提高:: ASIO :: async_read_until读取所有数据,而不只是一些 [英] boost::asio::async_read_until reads all data instead of just some
问题描述
我修改升压短耳回声例如使用 async_read_until
按字读输入字。即使我使用 async_read_until
,所有发送的数据似乎从套接字读取。可能有人请告知:
的#include< cstdlib>
#包括LT&;&iostream的GT;
#包括LT&;升压/ bind.hpp>
#包括LT&;升压/ asio.hpp>使用boost ::支持ASIO ::知识产权:: TCP;堂课
{
上市:
会话(提高:: ASIO :: io_service对象和放大器; io_service对象)
:socket_(io_service对象)
{
} TCP ::插座及放大器;插座()
{
返回socket_;
} 无效的start()
{
性病::法院LT&;<启动<<的std :: ENDL;
提高:: ASIO :: async_read_until(socket_,缓冲,'',
提高::绑定(安培;会议:: handle_read,为此,
提高:: ASIO ::占位符::错误
提高:: ASIO ::占位符:: bytes_transferred));
} 无效handle_read(常量的boost ::系统::错误_ code和;错误,
为size_t bytes_transferred)
{ 的std :: ostringstream SS;
SS<<&安培;缓冲;
性病::字符串s = ss.str();
性病::法院LT&;< S<<的std :: ENDL; 如果(!错误)
{
提高:: ASIO :: async_write(socket_,
提高:: ASIO ::缓冲液(S),
提高::绑定(安培;会议:: handle_write,为此,
提高:: ASIO ::占位符::错误));
}
其他
{
删除;
}
} 无效handle_write(常量的boost ::系统::错误_ code&安培;错误)
{
性病::法院LT&;<写处理<<的std :: ENDL;
如果(!错误)
{
}
其他
{
删除;
}
}私人的:
TCP ::插座socket_;
提高:: ASIO ::流缓冲缓冲;
};级服务器
{
上市:
服务器(提高:: ASIO :: io_service对象和放大器; io_service对象,短端口)
:io_service_(io_service对象)
acceptor_(io_service对象,TCP ::端点(TCP :: V4(),口))
{
会议* new_session =新的会话(io_service_);
acceptor_.async_accept(new_session->插座(),
提高::绑定(安培;服务器:: handle_accept,为此,new_session,
提高:: ASIO ::占位符::错误));
} 无效handle_accept(会话* new_session,
常量的boost ::系统::错误_ code&放;错误)
{
如果(!错误)
{
new_session->启动();
new_session =新的会话(io_service_);
acceptor_.async_accept(new_session->插座(),
提高::绑定(安培;服务器:: handle_accept,为此,new_session,
提高:: ASIO ::占位符::错误));
}
其他
{
删除new_session;
}
}私人的:
提高:: ASIO :: io_service对象和放大器; io_service_;
TCP ::受acceptor_;
};INT主(INT ARGC,CHAR *的argv [])
{
尝试
{
如果(的argc!= 2)
{
的std :: CERR<< 用法:async_tcp_echo_server<港口> \\ N的;
返回1;
} 提高:: ASIO :: io_service对象io_service对象; 使用命名空间std; //为的atoi。
服务器S(io_service对象,与atoi(ARGV [1])); io_service.run();
}
赶上(性病::例外急症)
{
的std :: CERR<< 例外:<< e.what()&所述;&下; \\ n;
} 返回0;
}
阅读<一href=\"http://www.boost.org/doc/libs/1_43_0/doc/html/boost_asio/reference/async_read_until/overload1.html\">description async_read_until的谨慎。它说:
成功async_read_until后
操作中,流缓冲可以含有
超出定界符附加数据
块引用>这意味着你的情况是,里面handle_read(),你应该只访问第一个
bytes_transferred
从缓冲区的字节。截至目前,你的bytes_transferred
参数未使用。I'm modify the Boost Asio echo example to use
async_read_until
to read the input word by word. Even though I am usingasync_read_until
, all the data sent seems to be read from the socket. Could someone please advise:#include <cstdlib> #include <iostream> #include <boost/bind.hpp> #include <boost/asio.hpp> using boost::asio::ip::tcp; class session { public: session(boost::asio::io_service& io_service) : socket_(io_service) { } tcp::socket& socket() { return socket_; } void start() { std::cout<<"starting"<<std::endl; boost::asio::async_read_until(socket_, buffer, ' ', boost::bind(&session::handle_read, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } void handle_read(const boost::system::error_code& error, size_t bytes_transferred) { std::ostringstream ss; ss<<&buffer; std::string s = ss.str(); std::cout<<s<<std::endl; if (!error) { boost::asio::async_write(socket_, boost::asio::buffer(s), boost::bind(&session::handle_write, this, boost::asio::placeholders::error)); } else { delete this; } } void handle_write(const boost::system::error_code& error) { std::cout<<"handling write"<<std::endl; if (!error) { } else { delete this; } } private: tcp::socket socket_; boost::asio::streambuf buffer; }; class server { public: server(boost::asio::io_service& io_service, short port) : io_service_(io_service), acceptor_(io_service, tcp::endpoint(tcp::v4(), port)) { session* new_session = new session(io_service_); acceptor_.async_accept(new_session->socket(), boost::bind(&server::handle_accept, this, new_session, boost::asio::placeholders::error)); } void handle_accept(session* new_session, const boost::system::error_code& error) { if (!error) { new_session->start(); new_session = new session(io_service_); acceptor_.async_accept(new_session->socket(), boost::bind(&server::handle_accept, this, new_session, boost::asio::placeholders::error)); } else { delete new_session; } } private: boost::asio::io_service& io_service_; tcp::acceptor acceptor_; }; int main(int argc, char* argv[]) { try { if (argc != 2) { std::cerr << "Usage: async_tcp_echo_server <port>\n"; return 1; } boost::asio::io_service io_service; using namespace std; // For atoi. server s(io_service, atoi(argv[1])); io_service.run(); } catch (std::exception& e) { std::cerr << "Exception: " << e.what() << "\n"; } return 0; }
解决方案Read the description of async_read_until carefully. It says:
After a successful async_read_until operation, the streambuf may contain additional data beyond the delimiter.
What this means in your case is that inside handle_read(), you should only access the first
bytes_transferred
bytes from the buffer. As of now, yourbytes_transferred
parameter is unused.这篇关于提高:: ASIO :: async_read_until读取所有数据,而不只是一些的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!