1"""Utils."""
2
3# standard
4from functools import wraps
5from inspect import getfullargspec
6from itertools import chain
7from os import environ
8from typing import Any, Callable, Dict
9
10
11class ValidationError(Exception):
12 """Exception class when validation failure occurs."""
13
14 def __init__(self, function: Callable[..., Any], arg_dict: Dict[str, Any], message: str = ""):
15 """Initialize Validation Failure."""
16 if message:
17 self.reason = message
18 self.func = function
19 self.__dict__.update(arg_dict)
20
21 def __repr__(self):
22 """Repr Validation Failure."""
23 return (
24 f"ValidationError(func={self.func.__name__}, "
25 + f"args={ ({k: v for (k, v) in self.__dict__.items() if k != 'func'}) })"
26 )
27
28 def __str__(self):
29 """Str Validation Failure."""
30 return repr(self)
31
32 def __bool__(self):
33 """Bool Validation Failure."""
34 return False
35
36
37def _func_args_as_dict(func: Callable[..., Any], *args: Any, **kwargs: Any):
38 """Return function's positional and key value arguments as an ordered dictionary."""
39 return dict(
40 list(zip(dict.fromkeys(chain(getfullargspec(func)[0], kwargs.keys())), args))
41 + list(kwargs.items())
42 )
43
44
45def validator(func: Callable[..., Any]):
46 """A decorator that makes given function validator.
47
48 Whenever the given `func` returns `False` this
49 decorator returns `ValidationError` object.
50
51 Examples:
52 >>> @validator
53 ... def even(value):
54 ... return not (value % 2)
55 >>> even(4)
56 True
57 >>> even(5)
58 ValidationError(func=even, args={'value': 5})
59
60 Args:
61 func:
62 Function which is to be decorated.
63
64 Returns:
65 (Callable[..., ValidationError | Literal[True]]):
66 A decorator which returns either `ValidationError`
67 or `Literal[True]`.
68
69 Raises:
70 (ValidationError): If `r_ve` or `RAISE_VALIDATION_ERROR` is `True`
71 """
72
73 @wraps(func)
74 def wrapper(*args: Any, **kwargs: Any):
75 raise_validation_error = False
76 if "r_ve" in kwargs:
77 raise_validation_error = True
78 del kwargs["r_ve"]
79 if environ.get("RAISE_VALIDATION_ERROR", "False") == "True":
80 raise_validation_error = True
81
82 try:
83 if raise_validation_error:
84 if func(*args, **kwargs):
85 return True
86 else:
87 raise ValidationError(func, _func_args_as_dict(func, *args, **kwargs))
88 else:
89 return (
90 True
91 if func(*args, **kwargs)
92 else ValidationError(func, _func_args_as_dict(func, *args, **kwargs))
93 )
94 except (ValueError, TypeError, UnicodeError) as exp:
95 if raise_validation_error:
96 raise ValidationError(
97 func, _func_args_as_dict(func, *args, **kwargs), str(exp)
98 ) from exp
99 else:
100 return ValidationError(func, _func_args_as_dict(func, *args, **kwargs), str(exp))
101
102 return wrapper