mirror of
https://github.com/psycopg/psycopg2.git
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424 lines
14 KiB
Python
424 lines
14 KiB
Python
"""Miscellaneous goodies for psycopg2
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This module is a generic place used to hold little helper functions
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and classes untill a better place in the distribution is found.
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"""
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# psycopg/extras.py - miscellaneous extra goodies for psycopg
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#
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# Copyright (C) 2003-2004 Federico Di Gregorio <fog@debian.org>
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by the
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# Free Software Foundation; either version 2, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY
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# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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# for more details.
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import os
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import time
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import re as regex
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try:
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import logging
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except:
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logging = None
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from psycopg2 import DATETIME, DataError
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from psycopg2 import extensions as _ext
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from psycopg2.extensions import cursor as _cursor
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from psycopg2.extensions import connection as _connection
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from psycopg2.extensions import adapt as _A
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class DictCursorBase(_cursor):
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"""Base class for all dict-like cursors."""
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def __init__(self, *args, **kwargs):
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if kwargs.has_key('row_factory'):
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row_factory = kwargs['row_factory']
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del kwargs['row_factory']
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else:
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raise NotImplementedError(
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"DictCursorBase can't be instantiated without a row factory.")
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_cursor.__init__(self, *args, **kwargs)
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self._query_executed = 0
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self.row_factory = row_factory
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def fetchone(self):
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res = _cursor.fetchone(self)
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if self._query_executed:
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self._build_index()
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return res
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def fetchmany(self, size=None):
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res = _cursor.fetchmany(self, size)
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if self._query_executed:
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self._build_index()
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return res
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def fetchall(self):
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res = _cursor.fetchall(self)
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if self._query_executed:
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self._build_index()
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return res
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def next(self):
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res = _cursor.fetchone(self)
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if res is None:
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raise StopIteration()
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if self._query_executed:
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self._build_index()
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return res
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class DictConnection(_connection):
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"""A connection that uses DictCursor automatically."""
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def cursor(self, name=None):
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if name is None:
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return _connection.cursor(self, cursor_factory=DictCursor)
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else:
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return _connection.cursor(self, name, cursor_factory=DictCursor)
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class DictCursor(DictCursorBase):
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"""A cursor that keeps a list of column name -> index mappings."""
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def __init__(self, *args, **kwargs):
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kwargs['row_factory'] = DictRow
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DictCursorBase.__init__(self, *args, **kwargs)
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def execute(self, query, vars=None, async=0):
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self.index = {}
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self._query_executed = 1
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return _cursor.execute(self, query, vars, async)
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def callproc(self, procname, vars=None):
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self.index = {}
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self._query_executed = 1
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return _cursor.callproc(self, procname, vars)
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def _build_index(self):
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if self._query_executed == 1 and self.description:
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for i in range(len(self.description)):
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self.index[self.description[i][0]] = i
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self._query_executed = 0
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class DictRow(list):
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"""A row object that allow by-colun-name access to data."""
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def __init__(self, cursor):
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self._index = cursor.index
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self[:] = [None] * len(cursor.description)
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def __getitem__(self, x):
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if type(x) != int:
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x = self._index[x]
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return list.__getitem__(self, x)
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def items(self):
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res = []
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for n, v in self._index.items():
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res.append((n, list.__getitem__(self, v)))
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return res
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def keys(self):
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return self._index.keys()
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def values(self):
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return tuple(self[:])
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def has_key(self, x):
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return self._index.has_key(x)
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def get(self, x, default=None):
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try:
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return self[x]
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except:
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return default
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def iteritems(self):
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for n, v in self._index.items():
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yield n, list.__getitem__(self, v)
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def iterkeys(self):
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return self._index.iterkeys()
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def itervalues(self):
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return list.__iter__(self)
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def copy(self):
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return dict(self.items())
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def __contains__(self, x):
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return self._index.__contains__(x)
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class RealDictConnection(_connection):
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"""A connection that uses RealDictCursor automatically."""
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def cursor(self, name=None):
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if name is None:
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return _connection.cursor(self, cursor_factory=RealDictCursor)
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else:
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return _connection.cursor(self, name, cursor_factory=RealDictCursor)
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class RealDictCursor(DictCursorBase):
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"""A cursor that uses a real dict as the base type for rows.
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Note that this cursor is extremely specialized and does not allow
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the normal access (using integer indices) to fetched data. If you need
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to access database rows both as a dictionary and a list, then use
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the generic DictCursor instead of RealDictCursor.
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"""
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def __init__(self, *args, **kwargs):
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kwargs['row_factory'] = RealDictRow
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DictCursorBase.__init__(self, *args, **kwargs)
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def execute(self, query, vars=None, async=0):
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self.column_mapping = []
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self._query_executed = 1
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return _cursor.execute(self, query, vars, async)
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def callproc(self, procname, vars=None):
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self.column_mapping = []
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self._query_executed = 1
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return _cursor.callproc(self, procname, vars)
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def _build_index(self):
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if self._query_executed == 1 and self.description:
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for item in self.description:
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self.column_mapping.append(item[0])
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self._query_executed = 0
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class RealDictRow(dict):
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def __init__(self, cursor):
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dict.__init__(self)
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self._column_mapping = cursor.column_mapping
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def __setitem__(self, name, value):
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if type(name) == type(0):
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name = self._column_mapping[name]
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return dict.__setitem__(self, name, value)
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class LoggingConnection(_connection):
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"""A connection that logs all queries to a file or logger object."""
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def initialize(self, logobj):
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"""Initialize the connection to log to `logobj`.
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The `logobj` parameter can be an open file object or a Logger instance
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from the standard logging module.
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"""
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self._logobj = logobj
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if logging and isinstance(logobj, logging.Logger):
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self.log = self._logtologger
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else:
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self.log = self._logtofile
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def filter(self, msg, curs):
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"""Filter the query before logging it.
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This is the method to overwrite to filter unwanted queries out of the
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log or to add some extra data to the output. The default implementation
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just does nothing.
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"""
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return msg
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def _logtofile(self, msg, curs):
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msg = self.filter(msg, curs)
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if msg: self._logobj.write(msg + os.linesep)
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def _logtologger(self, msg, curs):
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msg = self.filter(msg, curs)
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if msg: self._logobj.debug(msg)
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def _check(self):
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if not hasattr(self, '_logobj'):
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raise self.ProgrammingError(
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"LoggingConnection object has not been initialize()d")
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def cursor(self, name=None):
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self._check()
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if name is None:
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return _connection.cursor(self, cursor_factory=LoggingCursor)
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else:
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return _connection.cursor(self, name, cursor_factory=LoggingCursor)
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class LoggingCursor(_cursor):
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"""A cursor that logs queries using its connection logging facilities."""
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def execute(self, query, vars=None, async=0):
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try:
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return _cursor.execute(self, query, vars, async)
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finally:
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self.connection.log(self.query, self)
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def callproc(self, procname, vars=None):
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try:
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return _cursor.callproc(self, procname, vars)
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finally:
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self.connection.log(self.query, self)
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class MinTimeLoggingConnection(LoggingConnection):
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"""A connection that logs queries based on execution time.
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This is just an example of how to sub-class LoggingConnection to provide
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some extra filtering for the logged queries. Both the `.inizialize()` and
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`.filter()` methods are overwritten to make sure that only queries
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executing for more than `mintime` ms are logged.
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Note that this connection uses the specialized cursor MinTimeLoggingCursor.
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"""
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def initialize(self, logobj, mintime=0):
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LoggingConnection.initialize(self, logobj)
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self._mintime = mintime
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def filter(self, msg, curs):
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t = (time.time() - curs.timestamp) * 1000
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if t > self._mintime:
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return msg + os.linesep + " (execution time: %d ms)" % t
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def cursor(self, name=None):
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self._check()
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if name is None:
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return _connection.cursor(self, cursor_factory=MinTimeLoggingCursor)
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else:
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return _connection.cursor(self, name, cursor_factory=MinTimeLoggingCursor)
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class MinTimeLoggingCursor(LoggingCursor):
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"""The cursor sub-class companion to MinTimeLoggingConnection."""
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def execute(self, query, vars=None, async=0):
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self.timestamp = time.time()
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return LoggingCursor.execute(self, query, vars, async)
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def callproc(self, procname, vars=None):
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self.timestamp = time.time()
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return LoggingCursor.execute(self, procname, vars)
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# a dbtype and adapter for Python UUID type
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try:
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import uuid
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class UUID_adapter(object):
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"""Adapt Python's uuid.UUID type to PostgreSQL's uuid."""
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def __init__(self, uuid):
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self._uuid = uuid
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def prepare(self, conn):
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pass
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def getquoted(self):
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return "'"+str(self._uuid)+"'::uuid"
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__str__ = getquoted
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def register_uuid(oid=None, conn_or_curs=None):
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"""Create the UUID type and an uuid.UUID adapter."""
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if not oid: oid = 2950
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_ext.UUID = _ext.new_type((oid, ), "UUID",
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lambda data, cursor: data and uuid.UUID(data) or None)
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_ext.register_type(_ext.UUID, conn_or_curs)
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_ext.register_adapter(uuid.UUID, UUID_adapter)
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return _ext.UUID
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except ImportError, e:
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def register_uuid(oid=None):
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"""Create the UUID type and an uuid.UUID adapter.
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This is a fake function that will always raise an error because the
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import of the uuid module failed.
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"""
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raise e
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# a type, dbtype and adapter for PostgreSQL inet type
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class Inet(object):
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"""Wrap a string to allow for correct SQL-quoting of inet values.
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Note that this adapter does NOT check the passed value to make
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sure it really is an inet-compatible address but DOES call adapt()
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on it to make sure it is impossible to execute an SQL-injection
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by passing an evil value to the initializer.
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"""
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def __init__(self, addr):
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self.addr
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def prepare(self, conn):
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self._conn = conn
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def getquoted(self):
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obj = adapt(self.addr)
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if hasattr(obj, 'prepare'):
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obj.prepare(self._conn)
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return obj.getquoted()+"::inet"
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def __str__(self):
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return str(self.addr)
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def register_inet(oid=None, conn_or_curs=None):
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"""Create the INET type and an Inet adapter."""
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if not oid: oid = 869
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_ext.INET = _ext.new_type((oid, ), "INET",
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lambda data, cursor: data and Inet(data) or None)
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_ext.register_type(_ext.INET, conn_or_curs)
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return _ext.INET
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# safe management of times with a non-standard time zone
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def _convert_tstz_w_secs(s, cursor):
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try:
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return DATETIME(s, cursor)
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except (DataError,), exc:
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if exc.message != "unable to parse time":
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raise
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if regex.match('(\+|-)\d\d:\d\d:\d\d', s[-9:]) is None:
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raise
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# parsing doesn't succeed even if seconds are ":00" so truncate in
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# any case
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return DATETIME(s[:-3], cursor)
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def register_tstz_w_secs(oids=None, conn_or_curs=None):
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"""Register alternate type caster for TIMESTAMP WITH TIME ZONE.
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The Python datetime module cannot handle time zones with
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seconds in the UTC offset. There are, however, historical
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"time zones" which contain such offsets, eg. "Asia/Calcutta".
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In many cases those offsets represent true local time.
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If you encounter "unable to parse time" on a perfectly valid
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timestamp you likely want to try this type caster. It truncates
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the seconds from the time zone data and retries casting
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the timestamp. Note that this will generate timestamps
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which are INACCURATE by the number of seconds truncated
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(unless the seconds were 00).
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<oids>
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which OIDs to use this type caster for,
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defaults to TIMESTAMP WITH TIME ZONE
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<conn_or_curs>
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a cursor or connection if you want to attach
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this type caster to that only, defaults to
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None meaning all connections and cursors
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"""
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if oids is None:
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oids = (1184,) # hardcoded from PostgreSQL headers
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_ext.TSTZ_W_SECS = _ext.new_type(oids, 'TSTZ_W_SECS', _convert_tstz_w_secs)
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_ext.register_type(TSTZ_W_SECS, conn_or_curs)
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return _ext.TSTZ_W_SECS
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__all__ = [ k for k in locals().keys() if not k.startswith('_') ]
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