Fix Beta API metadata looseness

4 files changed, 79 insertions, 15 deletions

diff --git a/src/python/grpcio/grpc/beta/_client_adaptations.py b/src/python/grpcio/grpc/beta/_client_adaptations.py
index 73ce22fa98..dcaa0eeaa2 100644
--- a/src/python/grpcio/grpc/beta/_client_adaptations.py
+++ b/src/python/grpcio/grpc/beta/_client_adaptations.py
@@ -15,6 +15,7 @@
 
 import grpc
 from grpc import _common
+from grpc.beta import _metadata
 from grpc.beta import interfaces
 from grpc.framework.common import cardinality
 from grpc.framework.foundation import future
@@ -157,10 +158,10 @@ class _Rendezvous(future.Future, face.Call):
         return _InvocationProtocolContext()
 
     def initial_metadata(self):
-        return self._call.initial_metadata()
+        return _metadata.beta(self._call.initial_metadata())
 
     def terminal_metadata(self):
-        return self._call.terminal_metadata()
+        return _metadata.beta(self._call.terminal_metadata())
 
     def code(self):
         return self._call.code()
@@ -182,14 +183,14 @@ def _blocking_unary_unary(channel, group, method, timeout, with_call,
             response, call = multi_callable.with_call(
                 request,
                 timeout=timeout,
-                metadata=effective_metadata,
+                metadata=_metadata.unbeta(effective_metadata),
                 credentials=_credentials(protocol_options))
             return response, _Rendezvous(None, None, call)
         else:
             return multi_callable(
                 request,
                 timeout=timeout,
-                metadata=effective_metadata,
+                metadata=_metadata.unbeta(effective_metadata),
                 credentials=_credentials(protocol_options))
     except grpc.RpcError as rpc_error_call:
         raise _abortion_error(rpc_error_call)
@@ -206,7 +207,7 @@ def _future_unary_unary(channel, group, method, timeout, protocol_options,
     response_future = multi_callable.future(
         request,
         timeout=timeout,
-        metadata=effective_metadata,
+        metadata=_metadata.unbeta(effective_metadata),
         credentials=_credentials(protocol_options))
     return _Rendezvous(response_future, None, response_future)
 
@@ -222,7 +223,7 @@ def _unary_stream(channel, group, method, timeout, protocol_options, metadata,
     response_iterator = multi_callable(
         request,
         timeout=timeout,
-        metadata=effective_metadata,
+        metadata=_metadata.unbeta(effective_metadata),
         credentials=_credentials(protocol_options))
     return _Rendezvous(None, response_iterator, response_iterator)
 
@@ -241,14 +242,14 @@ def _blocking_stream_unary(channel, group, method, timeout, with_call,
             response, call = multi_callable.with_call(
                 request_iterator,
                 timeout=timeout,
-                metadata=effective_metadata,
+                metadata=_metadata.unbeta(effective_metadata),
                 credentials=_credentials(protocol_options))
             return response, _Rendezvous(None, None, call)
         else:
             return multi_callable(
                 request_iterator,
                 timeout=timeout,
-                metadata=effective_metadata,
+                metadata=_metadata.unbeta(effective_metadata),
                 credentials=_credentials(protocol_options))
     except grpc.RpcError as rpc_error_call:
         raise _abortion_error(rpc_error_call)
@@ -265,7 +266,7 @@ def _future_stream_unary(channel, group, method, timeout, protocol_options,
     response_future = multi_callable.future(
         request_iterator,
         timeout=timeout,
-        metadata=effective_metadata,
+        metadata=_metadata.unbeta(effective_metadata),
         credentials=_credentials(protocol_options))
     return _Rendezvous(response_future, None, response_future)
 
@@ -281,7 +282,7 @@ def _stream_stream(channel, group, method, timeout, protocol_options, metadata,
     response_iterator = multi_callable(
         request_iterator,
         timeout=timeout,
-        metadata=effective_metadata,
+        metadata=_metadata.unbeta(effective_metadata),
         credentials=_credentials(protocol_options))
     return _Rendezvous(None, response_iterator, response_iterator)
 
diff --git a/src/python/grpcio/grpc/beta/_metadata.py b/src/python/grpcio/grpc/beta/_metadata.py
new file mode 100644
index 0000000000..e135f4dff4
--- /dev/null
+++ b/src/python/grpcio/grpc/beta/_metadata.py
@@ -0,0 +1,49 @@
+# Copyright 2017 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""API metadata conversion utilities."""
+
+import collections
+
+_Metadatum = collections.namedtuple('_Metadatum', ('key', 'value',))
+
+
+def _beta_metadatum(key, value):
+    beta_key = key if isinstance(key, (bytes,)) else key.encode('ascii')
+    beta_value = value if isinstance(value, (bytes,)) else value.encode('ascii')
+    return _Metadatum(beta_key, beta_value)
+
+
+def _metadatum(beta_key, beta_value):
+    key = beta_key if isinstance(beta_key, (str,)) else beta_key.decode('utf8')
+    if isinstance(beta_value, (str,)) or key[-4:] == '-bin':
+        value = beta_value
+    else:
+        value = beta_value.decode('utf8')
+    return _Metadatum(key, value)
+
+
+def beta(metadata):
+    if metadata is None:
+        return ()
+    else:
+        return tuple(_beta_metadatum(key, value) for key, value in metadata)
+
+
+def unbeta(beta_metadata):
+    if beta_metadata is None:
+        return ()
+    else:
+        return tuple(
+            _metadatum(beta_key, beta_value)
+            for beta_key, beta_value in beta_metadata)
diff --git a/src/python/grpcio/grpc/beta/_server_adaptations.py b/src/python/grpcio/grpc/beta/_server_adaptations.py
index ec363e9bc9..1c22dbe3bb 100644
--- a/src/python/grpcio/grpc/beta/_server_adaptations.py
+++ b/src/python/grpcio/grpc/beta/_server_adaptations.py
@@ -18,6 +18,7 @@ import threading
 
 import grpc
 from grpc import _common
+from grpc.beta import _metadata
 from grpc.beta import interfaces
 from grpc.framework.common import cardinality
 from grpc.framework.common import style
@@ -65,14 +66,15 @@ class _FaceServicerContext(face.ServicerContext):
         return _ServerProtocolContext(self._servicer_context)
 
     def invocation_metadata(self):
-        return _common.to_cygrpc_metadata(
-            self._servicer_context.invocation_metadata())
+        return _metadata.beta(self._servicer_context.invocation_metadata())
 
     def initial_metadata(self, initial_metadata):
-        self._servicer_context.send_initial_metadata(initial_metadata)
+        self._servicer_context.send_initial_metadata(
+            _metadata.unbeta(initial_metadata))
 
     def terminal_metadata(self, terminal_metadata):
-        self._servicer_context.set_terminal_metadata(terminal_metadata)
+        self._servicer_context.set_terminal_metadata(
+            _metadata.unbeta(terminal_metadata))
 
     def code(self, code):
         self._servicer_context.set_code(code)
diff --git a/src/python/grpcio/grpc/beta/implementations.py b/src/python/grpcio/grpc/beta/implementations.py
index e52ce764b5..312daf033e 100644
--- a/src/python/grpcio/grpc/beta/implementations.py
+++ b/src/python/grpcio/grpc/beta/implementations.py
@@ -21,6 +21,7 @@ import threading  # pylint: disable=unused-import
 import grpc
 from grpc import _auth
 from grpc.beta import _client_adaptations
+from grpc.beta import _metadata
 from grpc.beta import _server_adaptations
 from grpc.beta import interfaces  # pylint: disable=unused-import
 from grpc.framework.common import cardinality  # pylint: disable=unused-import
@@ -31,7 +32,18 @@ from grpc.framework.interfaces.face import face  # pylint: disable=unused-import
 ChannelCredentials = grpc.ChannelCredentials
 ssl_channel_credentials = grpc.ssl_channel_credentials
 CallCredentials = grpc.CallCredentials
-metadata_call_credentials = grpc.metadata_call_credentials
+
+
+def metadata_call_credentials(metadata_plugin, name=None):
+
+    def plugin(context, callback):
+
+        def wrapped_callback(beta_metadata, error):
+            callback(_metadata.unbeta(beta_metadata), error)
+
+        metadata_plugin(context, wrapped_callback)
+
+    return grpc.metadata_call_credentials(plugin, name=name)
 
 
 def google_call_credentials(credentials):