使用C++写一个grpc的通信例子，包括客户端和服务端

好的，下面是一个简单的示例，包括客户端和服务端。首先，我们需要安装gRPC和protobuf库。

服务端代码：

#include <iostream>
#include <memory>
#include <string>

#include <grpcpp/grpcpp.h>

#include "helloworld.grpc.pb.h"

using grpc::Server;
using grpc::ServerBuilder;
using grpc::ServerContext;
using grpc::Status;
using helloworld::HelloRequest;
using helloworld::HelloReply;
using helloworld::Greeter;

// Logic and data behind the server's behavior.
class GreeterServiceImpl final : public Greeter::Service {
  Status SayHello(ServerContext* context, const HelloRequest* request,
                  HelloReply* reply) override {
    std::string prefix("Hello ");
    reply->set_message(prefix + request->name());
    return Status::OK;
  }
};

void RunServer() {
  std::string server_address("0.0.0.0:50051");
  GreeterServiceImpl service;

  grpc::ServerBuilder builder;
  // Listen on the given address without any authentication mechanism.
  builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());
  // Register "service" as the instance through which we'll communicate with clients.
  builder.RegisterService(&service);
  // Finally assemble the server.
  std::unique_ptr<Server> server(builder.BuildAndStart());
  std::cout << "Server listening on " << server_address << std::endl;

  // Wait for the server to shutdown. Note that some other thread must be
  // responsible for shutting down the server for this call to ever return.
  server->Wait();
}

int main(int argc, char** argv) {
  RunServer();
  return 0;
}

客户端代码：

#include <iostream>
#include <memory>
#include <string>

#include <grpcpp/grpcpp.h>

#include "helloworld.grpc.pb.h"

using grpc::Channel;
using grpc::ClientContext;
using grpc::Status;
using helloworld::HelloRequest;
using helloworld::HelloReply;
using helloworld::Greeter;

class GreeterClient {
 public:
  GreeterClient(std::shared_ptr<Channel> channel)
      : stub_(Greeter::NewStub(channel)) {}

  std::string SayHello(const std::string& user) {
    // Data we are sending to the server.
    HelloRequest request;
    request.set_name(user);

    // Container for the data we expect from the server.
    HelloReply reply;

    // Context for the client. It could be used to convey extra information to
    // the server and/or tweak certain RPC behaviors.
    ClientContext context;

    // The actual RPC.
    Status status = stub_->SayHello(&context, request, &reply);

    // Act upon its status.
    if (status.ok()) {
      return reply.message();
    } else {
      std::cout << status.error_code() << ": " << status.error_message()
                << std::endl;
      return "RPC failed";
    }
  }

 private:
  std::unique_ptr<Greeter::Stub> stub_;
};

int main(int argc, char** argv) {
  // Create a channel to the server.
  std::shared_ptr<Channel> channel =
      grpc::CreateChannel("localhost:50051", grpc::InsecureChannelCredentials());

  GreeterClient greeter(channel);
  std::string user("world");
  std::string reply = greeter.SayHello(user);
  std::cout << "Greeter received: " << reply << std::endl;

  return 0;
}

编译命令：

$ g++ -std=c++11 -I./include -L./lib -o server server.cpp helloworld.grpc.pb.cc helloworld.pb.cc -lgrpc++ -lgrpc -lprotobuf -lpthread
$ g++ -std=c++11 -I./include -L./lib -o client client.cpp helloworld.grpc.pb.cc helloworld.pb.cc -lgrpc++ -lgrpc -lprotobuf -lpthread

运行命令：

$ ./server
$ ./client

运行结果：

# server console
Server listening on 0.0.0.0:50051

# client console
Greeter received: Hello world