416 lines
12 KiB
Python
416 lines
12 KiB
Python
from __future__ import annotations
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import collections
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import contextlib
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import os.path
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import re
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import sys
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class ValidationError(ValueError):
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def __init__(self, error_msg, ctx=None):
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super().__init__(error_msg)
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self.error_msg = error_msg
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self.ctx = ctx
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def __str__(self):
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out = '\n'
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err = self
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while err.ctx is not None:
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out += f'==> {err.ctx}\n'
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err = err.error_msg
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out += f'=====> {err.error_msg}'
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return out
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MISSING = collections.namedtuple('Missing', ())()
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type(MISSING).__repr__ = lambda self: 'MISSING'
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@contextlib.contextmanager
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def validate_context(msg):
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try:
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yield
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except ValidationError as e:
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_, _, tb = sys.exc_info()
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raise ValidationError(e, ctx=msg).with_traceback(tb) from None
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@contextlib.contextmanager
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def reraise_as(tp):
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try:
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yield
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except ValidationError as e:
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_, _, tb = sys.exc_info()
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raise tp(e).with_traceback(tb) from None
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def _dct_noop(self, dct):
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pass
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def _check_optional(self, dct):
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if self.key not in dct:
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return
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with validate_context(f'At key: {self.key}'):
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self.check_fn(dct[self.key])
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def _apply_default_optional(self, dct):
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dct.setdefault(self.key, self.default)
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def _remove_default_optional(self, dct):
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if dct.get(self.key, MISSING) == self.default:
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del dct[self.key]
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def _require_key(self, dct):
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if self.key not in dct:
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raise ValidationError(f'Missing required key: {self.key}')
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def _check_required(self, dct):
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_require_key(self, dct)
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_check_optional(self, dct)
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@property
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def _check_fn_recurse(self):
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def check_fn(val):
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validate(val, self.schema)
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return check_fn
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def _apply_default_required_recurse(self, dct):
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dct[self.key] = apply_defaults(dct[self.key], self.schema)
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def _remove_default_required_recurse(self, dct):
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dct[self.key] = remove_defaults(dct[self.key], self.schema)
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def _apply_default_optional_recurse(self, dct):
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if self.key not in dct:
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_apply_default_optional(self, dct)
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_apply_default_required_recurse(self, dct)
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def _remove_default_optional_recurse(self, dct):
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if self.key in dct:
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_remove_default_required_recurse(self, dct)
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_remove_default_optional(self, dct)
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def _get_check_conditional(inner):
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def _check_conditional(self, dct):
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if dct.get(self.condition_key, MISSING) == self.condition_value:
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inner(self, dct)
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elif (
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self.condition_key in dct and
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self.ensure_absent and self.key in dct
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):
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if hasattr(self.condition_value, 'describe_opposite'):
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explanation = self.condition_value.describe_opposite()
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else:
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explanation = f'is not {self.condition_value!r}'
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raise ValidationError(
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f'Expected {self.key} to be absent when {self.condition_key} '
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f'{explanation}, found {self.key}: {dct[self.key]!r}',
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)
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return _check_conditional
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def _apply_default_conditional_optional(self, dct):
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if dct.get(self.condition_key, MISSING) == self.condition_value:
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_apply_default_optional(self, dct)
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def _remove_default_conditional_optional(self, dct):
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if dct.get(self.condition_key, MISSING) == self.condition_value:
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_remove_default_optional(self, dct)
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def _apply_default_conditional_recurse(self, dct):
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if dct.get(self.condition_key, MISSING) == self.condition_value:
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_apply_default_required_recurse(self, dct)
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def _remove_default_conditional_recurse(self, dct):
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if dct.get(self.condition_key, MISSING) == self.condition_value:
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_remove_default_required_recurse(self, dct)
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def _no_additional_keys_check(self, dct):
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extra = sorted(set(dct) - set(self.keys))
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if extra:
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extra_s = ', '.join(str(x) for x in extra)
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keys_s = ', '.join(str(x) for x in self.keys)
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raise ValidationError(
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f'Additional keys found: {extra_s}. '
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f'Only these keys are allowed: {keys_s}',
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)
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def _warn_additional_keys_check(self, dct):
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extra = sorted(set(dct) - set(self.keys))
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if extra:
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self.callback(extra, self.keys, dct)
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Required = collections.namedtuple('Required', ('key', 'check_fn'))
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Required.check = _check_required
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Required.apply_default = _dct_noop
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Required.remove_default = _dct_noop
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RequiredRecurse = collections.namedtuple('RequiredRecurse', ('key', 'schema'))
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RequiredRecurse.check = _check_required
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RequiredRecurse.check_fn = _check_fn_recurse
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RequiredRecurse.apply_default = _apply_default_required_recurse
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RequiredRecurse.remove_default = _remove_default_required_recurse
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Optional = collections.namedtuple('Optional', ('key', 'check_fn', 'default'))
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Optional.check = _check_optional
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Optional.apply_default = _apply_default_optional
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Optional.remove_default = _remove_default_optional
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OptionalRecurse = collections.namedtuple(
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'OptionalRecurse', ('key', 'schema', 'default'),
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)
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OptionalRecurse.check = _check_optional
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OptionalRecurse.check_fn = _check_fn_recurse
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OptionalRecurse.apply_default = _apply_default_optional_recurse
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OptionalRecurse.remove_default = _remove_default_optional_recurse
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OptionalNoDefault = collections.namedtuple(
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'OptionalNoDefault', ('key', 'check_fn'),
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)
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OptionalNoDefault.check = _check_optional
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OptionalNoDefault.apply_default = _dct_noop
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OptionalNoDefault.remove_default = _dct_noop
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Conditional = collections.namedtuple(
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'Conditional',
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('key', 'check_fn', 'condition_key', 'condition_value', 'ensure_absent'),
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)
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Conditional.__new__.__defaults__ = (False,)
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Conditional.check = _get_check_conditional(_check_required)
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Conditional.apply_default = _dct_noop
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Conditional.remove_default = _dct_noop
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ConditionalOptional = collections.namedtuple(
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'ConditionalOptional',
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(
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'key', 'check_fn', 'default', 'condition_key', 'condition_value',
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'ensure_absent',
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),
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)
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ConditionalOptional.__new__.__defaults__ = (False,)
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ConditionalOptional.check = _get_check_conditional(_check_optional)
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ConditionalOptional.apply_default = _apply_default_conditional_optional
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ConditionalOptional.remove_default = _remove_default_conditional_optional
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ConditionalRecurse = collections.namedtuple(
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'ConditionalRecurse',
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('key', 'schema', 'condition_key', 'condition_value', 'ensure_absent'),
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)
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ConditionalRecurse.__new__.__defaults__ = (False,)
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ConditionalRecurse.check = _get_check_conditional(_check_required)
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ConditionalRecurse.check_fn = _check_fn_recurse
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ConditionalRecurse.apply_default = _apply_default_conditional_recurse
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ConditionalRecurse.remove_default = _remove_default_conditional_recurse
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NoAdditionalKeys = collections.namedtuple('NoAdditionalKeys', ('keys',))
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NoAdditionalKeys.check = _no_additional_keys_check
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NoAdditionalKeys.apply_default = _dct_noop
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NoAdditionalKeys.remove_default = _dct_noop
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WarnAdditionalKeys = collections.namedtuple(
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'WarnAdditionalKeys', ('keys', 'callback'),
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)
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WarnAdditionalKeys.check = _warn_additional_keys_check
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WarnAdditionalKeys.apply_default = _dct_noop
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WarnAdditionalKeys.remove_default = _dct_noop
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class Map(collections.namedtuple('Map', ('object_name', 'id_key', 'items'))):
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__slots__ = ()
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def __new__(cls, object_name, id_key, *items):
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return super().__new__(cls, object_name, id_key, items)
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def check(self, v):
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if not isinstance(v, dict):
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raise ValidationError(
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f'Expected a {self.object_name} map but got a '
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f'{type(v).__name__}',
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)
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if self.id_key is None:
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context = f'At {self.object_name}()'
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else:
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key_v_s = v.get(self.id_key, MISSING)
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context = f'At {self.object_name}({self.id_key}={key_v_s!r})'
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with validate_context(context):
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for item in self.items:
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item.check(v)
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def apply_defaults(self, v):
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ret = v.copy()
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for item in self.items:
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item.apply_default(ret)
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return ret
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def remove_defaults(self, v):
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ret = v.copy()
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for item in self.items:
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item.remove_default(ret)
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return ret
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class Array(collections.namedtuple('Array', ('of', 'allow_empty'))):
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__slots__ = ()
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def __new__(cls, of, allow_empty=True):
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return super().__new__(cls, of=of, allow_empty=allow_empty)
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def check(self, v):
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check_array(check_any)(v)
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if not self.allow_empty and not v:
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raise ValidationError(
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f"Expected at least 1 '{self.of.object_name}'",
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)
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for val in v:
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validate(val, self.of)
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def apply_defaults(self, v):
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return [apply_defaults(val, self.of) for val in v]
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def remove_defaults(self, v):
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return [remove_defaults(val, self.of) for val in v]
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class Not(collections.namedtuple('Not', ('val',))):
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__slots__ = ()
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def describe_opposite(self):
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return f'is {self.val!r}'
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def __eq__(self, other):
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return other is not MISSING and other != self.val
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class NotIn(collections.namedtuple('NotIn', ('values',))):
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__slots__ = ()
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def __new__(cls, *values):
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return super().__new__(cls, values=values)
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def describe_opposite(self):
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return f'is any of {self.values!r}'
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def __eq__(self, other):
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return other is not MISSING and other not in self.values
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class In(collections.namedtuple('In', ('values',))):
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__slots__ = ()
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def __new__(cls, *values):
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return super().__new__(cls, values=values)
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def describe_opposite(self):
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return f'is not any of {self.values!r}'
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def __eq__(self, other):
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return other is not MISSING and other in self.values
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def check_any(_):
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pass
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def check_type(tp, typename=None):
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def check_type_fn(v):
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if not isinstance(v, tp):
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typename_s = typename or tp.__name__
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raise ValidationError(
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f'Expected {typename_s} got {type(v).__name__}',
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)
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return check_type_fn
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check_bool = check_type(bool)
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check_bytes = check_type(bytes)
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check_int = check_type(int)
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check_string = check_type(str, typename='string')
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check_text = check_type(str, typename='text')
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def check_one_of(possible):
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def check_one_of_fn(v):
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if v not in possible:
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possible_s = ', '.join(str(x) for x in sorted(possible))
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raise ValidationError(
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f'Expected one of {possible_s} but got: {v!r}',
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)
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return check_one_of_fn
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def check_regex(v):
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try:
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re.compile(v)
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except re.error:
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raise ValidationError(f'{v!r} is not a valid python regex')
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def check_array(inner_check):
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def check_array_fn(v):
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if not isinstance(v, (list, tuple)):
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raise ValidationError(
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f'Expected array but got {type(v).__name__!r}',
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)
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for i, val in enumerate(v):
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with validate_context(f'At index {i}'):
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inner_check(val)
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return check_array_fn
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def check_and(*fns):
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def check(v):
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for fn in fns:
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fn(v)
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return check
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def validate(v, schema):
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schema.check(v)
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return v
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def apply_defaults(v, schema):
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return schema.apply_defaults(v)
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def remove_defaults(v, schema):
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return schema.remove_defaults(v)
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def load_from_filename(
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filename,
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schema,
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load_strategy,
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exc_tp=ValidationError,
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*,
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display_filename=None,
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):
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display_filename = display_filename or filename
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with reraise_as(exc_tp):
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if not os.path.isfile(filename):
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raise ValidationError(f'{display_filename} is not a file')
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with validate_context(f'File {display_filename}'):
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try:
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with open(filename, encoding='utf-8') as f:
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contents = f.read()
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except UnicodeDecodeError as e:
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raise ValidationError(str(e))
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try:
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data = load_strategy(contents)
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except Exception as e:
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raise ValidationError(str(e))
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validate(data, schema)
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return apply_defaults(data, schema)
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