• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1# Copyright 2017 gRPC authors.
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#     http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14"""Interceptor that adds headers to outgoing requests."""
15
16import grpc
17
18
19class _ConcreteValue(grpc.Future):
20
21    def __init__(self, result):
22        self._result = result
23
24    def cancel(self):
25        return False
26
27    def cancelled(self):
28        return False
29
30    def running(self):
31        return False
32
33    def done(self):
34        return True
35
36    def result(self, timeout=None):
37        return self._result
38
39    def exception(self, timeout=None):
40        return None
41
42    def traceback(self, timeout=None):
43        return None
44
45    def add_done_callback(self, fn):
46        fn(self._result)
47
48
49class DefaultValueClientInterceptor(grpc.UnaryUnaryClientInterceptor,
50                                    grpc.StreamUnaryClientInterceptor):
51
52    def __init__(self, value):
53        self._default = _ConcreteValue(value)
54
55    def _intercept_call(self, continuation, client_call_details,
56                        request_or_iterator):
57        response = continuation(client_call_details, request_or_iterator)
58        return self._default if response.exception() else response
59
60    def intercept_unary_unary(self, continuation, client_call_details, request):
61        return self._intercept_call(continuation, client_call_details, request)
62
63    def intercept_stream_unary(self, continuation, client_call_details,
64                               request_iterator):
65        return self._intercept_call(continuation, client_call_details,
66                                    request_iterator)
67