103 lines
3.1 KiB
Python
103 lines
3.1 KiB
Python
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"""Utils."""
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# standard
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from functools import wraps
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from inspect import getfullargspec
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from itertools import chain
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from os import environ
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from typing import Any, Callable, Dict
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class ValidationError(Exception):
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"""Exception class when validation failure occurs."""
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def __init__(self, function: Callable[..., Any], arg_dict: Dict[str, Any], message: str = ""):
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"""Initialize Validation Failure."""
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if message:
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self.reason = message
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self.func = function
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self.__dict__.update(arg_dict)
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def __repr__(self):
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"""Repr Validation Failure."""
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return (
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f"ValidationError(func={self.func.__name__}, "
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+ f"args={ ({k: v for (k, v) in self.__dict__.items() if k != 'func'}) })"
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)
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def __str__(self):
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"""Str Validation Failure."""
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return repr(self)
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def __bool__(self):
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"""Bool Validation Failure."""
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return False
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def _func_args_as_dict(func: Callable[..., Any], *args: Any, **kwargs: Any):
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"""Return function's positional and key value arguments as an ordered dictionary."""
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return dict(
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list(zip(dict.fromkeys(chain(getfullargspec(func)[0], kwargs.keys())), args))
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+ list(kwargs.items())
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)
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def validator(func: Callable[..., Any]):
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"""A decorator that makes given function validator.
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Whenever the given `func` returns `False` this
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decorator returns `ValidationError` object.
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Examples:
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>>> @validator
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... def even(value):
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... return not (value % 2)
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>>> even(4)
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True
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>>> even(5)
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ValidationError(func=even, args={'value': 5})
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Args:
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func:
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Function which is to be decorated.
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Returns:
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(Callable[..., ValidationError | Literal[True]]):
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A decorator which returns either `ValidationError`
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or `Literal[True]`.
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Raises:
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(ValidationError): If `r_ve` or `RAISE_VALIDATION_ERROR` is `True`
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"""
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@wraps(func)
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def wrapper(*args: Any, **kwargs: Any):
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raise_validation_error = False
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if "r_ve" in kwargs:
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raise_validation_error = True
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del kwargs["r_ve"]
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if environ.get("RAISE_VALIDATION_ERROR", "False") == "True":
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raise_validation_error = True
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try:
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if raise_validation_error:
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if func(*args, **kwargs):
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return True
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else:
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raise ValidationError(func, _func_args_as_dict(func, *args, **kwargs))
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else:
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return (
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True
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if func(*args, **kwargs)
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else ValidationError(func, _func_args_as_dict(func, *args, **kwargs))
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)
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except (ValueError, TypeError, UnicodeError) as exp:
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if raise_validation_error:
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raise ValidationError(
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func, _func_args_as_dict(func, *args, **kwargs), str(exp)
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) from exp
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else:
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return ValidationError(func, _func_args_as_dict(func, *args, **kwargs), str(exp))
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return wrapper
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