grpc c++语言hello world

1.定义proto

syntax = "proto3";

option java_package = "io.grpc.examples";

package helloworld;

//问候服务定义
service Greeter {
        //发送消息
        rpc SayHello(HelloRequest) returns (HelloReply){}
}

//请求消息包含name
message HelloRequest {
        string name = 1;
}

//响应消息包含message
message HelloReply {
        string message = 1;
}

2.生成helloworld.pb.h和helloworld.pb.cc

$ protoc --cpp_out=. helloworld.proto

3.生成helloworld.grpc.pb.h和helloworld.grpc.pb.cc

$ protoc --grpc_out=. --plugin=protoc-gen-grpc=/usr/local/bin/grpc_cpp_plugin helloworld.proto

4.服务端代码server.c

#include <iostream>
#include <memory>
#include <string>
 
#include <grpcpp/grpcpp.h>
 
#ifdef BAZEL_BUILD
#include "examples/protos/helloworld.grpc.pb.h"
#else
#include "helloworld.grpc.pb.h"
#endif
 
using grpc::Server;
using grpc::ServerBuilder;
using grpc::ServerContext;
using grpc::Status;
using helloworld::HelloRequest;
using helloworld::HelloReply;
using helloworld::Greeter;
 
//服务端行为
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;
 
    ServerBuilder builder;

    //在没有任何身份验证机制的情况下监听给定的地址
    builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());

    //注册服务
    builder.RegisterService(&service);

    //启动服务
    std::unique_ptr<Server> server(builder.BuildAndStart());
    std::cout << "Server listening on " << server_address << std::endl;
 
    //等待服务
    server->Wait();
}
 
int main(int argc, char **argv)
{
    RunServer();
 
    return 0;
}

5.客户端代码client.c

#include <iostream>
#include <memory>
#include <string>
 
#include <grpcpp/grpcpp.h>
 
#ifdef BAZEL_BUILD
#include "examples/protos/helloworld.grpc.pb.h"
#else
#include "helloworld.grpc.pb.h"
#endif
 
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)) {}
 
    //客户端请求函数
    std::string SayHello(const std::string &user)
    {
        //我们将要发送到服务器端的数据
        HelloRequest request;
        request.set_name(user);
 
        //我们从服务端收到的数据
        HelloReply reply;
 
        //客户端RPC上下文
        ClientContext context;
 
        //调用rpc函数
        Status status = stub_->SayHello(&context, request, &reply);
 
        //返回结果处理
        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)
{
    GreeterClient greeter(grpc::CreateChannel("127.0.0.1:50051", grpc::InsecureChannelCredentials()));

    std::string user("world");

    std::string reply = greeter.SayHello(user);

    std::cout << "Greeter received: " << reply << std::endl;
 
    return 0;
}

6.编译服务端及客户端

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

7.运行服务端及客户端

$ ./server 
Server listening on 0.0.0.0:50051
$ ./client 
Greeter received: Hello world