1 /*
2 *
3 * Copyright 2015 gRPC authors.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19 #include <iostream>
20 #include <memory>
21 #include <string>
22
23 #include <grpcpp/grpcpp.h>
24
25 #ifdef BAZEL_BUILD
26 #include "examples/protos/helloworld.grpc.pb.h"
27 #else
28 #include "helloworld.grpc.pb.h"
29 #endif
30
31 using grpc::Channel;
32 using grpc::ChannelArguments;
33 using grpc::ClientContext;
34 using grpc::Status;
35 using helloworld::HelloRequest;
36 using helloworld::HelloReply;
37 using helloworld::Greeter;
38
39 class GreeterClient {
40 public:
GreeterClient(std::shared_ptr<Channel> channel)41 GreeterClient(std::shared_ptr<Channel> channel)
42 : stub_(Greeter::NewStub(channel)) {}
43
44 // Assembles the client's payload, sends it and presents the response back
45 // from the server.
SayHello(const std::string & user)46 std::string SayHello(const std::string& user) {
47 // Data we are sending to the server.
48 HelloRequest request;
49 request.set_name(user);
50
51 // Container for the data we expect from the server.
52 HelloReply reply;
53
54 // Context for the client. It could be used to convey extra information to
55 // the server and/or tweak certain RPC behaviors.
56 ClientContext context;
57
58 // The actual RPC.
59 Status status = stub_->SayHello(&context, request, &reply);
60
61 // Act upon its status.
62 if (status.ok()) {
63 return reply.message();
64 } else {
65 std::cout << status.error_code() << ": " << status.error_message()
66 << std::endl;
67 return "RPC failed";
68 }
69 }
70
71 private:
72 std::unique_ptr<Greeter::Stub> stub_;
73 };
74
main(int argc,char ** argv)75 int main(int argc, char** argv) {
76 // Instantiate the client. It requires a channel, out of which the actual RPCs
77 // are created. This channel models a connection to an endpoint (in this case,
78 // localhost at port 50051). We indicate that the channel isn't authenticated
79 // (use of InsecureChannelCredentials()).
80 ChannelArguments args;
81 // Set the load balancing policy for the channel.
82 args.SetLoadBalancingPolicyName("round_robin");
83 GreeterClient greeter(grpc::CreateCustomChannel(
84 "localhost:50051", grpc::InsecureChannelCredentials(), args));
85 std::string user("world");
86 std::string reply = greeter.SayHello(user);
87 std::cout << "Greeter received: " << reply << std::endl;
88
89 return 0;
90 }
91