introduce PropertyValidator (wrapper)

owrx/property/__init__.py

@@ -24,7 +24,6 @@ class Subscription(object):
 class PropertyManager(ABC):
     def __init__(self):
         self.subscribers = []
-        self.validators = {}
 
     @abstractmethod
     def __getitem__(self, item):
@@ -83,9 +82,6 @@ class PropertyManager(ABC):
             except Exception as e:
                 logger.exception(e)
 
-    def setValidator(self, name, validator):
-        self.validators[name] = Validator.of(validator)
-
 
 class PropertyLayer(PropertyManager):
     def __init__(self):
@@ -153,6 +149,49 @@ class PropertyFilter(PropertyManager):
         return [k for k in self.pm.keys() if k in self.props]
 
 
+class PropertyValidationError(Exception):
+    def __init__(self, key, value):
+        super().__init__('Invalid value for property "{key}": "{value}"'.format(key=key, value=str(value)))
+
+
+class PropertyValidator(PropertyManager):
+    def __init__(self, pm: PropertyManager, validators=None):
+        self.pm = pm
+        if validators is None:
+            self.validators = {}
+        else:
+            self.validators = {k: Validator.of(v) for k, v in validators.items()}
+        super().__init__()
+
+    def validate(self, key, value):
+        if key not in self.validators:
+            return
+        if not self.validators[key].isValid(value):
+            raise PropertyValidationError(key, value)
+
+    def setValidator(self, key, validator):
+        self.validators[key] = Validator.of(validator)
+
+    def __getitem__(self, item):
+        return self.pm.__getitem__(item)
+
+    def __setitem__(self, key, value):
+        self.validate(key, value)
+        return self.pm.__setitem__(key, value)
+
+    def __contains__(self, item):
+        return self.pm.__contains__(item)
+
+    def __dict__(self):
+        return self.pm.__dict__()
+
+    def __delitem__(self, key):
+        return self.pm.__delitem__(key)
+
+    def keys(self):
+        return self.pm.keys()
+
+
 class PropertyStack(PropertyManager):
     def __init__(self):
         super().__init__()

test/property/test_property_validator.py

@@ -0,0 +1,37 @@
+from unittest import TestCase
+from owrx.property import PropertyLayer, PropertyValidator, PropertyValidationError
+from owrx.property.validators import NumberValidator, StringValidator
+
+
+class PropertyValidatorTest(TestCase):
+    def testPassesUnvalidated(self):
+        pm = PropertyLayer()
+        pv = PropertyValidator(pm)
+        pv["testkey"] = "testvalue"
+        self.assertEqual(pv["testkey"], "testvalue")
+        self.assertEqual(pm["testkey"], "testvalue")
+
+    def testPassesValidValue(self):
+        pv = PropertyValidator(PropertyLayer(), {"testkey": NumberValidator()})
+        pv["testkey"] = 42
+        self.assertEqual(pv["testkey"], 42)
+
+    def testThrowsErrorOnInvalidValue(self):
+        pv = PropertyValidator(PropertyLayer(), {"testkey": NumberValidator()})
+        with self.assertRaises(PropertyValidationError):
+            pv["testkey"] = "text"
+
+    def testSetValidator(self):
+        pv = PropertyValidator(PropertyLayer())
+        pv.setValidator("testkey", NumberValidator())
+        with self.assertRaises(PropertyValidationError):
+            pv["testkey"] = "text"
+
+    def testUpdateValidator(self):
+        pv = PropertyValidator(PropertyLayer(), {"testkey": StringValidator()})
+        # this should pass
+        pv["testkey"] = "text"
+        pv.setValidator("testkey", NumberValidator())
+        # this should raise
+        with self.assertRaises(PropertyValidationError):
+            pv["testkey"] = "text"