1 #include "greeter.grpc.fb.h"
2 #include "greeter_generated.h"
3
4 #include <grpc++/grpc++.h>
5
6 #include <iostream>
7 #include <memory>
8 #include <string>
9
10 class GreeterServiceImpl final : public Greeter::Service {
SayHello(grpc::ServerContext * context,const flatbuffers::grpc::Message<HelloRequest> * request_msg,flatbuffers::grpc::Message<HelloReply> * response_msg)11 virtual grpc::Status SayHello(
12 grpc::ServerContext *context,
13 const flatbuffers::grpc::Message<HelloRequest> *request_msg,
14 flatbuffers::grpc::Message<HelloReply> *response_msg) override {
15 // flatbuffers::grpc::MessageBuilder mb_;
16 // We call GetRoot to "parse" the message. Verification is already
17 // performed by default. See the notes below for more details.
18 const HelloRequest *request = request_msg->GetRoot();
19
20 // Fields are retrieved as usual with FlatBuffers
21 const std::string &name = request->name()->str();
22
23 // `flatbuffers::grpc::MessageBuilder` is a `FlatBufferBuilder` with a
24 // special allocator for efficient gRPC buffer transfer, but otherwise
25 // usage is the same as usual.
26 auto msg_offset = mb_.CreateString("Hello, " + name);
27 auto hello_offset = CreateHelloReply(mb_, msg_offset);
28 mb_.Finish(hello_offset);
29
30 // The `ReleaseMessage<T>()` function detaches the message from the
31 // builder, so we can transfer the resopnse to gRPC while simultaneously
32 // detaching that memory buffer from the builer.
33 *response_msg = mb_.ReleaseMessage<HelloReply>();
34 assert(response_msg->Verify());
35
36 // Return an OK status.
37 return grpc::Status::OK;
38 }
39
SayManyHellos(grpc::ServerContext * context,const flatbuffers::grpc::Message<ManyHellosRequest> * request_msg,grpc::ServerWriter<flatbuffers::grpc::Message<HelloReply>> * writer)40 virtual grpc::Status SayManyHellos(
41 grpc::ServerContext *context,
42 const flatbuffers::grpc::Message<ManyHellosRequest> *request_msg,
43 grpc::ServerWriter<flatbuffers::grpc::Message<HelloReply>> *writer)
44 override {
45 // The streaming usage below is simply a combination of standard gRPC
46 // streaming with the FlatBuffers usage shown above.
47 const ManyHellosRequest *request = request_msg->GetRoot();
48 const std::string &name = request->name()->str();
49 int num_greetings = request->num_greetings();
50
51 for (int i = 0; i < num_greetings; i++) {
52 auto msg_offset = mb_.CreateString("Many hellos, " + name);
53 auto hello_offset = CreateHelloReply(mb_, msg_offset);
54 mb_.Finish(hello_offset);
55 writer->Write(mb_.ReleaseMessage<HelloReply>());
56 }
57
58 return grpc::Status::OK;
59 }
60
61 flatbuffers::grpc::MessageBuilder mb_;
62 };
63
RunServer()64 void RunServer() {
65 std::string server_address("0.0.0.0:50051");
66 GreeterServiceImpl service;
67
68 grpc::ServerBuilder builder;
69 builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());
70 builder.RegisterService(&service);
71 std::unique_ptr<grpc::Server> server(builder.BuildAndStart());
72 std::cerr << "Server listening on " << server_address << std::endl;
73
74 server->Wait();
75 }
76
main(int argc,const char * argv[])77 int main(int argc, const char *argv[]) {
78 RunServer();
79 return 0;
80 }
81