Each Ursula in a concat'd bytestring is variable length.

nucypher/network/middleware.py

@@ -134,7 +134,7 @@ class RestMiddleware:
             params = {}
 
         if announce_nodes:
-            payload = bytes().join(bytes(n) for n in announce_nodes)
+            payload = bytes().join(bytes(VariableLengthBytestring(n)) for n in announce_nodes)
             response = client.post("https://{}/node_metadata".format(url),
                                      verify=certificate_filepath,
                                      data=payload, timeout=2, params=params)

nucypher/network/nodes.py

@@ -29,7 +29,7 @@ import OpenSSL
 import maya
 import requests
 import time
-from bytestring_splitter import BytestringSplitter
+from bytestring_splitter import BytestringSplitter, VariableLengthBytestring
 from constant_sorrow import constants
 from cryptography.hazmat.primitives.serialization import Encoding
 from cryptography.x509 import Certificate, NameOID
@@ -515,7 +515,7 @@ class Learner:
             if self._crashed:
                 return self._crashed
             rounds_undertaken = self._learning_round - starting_round
-            if addresses.issubset(self.__known_nodes):
+            if addresses.issubset(self.known_nodes.addresses()):
                 if rounds_undertaken:
                     self.log.info("Learned about all nodes after {} rounds.".format(rounds_undertaken))
                 return True
@@ -638,7 +638,7 @@ class Learner:
             # TODO: What to do if the teacher improperly signed the node payload?
             raise
 
-        fleet_state_checksum_bytes, fleet_state_updated_bytes, nodes = FleetStateTracker.snapshot_splitter(node_payload,
+        fleet_state_checksum_bytes, fleet_state_updated_bytes, node_payload = FleetStateTracker.snapshot_splitter(node_payload,
                                                                                                            return_remainder=True)
         current_teacher.last_seen = maya.now()
         # TODO: This is weird - let's get a stranger FleetState going.
@@ -653,7 +653,7 @@ class Learner:
         if response.status_code == 204:
             return constants.FLEET_STATES_MATCH
 
-        node_list = Ursula.batch_from_bytes(nodes, federated_only=self.federated_only)  # TODO: 466
+        node_list = Ursula.batch_from_bytes(node_payload, federated_only=self.federated_only)  # TODO: 466
 
         new_nodes = []
         for node in node_list:

nucypher/network/server.py

@@ -169,8 +169,9 @@ class ProxyRESTRoutes:
     def all_known_nodes(self, request: Request):
         headers = {'Content-Type': 'application/octet-stream'}
         payload = self._node_tracker.snapshot()
-        ursulas_as_bytes = bytes().join(bytes(n) for n in self._node_tracker)
-        ursulas_as_bytes += self._node_bytes_caster()
+        ursulas_as_vbytes = (VariableLengthBytestring(n) for n in self._node_tracker)
+        ursulas_as_bytes = bytes().join(bytes(u) for u in ursulas_as_vbytes)
+        ursulas_as_bytes += VariableLengthBytestring(self._node_bytes_caster())
 
         payload += ursulas_as_bytes
 

nucypher/utilities/sandbox/middleware.py

@@ -18,6 +18,7 @@ along with nucypher.  If not, see <https://www.gnu.org/licenses/>.
 
 from apistar import TestClient
 
+from bytestring_splitter import VariableLengthBytestring
 from nucypher.characters.lawful import Ursula
 from nucypher.crypto.kits import RevocationKit
 from nucypher.network.middleware import RestMiddleware
@@ -118,5 +119,6 @@ class EvilMiddleWare(MockRestMiddleware):
         mock_client = self._get_mock_client_by_ursula(ursula)
         response = mock_client.post("http://localhost/node_metadata".format(mock_client),
                                     verify=False,
-                                    data=bytes(shitty_interface_id))
+                                    data=bytes(VariableLengthBytestring(shitty_interface_id))
+                                    )
         return response

tests/cli/test_run_ursula.py

@@ -25,6 +25,7 @@ from twisted.internet.error import CannotListenError
 from nucypher.cli import cli
 from nucypher.characters.base import Learner
 from nucypher.utilities.sandbox.constants import TEST_URSULA_INSECURE_DEVELOPMENT_PASSWORD
+from nucypher.utilities.sandbox.ursula import UrsulaCommandProtocol
 
 
 @pytest.mark.skip()

tests/config/test_firstula_circumstances.py

@@ -16,9 +16,8 @@ along with nucypher.  If not, see <https://www.gnu.org/licenses/>.
 """
 from functools import partial
 
-import maya
-import pytest
 import pytest_twisted
+from cryptography.hazmat.primitives import serialization
 from twisted.internet.threads import deferToThread
 
 from nucypher.network.middleware import RestMiddleware
@@ -62,15 +61,10 @@ def test_get_cert_from_running_seed_node(ursula_federated_test_config):
 
     def start_lonely_learning_loop():
         any_other_ursula.start_learning_loop()
-        start = maya.now()
-        while not firstula in any_other_ursula.known_nodes:
-            passed = maya.now() - start
-            if passed.seconds > 2:
-                pytest.fail("Didn't find the seed node.")
+        any_other_ursula.block_until_specific_nodes_are_known(set([firstula.checksum_public_address]), timeout=2)
 
     yield deferToThread(start_lonely_learning_loop)
     assert firstula in any_other_ursula.known_nodes
 
-    certificate_as_learned = list(any_other_ursula.known_nodes)[0].certificate
-    assert certificate_as_learned == certificate_as_deployed
-    any_other_ursula.stop_learning_loop()
+    firstula_as_learned = any_other_ursula.known_nodes[firstula.checksum_public_address]
+    assert certificate_as_deployed == firstula_as_learned.certificate