RPC: Specify encoding to msgpack.Packer/Unpacker

Currently, RPC requests using rpc_cli.py will crash on Python 3,
because the decoded string through msgpack-rpc is not str type
when the default encoding is not specified into msgpack.Unpacker.
On Python 2, bytes type is the same as str type, and this problem
does not occur.

The old spec of msgpack had no notation of the encoding, but now,
msgpack defines "UTF-8" as the default encoding and has the explicit
type definitions for String and Binary.
  https://github.com/msgpack/msgpack/blob/master/spec.md

This patch fixes to specify the encoding to msgpack.Packer/Unpacker
and enable to use Binary type when packing for the Python 3
compatibility.

Signed-off-by: IWASE Yusuke <iwase.yusuke0@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

1 files changed, 9 insertions, 11 deletions

diff --git a/ryu/lib/rpc.py b/ryu/lib/rpc.py
index ed38f976..bb4742a0 100644
--- a/ryu/lib/rpc.py
+++ b/ryu/lib/rpc.py
@@ -14,8 +14,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# msgpack-rpc
-# http://wiki.msgpack.org/display/MSGPACK/RPC+specification
+# Specification:
+# - msgpack
+#   https://github.com/msgpack/msgpack/blob/master/spec.md
+# - msgpack-rpc
+#   https://github.com/msgpack-rpc/msgpack-rpc/blob/master/spec.md
 
 from collections import deque
 import select
@@ -36,13 +39,8 @@ class MessageEncoder(object):
     """
     def __init__(self):
         super(MessageEncoder, self).__init__()
-        # note: on-wire msgpack has no notion of encoding.
-        # the msgpack-python library implicitly converts unicode to
-        # utf-8 encoded bytes by default.  we don't want to rely on
-        # the behaviour though because it seems to be going to change.
-        # cf. https://gist.github.com/methane/5022403
-        self._packer = msgpack.Packer(encoding=None)
-        self._unpacker = msgpack.Unpacker(encoding=None)
+        self._packer = msgpack.Packer(encoding='utf-8', use_bin_type=True)
+        self._unpacker = msgpack.Unpacker(encoding='utf-8')
         self._next_msgid = 0
 
     def _create_msgid(self):
@@ -51,7 +49,7 @@ class MessageEncoder(object):
         return this_id
 
     def create_request(self, method, params):
-        assert isinstance(method, six.binary_type)
+        assert isinstance(method, (str, six.binary_type))
         assert isinstance(params, list)
         msgid = self._create_msgid()
         return (self._packer.pack(
@@ -64,7 +62,7 @@ class MessageEncoder(object):
         return self._packer.pack([MessageType.RESPONSE, msgid, error, result])
 
     def create_notification(self, method, params):
-        assert isinstance(method, six.binary_type)
+        assert isinstance(method, (str, six.binary_type))
         assert isinstance(params, list)
         return self._packer.pack([MessageType.NOTIFY, method, params])