375 lines
10 KiB
Python
375 lines
10 KiB
Python
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"""
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Validation errors, and some surrounding helpers.
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"""
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from collections import defaultdict, deque
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import itertools
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import pprint
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import textwrap
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import attr
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from jsonschema import _utils
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from jsonschema.compat import PY3, iteritems
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WEAK_MATCHES = frozenset(["anyOf", "oneOf"])
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STRONG_MATCHES = frozenset()
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_unset = _utils.Unset()
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class _Error(Exception):
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def __init__(
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self,
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message,
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validator=_unset,
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path=(),
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cause=None,
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context=(),
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validator_value=_unset,
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instance=_unset,
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schema=_unset,
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schema_path=(),
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parent=None,
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):
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super(_Error, self).__init__(
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message,
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validator,
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path,
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cause,
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context,
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validator_value,
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instance,
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schema,
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schema_path,
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parent,
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)
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self.message = message
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self.path = self.relative_path = deque(path)
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self.schema_path = self.relative_schema_path = deque(schema_path)
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self.context = list(context)
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self.cause = self.__cause__ = cause
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self.validator = validator
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self.validator_value = validator_value
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self.instance = instance
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self.schema = schema
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self.parent = parent
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for error in context:
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error.parent = self
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def __repr__(self):
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return "<%s: %r>" % (self.__class__.__name__, self.message)
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def __unicode__(self):
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essential_for_verbose = (
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self.validator, self.validator_value, self.instance, self.schema,
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)
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if any(m is _unset for m in essential_for_verbose):
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return self.message
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pschema = pprint.pformat(self.schema, width=72)
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pinstance = pprint.pformat(self.instance, width=72)
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return self.message + textwrap.dedent("""
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Failed validating %r in %s%s:
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%s
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On %s%s:
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%s
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""".rstrip()
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) % (
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self.validator,
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self._word_for_schema_in_error_message,
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_utils.format_as_index(list(self.relative_schema_path)[:-1]),
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_utils.indent(pschema),
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self._word_for_instance_in_error_message,
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_utils.format_as_index(self.relative_path),
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_utils.indent(pinstance),
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)
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if PY3:
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__str__ = __unicode__
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else:
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def __str__(self):
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return unicode(self).encode("utf-8")
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@classmethod
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def create_from(cls, other):
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return cls(**other._contents())
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@property
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def absolute_path(self):
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parent = self.parent
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if parent is None:
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return self.relative_path
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path = deque(self.relative_path)
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path.extendleft(reversed(parent.absolute_path))
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return path
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@property
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def absolute_schema_path(self):
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parent = self.parent
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if parent is None:
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return self.relative_schema_path
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path = deque(self.relative_schema_path)
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path.extendleft(reversed(parent.absolute_schema_path))
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return path
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def _set(self, **kwargs):
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for k, v in iteritems(kwargs):
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if getattr(self, k) is _unset:
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setattr(self, k, v)
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def _contents(self):
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attrs = (
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"message", "cause", "context", "validator", "validator_value",
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"path", "schema_path", "instance", "schema", "parent",
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)
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return dict((attr, getattr(self, attr)) for attr in attrs)
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class ValidationError(_Error):
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"""
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An instance was invalid under a provided schema.
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"""
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_word_for_schema_in_error_message = "schema"
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_word_for_instance_in_error_message = "instance"
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class SchemaError(_Error):
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"""
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A schema was invalid under its corresponding metaschema.
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"""
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_word_for_schema_in_error_message = "metaschema"
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_word_for_instance_in_error_message = "schema"
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@attr.s(hash=True)
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class RefResolutionError(Exception):
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"""
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A ref could not be resolved.
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"""
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_cause = attr.ib()
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def __str__(self):
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return str(self._cause)
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class UndefinedTypeCheck(Exception):
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"""
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A type checker was asked to check a type it did not have registered.
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"""
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def __init__(self, type):
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self.type = type
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def __unicode__(self):
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return "Type %r is unknown to this type checker" % self.type
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if PY3:
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__str__ = __unicode__
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else:
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def __str__(self):
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return unicode(self).encode("utf-8")
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class UnknownType(Exception):
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"""
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A validator was asked to validate an instance against an unknown type.
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"""
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def __init__(self, type, instance, schema):
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self.type = type
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self.instance = instance
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self.schema = schema
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def __unicode__(self):
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pschema = pprint.pformat(self.schema, width=72)
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pinstance = pprint.pformat(self.instance, width=72)
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return textwrap.dedent("""
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Unknown type %r for validator with schema:
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%s
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While checking instance:
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%s
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""".rstrip()
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) % (self.type, _utils.indent(pschema), _utils.indent(pinstance))
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if PY3:
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__str__ = __unicode__
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else:
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def __str__(self):
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return unicode(self).encode("utf-8")
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class FormatError(Exception):
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"""
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Validating a format failed.
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"""
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def __init__(self, message, cause=None):
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super(FormatError, self).__init__(message, cause)
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self.message = message
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self.cause = self.__cause__ = cause
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def __unicode__(self):
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return self.message
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if PY3:
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__str__ = __unicode__
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else:
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def __str__(self):
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return self.message.encode("utf-8")
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class ErrorTree(object):
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"""
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ErrorTrees make it easier to check which validations failed.
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"""
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_instance = _unset
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def __init__(self, errors=()):
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self.errors = {}
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self._contents = defaultdict(self.__class__)
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for error in errors:
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container = self
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for element in error.path:
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container = container[element]
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container.errors[error.validator] = error
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container._instance = error.instance
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def __contains__(self, index):
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"""
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Check whether ``instance[index]`` has any errors.
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"""
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return index in self._contents
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def __getitem__(self, index):
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"""
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Retrieve the child tree one level down at the given ``index``.
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If the index is not in the instance that this tree corresponds to and
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is not known by this tree, whatever error would be raised by
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``instance.__getitem__`` will be propagated (usually this is some
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subclass of `exceptions.LookupError`.
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"""
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if self._instance is not _unset and index not in self:
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self._instance[index]
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return self._contents[index]
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def __setitem__(self, index, value):
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"""
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Add an error to the tree at the given ``index``.
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"""
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self._contents[index] = value
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def __iter__(self):
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"""
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Iterate (non-recursively) over the indices in the instance with errors.
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"""
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return iter(self._contents)
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def __len__(self):
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"""
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Return the `total_errors`.
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"""
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return self.total_errors
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def __repr__(self):
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return "<%s (%s total errors)>" % (self.__class__.__name__, len(self))
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@property
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def total_errors(self):
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"""
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The total number of errors in the entire tree, including children.
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"""
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child_errors = sum(len(tree) for _, tree in iteritems(self._contents))
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return len(self.errors) + child_errors
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def by_relevance(weak=WEAK_MATCHES, strong=STRONG_MATCHES):
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"""
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Create a key function that can be used to sort errors by relevance.
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Arguments:
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weak (set):
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a collection of validator names to consider to be "weak".
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If there are two errors at the same level of the instance
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and one is in the set of weak validator names, the other
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error will take priority. By default, :validator:`anyOf` and
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:validator:`oneOf` are considered weak validators and will
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be superseded by other same-level validation errors.
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strong (set):
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a collection of validator names to consider to be "strong"
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"""
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def relevance(error):
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validator = error.validator
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return -len(error.path), validator not in weak, validator in strong
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return relevance
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relevance = by_relevance()
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def best_match(errors, key=relevance):
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"""
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Try to find an error that appears to be the best match among given errors.
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In general, errors that are higher up in the instance (i.e. for which
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`ValidationError.path` is shorter) are considered better matches,
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since they indicate "more" is wrong with the instance.
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If the resulting match is either :validator:`oneOf` or :validator:`anyOf`,
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the *opposite* assumption is made -- i.e. the deepest error is picked,
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since these validators only need to match once, and any other errors may
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not be relevant.
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Arguments:
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errors (collections.Iterable):
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the errors to select from. Do not provide a mixture of
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errors from different validation attempts (i.e. from
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different instances or schemas), since it won't produce
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sensical output.
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key (collections.Callable):
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the key to use when sorting errors. See `relevance` and
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transitively `by_relevance` for more details (the default is
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to sort with the defaults of that function). Changing the
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default is only useful if you want to change the function
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that rates errors but still want the error context descent
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done by this function.
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Returns:
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the best matching error, or ``None`` if the iterable was empty
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.. note::
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This function is a heuristic. Its return value may change for a given
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set of inputs from version to version if better heuristics are added.
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"""
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errors = iter(errors)
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best = next(errors, None)
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if best is None:
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return
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best = max(itertools.chain([best], errors), key=key)
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while best.context:
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best = min(best.context, key=key)
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return best
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