Return None on vlaue_for_protocol that does not have any value

Author: ntninja

multiaddr/multiaddr.py

@@ -110,7 +110,21 @@ def decapsulate(self, other):
         return Multiaddr(s1[:idx])
 
     def value_for_protocol(self, proto):
-        """Return the value (if any) following the specified protocol."""
+        """Return the value (if any) following the specified protocol
+        
+        Returns
+        -------
+        union[object, NoneType]
+            The parsed protocol value for the given protocol code or ``None``
+            if the given protocol does not require any value
+        
+        Raises
+        ------
+        ~multiaddr.exceptions.BinaryParseError
+            The stored MultiAddr binary representation is invalid
+        ~multiaddr.exceptions.ProtocolLookupError
+            MultiAddr does not contain any instance of this protocol
+        """
         if not isinstance(proto, protocols.Protocol):
             if isinstance(proto, int):
                 proto = protocols.protocol_with_code(proto)
@@ -129,6 +143,6 @@ def value_for_protocol(self, proto):
                         six.raise_from(exceptions.BinaryParseError(str(exc), self.to_bytes(), proto2.name, exc), exc)
                 else:
                     # We were given something like '/utp', which doesn't have
-                    # an address, so return ''
-                    return ''
+                    # an address, so return None
+                    return None
         raise exceptions.ProtocolLookupError(proto, str(self))

tests/test_multiaddr.py

@@ -190,17 +190,17 @@ def test_get_value():
         "p2p/QmbHVEEepCi7rn7VL7Exxpd2Ci9NNB6ifvqwhsrbRMgQFP")
 
     assert_value_for_proto(ma, P_IP4, "127.0.0.1")
-    assert_value_for_proto(ma, P_UTP, "")
+    assert_value_for_proto(ma, P_UTP, None)
     assert_value_for_proto(ma, P_TCP, "5555")
     assert_value_for_proto(ma, P_UDP, "1234")
     assert_value_for_proto(
         ma, P_P2P, "QmbHVEEepCi7rn7VL7Exxpd2Ci9NNB6ifvqwhsrbRMgQFP")
     assert_value_for_proto(ma, "ip4", "127.0.0.1")
-    assert_value_for_proto(ma, "utp", "")
+    assert_value_for_proto(ma, "utp", None)
     assert_value_for_proto(ma, "tcp", "5555")
     assert_value_for_proto(ma, "udp", "1234")
     assert_value_for_proto(ma, protocol_with_name("ip4"), "127.0.0.1")
-    assert_value_for_proto(ma, protocol_with_name("utp"), "")
+    assert_value_for_proto(ma, protocol_with_name("utp"), None)
     assert_value_for_proto(ma, protocol_with_name("tcp"), "5555")
     assert_value_for_proto(ma, protocol_with_name("udp"), "1234")
 
@@ -224,7 +224,7 @@ def test_get_value():
     a = Multiaddr("/ip4/0.0.0.0/udp/12345/utp")  # ending in a no-value one.
     assert_value_for_proto(a, P_IP4, "0.0.0.0")
     assert_value_for_proto(a, P_UDP, "12345")
-    assert_value_for_proto(a, P_UTP, "")
+    assert_value_for_proto(a, P_UTP, None)
 
     a = Multiaddr("/ip4/0.0.0.0/unix/a/b/c/d")  # ending in a path one.
     assert_value_for_proto(a, P_IP4, "0.0.0.0")