def from_arguments(cls: Type[T],
arguments: QueryString,
default_to_descending: bool = False) -> T:
order = arguments.optionally_parse_string(key='order', max_length=32)
if order is None:
if default_to_descending is False:
raise BadRequest(
'Supply order=[ascending|descending] parameter')
return cls(True)
if order.lower() == 'ascending':
return cls(True)
if order.lower() == 'descending':
return cls(False)
raise BadRequest('Acceptable `order` values: ascending, descending')
def optionally_from_arguments(cls: Type[T],
arguments: QueryString,
max_length: int = 64,
min_length: int = 3,
fallback_to_wildcard: bool = False,
key='fragment') -> Optional[T]:
fragment = arguments.optionally_parse_string(key=key,
max_length=max_length,
min_length=min_length,
allow_whitespace=True)
if fragment is None and fallback_to_wildcard is False:
return None
if fragment is None and fallback_to_wildcard is True:
return cls.with_wildcard()
return cls(fragment)
def optionally_from_arguments(
cls: Type[T],
arguments: QueryString,
available: Optional[Dict[str, T]] = None,
key: str = 'order_by',
fallback_to: Optional[T] = None) -> Optional[T]:
if available is None:
if not isinstance(cls.available, dict):
raise RuntimeError('implement .available order by values')
available = cls.available
term = arguments.optionally_parse_string(key)
if term is None:
return fallback_to
if term not in available.keys():
raise BadRequest('Invalid {k} value. Valid values: {v}'.format(
k=key, v=', '.join(available.keys())))
return available[term]