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Protobuf-RPC for C++

Talks: Go/C++语言Protobuf-RPC简介

Install

1. Install CMake and VS2010(Windows)/gcc(Unix)
2. cd ${protorpc_root}/protobuf and build with cmake

Add xml support (with --cxx_out option):

New API for message:

// Parse a protocol buffer contained in a string.
bool ParseFromXmlString(const string& data);
// Like ParseFromXmlString(), but accepts messages that are missing
// required fields.
bool ParsePartialFromXmlString(const string& data);

// Serialize the message and store it in the given string.  All required
// fields must be set.
bool SerializeToXmlString(string* output) const;
// Like SerializeToXmlString(), but allows missing required fields.
bool SerializePartialToXmlString(string* output) const;

Here is the simple code(${protorpc_root}/protobuf/src/google/protobuf/xml/example/xmltest.cc):

#include <stdio.h>

#include "./xml.pb/XmlTest.pb.h"

int main() {
    google::protobuf::xml::PbXmlTest pb1;
    google::protobuf::xml::PbXmlTest pb2;

    pb1.set_b(true);
    pb1.set_i(1001);
    pb1.set_f(0.123f);
    pb1.set_e(google::protobuf::xml::PB_VALUE_TYPE_INT);
    pb1.mutable_m()->set_b(false);
    pb1.mutable_m()->set_i(145);

    std::string xmlString;
    bool rv1 = pb1.SerializeToXmlString(&xmlString);
    printf("pb1 xml:\n%s\n", xmlString.c_str());

    bool b = pb2.ParseFromXmlString(xmlString);
    printf("pb2 dbg string:\n%s\n", pb2.DebugString().c_str());

    return 0;
}

Implement Protobuf-RPC (with --cxx_out option):

C++ use the same protocol as Go, so we can communication with C++ and Go with Protobuf-RPC.

Here is a simple proto file(${protorpc_root}/protobuf/src/google/protobuf/rpc/service.pb):

package service;

option cc_generic_services = true;
option java_generic_services = true;
option py_generic_services = true;

message EchoRequest {
    optional string msg = 1;
}

message EchoResponse {
    optional string msg = 1;
}

service EchoService {
    rpc echo (EchoRequest) returns (EchoResponse);
}

service EchoServiceA {
    rpc echo (EchoRequest) returns (EchoResponse);
}

service EchoServiceB {
    rpc echo (EchoRequest) returns (EchoResponse);
}

Then use new protoc with --cxx_out option to generate "arith.pb.{h|cc}" file(include rpc stub):

${protorpc_root}/protobuf/bin/protoc --cxx_out=. echo.proto

The server calls (for TCP service):

#include "echo.pb.h"

class EchoService: public service::EchoService {
public:
    inline EchoService() {}
    virtual ~EchoService() {}

    virtual const google::protobuf::rpc::Error Echo(
        const service::EchoRequest* request,
        service::EchoResponse* response
    ) {
        response->set_msg(request->msg());
        return google::protobuf::rpc::Error::Nil();
    }
};

int main() {
    google::protobuf::rpc::Server server;

    server.AddService(new EchoService, true);

    server.Serve(9527);
}

At this point, clients can see a service EchoService with methods EchoService.Echo. To invoke one, a client first dials the server:

#include <google/protobuf/rpc/rpc_server.h>
#include <google/protobuf/rpc/rpc_client.h>

#include "arith.pb.h"

int main() {
    google::protobuf::rpc::Client client("127.0.0.1", 9527);

    service::EchoService::Stub echoStub(&client);

    service::EchoRequest echoArgs;
    service::EchoResponse echoReply;
    google::protobuf::rpc::Error err;

    // EchoService.echo
    echoArgs.set_msg("Hello Protobuf-RPC!");
    err = echoStub.echo(&echoArgs, &echoReply);
    if(!err.IsNil()) {
        fprintf(stderr, "echoStub.echo: %s\n", err.String().c_str());
        return -1;
    }
    if(echoReply.msg() != echoArgs.msg()) {
        fprintf(stderr, "echoStub.echo: expected = \"%s\", got = \"%s\"\n",
            echoArgs.msg().c_str(), echoReply.msg().c_str()
        );
        return -1;
    }

    // EchoService.echo: Use Client
    echoArgs.set_msg("Hello Protobuf-RPC!");
    err = client.CallMethod("EchoService.Echo", &echoArgs, &echoReply);
    if(!err.IsNil()) {
        fprintf(stderr, "EchoService.echo: %s\n", err.String().c_str());
        return -1;
    }
    if(echoReply.msg() != echoArgs.msg()) {
        fprintf(stderr, "EchoService.echo: expected = \"%s\", got = \"%s\"\n",
            echoArgs.msg().c_str(), echoReply.msg().c_str()
        );
        return -1;
    }

    return 0;
}

BUGS

Please report bugs to chaishushan@gmail.com.

Thanks!