Apache Thrift:返回列表/容器

Question

我做了一个简单的thrift文件:

thrifttest.thrift

namespace cpp thrifttest
namespace d thrifttest
namespace java thrifttest
namespace php thrifttest
namespace perl thrifttest

service Test {

    list<i64> ping();

}

并在shell中运行"thrift --gen cpp thrifttest.thrift"

但是,当我查看gen-cpp/Test_server.skeleton.cpp时,它使i64列表成为参数,而不是返回类型:

Test_server.skeleton.cpp(摘录)

void ping(std::vector<int64_t> & _return) {
    // Your implementation goes here
    printf("ping\n");
}

在我的server.cpp程序中,在我创建一个返回"std :: vector&"的函数ping()后,编译器会抱怨

错误:无法分配抽象类型的对象'TestHandler'server.cpp:30:7:注意:因为以下虚函数在'TestHandler'中是纯的:

这是server.cpp server.cpp的完整代码

#include <thrift/concurrency/ThreadManager.h>
#include <thrift/concurrency/PosixThreadFactory.h>
#include <thrift/protocol/TBinaryProtocol.h>
#include <thrift/server/TSimpleServer.h>
#include <thrift/server/TThreadPoolServer.h>
#include <thrift/server/TThreadedServer.h>
#include <thrift/transport/TServerSocket.h>
#include <thrift/transport/TTransportUtils.h>

#include <iostream>
#include <stdexcept>
#include <sstream>

#include "gen-cpp/Test.h"

using namespace std;
using namespace apache::thrift;
using namespace apache::thrift::protocol;
using namespace apache::thrift::transport;
using namespace apache::thrift::server;

using boost::shared_ptr;

using namespace thrifttest;

using namespace boost;

unsigned long giant[100];

class TestHandler : virtual public TestIf {
 public:
  TestHandler() {
      for (int i = 0; i < 100; i++) {
          giant[i] = -1;
      }
  }


  std::vector<int64_t> & ping() {
        return (std::vector<int64_t> &)giant;
    }

  void ping(std::vector<int64_t> & bla) {}
};

int main(int argc, char **argv) {

  shared_ptr<TestHandler> handler(new TestHandler());
  shared_ptr<TProcessor> processor(new TestProcessor(handler));
  shared_ptr<TServerTransport> serverTransport(new TServerSocket(port));
  shared_ptr<TTransportFactory> transportFactory(new TBufferedTransportFactory());
  shared_ptr<TProtocolFactory> protocolFactory(new TBinaryProtocolFactory());

  TSimpleServer server(processor,
                       serverTransport,
                       transportFactory,
                       protocolFactory);

  printf("Starting the server...\n");
  server.serve();
  printf("done.\n");
  return 0;
}

Answer 1

我偶然发现了一篇文章(StackOverflow:处理C中的Apache Thrift List Map返回类型),讨论了这个问题(虽然答案在我的案例中不起作用).事实证明,thrift使用pass-by-reference语法,即使"Thrift使用按值传递模型" - Gupta.所以这是一个例子:

.thrift文件

service Test {

    list<string> ping();
}

服务器端

void ping(std::vector<string> & _return) {
    _return.push_back("hello");    //initialize the vector _return with values "hello","world"
    _return.push_back("world");
}

客户端

std::vector<string> result;     //create vector "result" for storing the values
client.ping(result);
printf("%s %s!\n", result[0].c_str(), result[1].c_str());   //c_str() turns the vector string into a C-style string

客户端输出(启动服务器后)

你好,世界!

并且感谢Thrift缺乏文档,我爆炸了!#4hoursgoogling和哭泣