boost :: asio :: acceptor - 接受新的传入连接，而旧的连接仍然打开

我正在编写基于boost asio的代理服务器 . 在我的代码中负责接受从浏览器到代理服务器的传入连接的部分，我正面临着我不完全理解的行为 .

所以 - 我正在使用下一个构造函数创建acceptor对象：

_acceptor(_io_service, boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), port ), true)

开始在这里听（start_accept）：

_new_connection.reset(new connection(*_io_services.front(), _connection_id));
_acceptor.async_accept(_new_connection->get_socket(),
                            boost::bind(&server::handle_accept, this,
                                        boost::asio::placeholders::error));

和handle_accept

if (!error) {
    _new_connection->start();
}

// continue waiting for incoming connections
start_accept();

通常，我接受传入连接的代码与HTTP Server 2示例中的相同

问题仅在第一个传入连接未关闭时出现，然后第二个传入将排队等待，直到第一个连接将关闭 .

根据这两个答案：boost::asio acceptor reopen and async read after EOF

How to launch an "event" when my Boost::asio tcp server just start running ( AKA io_service.run() )?

acceptor对象将所有传入连接添加到队列中，并且在挂起连接不会被关闭之前不会接受它们 .

我希望立即处理所有传入连接 - 因此它们在接受器队列中没有待处理，到目前为止我找不到任何解决方案 .

能帮助我，实现这个的正确方法是什么？

connection-> start（）函数

void
connection::start() {
    _bsocket.async_read_some(boost::asio::buffer(_bbuffer),
            boost::bind(&connection::handle_browser_read_headers,
                        shared_from_this(),
                        boost::asio::placeholders::error,
                        boost::asio::placeholders::bytes_transferred
        ));
}

Graphical representation更新：提升asio日志

@asio|1368460995.389629|0*1|socket@00CCFBE4.async_accept
@asio|1368461003.855113|>1|ec=system:0
@asio|1368461003.855113|1*2|socket@00E26850.async_receive
@asio|1368461003.855113|>2|ec=system:0,bytes_transferred=318
@asio|1368461003.856113|1*3|socket@00CCFBE4.async_accept
@asio|1368461003.856113|<1|
@asio|1368461003.856113|2*4|resolver@00E268D8.async_resolve
@asio|1368461003.856113|<2|
@asio|1368461003.866114|>4|ec=system:0,...
@asio|1368461003.866114|4*5|socket@00E26894.async_connect
@asio|1368461003.868114|<4|
@asio|1368461004.204133|>5|ec=system:0
@asio|1368461004.204133|5*6|socket@00E26894.async_send
@asio|1368461004.204133|<5|
@asio|1368461004.204133|>6|ec=system:0,bytes_transferred=302
@asio|1368461004.204133|6*7|socket@00E26894.async_receive
@asio|1368461004.204133|<6|
@asio|1368461004.613156|>7|ec=system:0,bytes_transferred=16384
@asio|1368461004.613156|7*8|socket@00E26850.async_send
@asio|1368461004.614157|<7|
@asio|1368461004.614157|>8|ec=system:0,bytes_transferred=16384
@asio|1368461004.614157|8*9|socket@00E26894.async_receive
@asio|1368461004.614157|<8|
@asio|1368461004.614157|>9|ec=system:0,bytes_transferred=1946
@asio|1368461004.614157|9*10|socket@00E26850.async_send
@asio|1368461004.614157|<9|
@asio|1368461004.614157|>10|ec=system:0,bytes_transferred=1946
@asio|1368461004.614157|10*11|socket@00E26894.async_receive
@asio|1368461004.614157|<10|
@asio|1368461004.618157|>11|ec=system:0,bytes_transferred=14080
@asio|1368461004.618157|11*12|socket@00E26850.async_send
@asio|1368461004.619157|<11|
@asio|1368461004.619157|>12|ec=system:0,bytes_transferred=14080
@asio|1368461004.619157|12*13|socket@00E26894.async_receive
@asio|1368461004.619157|<12|
@asio|1368461019.248994|>13|ec=asio.misc:2,bytes_transferred=0
@asio|1368461019.248994|13|socket@00E26894.close
@asio|1368461019.248994|13|socket@00E26850.close
@asio|1368461019.248994|<13|
@asio|1368461019.253994|0|resolver@00E268D8.cancel
@asio|1368461019.253994|>3|ec=system:0
@asio|1368461019.253994|3*14|socket@00E32688.async_receive
@asio|1368461019.254994|3*15|socket@00CCFBE4.async_accept
@asio|1368461019.254994|<3|
@asio|1368461019.254994|>14|ec=system:0,bytes_transferred=489
@asio|1368461019.254994|14*16|resolver@00E32710.async_resolve
@asio|1368461019.254994|<14|
@asio|1368461019.281995|>16|ec=system:0,...
@asio|1368461019.281995|16*17|socket@00E326CC.async_connect
@asio|1368461019.282996|<16|
@asio|1368461019.293996|>17|ec=system:0
@asio|1368461019.293996|17*18|socket@00E326CC.async_send
@asio|1368461019.293996|<17|
@asio|1368461019.293996|>18|ec=system:0,bytes_transferred=470
@asio|1368461019.293996|18*19|socket@00E326CC.async_receive
@asio|1368461019.293996|<18|
@asio|1368461019.315997|>19|ec=system:0,bytes_transferred=11001
@asio|1368461019.315997|19*20|socket@00E32688.async_send
@asio|1368461019.349999|<19|
@asio|1368461019.349999|>20|ec=system:0,bytes_transferred=11001
@asio|1368461019.349999|20|socket@00E326CC.close
@asio|1368461019.349999|20|socket@00E32688.close
@asio|1368461019.349999|<20|
@asio|1368461019.349999|0|resolver@00E32710.cancel

我发现acceptor的行为取决于我用于从服务器套接字读取数据的函数 . 连接类从浏览器读取数据，修改请求URL，连接到主机并发送请求，然后从服务器读取响应并将其写回浏览器 . 所以在我需要读取服务器主体的那一刻 - 我使用这个功能

_ssocket.async_read_some(boost::asio::buffer(_sbuffer),
            boost::bind(&connection::handle_server_read_body,
                    shared_from_this(),
                    boost::asio::placeholders::error,
                    boost::asio::placeholders::bytes_transferred
        ));

如果在服务响应头中没有指定content-length，那我就读到EOF . 如果调用了async_read_some函数并且没有更多数据要在套接字上读取它等待〜15秒才会引发EOF . 接受者不接受15秒内的所有新传入连接 .

但如果我正在使用async_read的另一个变种 -

boost::asio::async_read(_ssocket, boost::asio::buffer(_sbuffer),
            boost::bind(&connection::handle_server_read_body,
                    shared_from_this(),
                    boost::asio::placeholders::error,
                    boost::asio::placeholders::bytes_transferred
        ));

传入的连接被接受就好了 . 但它的boost :: asio :: async_read工作有点慢，它等待从socket读取数据，并且在读取数据之前不会调用处理程序，所以 - 我想我会指定transfer_at_least

boost::asio::async_read(_ssocket, boost::asio::buffer(_sbuffer), boost::asio::transfer_at_least(1),
            boost::bind(&connection::handle_server_read_body,
                    shared_from_this(),
                    boost::asio::placeholders::error,
                    boost::asio::placeholders::bytes_transferred
        ));

是的，它变得更好 - 但接受新连接的问题还是：/

• async_read_some和boost :: asio :: async_read之间的真正区别是什么 - 感觉有些东西被阻止了 .