys(self): return iter(self._index) def values(self): g = super().__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 __reduce__(self): # this is apparently useless, but it fixes #1073 return super().__reduce__() def __getstate__(self): return self[:], self._index.copy() def __setstate__(self, data): self[:] = data[0] self._index = data[1] class RealDictConnection(_connection): """A connection that uses `RealDictCursor` automatically.""" def cursor(self, *args, **kwargs): kwargs.setdefault('cursor_factory', self.cursor_factory or RealDictCursor) return super().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().__init__(*args, **kwargs) def execute(self, query, vars=None): self.column_mapping = [] self._query_executed = True return super().execute(query, vars) def callproc(self, procname, vars=None): self.column_mapping = [] self._query_executed = True return super().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().__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().__setitem__(mapping[key], value) if key == len(mapping) - 1: # Row building finished del self[RealDictRow] return super().__setitem__(key, value) class NamedTupleConnection(_connection): """A connection that uses `NamedTupleCursor` automatically.""" def cursor(self, *args, **kwargs): kwargs.setdefault('cursor_factory', self.cursor_factory or NamedTupleCursor) return super().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().execute(query, vars) def executemany(self, query, vars): self.Record = None return super().executemany(query, vars) def callproc(self, procname, vars=None): self.Record = None return super().callproc(procname, vars) def fetchone(self): t = super().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().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().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().__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 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 = _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/LoggerAdapter instance from the standard logging module. """ self._logobj = logobj if _logging and isinstance( logobj, (_logging.Logger, _logging.LoggerAdapter)): 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 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', self.cursor_factory or LoggingCursor) return super().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().execute(query, vars) finally: self.connection.log(self.query, self) def callproc(self, procname, vars=None): try: return super().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 isinstance(msg, bytes): msg = msg.decode(_ext.encodings[self.encoding], 'replace') return f"{msg}{_os.linesep} (execution time: {t} ms)" def cursor(self, *args, **kwargs): kwargs.setdefault('cursor_factory', self.cursor_factory or 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().__init__(*args, **kwargs) class PhysicalReplicationConnection(_replicationConnection): def __init__(self, *args, **kwargs): kwargs['replication_type'] = REPLICATION_PHYSICAL super().__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 = f"CREATE_REPLICATION_SLOT {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 += f"LOGICAL {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( f"unrecognized replication type: {repr(slot_type)}") self.execute(command) def drop_replication_slot(self, slot_name): """Drop streaming replication slot.""" command = f"DROP_REPLICATION_SLOT {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 += f"SLOT {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 += f"SLOT {quote_ident(slot_name, self)} " # don't add "PHYSICAL", before 9.4 it was just START_REPLICATION XXX/XXX else: raise psycopg2.ProgrammingError( f"unrecognized replication type: {repr(slot_type)}") if type(start_lsn) is str: lsn = start_lsn.split('/') lsn = f"{int(lsn[0], 16):X}/{int(lsn[1], 16):08X}" else: lsn = f"{start_lsn >> 32 & 4294967295:X}/{start_lsn & 4294967295:08X}" command += lsn if timeline != 0: if slot_type == REPLICATION_LOGICAL: raise psycopg2.ProgrammingError( "cannot specify timeline for logical replication") command += f" TIMELINE {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 += f"{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: """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 (f"'{self._uuid}'::uuid").encode('utf8') def __str__(self): return f"'{self._uuid}'::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: """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 f"{self.__class__.__name__}({self.addr!r})" 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(f"bad state from poll: {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: """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( f"error parsing hstore pair at char {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( f"error parsing hstore: unparsed data after char {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(f"""SELECT t.oid, {typarray} FROM pg_type t JOIN pg_namespace ns ON typnamespace = ns.oid WHERE typname = 'hstore'; """) 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 HSTORE = _ext.new_type(oid, "HSTORE", HstoreAdapter.parse) _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: """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,), f"{name}ARRAY", 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(f"can't parse type: {s!r}") 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): name = _re_clean.sub('_', name) 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() if not recs: # The above algorithm doesn't work for customized seach_path # (#1487) The implementation below works better, but, to guarantee # backwards compatibility, use it only if the original one failed. try: savepoint = False # Because we executed statements earlier, we are either INTRANS # or we are IDLE only if the transaction is autocommit, in # which case we don't need the savepoint anyway. if conn.status == _ext.STATUS_IN_TRANSACTION: curs.execute("SAVEPOINT register_type") savepoint = True curs.execute("""\ SELECT t.oid, %s, attname, atttypid, typname, nspname FROM pg_type t JOIN pg_namespace ns ON typnamespace = ns.oid JOIN pg_attribute a ON attrelid = typrelid WHERE t.oid = %%s::regtype AND attnum > 0 AND NOT attisdropped ORDER BY attnum; """ % typarray, (name, )) except psycopg2.ProgrammingError: pass else: recs = curs.fetchall() if recs: tname = recs[0][4] schema = recs[0][5] finally: if savepoint: curs.execute("ROLLBACK TO SAVEPOINT register_type") # 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( f"PostgreSQL type '{name}' not found") 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 # ascii except alnum and underscore _re_clean = _re.compile( '[' + _re.escape(' !"#$%&\'()*+,-./:;<=>?@[\\]^`{|}~') + ']')