blog/A-IT/10-编程语言/c.c++/工具类库/grpc

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

#include <grpcpp/grpcpp.h>
#include <grpcpp/health_check_service_interface.h>
#include <grpcpp/ext/proto_server_reflection_plugin.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;

// 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::EnableDefaultHealthCheckService(true);
  grpc::reflection::InitProtoReflectionServerBuilderPlugin();
  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. In this case it corresponds to an *synchronous* service.
  builder.RegisterService(&service);  // 向rpc框架注册rpc接口
  // 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;
}

#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)) {}

  // Assembles the client's payload, sends it and presents the response back
  // from the server.
  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) {
  // Instantiate the client. It requires a channel, out of which the actual RPCs
  // are created. This channel models a connection to an endpoint specified by
  // the argument "--target=" which is the only expected argument.
  // We indicate that the channel isn't authenticated (use of
  // InsecureChannelCredentials()).
  std::string target_str;
  std::string arg_str("--target");
  if (argc > 1) {
    std::string arg_val = argv[1];
    size_t start_pos = arg_val.find(arg_str);
    if (start_pos != std::string::npos) {
      start_pos += arg_str.size();
      if (arg_val[start_pos] == '=') {
        target_str = arg_val.substr(start_pos + 1);
      } else {
        std::cout << "The only correct argument syntax is --target=" << std::endl;
        return 0;
      }
    } else {
      std::cout << "The only acceptable argument is --target=" << std::endl;
      return 0;
    }
  } else {
    target_str = "localhost:50051";
  }
  GreeterClient greeter(grpc::CreateChannel(
      target_str, grpc::InsecureChannelCredentials()));
  std::string user("world");
  std::string reply = greeter.SayHello(user);
  std::cout << "Greeter received: " << reply << std::endl;

  return 0;
}

class SudokuService::Stub final : public ::grpc::internal::StubInterface {
public:
  // 创建 Stub 对象
  Stub(const std::shared_ptr< ::grpc::ChannelInterface>& channel) 
    : ::grpc::internal::StubInterface(channel) {}

  // Solve 方法的同步调用版本
  ::grpc::Status Solve(::grpc::ClientContext* context, const ::SudokuRequest& request, ::SudokuResponse* response) {
    return ::grpc::internal::BlockingUnaryCall(channel_.get(), rpcmethod_Solve_, context, request, response);
  }

  // Solve 方法的异步调用版本（客户端使用）
  std::unique_ptr< ::grpc::ClientAsyncResponseReader< ::SudokuResponse>> AsyncSolve(::grpc::ClientContext* context, const ::SudokuRequest& request, ::grpc::CompletionQueue* cq) {
    return ::grpc::internal::ClientAsyncResponseReaderFactory< ::SudokuResponse>::Create(channel_.get(), cq, rpcmethod_Solve_, context, request, true);
  }

  // 异步调用版本的非阻塞方式
  std::unique_ptr< ::grpc::ClientAsyncResponseReader< ::SudokuResponse>> PrepareAsyncSolve(::grpc::ClientContext* context, const ::SudokuRequest& request, ::grpc::CompletionQueue* cq) {
    return ::grpc::internal::ClientAsyncResponseReaderFactory< ::SudokuResponse>::Create(channel_.get(), cq, rpcmethod_Solve_, context, request, false);
  }

private:
  // Solve 方法的定义
  const ::grpc::internal::RpcMethod rpcmethod_Solve_ = 
    ::grpc::internal::RpcMethod("SudokuService/Solve", ::grpc::internal::RpcMethod::NORMAL_RPC, channel_);
};

class SudokuService::Service : public ::grpc::Service {
public:
  Service() {
    AddMethod(new ::grpc::internal::RpcServiceMethod(
      "SudokuService/Solve",
      ::grpc::internal::RpcMethod::NORMAL_RPC,
      new ::grpc::internal::RpcMethodHandler< SudokuService::Service, ::SudokuRequest, ::SudokuResponse>(
        std::mem_fn(&SudokuService::Service::Solve), this)));
  }

  // 需要服务端重写的虚方法
  virtual ::grpc::Status Solve(::grpc::ServerContext* context, const ::SudokuRequest* request, ::SudokuResponse* response) {
    // 默认返回未实现状态，必须由服务端实现这个方法
    return ::grpc::Status(::grpc::StatusCode::UNIMPLEMENTED, "");
  }
};