WIP: Start transforming properties.
Greg Back
parent
e5610ff81b
commit
cf688c3851
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@ -23,6 +23,16 @@ class STIXJSONEncoder(json.JSONEncoder):
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return super(STIXJSONEncoder, self).default(obj)
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def get_required_properties(properties):
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for k, v in properties.items():
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if isinstance(v, dict):
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if v.get('required'):
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yield k
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else: # This is a Property subclass
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if v.required:
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yield k
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class _STIXBase(collections.Mapping):
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"""Base class for STIX object types"""
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@ -30,31 +40,16 @@ class _STIXBase(collections.Mapping):
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def _make_id(cls):
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return cls._type + "--" + str(uuid.uuid4())
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def __init__(self, **kwargs):
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# TODO: remove this
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def _handle_old_style_property(self, prop_name, prop_metadata, kwargs):
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cls = self.__class__
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class_name = cls.__name__
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# Use the same timestamp for any auto-generated datetimes
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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 TypeError("unexpected keyword arguments: " + str(extra_kwargs))
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required_fields = [k for k, v in cls._properties.items() if v.get('required')]
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missing_kwargs = set(required_fields) - set(kwargs)
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if missing_kwargs:
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msg = "Missing required field(s) for {type}: ({fields})."
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field_list = ", ".join(x for x in sorted(list(missing_kwargs)))
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raise ValueError(msg.format(type=class_name, fields=field_list))
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for prop_name, prop_metadata in cls._properties.items():
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if prop_name not in kwargs:
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if prop_metadata.get('default'):
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default = prop_metadata['default']
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if default == NOW:
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kwargs[prop_name] = now
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kwargs[prop_name] = self.__now
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else:
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kwargs[prop_name] = default(cls)
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elif prop_metadata.get('fixed'):
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@ -79,6 +74,33 @@ class _STIXBase(collections.Mapping):
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)
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raise ValueError(msg)
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def __init__(self, **kwargs):
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cls = self.__class__
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class_name = cls.__name__
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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 TypeError("unexpected keyword arguments: " + str(extra_kwargs))
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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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msg = "Missing required field(s) for {type}: ({fields})."
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field_list = ", ".join(x for x in sorted(list(missing_kwargs)))
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raise ValueError(msg.format(type=class_name, fields=field_list))
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for prop_name, prop_metadata in cls._properties.items():
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if isinstance(prop_metadata, dict):
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self._handle_old_style_property(prop_name, prop_metadata, kwargs)
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else: # This is a Property Subclasses
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# self.check_property(prop_name, prop_metadata, kwargs)
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pass
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self._inner = kwargs
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def __getitem__(self, key):
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@ -92,10 +114,13 @@ class _STIXBase(collections.Mapping):
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# Handle attribute access just like key access
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def __getattr__(self, name):
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if name.startswith('_'):
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return super(_STIXBase, self).__getattr__(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':
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if name != '_inner' and not name.startswith("_STIXBase__"):
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print(name)
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raise ValueError("Cannot modify properties after creation.")
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super(_STIXBase, self).__setattr__(name, value)
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@ -0,0 +1,110 @@
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import uuid
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class Property(object):
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"""Represent a property of STIX data type.
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Subclasses can define the following attributes as keyword arguments to
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__init__():
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- `required` - If `True`, the property must be provided when creating an
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object with that property. No default value exists for these properties.
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(Default: `False`)
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- `fixed` - This provides a constant default value. Users are free to
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provide this value explicity when constructing an object (which allows
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you to copy *all* values from an existing object to a new object), but
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if the user provides a value other than the `fixed` value, it will raise
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an error. This is semantically equivalent to defining both:
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- a `validate()` function that checks if the value matches the fixed
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value, and
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- a `default()` function that returns the fixed value.
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(Default: `None`)
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Subclasses can also define the following functions.
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- `def clean(self, value) -> any:`
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- Transform `value` into a valid value for this property. This should
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raise a ValueError if such no such transformation is possible.
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- `def validate(self, value) -> any:`
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- check that `value` is valid for this property. This should return
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a valid value (possibly modified) for this property, or raise a
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ValueError if the value is not valid.
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(Default: if `clean` is defined, it will attempt to call `clean` and
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return the result or pass on a ValueError that `clean` raises. If
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`clean` is not defined, this will return `value` unmodified).
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- `def default(self):`
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- provide a default value for this property.
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- `default()` can return the special value `NOW` to use the current
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time. This is useful when several timestamps in the same object need
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to use the same default value, so calling now() for each field--
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likely several microseconds apart-- does not work.
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Subclasses can instead provide lambda functions for `clean`, and `default`
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as keyword arguments. `validate` should not be provided as a lambda since
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lambdas cannot raise their own exceptions.
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"""
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def __init__(self, required=False, fixed=None, clean=None, validate=None, default=None):
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self.required = required
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if fixed:
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self.validate = lambda x: x == fixed
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self.default = lambda: fixed
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if clean:
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self.clean = clean
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if validate:
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self.validate = validate
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if default:
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self.default = default
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def clean(self, value):
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raise NotImplementedError
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def validate(self, value):
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try:
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value = self.clean(value)
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except NotImplemetedError:
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pass
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return value
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class TypeProperty(Property):
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def __init__(self, type):
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self.type = type
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def validate(self, value):
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if value != self.type:
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raise ValueError("Invalid type value")
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def default(self):
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return self.type
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class List(Property):
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def __init__(self, contained):
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"""
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contained should be a type whose constructor creates an object from the value
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"""
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self.contained = contained
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def validate(self, value):
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# TODO: ensure iterable
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for item in value:
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self.contained.validate(item)
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def clean(self, value):
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return [self.contained(x) for x in value]
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class IDProperty(Property):
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def __init__(self, type):
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self.type = type
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def validate(self, value):
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# TODO: validate GUID as well
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return value.startswith(self.type + "--")
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def default(self):
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return self.type + "--" + str(uuid.uuid4())
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@ -0,0 +1,54 @@
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import pytest
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from stix2.properties import Property, IDProperty
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def test_property():
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p = Property()
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assert p.required is False
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def test_basic_validate():
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class Prop(Property):
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def validate(self, value):
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if value == 42:
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return value
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else:
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raise ValueError("Must be 42")
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p = Prop()
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assert p.validate(42) == 42
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with pytest.raises(ValueError):
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p.validate(41)
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def test_default_field():
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class Prop(Property):
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def default(self):
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return 77
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p = Prop()
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assert p.default() == 77
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def test_fixed_property():
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p = Property(fixed="2.0")
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assert p.validate("2.0") is True
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assert p.validate("x") is False
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assert p.validate(2.0) is False
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assert p.default() == "2.0"
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def test_id_property():
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idprop = IDProperty('my-type')
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assert idprop.validate('my-type--90aaca8a-1110-5d32-956d-ac2f34a1bd8c') is True
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assert idprop.validate('not-my-type--90aaca8a-1110-5d32-956d-ac2f34a1bd8c') is False
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assert idprop.validate(idprop.default())
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