1 // Copyright 2022 the 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
15 #include <iostream>
16 #include <memory>
17 #include <string>
18
19 #include "examples/protos/helloworld.grpc.pb.h"
20
21 #include <grpcpp/grpcpp.h>
22
23 using grpc::Channel;
24 using grpc::ClientContext;
25 using grpc::Status;
26 using helloworld::Greeter;
27 using helloworld::HelloReply;
28 using helloworld::HelloRequest;
29
30 class GreeterClient {
31 public:
GreeterClient(std::shared_ptr<Channel> channel)32 GreeterClient(std::shared_ptr<Channel> channel)
33 : stub_(Greeter::NewStub(channel)) {}
34
35 // Assembles the client's payload, sends it and presents the response back
36 // from the server.
SayHello(const std::string & user)37 std::string SayHello(const std::string& user) {
38 // Data we are sending to the server.
39 HelloRequest request;
40 request.set_name(user);
41
42 // Container for the data we expect from the server.
43 HelloReply reply;
44
45 // Context for the client. It could be used to convey extra information to
46 // the server and/or tweak certain RPC behaviors.
47 ClientContext context;
48
49 // The actual RPC.
50 Status status = stub_->SayHello(&context, request, &reply);
51
52 // Act upon its status.
53 if (status.ok()) {
54 return reply.message();
55 } else {
56 std::cout << status.error_code() << ": " << status.error_message()
57 << std::endl;
58 return "RPC failed";
59 }
60 }
61
62 private:
63 std::unique_ptr<Greeter::Stub> stub_;
64 };
65
main(int argc,char ** argv)66 int main(int argc, char** argv) {
67 // Instantiate the client. It requires a channel, out of which the actual RPCs
68 // are created. This channel models a connection to an endpoint specified by
69 // the argument "--target=" which is the only expected argument.
70 // We indicate that the channel isn't authenticated (use of
71 // InsecureChannelCredentials()).
72 std::string target_str;
73 std::string arg_str("--target");
74 if (argc > 1) {
75 std::string arg_val = argv[1];
76 size_t start_pos = arg_val.find(arg_str);
77 if (start_pos != std::string::npos) {
78 start_pos += arg_str.size();
79 if (arg_val[start_pos] == '=') {
80 target_str = arg_val.substr(start_pos + 1);
81 } else {
82 std::cout << "The only correct argument syntax is --target="
83 << std::endl;
84 return 0;
85 }
86 } else {
87 std::cout << "The only acceptable argument is --target=" << std::endl;
88 return 0;
89 }
90 } else {
91 target_str = "unix:/tmp/server";
92 }
93 GreeterClient greeter(
94 grpc::CreateChannel(target_str, grpc::InsecureChannelCredentials()));
95 std::string user("world");
96 std::string reply(greeter.SayHello(user));
97 std::cout << "Greeter received: " << reply << std::endl;
98
99 return 0;
100 }
101