def string_to_datatype(string_value):
"""Converts a string representation of a value into its original datatype."""
string_value = string_value.strip(' "')
# try to return as boolean or none
retval = string_value
if string_value.lower() in ['true', 'false', 'none']:
retval = eval(string_value)
return retval
# try to return as a decimal
try:
value = Decimal(string_value)
if str(value) == string_value:
retval = value
except ValueError:
pass
except InvalidOperation:
pass
# try to return as an integer
try:
value = int(string_value)
if str(value) == string_value:
retval = value
except ValueError:
pass
# try to return as date
try:
value = parser.parse(string_value)
if value.strftime('%Y-%m-%d') == string_value:
retval = value.date()
except ValueError:
pass
except TypeError:
pass
# try to return as datetime
try:
value = parser.parse(string_value)
if value.strftime('%Y-%m-%d %H:%M') == string_value:
retval = value
except ValueError:
pass
except TypeError:
pass
# otherwise return string value
return retval
def coerce_value(cls, column, value, size_check=True):
if value is None:
if not column.nullable:
raise ValueError(
f'Null value not allowed for property {column.key} of type '
f'{cls!r}')
return None
try:
python_type = column.type.python_type
except NotImplementedError:
# SA types that don't implement python_type treated early and explicity
if column.type is HSTORE or type(column.type) is HSTORE:
if value is None or isinstance(value, dict):
# coerce all non-string values of hstore dict
return {key: str(val) for key, val in value.items()}
raise ValueError(
f'Invalid type {type(value)!r} for property {column.key} of '
f'class {cls!r}')
if column.type is UUID or type(column.type) is UUID:
if column.type.as_uuid:
if type(value) is int:
return uuid.UUID(int=value)
return uuid.UUID(value)
return str(value)
raise NotImplementedError(f'py_liant does not support {column.type!r} '
'yet')
if python_type is str:
if value is not str:
value = str(value)
if isinstance(column.type, String) and hasattr(column.type, "length") \
and value is not None and column.type.length is not None \
and column.type.length < len(value) and size_check:
raise ValueError(
f'Text value too large for property {column.key} of class '
f'{cls!r}, limit {column.type.length}')
if python_type is int:
try:
value = int(value)
except ValueError:
raise ValueError(
'Could not convert value to target type for property '
f'{column.key} of class {cls!r}')
if python_type is Decimal and value is not None \
and type(value) is not Decimal:
try:
value = Decimal(value)
except ArithmeticError:
raise ValueError(
'Could not convert value to target type for property '
f'{column.key} of class {cls!r}')
if python_type is float and value is not None and type(value) is not float:
try:
value = float(value)
except ValueError:
raise ValueError(
'Could not convert value to target type for property '
f'{column.key} of class {cls!r}')
if python_type is bool and value is not None and type(value) is not bool:
try:
if type(value) is str:
value = asbool(value)
elif type(value) is int:
if value not in [0, 1]:
raise ValueError
value = bool(value)
else:
raise ValueError(
'Could not convert value to target type for property '
f'{column.key} of class {cls!r}')
except ValueError:
raise ValueError(
f'Expected boolean value for property {column.key} of class '
f'{cls!r}, received {type(value)!r} instead')
if python_type in (datetime, date, time):
try:
use_timezone = False
if isinstance(column.type, (DateTime, Time)):
use_timezone = column.type.timezone
def tzinfos(name, offset):
if offset is not None:
return tz.tzoffset(name, offset)
return tz.gettz(name) or None
value = parser.parse(value,
tzinfos=tzinfos,
ignoretz=not use_timezone)
if python_type is date:
value = value.date()
if python_type is time:
value = value.timetz() if use_timezone else value.time()
except ValueError:
raise ValueError(
'Could not convert value to target type for property '
f'{column.key} of class {cls!r}')
if python_type is bytes:
return base64.b64decode(value)
if python_type is list:
if column.type is ARRAY or isinstance(column.type, ARRAY):
# use SQL casting for arrays
return cast(value, column.type)
raise NotImplementedError(f'py_liant does not support {column.type!r} '
'yet')
if issubclass(python_type, Enum) and value is not None:
value = str(value)
try:
value = next(item for item in python_type
if item.name == value or item.value == value)
except StopIteration:
raise ValueError(
'Could not convert value to target type for property '
f'{column.key} of class {cls!r}')
return value
