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@JellyWX
Created July 31, 2019 11:10
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Small form modelling system for Flask
import typing
from werkzeug.security import generate_password_hash, check_password_hash
from werkzeug import ImmutableMultiDict
class Field():
class FieldLengthExceeded(Exception):
pass
class MissingFieldData(Exception):
pass
def __init__(self, name: str, *, strict: bool=False, max_length: int=1024):
self.name: str = name
self._raw_value: typing.Optional[str] = None
self._strict: bool = strict
self._max_length: int = max_length
@property
def value(self) -> typing.Optional[str]:
return self._value
@value.setter
def value(self, value):
if value is not None and len(value) > self._max_length:
raise self.FieldLengthExceeded
else:
self._value = value
def validate(self):
if self._raw_value is None and self._strict:
raise self.MissingFieldData
elif self._value is not None:
self._type_specific_validation()
def _type_specific_validation(self):
pass
class IntegerField(Field):
class InvalidInteger(Exception):
pass
def _type_specific_validation(self):
if not all([x in '0123456789' for x in self._value]):
raise self.InvalidInteger
@Field.value.getter
def value(self) -> typing.Optional[int]:
return self._value if self._value is None else int(self._value)
class PasswordField(Field):
class Password(str):
def __eq__(self, comparator):
return check_password_hash(self, comparator)
@Field.value.getter
def value(self) -> typing.Optional[Password]:
return self._value if self._value is None else self.Password(generate_password_hash(self._value))
class EmailField(Field):
class InvalidEmail(Exception):
pass
def _type_specific_validation(self):
if '@' not in self._value:
raise self.InvalidEmail
class FormDeserializer():
def __init__(self, data: ImmutableMultiDict):
for attrib in dir(self):
d = getattr(self, attrib)
if isinstance(d, Field):
# Get the attribute from the form data
v: typing.Optional[str] = data.get(d.name, None)
d.value = v
# Check the value is valid
d.validate()
# Finally, rebind to the value of the field
self.__dict__[attrib] = d.value
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