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"""Base class for interceptors that operate on all RPC types."""
15
16import grpc
17
18
19class _GenericClientInterceptor(
20        grpc.UnaryUnaryClientInterceptor, grpc.UnaryStreamClientInterceptor,
21        grpc.StreamUnaryClientInterceptor, grpc.StreamStreamClientInterceptor):
22
23    def __init__(self, interceptor_function):
24        self._fn = interceptor_function
25
26    def intercept_unary_unary(self, continuation, client_call_details, request):
27        new_details, new_request_iterator, postprocess = self._fn(
28            client_call_details, iter((request,)), False, False)
29        response = continuation(new_details, next(new_request_iterator))
30        return postprocess(response) if postprocess else response
31
32    def intercept_unary_stream(self, continuation, client_call_details,
33                               request):
34        new_details, new_request_iterator, postprocess = self._fn(
35            client_call_details, iter((request,)), False, True)
36        response_it = continuation(new_details, next(new_request_iterator))
37        return postprocess(response_it) if postprocess else response_it
38
39    def intercept_stream_unary(self, continuation, client_call_details,
40                               request_iterator):
41        new_details, new_request_iterator, postprocess = self._fn(
42            client_call_details, request_iterator, True, False)
43        response = continuation(new_details, new_request_iterator)
44        return postprocess(response) if postprocess else response
45
46    def intercept_stream_stream(self, continuation, client_call_details,
47                                request_iterator):
48        new_details, new_request_iterator, postprocess = self._fn(
49            client_call_details, request_iterator, True, True)
50        response_it = continuation(new_details, new_request_iterator)
51        return postprocess(response_it) if postprocess else response_it
52
53
54def create(intercept_call):
55    return _GenericClientInterceptor(intercept_call)
56