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#include "greeter.grpc.fb.h"
#include "greeter_generated.h"
#include <grpcpp/grpcpp.h>
#include <iostream>
#include <memory>
#include <string>
class GreeterServiceImpl final : public Greeter::Service {
virtual grpc::Status SayHello(
grpc::ServerContext *context,
const flatbuffers::grpc::Message<HelloRequest> *request_msg,
flatbuffers::grpc::Message<HelloReply> *response_msg) override {
flatbuffers::grpc::MessageBuilder mb_;
// We call GetRoot to "parse" the message. Verification is already
// performed by default. See the notes below for more details.
const HelloRequest *request = request_msg->GetRoot();
// Fields are retrieved as usual with FlatBuffers
const std::string &name = request->name()->str();
// `flatbuffers::grpc::MessageBuilder` is a `FlatBufferBuilder` with a
// special allocator for efficient gRPC buffer transfer, but otherwise
// usage is the same as usual.
auto msg_offset = mb_.CreateString("Hello, " + name);
auto hello_offset = CreateHelloReply(mb_, msg_offset);
mb_.Finish(hello_offset);
// The `ReleaseMessage<T>()` function detaches the message from the
// builder, so we can transfer the resopnse to gRPC while simultaneously
// detaching that memory buffer from the builer.
*response_msg = mb_.ReleaseMessage<HelloReply>();
assert(response_msg->Verify());
// Return an OK status.
return grpc::Status::OK;
}
virtual grpc::Status SayManyHellos(
grpc::ServerContext *context,
const flatbuffers::grpc::Message<ManyHellosRequest> *request_msg,
grpc::ServerWriter<flatbuffers::grpc::Message<HelloReply>> *writer)
override {
// The streaming usage below is simply a combination of standard gRPC
// streaming with the FlatBuffers usage shown above.
const ManyHellosRequest *request = request_msg->GetRoot();
const std::string &name = request->name()->str();
int num_greetings = request->num_greetings();
for (int i = 0; i < num_greetings; i++) {
auto msg_offset = mb_.CreateString("Many hellos, " + name);
auto hello_offset = CreateHelloReply(mb_, msg_offset);
mb_.Finish(hello_offset);
writer->Write(mb_.ReleaseMessage<HelloReply>());
}
return grpc::Status::OK;
}
flatbuffers::grpc::MessageBuilder mb_;
};
void RunServer() {
std::string server_address("0.0.0.0:50051");
GreeterServiceImpl service;
grpc::ServerBuilder builder;
builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());
builder.RegisterService(&service);
std::unique_ptr<grpc::Server> server(builder.BuildAndStart());
std::cerr << "Server listening on " << server_address << std::endl;
server->Wait();
}
int main(int argc, const char *argv[]) {
RunServer();
return 0;
}
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