"""Miscellaneous goodies for psycopg2 This module is a generic place used to hold little helper functions and classes untill a better place in the distribution is found. """ # psycopg/extras.py - miscellaneous extra goodies for psycopg # # Copyright (C) 2003-2010 Federico Di Gregorio # # 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 import sys import time import warnings import re as regex try: import logging except: logging = None import psycopg2 from psycopg2 import extensions as _ext from psycopg2.extensions import cursor as _cursor from psycopg2.extensions import connection as _connection from psycopg2.extensions import adapt as _A from psycopg2.extensions import b 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.") _cursor.__init__(self, *args, **kwargs) self._query_executed = 0 self._prefetch = 0 self.row_factory = row_factory def fetchone(self): if self._prefetch: res = _cursor.fetchone(self) if self._query_executed: self._build_index() if not self._prefetch: res = _cursor.fetchone(self) return res def fetchmany(self, size=None): if self._prefetch: res = _cursor.fetchmany(self, size) if self._query_executed: self._build_index() if not self._prefetch: res = _cursor.fetchmany(self, size) return res def fetchall(self): if self._prefetch: res = _cursor.fetchall(self) if self._query_executed: self._build_index() if not self._prefetch: res = _cursor.fetchall(self) return res def __iter__(self): if self._prefetch: res = _cursor.__iter__(self) first = res.next() if self._query_executed: self._build_index() if not self._prefetch: res = _cursor.__iter__(self) first = res.next() yield first while 1: yield res.next() class DictConnection(_connection): """A connection that uses `DictCursor` automatically.""" def cursor(self, *args, **kwargs): kwargs.setdefault('cursor_factory', DictCursor) return _connection.cursor(self, *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 DictCursorBase.__init__(self, *args, **kwargs) self._prefetch = 1 def execute(self, query, vars=None): self.index = {} self._query_executed = 1 return DictCursorBase.execute(self, query, vars) def callproc(self, procname, vars=None): self.index = {} self._query_executed = 1 return DictCursorBase.callproc(self, procname, vars) def _build_index(self): if self._query_executed == 1 and self.description: for i in range(len(self.description)): self.index[self.description[i][0]] = i self._query_executed = 0 class DictRow(list): """A row object that allow by-colmun-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 list.__getitem__(self, x) def __setitem__(self, x, v): if not isinstance(x, (int, slice)): x = self._index[x] list.__setitem__(self, x, v) def items(self): return list(self.iteritems()) def keys(self): return self._index.keys() def values(self): return tuple(self[:]) def has_key(self, x): return x in self._index def get(self, x, default=None): try: return self[x] except: return default def iteritems(self): for n, v in self._index.iteritems(): yield n, list.__getitem__(self, v) def iterkeys(self): return self._index.iterkeys() def itervalues(self): return list.__iter__(self) def copy(self): return dict(self.iteritems()) def __contains__(self, x): return x in self._index # grop the crusty Py2 methods if sys.version_info[0] > 2: items = iteritems; del iteritems keys = iterkeys; del iterkeys values = itervalues; del itervalues del has_key class RealDictConnection(_connection): """A connection that uses `RealDictCursor` automatically.""" def cursor(self, *args, **kwargs): kwargs.setdefault('cursor_factory', RealDictCursor) return _connection.cursor(self, *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 DictCursorBase.__init__(self, *args, **kwargs) self._prefetch = 0 def execute(self, query, vars=None): self.column_mapping = [] self._query_executed = 1 return DictCursorBase.execute(self, query, vars) def callproc(self, procname, vars=None): self.column_mapping = [] self._query_executed = 1 return DictCursorBase.callproc(self, procname, vars) def _build_index(self): if self._query_executed == 1 and self.description: for i in range(len(self.description)): self.column_mapping.append(self.description[i][0]) self._query_executed = 0 class RealDictRow(dict): """A `!dict` subclass representing a data record.""" __slots__ = ('_column_mapping') def __init__(self, cursor): dict.__init__(self) # Required for named cursors if cursor.description and not cursor.column_mapping: cursor._build_index() self._column_mapping = cursor.column_mapping def __setitem__(self, name, value): if type(name) == int: name = self._column_mapping[name] return dict.__setitem__(self, name, value) class NamedTupleConnection(_connection): """A connection that uses `NamedTupleCursor` automatically.""" def cursor(self, *args, **kwargs): kwargs.setdefault('cursor_factory', NamedTupleCursor) return _connection.cursor(self, *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 def execute(self, query, vars=None): self.Record = None return _cursor.execute(self, query, vars) def executemany(self, query, vars): self.Record = None return _cursor.executemany(self, query, vars) def callproc(self, procname, vars=None): self.Record = None return _cursor.callproc(self, procname, vars) def fetchone(self): t = _cursor.fetchone(self) if t is not None: nt = self.Record if nt is None: nt = self.Record = self._make_nt() return nt(*t) def fetchmany(self, size=None): ts = _cursor.fetchmany(self, size) nt = self.Record if nt is None: nt = self.Record = self._make_nt() return [nt(*t) for t in ts] def fetchall(self): ts = _cursor.fetchall(self) nt = self.Record if nt is None: nt = self.Record = self._make_nt() return [nt(*t) for t in ts] def __iter__(self): it = _cursor.__iter__(self) t = it.next() nt = self.Record if nt is None: nt = self.Record = self._make_nt() yield nt(*t) while 1: yield nt(*it.next()) try: from collections import namedtuple except ImportError, _exc: def _make_nt(self): raise self._exc else: def _make_nt(self, namedtuple=namedtuple): return namedtuple("Record", [d[0] for d in self.description or ()]) class LoggingConnection(_connection): """A connection that logs all queries to a file or logger__ object. .. __: http://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: 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 _connection.cursor(self, *args, **kwargs) class LoggingCursor(_cursor): """A cursor that logs queries using its connection logging facilities.""" def execute(self, query, vars=None): try: return _cursor.execute(self, query, vars) finally: self.connection.log(self.query, self) def callproc(self, procname, vars=None): try: return _cursor.callproc(self, 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 `inizialize()` 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: 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.execute(self, procname, vars) # a dbtype and adapter for Python UUID type class UUID_adapter(object): """Adapt Python's uuid.UUID__ type to PostgreSQL's uuid__. .. __: http://docs.python.org/library/uuid.html .. __: http://www.postgresql.org/docs/current/static/datatype-uuid.html """ def __init__(self, uuid): self._uuid = uuid def prepare(self, conn): pass def getquoted(self): return "'"+str(self._uuid)+"'::uuid" __str__ = getquoted 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, foo): if foo 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. """ 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 register_tstz_w_secs(oids=None, conn_or_curs=None): """The function used to register an alternate type caster for :sql:`TIMESTAMP WITH TIME ZONE` to deal with historical time zones with seconds in the UTC offset. These are now correctly handled by the default type caster, so currently the function doesn't do anything. """ warnings.warn("deprecated", DeprecationWarning) import select from psycopg2.extensions import POLL_OK, POLL_READ, POLL_WRITE from psycopg2 import OperationalError 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 `!select()` to wait for data available. """ while 1: 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 OperationalError("bad state from poll: %s" % state) 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.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.iteritems(): 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(self.wrapped.keys()) k.prepare(self.conn) v = _ext.adapt(self.wrapped.values()) v.prepare(self.conn) return b("hstore(") + k.getquoted() + b(", ") + v.getquoted() + b(")") getquoted = _getquoted_9 _re_hstore = regex.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. """, regex.VERBOSE) @classmethod def parse(self, s, cur, _bsdec=regex.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. """ if hasattr(conn_or_curs, 'execute'): conn = conn_or_curs.connection curs = conn_or_curs else: conn = conn_or_curs curs = conn_or_curs.cursor() # 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.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): """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 `) 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. .. versionchanged:: 2.4 added the *oid* parameter. If not specified, the typecaster is installed also if |hstore| is not installed in the :sql:`public` schema. .. versionchanged:: 2.4.3 added support for |hstore| array. """ 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 sys.version_info[0] < 3 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 `). .. attribute:: name The name of the PostgreSQL type. .. attribute:: oid The oid of the PostgreSQL type. .. attribute:: array_oid The oid of the PostgreSQL array type, if available. .. attribute:: type The type of the Python objects returned. If :py:func:`collections.namedtuple()` is available, it is a named tuple with attributes equal to the type components. Otherwise it is just the `!tuple` object. .. attribute:: attnames List of component names of the type to be casted. .. attribute:: atttypes List of component type oids of the type to be casted. """ def __init__(self, name, oid, attrs, array_oid=None): self.name = name 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))) attrs = [ curs.cast(oid, token) for oid, token in zip(self.atttypes, tokens) ] return self._ctor(*attrs) _re_tokenize = regex.compile(r""" \(? ([,)]) # an empty token, representing NULL | \(? " ((?: [^"] | "")*) " [,)] # or a quoted string | \(? ([^",)]+) [,)] # or an unquoted string """, regex.VERBOSE) _re_undouble = regex.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): rv.append(None) elif m.group(2): 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): try: from collections import namedtuple except ImportError: self.type = tuple self._ctor = lambda *args: tuple(args) else: self.type = namedtuple(name, attnames) self._ctor = self.type @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. """ if hasattr(conn_or_curs, 'execute'): conn = conn_or_curs.connection curs = conn_or_curs else: conn = conn_or_curs curs = conn_or_curs.cursor() # 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.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 CompositeCaster(tname, type_oid, type_attrs, array_oid=array_oid) def register_composite(name, conn_or_curs, globally=False): """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 :return: the registered `CompositeCaster` instance responsible for the conversion .. versionchanged:: 2.4.3 added support for array of composite types """ caster = CompositeCaster._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 __all__ = filter(lambda k: not k.startswith('_'), locals().keys())