1 files changed, 68 insertions, 0 deletions
diff --git a/examples/python/interceptors/default_value/default_value_client_interceptor.py b/examples/python/interceptors/default_value/default_value_client_interceptor.py
new file mode 100644
index 0000000000..c549f2b861
--- /dev/null
+++ b/examples/python/interceptors/default_value/default_value_client_interceptor.py
@@ -0,0 +1,68 @@
+# 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.
+"""Interceptor that adds headers to outgoing requests."""
+
+import collections
+
+import grpc
+
+
+class _ConcreteValue(grpc.Future):
+
+    def __init__(self, result):
+        self._result = result
+
+    def cancel(self):
+        return False
+
+    def cancelled(self):
+        return False
+
+    def running(self):
+        return False
+
+    def done(self):
+        return True
+
+    def result(self, timeout=None):
+        return self._result
+
+    def exception(self, timeout=None):
+        return None
+
+    def traceback(self, timeout=None):
+        return None
+
+    def add_done_callback(self, fn):
+        fn(self._result)
+
+
+class DefaultValueClientInterceptor(grpc.UnaryUnaryClientInterceptor,
+                                    grpc.StreamUnaryClientInterceptor):
+
+    def __init__(self, value):
+        self._default = _ConcreteValue(value)
+
+    def _intercept_call(self, continuation, client_call_details,
+                        request_or_iterator):
+        response = continuation(client_call_details, request_or_iterator)
+        return self._default if response.exception() else response
+
+    def intercept_unary_unary(self, continuation, client_call_details, request):
+        return self._intercept_call(continuation, client_call_details, request)
+
+    def intercept_stream_unary(self, continuation, client_call_details,
+                               request_iterator):
+        return self._intercept_call(continuation, client_call_details,
+                                    request_iterator)