localize certificate references on VerifiableNode

nucypher/crypto/api.py

@@ -115,8 +115,8 @@ def ecdsa_verify(message: bytes,
 
 
 def _save_tls_certificate(certificate: Certificate,
-                          full_filepath,
-                          force: bool = True,
+                          full_filepath: str,
+                          force: bool = True,  # TODO
                           ) -> str:
     if force is False and os.path.isfile(full_filepath):
         raise FileExistsError('A TLS certificate already exists at {}.'.format(full_filepath))
@@ -125,6 +125,8 @@ def _save_tls_certificate(certificate: Certificate,
         public_pem_bytes = certificate.public_bytes(Encoding.PEM)
         certificate_file.write(public_pem_bytes)
 
+    return full_filepath
+
 
 def load_tls_certificate(filepath: str) -> Certificate:
     """Deserialize an X509 certificate from a filepath"""
@@ -140,10 +142,9 @@ def load_tls_certificate(filepath: str) -> Certificate:
 def generate_self_signed_certificate(common_name: str,
                                      curve: EllipticCurve,
                                      host: str,
-                                     certificate_dir: str,
                                      private_key: _EllipticCurvePrivateKey = None,
                                      days_valid: int = 365
-                                     ) -> Tuple[Certificate, _EllipticCurvePrivateKey, str]:
+                                     ) -> Tuple[Certificate, _EllipticCurvePrivateKey]:
 
     if not private_key:
         private_key = ec.generate_private_key(curve, default_backend())

nucypher/network/nodes.py

@@ -1,5 +1,8 @@
+import os
+
 import OpenSSL
 from constant_sorrow import constants
+from cryptography.x509 import Certificate
 from eth_keys.datatypes import Signature as EthSignature
 
 from nucypher.crypto.api import _save_tls_certificate
@@ -17,13 +20,19 @@ class VerifiableNode:
     _verified_node = False
 
     def __init__(self,
+                 certificate: Certificate,
+                 certificate_filepath: str,
                  interface_signature=constants.NOT_SIGNED.bool_value(False),
-                 certificate_filepath: str = None,
                  ) -> None:
 
-        self.certificate_filepath = certificate_filepath  # TODO: This gets messy when it is None (although it being None is actually reasonable in some cases, at least for testing).  Let's make this a method instead that inspects the TLSHostingPower (similar to get_deployer()).
+        self.certificate = certificate
+        self.certificate_filepath = certificate_filepath
         self._interface_signature_object = interface_signature
 
+        # TODO: This gets messy when it is None
+        # (although it being None is actually reasonable in some cases, at least for testing).
+        # Let's make this a method instead that inspects the TLSHostingPower (similar to get_deployer()).
+
     class InvalidNode(SuspiciousActivity):
         """
         Raised when a node has an invalid characteristic - stamp, interface, or address.
@@ -34,6 +43,12 @@ class VerifiableNode:
         Raise when a Character tries to use another Character as decentralized when the latter is federated_only.
         """
 
+    @classmethod
+    def from_tls_hosting_power(cls, tls_hosting_power: TLSHostingPower, *args, **kwargs):
+        certificate_filepath = tls_hosting_power.keypair.certificate_filepath
+        certificate = tls_hosting_power.keypair.certificate
+        return cls(certificate=certificate, certificate_filepath=certificate_filepath, *args, **kwargs)
+
     def _stamp_has_valid_wallet_signature(self):
         signature_bytes = self._evidence_of_decentralized_identity
         if signature_bytes is constants.NOT_SIGNED:
@@ -141,21 +156,28 @@ class VerifiableNode:
                 raise NoSigningPower("This Ursula is a Stranger; you didn't init with an interface signature, so you can't verify.")
         return self._interface_signature_object
 
-    def certificate(self):
-        return self._crypto_power.power_ups(TLSHostingPower).keypair.certificate
-
-    def save_certificate_to_disk(self, directory):
-        x509 = OpenSSL.crypto.X509.from_cryptography(self.certificate())
+    @property
+    def common_name(self):
+        x509 = OpenSSL.crypto.X509.from_cryptography(self.certificate)
         subject_components = x509.get_subject().get_components()
         common_name_as_bytes = subject_components[0][1]
         common_name_from_cert = common_name_as_bytes.decode()
+        return common_name_from_cert
+
+    @property
+    def certificate_filename(self):
+        return self.common_name + '.pem'  # TODO: use cert encoding..?
+
+    def save_certificate_to_disk(self, directory):
+        x509 = OpenSSL.crypto.X509.from_cryptography(self.certificate)
+        subject_components = x509.get_subject().get_components()
+        common_name_as_bytes = subject_components[0][1]
+        common_name_from_cert = common_name_as_bytes.decode()
+
         if not self.checksum_public_address == common_name_from_cert:
             # TODO: It's better for us to have checked this a while ago so that this situation is impossible.  #443
-            raise ValueError(
-                "You passed a common_name that is not the same one as the cert.  Why?  FWIW, You don't even need to pass a common name here; the cert will be saved according to the name on the cert itself.")
-
-        certificate_filepath = "{}/{}".format(directory,
-                                              common_name_from_cert)  # TODO: Do this with proper path tooling.
-        _save_tls_certificate(self.certificate(), full_filepath=certificate_filepath)
+            raise ValueError("You passed a common_name that is not the same one as the cert.  Why?  FWIW, You don't even need to pass a common name here; the cert will be saved according to the name on the cert itself.")
 
+        certificate_filepath = os.path.join(directory, self.certificate_filename)
+        _save_tls_certificate(self.certificate, full_filepath=certificate_filepath)
         self.certificate_filepath = certificate_filepath