Convert REF_PROPERTY to ReferenceProperty

stix2/common.py

@@ -3,17 +3,9 @@
 import re
 
 from .base import _STIXBase
-from .properties import Property, BooleanProperty
+from .properties import Property, BooleanProperty, ReferenceProperty
 from .utils import NOW
 
-ref_regex = ("^[a-z][a-z-]+[a-z]--[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}"
-             "-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$")
-
-REF_PROPERTY = {
-    'validate': (lambda x, val: re.match(ref_regex, val)),
-    'error_msg': "{type} {field} values must consist of a valid STIX type name and a valid UUID, separated by '--'."
-}
-
 COMMON_PROPERTIES = {
     # 'type' and 'id' should be defined on each individual type
     'created': {
@@ -24,7 +16,7 @@ COMMON_PROPERTIES = {
     },
     'external_references': {},
     'revoked': BooleanProperty(),
-    'created_by_ref': REF_PROPERTY
+    'created_by_ref': ReferenceProperty(),
 }
 
 

stix2/properties.py

@@ -1,3 +1,4 @@
+import re
 import uuid
 
 
@@ -117,3 +118,16 @@ class BooleanProperty(Property):
         if not isinstance(value, bool):
             raise ValueError("must be a boolean value.")
         return value
+
+
+REF_REGEX = re.compile("^[a-z][a-z-]+[a-z]--[0-9a-fA-F]{8}-[0-9a-fA-F]{4}"
+                       "-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$")
+
+
+class ReferenceProperty(Property):
+    # TODO: support references that must be to a specific object type
+
+    def validate(self, value):
+        if not REF_REGEX.match(value):
+            raise ValueError("must match <object-type>--<guid>.")
+        return value

stix2/test/test_properties.py

@@ -1,6 +1,7 @@
 import pytest
 
-from stix2.properties import Property, BooleanProperty, IDProperty, TypeProperty
+from stix2.properties import (Property, BooleanProperty, IDProperty,
+                              ReferenceProperty, TypeProperty)
 
 
 def test_property():
@@ -76,3 +77,11 @@ def test_boolean_property():
         print(invalid)
         with pytest.raises(ValueError):
             bool_prop.validate(invalid)
+
+
+def test_reference_property():
+    ref_prop = ReferenceProperty()
+
+    assert ref_prop.validate("my-type--3a331bfe-0566-55e1-a4a0-9a2cd355a300")
+    with pytest.raises(ValueError):
+        ref_prop.validate("foo")

stix2/test/test_stix2.py

@@ -179,7 +179,7 @@ def test_indicator_required_field_pattern():
 def test_indicator_created_ref_invalid_format():
     with pytest.raises(ValueError) as excinfo:
         indicator = stix2.Indicator(created_by_ref='myprefix--12345678', **INDICATOR_KWARGS)
-    assert str(excinfo.value) == "Indicator created_by_ref values must consist of a valid STIX type name and a valid UUID, separated by '--'."
+    assert str(excinfo.value) == "Invalid value for Indicator 'created_by_ref': must match <object-type>--<guid>."
 
 
 def test_indicator_revoked_invalid():