Qt中调用gRPC

RPC是Remote Procedure Call的简称，中文叫远程过程调用。
gRPC是由 google开发的一个高性能、通用的开源RPC框架，主要面向移动应用开发且基于HTTP/2协议标准而设计，同时支持大多数流行的编程语言。

一.编译gRPC

操作系统：windows 10
Qt：5.12.10 MinGW64
CMake：3.13.3
NASM：2.16
这里因为项目需要，编译MinGW64版本的gRPC。Qt安装完成后将下列路径添加到环境变量：

D:\Qt\Qt5.12.10\Tools\mingw730_64\bin
D:\Qt\Qt5.12.10\5.12.10\mingw73_64\bin

1.克隆源码

grpc源码地址：https://github.com/grpc/grpc

git clone [e-mail]:grpc/grpc.git

grpc源码下载完后，找到源码根目录下的.gitmodules文件，文件中是grpc编译所需要的子模块，将文件中的url由https地址改为ssh地址，即将https://替换为git@，将.com/替换为.com: 不这么做的话，很多子模块都会下载失败。
替换完成后的文件如下所示：

[submodule "third_party/abseil-cpp"]
	path = third_party/abseil-cpp
	url = [e-mail]:abseil/abseil-cpp.git
[submodule "third_party/benchmark"]
	path = third_party/benchmark
	url = [e-mail]:google/benchmark
[submodule "third_party/bloaty"]
	path = third_party/bloaty
	url = [e-mail]:google/bloaty.git
[submodule "third_party/boringssl-with-bazel"]
	path = third_party/boringssl-with-bazel
	url = [e-mail]:google/boringssl.git
[submodule "third_party/cares/cares"]
	path = third_party/cares/cares
	url = [e-mail]:c-ares/c-ares.git
[submodule "third_party/envoy-api"]
	path = third_party/envoy-api
	url = [e-mail]:envoyproxy/data-plane-api.git
[submodule "third_party/googleapis"]
	path = third_party/googleapis
	url = [e-mail]:googleapis/googleapis.git
[submodule "third_party/googletest"]
	path = third_party/googletest
	url = [e-mail]:google/googletest.git
[submodule "third_party/libuv"]
	path = third_party/libuv
	url = [e-mail]:libuv/libuv.git
[submodule "third_party/opencensus-proto"]
	path = third_party/opencensus-proto
	url = [e-mail]:census-instrumentation/opencensus-proto.git
[submodule "third_party/opentelemetry"]
	path = third_party/opentelemetry
	url = [e-mail]:open-telemetry/opentelemetry-proto.git
[submodule "third_party/protobuf"]
	path = third_party/protobuf
	url = [e-mail]:protocolbuffers/protobuf.git
[submodule "third_party/protoc-gen-validate"]
	path = third_party/protoc-gen-validate
	url = [e-mail]:envoyproxy/protoc-gen-validate.git
[submodule "third_party/re2"]
	path = third_party/re2
	url = [e-mail]:google/re2.git
[submodule "third_party/xds"]
	path = third_party/xds
	url = [e-mail]:cncf/xds.git
[submodule "third_party/zlib"]
	path = third_party/zlib
	url = [e-mail]:madler/zlib
	# When using CMake to build, the zlib submodule ends up with a
	# generated file that makes Git consider the submodule dirty. This
	# state can be ignored for day-to-day development on gRPC.
	ignore = dirty

接着下载子模块

cd grpc
git submodule update --init
#如果某个子模块下载失败，则可多次执行下方命令
git submodule update --recursive

2.CMake构建

在grpc目录下新建mingw64文件夹，打开CMake，选择源码路径和构建路径

点击Configure按钮，在弹出框中选择MinGW Makefiles，点击Finish按钮

配置完成，显示Configuring done。需要注意的是必须安装NASM，否则会Configure失败

点击Generate按钮，生成Makefile文件，显示Generating done。记住图中的几个路径，是gRPC最终安装的位置

3.编译

以管理员身份打开Qt 5.12.10（MinGW 7.3.0 64-bit），因为gPRC安装的路径在C盘，不用管理员身份可能会安装失败，提示如下错误：
CMake Error at cmake_install.cmake:36 (file):
  file cannot create directory: C:/Program Files (x86)/grpc/lib.  Maybe need
  administrative privileges.

进入mingw64目录

mingw32-make

我这编译的时候遇到了3个错误
①D:\grpc\src\core\lib\event_engine\tcp_socket_utils.cc:279:64: error: invalid conversion from 'const void*' to 'PVOID {aka void*}' [-fpermissive]
       inet_ntop(addr->sa_family, ip, ntop_buf, sizeof(ntop_buf)) != nullptr) {

解决方法：打开tcp_socket_utils.cc，将ip强制转换为void *
inet_ntop(addr->sa_family, (void *)ip, ntop_buf, sizeof(ntop_buf)) != nullptr) {
②D:\grpc\src\core\lib\event_engine\windows\iocp.cc:143:46: error: 'WSA_FLAG_NO_HANDLE_INHERIT' was not declared in this scope
                           wsa_socket_flags | WSA_FLAG_NO_HANDLE_INHERIT);
                                              ^~~~~~~~~~~~~~~~~~~~~~~~~~
D:\grpc\src\core\lib\event_engine\windows\iocp.cc:143:46: note: suggested alternative: 'UNW_FLAG_NHANDLER'
                           wsa_socket_flags | WSA_FLAG_NO_HANDLE_INHERIT);
解决方法：打开iocp.cc，将WSA_FLAG_NO_HANDLE_INHERIT改为0x80

DWORD IOCP::WSASocketFlagsInit() {
  DWORD wsa_socket_flags = WSA_FLAG_OVERLAPPED;
  /* WSA_FLAG_NO_HANDLE_INHERIT may be not supported on the older Windows
     versions, see
     https://msdn.microsoft.com/en-us/library/windows/desktop/ms742212(v=vs.85).aspx
     for details. */
  SOCKET sock = WSASocket(AF_INET6, SOCK_STREAM, IPPROTO_TCP, NULL, 0,
                          wsa_socket_flags | 0x80);
  if (sock != INVALID_SOCKET) {
    /* Windows 7, Windows 2008 R2 with SP1 or later */
    wsa_socket_flags |= 0x80;
    closesocket(sock);
  }
  return wsa_socket_flags;
}

之所以这样改，是因为枚举WSA_FLAG_NO_HANDLE_INHERIT的值就是0x80，如下图所示

③D:/grpc/third_party/protobuf/src/google/protobuf/stubs/mutex.h:124:29: error: temporary of non-literal type 'google::protobuf::internal::CallOnceInitializedMutex<std::mutex>' in a constant expression
   constexpr WrappedMutex() {}
解决方法：这是由于protobuf的版本太高导致的，需手动下载protobuf-all-3.16.3，拷贝到./grpc/third_party/protobuf中，重新编译即可

4.安装

mingw32-make install

二.调用gRPC

grpc编译完后，在C:\Program Files (x86)\grpc目录下有编译好的grpc的应用程序、库文件、头文件。将地址C:\Program Files (x86)\grpc\bin添加到环境变量

1.编写.proto文件，生成cpp文件

新建文件helloworld.proto，输入如下内容

syntax = "proto3";

package helloworld;

// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string greeting = 1;
}

打开cmd，进入helloworld.proto文件所在目录，依次执行如下命令

protoc.exe ./helloworld.proto --cpp_out=./
protoc.exe ./helloworld.proto --plugin=protoc-gen-grpc="C:/Program Files (x86)/grpc/bin/grpc_cpp_plugin.exe" --grpc_out=./

生成如下四个pb文件
helloworld.pb.h
helloworld.pb.cc
helloworld.grpc.pb.h
helloworld.grpc.pb.cc

2.客户端

在Qt中新建控制台工程GRPC_Client，将上面的四个pb文件添加到工程中，main.cpp修改为如下所示

#include <QCoreApplication>

#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::Greeter;
using helloworld::HelloReply;
using helloworld::HelloRequest;

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.greeting();
        } 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[])
{
    QCoreApplication a(argc, argv);

    GreeterClient greeter(
                grpc::CreateChannel("localhost:50051", grpc::InsecureChannelCredentials()));
    std::string user("world");
    std::string reply = greeter.SayHello(user);
    std::cout << "Greeter received: " << reply << std::endl;
    return a.exec();
}

3.服务端

在Qt中新建控制台工程GRPC_Server，将上面的四个pb文件添加到工程中，main.cpp修改为如下所示

#include <QCoreApplication>
#include <iostream>
#include <memory>
#include <string>
#include <grpcpp/ext/proto_server_reflection_plugin.h>
#include <grpcpp/grpcpp.h>
#include <grpcpp/health_check_service_interface.h>
#include "helloworld.grpc.pb.h"

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

// 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_greeting(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);
  // 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[])
{
    QCoreApplication a(argc, argv);

    RunServer();
    return a.exec();
}

4.pro文件配置

GRPC_Client.pro和GRPC_Server.pro中都要添加如下内容

GRPC_HOME="C:/Program Files (x86)/grpc"

INCLUDEPATH += $$GRPC_HOME/include

LIBS += -L$$GRPC_HOME/lib -lgrpc++ -lgrpc -lgpr -lgrpc_plugin_support -lgrpc_unsecure -lgrpc++_alts \
-lgrpc++_error_details -lgrpc++_reflection -lgrpc++_unsecure -lgrpcpp_channelz -laddress_sorting \
-lcares -labsl_bad_any_cast_impl -labsl_bad_optional_access -labsl_bad_variant_access -labsl_civil_time \
-labsl_cordz_info -labsl_cord -labsl_cordz_functions -labsl_cordz_handle -labsl_cord_internal \
-labsl_cordz_sample_token -labsl_exponential_biased -labsl_flags -labsl_flags_commandlineflag \
-labsl_flags_commandlineflag_internal -labsl_flags_config -labsl_flags_internal -labsl_flags_marshalling \
-labsl_flags_parse -labsl_flags_private_handle_accessor -labsl_flags_program_name -labsl_flags_reflection \
-labsl_flags_usage -labsl_flags_usage_internal -labsl_synchronization -labsl_graphcycles_internal -labsl_hash \
-labsl_city -labsl_hashtablez_sampler -labsl_log_severity -labsl_low_level_hash -labsl_periodic_sampler \
-labsl_random_internal_pool_urbg -labsl_random_internal_seed_material -labsl_random_internal_randen_hwaes_impl \
-labsl_random_distributions -labsl_random_internal_distribution_test_util -labsl_random_internal_platform \
-labsl_random_internal_randen -labsl_random_internal_randen_hwaes -labsl_random_internal_randen_slow \
-labsl_random_seed_gen_exception -labsl_random_seed_sequences -labsl_raw_hash_set -labsl_scoped_set_env \
-labsl_spinlock_wait -labsl_status -labsl_statusor -labsl_str_format_internal -labsl_strerror -labsl_symbolize \
-labsl_failure_signal_handler -labsl_examine_stack -labsl_stacktrace -labsl_leak_check \
-labsl_debugging_internal -labsl_demangle_internal -labsl_strings -labsl_strings_internal -labsl_malloc_internal \
-labsl_raw_logging_internal -labsl_throw_delegate -labsl_time -labsl_time_zone -labsl_int128 -labsl_base -lre2 \
-lupb -lprotobuf -llibprotoc -lzlib.dll -lssl -lcrypto -ldbghelp

LIBS += -lWS2_32 -lAdvapi32 -lbcrypt

DEFINES += _WIN32_WINNT=0x600

注：GRPC_HOME=“C:/Program Files (x86)/grpc” 路径加引号的原因是路径中存在空格

5.运行

先运行GRPC_Server，再运行GRPC_Client，结果如下所示

参考链接： https://blog.csdn.net/u014340533/article/details/125539126

原文链接：https://blog.csdn.net/caoshangpa/article/details/128402625