Add a base validation layer to CBORSerializable

Author: cffls

pycardano/exception.py

@@ -14,6 +14,10 @@ class InvalidAddressInputException(PyCardanoException):
     pass
 
 
+class InvalidDataException(PyCardanoException):
+    pass
+
+
 class InvalidArgumentException(PyCardanoException):
     pass
 

pycardano/serialization.py

@@ -93,7 +93,7 @@ def default_encoder(
             encoder.encode(item)
         encoder.write(b"\xff")
     else:
-        encoder.encode(value.to_primitive())
+        encoder.encode(value.to_validated_primitive())
 
 
 @typechecked
@@ -126,7 +126,7 @@ def to_shallow_primitive(self) -> Primitive:
             :const:`Primitive`: A CBOR primitive.
 
         Raises:
-            :class:`pycardano.exception.SerializeException`: When the object could not be converted to CBOR primitive
+            SerializeException: When the object could not be converted to CBOR primitive
                 types.
         """
         raise NotImplementedError(
@@ -140,7 +140,7 @@ def to_primitive(self) -> Primitive:
             :const:`Primitive`: A CBOR primitive.
 
         Raises:
-            :class:`pycardano.exception.SerializeException`: When the object or its elements could not be converted to
+            SerializeException: When the object or its elements could not be converted to
                 CBOR primitive types.
         """
         result = self.to_shallow_primitive()
@@ -189,6 +189,28 @@ def _dfs(value):
 
         return _dfs(result)
 
+    def validate(self):
+        """Validate the data stored in the current instance. Defaults to always pass.
+
+        Raises:
+            InvalidDataException: When the data is invalid.
+        """
+        pass
+
+    def to_validated_primitive(self) -> Primitive:
+        """Convert the instance and its elements to CBOR primitives recursively with data validated by :meth:`validate`
+        method.
+
+        Returns:
+            :const:`Primitive`: A CBOR primitive.
+
+        Raises:
+            SerializeException: When the object or its elements could not be converted to
+                CBOR primitive types.
+        """
+        self.validate()
+        return self.to_primitive()
+
     @classmethod
     def from_primitive(cls: CBORBase, value: Primitive) -> CBORBase:
         """Turn a CBOR primitive to its original class type.
@@ -201,7 +223,7 @@ def from_primitive(cls: CBORBase, value: Primitive) -> CBORBase:
             CBORBase: A CBOR serializable object.
 
         Raises:
-            :class:`pycardano.exception.DeserializeException`: When the object could not be restored from primitives.
+            DeserializeException: When the object could not be restored from primitives.
         """
         raise NotImplementedError(
             f"'from_primitive()' is not implemented by {cls.__name__}."
@@ -427,7 +449,7 @@ def to_shallow_primitive(self) -> List[Primitive]:
             :const:`Primitive`: A CBOR primitive.
 
         Raises:
-            :class:`pycardano.exception.SerializeException`: When the object could not be converted to CBOR primitive
+            SerializeException: When the object could not be converted to CBOR primitive
                 types.
         """
         primitives = []
@@ -450,7 +472,7 @@ def from_primitive(cls: ArrayBase, values: List[Primitive]) -> ArrayBase:
             :const:`ArrayBase`: Restored object.
 
         Raises:
-            :class:`pycardano.exception.DeserializeException`: When the object could not be restored from primitives.
+            DeserializeException: When the object could not be restored from primitives.
         """
         all_fields = [f for f in fields(cls) if f.init]
         if type(values) != list:
@@ -678,7 +700,7 @@ def from_primitive(cls: DictBase, value: dict) -> DictBase:
             :const:`DictBase`: Restored object.
 
         Raises:
-            :class:`pycardano.exception.DeserializeException`: When the object could not be restored from primitives.
+            DeserializeException: When the object could not be restored from primitives.
         """
         if not value:
             raise DeserializeException(f"Cannot accept empty value {value}.")