102 lines
3.3 KiB
Python
102 lines
3.3 KiB
Python
"""Base class for type definitions in the stix2 library."""
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import collections
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import datetime as dt
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import json
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from .exceptions import ExtraFieldsError, ImmutableError, InvalidValueError, \
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MissingFieldsError
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from .utils import format_datetime, get_timestamp, NOW
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__all__ = ['STIXJSONEncoder', '_STIXBase']
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DEFAULT_ERROR = "{type} must have {field}='{expected}'."
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class STIXJSONEncoder(json.JSONEncoder):
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def default(self, obj):
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if isinstance(obj, (dt.date, dt.datetime)):
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return format_datetime(obj)
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elif isinstance(obj, _STIXBase):
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return dict(obj)
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else:
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return super(STIXJSONEncoder, self).default(obj)
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def get_required_properties(properties):
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return (k for k, v in properties.items() if v.required)
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class _STIXBase(collections.Mapping):
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"""Base class for STIX object types"""
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def _check_property(self, prop_name, prop, kwargs):
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if prop_name not in kwargs:
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if hasattr(prop, 'default'):
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value = prop.default()
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if value == NOW:
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value = self.__now
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kwargs[prop_name] = value
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if prop_name in kwargs:
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try:
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kwargs[prop_name] = prop.clean(kwargs[prop_name])
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except ValueError as exc:
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raise InvalidValueError(self.__class__, prop_name, reason=str(exc))
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def __init__(self, **kwargs):
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cls = self.__class__
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# Use the same timestamp for any auto-generated datetimes
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self.__now = get_timestamp()
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# Detect any keyword arguments not allowed for a specific type
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extra_kwargs = list(set(kwargs) - set(cls._properties))
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if extra_kwargs:
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raise ExtraFieldsError(cls, extra_kwargs)
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# Detect any missing required fields
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required_fields = get_required_properties(cls._properties)
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missing_kwargs = set(required_fields) - set(kwargs)
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if missing_kwargs:
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raise MissingFieldsError(cls, missing_kwargs)
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for prop_name, prop_metadata in cls._properties.items():
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self._check_property(prop_name, prop_metadata, kwargs)
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self._inner = kwargs
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if self.granular_markings:
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for m in self.granular_markings:
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# TODO: check selectors
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pass
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def __getitem__(self, key):
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return self._inner[key]
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def __iter__(self):
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return iter(self._inner)
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def __len__(self):
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return len(self._inner)
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# Handle attribute access just like key access
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def __getattr__(self, name):
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return self.get(name)
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def __setattr__(self, name, value):
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if name != '_inner' and not name.startswith("_STIXBase__"):
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raise ImmutableError
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super(_STIXBase, self).__setattr__(name, value)
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def __str__(self):
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# TODO: put keys in specific order. Probably need custom JSON encoder.
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return json.dumps(self, indent=4, sort_keys=True, cls=STIXJSONEncoder,
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separators=(",", ": ")) # Don't include spaces after commas.
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def __repr__(self):
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props = [(k, self[k]) for k in sorted(self._properties) if self.get(k)]
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return "{0}({1})".format(self.__class__.__name__,
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", ".join(["{0!s}={1!r}".format(k, v) for k, v in props]))
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