Add RetrievalKit field for marshalling/unmarshalling of request/response data that requires a RetrievalKit - intended to be part of Bob's retrieve schema in Porter.

nucypher/utilities/porter/control/specifications/fields/retrieve.py

@@ -0,0 +1,31 @@
+"""
+ This file is part of nucypher.
+
+ nucypher is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ nucypher is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with nucypher.  If not, see <https://www.gnu.org/licenses/>.
+"""
+
+from nucypher.control.specifications.exceptions import InvalidInputData
+from nucypher.control.specifications.fields import Base64BytesRepresentation
+from nucypher.crypto.kits import RetrievalKit as RetrievalKitClass
+
+
+# TODO should this be moved to character control - would this be used by a Bob character control endpoint?
+class RetrievalKit(Base64BytesRepresentation):
+    def _deserialize(self, value, attr, data, **kwargs):
+        try:
+            # decode base64 to bytes
+            retrieval_kit_bytes = super()._deserialize(value, attr, data, **kwargs)
+            return RetrievalKitClass.from_bytes(retrieval_kit_bytes)
+        except Exception as e:
+            raise InvalidInputData(f"Could not convert input for {self.name} to a valid checksum address: {e}")

tests/unit/test_porter.py

@@ -20,10 +20,13 @@ import pytest
 
 from nucypher.control.specifications.exceptions import InvalidInputData
 from nucypher.control.specifications.fields import StringList
+from nucypher.crypto.kits import RetrievalKit as RetrievalKitClass
+from nucypher.crypto.umbral_adapter import SecretKey, encrypt
 from nucypher.utilities.porter.control.specifications.fields import (
     HRAC,
     UrsulaChecksumAddress,
 )
+from nucypher.utilities.porter.control.specifications.fields.retrieve import RetrievalKit
 from tests.utils.policy import retrieval_request_setup
 
 
@@ -131,3 +134,25 @@ def test_ursula_checksum_address_string_list_field(get_random_checksum_address):
 
     with pytest.raises(InvalidInputData):
         field._deserialize(value=f"{ursula_1},{ursula_2},{ursula_3},{ursula_4},0xdeadbeef", attr=None, data=None)
+
+
+def test_retrieval_kit_field():
+    encrypting_key = SecretKey.random().public_key()
+    capsule, _ = encrypt(encrypting_key, b'testing_retrieval_kit')
+
+    retrieval_kit = RetrievalKitClass(capsule, set())
+
+    field = RetrievalKit()
+    serialized = field._serialize(value=retrieval_kit, attr=None, obj=None)
+    assert serialized == b64encode(bytes(retrieval_kit)).decode()
+
+    deserialized = field.deserialize(value=serialized, attr=None, data=None)
+    assert isinstance(deserialized, RetrievalKitClass)
+    assert deserialized.capsule == capsule
+    assert len(deserialized.queried_addresses) == 0
+
+    with pytest.raises(InvalidInputData):
+        field.deserialize(value=b"non_base_64_data", attr=None, data=None)
+
+    with pytest.raises(InvalidInputData):
+        field.deserialize(value=b64encode(b"invalid_retrieval_kit_bytes").decode(), attr=None, data=None)