Question

我正在学习提升asio并且有错误。我写了简单的客户端（我可以从它发送数据但是当我读取数据时我甚至无法编译它）我使用协议缓冲区来序列化数据。所以文件#include＆＃34; test.pb.h＆＃34;是probuffer类

我的代码客户端：

#include <boost/array.hpp>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <boost/foreach.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/thread/thread.hpp>
#include <cstdlib>
#include <iostream>
#include <string>
#include <thread>
#include "test.pb.h"
using boost::asio::ip::tcp;

int main(int argc, char** argv)
{
try
{
    // connect to the server:
    boost::asio::io_service io_service;
    tcp::resolver resolver(io_service);
    std::string const server_address = "localhost";
    std::string const server_port    = "10000";

    tcp::resolver::query query(server_address, server_port);
    tcp::resolver::iterator endpoint_iterator = resolver.resolve(query);
    tcp::socket socket(io_service);
    boost::asio::connect(socket, endpoint_iterator);
    //while ( true)
    {
        Person p = Person();
        p.set_id(22);
        p.set_name("Jack vorobey");

     //   std::cout << p.id();
   //     std::cout << p.name();

        std::string data; // this will hold serialized data
        bool ok = p.SerializeToString(&data);
        assert(ok);

        //    std::cout << data.size() << std::endl;
        boost::asio::write(socket, boost::asio::buffer(data)) 

        boost::asio::read(socket, boost::asio::buffer(data));;




   // break; // Connection closed cleanly by peer.

  //      std::cout << data.size() << std::endl;  // shows a reduction in amount of   
remaining data
//      boost::asio::read(socket, boost::asio::buffer(data) /*,  
    }
boost::asio::transfer_exactly(65536) */);
}
catch (std::exception& e)
{
    //std::cerr << e.what(luuu) << std::endl;
}
std::cout << "\nClosing";
std::string dummy;
}

我的错误代码我不明白：错误C2679：二进制＆＃39; =＆＃39; ：没有找到哪个运算符采用类型＆＃39; const boost :: asio :: const_buffer＆＃39;的右手操作数。（或者没有可接受的转换） 1 GT; c：\ local \ boost_1_55_0 \ boost \ asio \ buffer.hpp（136）：可能是＆＃39; boost :: asio :: mutable_buffer＆amp; boost :: asio :: mutable_buffer :: operator =（const boost :: asio :: mutable_buffer＆amp;）＆＃39; 1 GT;试图匹配参数列表＆＃39;（boost :: asio :: mutable_buffer，const boost :: asio :: const_buffer）＆＃39;

Answer 1

这是因为template<typename Elem, typename Traits, typename Allocator> const_buffers_1 buffer(const std::basic_string<Elem, Traits, Allocator> &)返回const_buffers_1的实例（这是ConstBufferSequence概念的模型）。当然，您无法将数据读入常量缓冲区。

不要将数据读入std::string，因为它不是为此而设（请注意其c_str()和data()成员函数返回const char*）。相反，请分配另一个缓冲区或使用asio::streambuf。

Answer 2

您可以使用streambuf，或指定（预分配！）大小：

#include <boost/asio.hpp>
#include <string>

using boost::asio::ip::tcp;

int main()
{
    boost::asio::io_service io_service;
    tcp::resolver resolver(io_service);

    tcp::socket socket(io_service);
    boost::asio::connect(socket, resolver.resolve(tcp::resolver::query("localhost", "10000")));

    std::string request("request");
    boost::asio::write(socket, boost::asio::buffer(request));

#if 0
    std::string response;
    response.resize(32);
    boost::asio::read(socket, boost::asio::buffer(&response[0], response.size()));
#else
    boost::asio::streambuf response;
    boost::asio::read(socket, response);
#endif
}

在客户端使用boost asio读取数据

2 个答案: