102 lines
3.5 KiB
Python
102 lines
3.5 KiB
Python
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# processors.py
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# Copyright (C) 2010 Gaetan de Menten gdementen@gmail.com
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: http://www.opensource.org/licenses/mit-license.php
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"""defines generic type conversion functions, as used in bind and result
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processors.
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They all share one common characteristic: None is passed through unchanged.
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"""
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import codecs
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import re
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import datetime
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def str_to_datetime_processor_factory(regexp, type_):
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rmatch = regexp.match
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# Even on python2.6 datetime.strptime is both slower than this code
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# and it does not support microseconds.
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def process(value):
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if value is None:
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return None
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else:
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return type_(*map(int, rmatch(value).groups(0)))
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return process
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try:
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from sqlalchemy.cprocessors import UnicodeResultProcessor, \
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DecimalResultProcessor, \
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to_float, to_str, int_to_boolean, \
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str_to_datetime, str_to_time, \
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str_to_date
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def to_unicode_processor_factory(encoding, errors=None):
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# this is cumbersome but it would be even more so on the C side
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if errors is not None:
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return UnicodeResultProcessor(encoding, errors).process
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else:
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return UnicodeResultProcessor(encoding).process
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def to_decimal_processor_factory(target_class, scale=10):
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# Note that the scale argument is not taken into account for integer
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# values in the C implementation while it is in the Python one.
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# For example, the Python implementation might return
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# Decimal('5.00000') whereas the C implementation will
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# return Decimal('5'). These are equivalent of course.
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return DecimalResultProcessor(target_class, "%%.%df" % scale).process
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except ImportError:
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def to_unicode_processor_factory(encoding, errors=None):
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decoder = codecs.getdecoder(encoding)
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def process(value):
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if value is None:
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return None
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else:
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# decoder returns a tuple: (value, len). Simply dropping the
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# len part is safe: it is done that way in the normal
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# 'xx'.decode(encoding) code path.
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return decoder(value, errors)[0]
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return process
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def to_decimal_processor_factory(target_class, scale=10):
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fstring = "%%.%df" % scale
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def process(value):
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if value is None:
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return None
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else:
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return target_class(fstring % value)
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return process
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def to_float(value):
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if value is None:
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return None
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else:
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return float(value)
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def to_str(value):
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if value is None:
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return None
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else:
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return str(value)
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def int_to_boolean(value):
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if value is None:
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return None
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else:
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return value and True or False
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DATETIME_RE = re.compile("(\d+)-(\d+)-(\d+) (\d+):(\d+):(\d+)(?:\.(\d+))?")
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TIME_RE = re.compile("(\d+):(\d+):(\d+)(?:\.(\d+))?")
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DATE_RE = re.compile("(\d+)-(\d+)-(\d+)")
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str_to_datetime = str_to_datetime_processor_factory(DATETIME_RE,
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datetime.datetime)
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str_to_time = str_to_datetime_processor_factory(TIME_RE, datetime.time)
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str_to_date = str_to_datetime_processor_factory(DATE_RE, datetime.date)
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