"""Implementation of the Range type and adaptation
"""
# psycopg/_range.py - Implementation of the Range type and adaptation
#
# Copyright (C) 2012-2019 Daniele Varrazzo <daniele.varrazzo@gmail.com>
# 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 re
from psycopg2._psycopg import ProgrammingError, InterfaceError
from psycopg2.extensions import ISQLQuote, adapt, register_adapter
from psycopg2.extensions import new_type, new_array_type, register_type
class Range:
"""Python representation for a PostgreSQL |range|_ type.
:param lower: lower bound for the range. `!None` means unbound
:param upper: upper bound for the range. `!None` means unbound
:param bounds: one of the literal strings ``()``, ``[)``, ``(]``, ``[]``,
representing whether the lower or upper bounds are included
:param empty: if `!True`, the range is empty
"""
__slots__ = ('_lower', '_upper', '_bounds')
def __init__(self, lower=None, upper=None, bounds='[)', empty=False):
if not empty:
if bounds not in ('[)', '(]', '()', '[]'):
raise ValueError(f"bound flags not valid: {bounds!r}")
self._lower = lower
self._upper = upper
self._bounds = bounds
else:
self._lower = self._upper = self._bounds = None
def __repr__(self):
if self._bounds is None:
return f"{self.__class__.__name__}(empty=True)"
else:
return "{}({!r}, {!r}, {!r})".format(self.__class__.__name__,
self._lower, self._upper, self._bounds)
def __str__(self):
if self._bounds is None:
return 'empty'
items = [
self._bounds[0],
str(self._lower),
', ',
str(self._upper),
self._bounds[1]
]
return ''.join(items)
@property
def lower(self):
"""The lower bound of the range. `!None` if empty or unbound."""
return self._lower
@property
def upper(self):
"""The upper bound of the range. `!None` if empty or unbound."""
return self._upper
@property
def isempty(self):
"""`!True` if the range is empty."""
return self._bounds is None
@property
def lower_inf(self):
"""`!True` if the range doesn't have a lower bound."""
if self._bounds is None:
return False
return self._lower is None
@property
def upper_inf(self):
"""`!True` if the range doesn't have an upper bound."""
if self._bounds is None:
return False
return self._upper is None
@property
def lower_inc(self):
"""`!True` if the lower bound is included in the range."""
if self._bounds is None or self._lower is None:
return False
return self._bounds[0] == '['
@property
def upper_inc(self):
"""`!True` if the upper bound is included in the range."""
if self._bounds is None or self._upper is None:
return False
return self._bounds[1] == ']'
def __contains__(self, x):
if self._bounds is None:
return False
if self._lower is not None:
if self._bounds[0] == '[':
if x < self._lower:
return False
else:
if x <= self._lower:
return False
if self._upper is not None:
if self._bounds[1] == ']':
if x > self._upper:
return False
else:
if x >= self._upper:
return False
return True
def __bool__(self):
return self._bounds is not None
def __eq__(self, other):
if not isinstance(other, Range):
return False
return (self._lower == other._lower
and self._upper == other._upper
and self._bounds == other._bounds)
def __ne__(self, other):
return not self.__eq__(other)
def __hash__(self):
return hash((self._lower, self._upper, self._bounds))
# as the postgres docs describe for the server-side stuff,
# ordering is rather arbitrary, but will remain stable
# and consistent.
def __lt__(self, other):
if not isinstance(other, Range):
return NotImplemented
for attr in ('_lower', '_upper', '_bounds'):
self_value = getattr(self, attr)
other_value = getattr(other, attr)
if self_value == other_value:
pass
elif self_value is None:
return True
elif other_value is None:
return False
else:
return self_value < other_value
return False
def __le__(self, other):
if self == other:
return True
else:
return self.__lt__(other)
def __gt__(self, other):
if isinstance(other, Range):
return other.__lt__(self)
else:
return NotImplemented
def __ge__(self, other):
if self == other:
return True
else:
return self.__gt__(other)
def __getstate__(self):
return {slot: getattr(self, slot)
for slot in self.__slots__ if hasattr(self, slot)}
def __setstate__(self, state):
for slot, value in state.items():
setattr(self, slot, value)
def register_range(pgrange, pyrange, conn_or_curs, globally=False):
"""Create and register an adapter and the typecasters to convert between
a PostgreSQL |range|_ type and a PostgreSQL `Range` subclass.
:param pgrange: the name of the PostgreSQL |range| type. Can be
schema-qualified
:param pyrange: a `Range` strict subclass, or just a name to give to a new
class
:param conn_or_curs: a connection or cursor used to find the oid of the
range and its subtype; 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: `RangeCaster` instance responsible for the conversion
If a string is passed to *pyrange*, a new `Range` subclass is created
with such name and will be available as the `~RangeCaster.range` attribute
of the returned `RangeCaster` object.
The function queries the database on *conn_or_curs* to inspect the
*pgrange* type and raises `~psycopg2.ProgrammingError` if the type is not
found. If querying the database is not advisable, use directly the
`RangeCaster` class and register the adapter and typecasters using the
provided functions.
"""
caster = RangeCaster._from_db(pgrange, pyrange, conn_or_curs)
caster._register(not globally and conn_or_curs or None)
return caster
class RangeAdapter:
"""`ISQLQuote` adapter for `Range` subclasses.
This is an abstract class: concrete classes must set a `name` class
attribute or override `getquoted()`.
"""
name = None
def __init__(self, adapted):
self.adapted = adapted
def __conform__(self, proto):
if self._proto is ISQLQuote:
return self
def prepare(self, conn):
self._conn = conn
def getquoted(self):
if self.name is None:
raise NotImplementedError(
'RangeAdapter must be subclassed overriding its name '
'or the getquoted() method')
r = self.adapted
if r.isempty:
return b"'empty'::" + self.name.encode('utf8')
if r.lower is not None:
a = adapt(r.lower)
if hasattr(a, 'prepare'):
a.prepare(self._conn)
lower = a.getquoted()
else:
lower = b'NULL'
if r.upper is not None:
a = adapt(r.upper)
if hasattr(a, 'prepare'):
a.prepare(self._conn)
upper = a.getquoted()
else:
upper = b'NULL'
return self.name.encode('utf8') + b'(' + lower + b', ' + upper \
+ b", '" + r._bounds.encode('utf8') + b"')"
class RangeCaster:
"""Helper class to convert between `Range` and PostgreSQL range types.
Objects of this class are usually created by `register_range()`. Manual
creation could be useful if querying the database is not advisable: in
this case the oids must be provided.
"""
def __init__(self, pgrange, pyrange, oid, subtype_oid, array_oid=None):
self.subtype_oid = subtype_oid
self._create_ranges(pgrange, pyrange)
name = self.adapter.name or self.adapter.__class__.__name__
self.typecaster = new_type((oid,), name, self.parse)
if array_oid is not None:
self.array_typecaster = new_array_type(
(array_oid,), name + "ARRAY", self.typecaster)
else:
self.array_typecaster = None
def _create_ranges(self, pgrange, pyrange):
"""Create Range and RangeAdapter classes if needed."""
# if got a string create a new RangeAdapter concrete type (with a name)
# else take it as an adapter. Passing an adapter should be considered
# an implementation detail and is not documented. It is currently used
# for the numeric ranges.
self.adapter = None
if isinstance(pgrange, str):
self.adapter = type(pgrange, (RangeAdapter,), {})
self.adapter.name = pgrange
else:
try:
if issubclass(pgrange, RangeAdapter) \
and pgrange is not RangeAdapter:
self.adapter = pgrange
except TypeError:
pass
if self.adapter is None:
raise TypeError(
'pgrange must be a string or a RangeAdapter strict subclass')
self.range = None
try:
if isinstance(pyrange, str):
self.range = type(pyrange, (Range,), {})
if issubclass(pyrange, Range) and pyrange is not Range:
self.range = pyrange
except TypeError:
pass
if self.range is None:
raise TypeError(
'pyrange must be a type or a Range strict subclass')
@classmethod
def _from_db(self, name, pyrange, conn_or_curs):
"""Return a `RangeCaster` instance for the type *pgrange*.
Raise `ProgrammingError` if the type is not found.
"""
from psycopg2.extensions import STATUS_IN_TRANSACTION
from psycopg2.extras import _solve_conn_curs
conn, curs = _solve_conn_curs(conn_or_curs)
if conn.info.server_version < 90200:
raise ProgrammingError("range types not available in version %s"
% conn.info.server_version)
# 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'
# get the type oid and attributes
curs.execute("""\
select rngtypid, rngsubtype, typarray
from pg_range r
join pg_type t on t.oid = rngtypid
join pg_namespace ns on ns.oid = typnamespace
where typname = %s and ns.nspname = %s;
""", (tname, schema))
rec = curs.fetchone()
if not rec:
# 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 == STATUS_IN_TRANSACTION:
curs.execute("SAVEPOINT register_type")
savepoint = True
curs.execute("""\
SELECT rngtypid, rngsubtype, typarray, typname, nspname
from pg_range r
join pg_type t on t.oid = rngtypid
join pg_namespace ns on ns.oid = typnamespace
WHERE t.oid = %s::regtype
""", (name, ))
except ProgrammingError:
pass
else:
rec = curs.fetchone()
if rec:
tname, schema = rec[3:]
finally:
if savepoint:
curs.execute("ROLLBACK TO SAVEPOINT register_type")
# revert the status of the connection as before the command
if conn_status != STATUS_IN_TRANSACTION and not conn.autocommit:
conn.rollback()
if not rec:
raise ProgrammingError(
f"PostgreSQL range '{name}' not found")
type, subtype, array = rec[:3]
return RangeCaster(name, pyrange,
oid=type, subtype_oid=subtype, array_oid=array)
_re_range = re.compile(r"""
( \(|\[ ) # lower bound flag
(?: # lower bound:
" ( (?: [^"] | "")* ) " # - a quoted string
| ( [^",]+ ) # - or an unquoted string
)? # - or empty (not catched)
,
(?: # upper bound:
" ( (?: [^"] | "")* ) " # - a quoted string
| ( [^"\)\]]+ ) # - or an unquoted string
)? # - or empty (not catched)
( \)|\] ) # upper bound flag
""", re.VERBOSE)
_re_undouble = re.compile(r'(["\\])\1')
def parse(self, s, cur=None):
if s is None:
return None
if s == 'empty':
return self.range(empty=True)
m = self._re_range.match(s)
if m is None:
raise InterfaceError(f"failed to parse range: '{s}'")
lower = m.group(3)
if lower is None:
lower = m.group(2)
if lower is not None:
lower = self._re_undouble.sub(r"\1", lower)
upper = m.group(5)
if upper is None:
upper = m.group(4)
if upper is not None:
upper = self._re_undouble.sub(r"\1", upper)
if cur is not None:
lower = cur.cast(self.subtype_oid, lower)
upper = cur.cast(self.subtype_oid, upper)
bounds = m.group(1) + m.group(6)
return self.range(lower, upper, bounds)
def _register(self, scope=None):
register_type(self.typecaster, scope)
if self.array_typecaster is not None:
register_type(self.array_typecaster, scope)
register_adapter(self.range, self.adapter)
[docs]class NumericRange(Range):
"""A `Range` suitable to pass Python numeric types to a PostgreSQL range.
PostgreSQL types :sql:`int4range`, :sql:`int8range`, :sql:`numrange` are
casted into `!NumericRange` instances.
"""
pass
class DateRange(Range):
"""Represents :sql:`daterange` values."""
pass
class DateTimeRange(Range):
"""Represents :sql:`tsrange` values."""
pass
class DateTimeTZRange(Range):
"""Represents :sql:`tstzrange` values."""
pass
# Special adaptation for NumericRange. Allows to pass number range regardless
# of whether they are ints, floats and what size of ints are, which are
# pointless in Python world. On the way back, no numeric range is casted to
# NumericRange, but only to their subclasses
class NumberRangeAdapter(RangeAdapter):
"""Adapt a range if the subtype doesn't need quotes."""
def getquoted(self):
r = self.adapted
if r.isempty:
return b"'empty'"
if not r.lower_inf:
# not exactly: we are relying that none of these object is really
# quoted (they are numbers). Also, I'm lazy and not preparing the
# adapter because I assume encoding doesn't matter for these
# objects.
lower = adapt(r.lower).getquoted().decode('ascii')
else:
lower = ''
if not r.upper_inf:
upper = adapt(r.upper).getquoted().decode('ascii')
else:
upper = ''
return (f"'{r._bounds[0]}{lower},{upper}{r._bounds[1]}'").encode('ascii')
# TODO: probably won't work with infs, nans and other tricky cases.
register_adapter(NumericRange, NumberRangeAdapter)
# Register globally typecasters and adapters for builtin range types.
# note: the adapter is registered more than once, but this is harmless.
int4range_caster = RangeCaster(NumberRangeAdapter, NumericRange,
oid=3904, subtype_oid=23, array_oid=3905)
int4range_caster._register()
int8range_caster = RangeCaster(NumberRangeAdapter, NumericRange,
oid=3926, subtype_oid=20, array_oid=3927)
int8range_caster._register()
numrange_caster = RangeCaster(NumberRangeAdapter, NumericRange,
oid=3906, subtype_oid=1700, array_oid=3907)
numrange_caster._register()
daterange_caster = RangeCaster('daterange', DateRange,
oid=3912, subtype_oid=1082, array_oid=3913)
daterange_caster._register()
tsrange_caster = RangeCaster('tsrange', DateTimeRange,
oid=3908, subtype_oid=1114, array_oid=3909)
tsrange_caster._register()
tstzrange_caster = RangeCaster('tstzrange', DateTimeTZRange,
oid=3910, subtype_oid=1184, array_oid=3911)
tstzrange_caster._register()