我无法优雅地停止类似的服务器(stackoverflow.com/questions/50833730/...)。– metalfox 4 小时前
这是显示如何处理的最小更改
- 关闭会话的退出命令
- 关闭服务器的 Shutdown 命令(因此它停止接受连接并在最后一个会话退出后终止)
Live On Coliru
#include <boost/asio.hpp>
#include <iostream>
using boost::asio::ip::tcp;
using boost::system::error_code;
using boost::asio::streambuf;
int main() {
boost::asio::io_service svc;
tcp::acceptor a(svc);
a.open(tcp::v4());
a.set_option(tcp::acceptor::reuse_address(true));
a.bind({{}, 6767}); // bind to port 6767 on localhost
a.listen(5);
using session = std::shared_ptr<tcp::socket>;
std::function<void()> do_accept;
std::function<void(session)> do_session;
do_session = [&](session s) {
// do a read
auto buf = std::make_shared<boost::asio::streambuf>();
async_read_until(*s, *buf, "\n", [&,s,buf](error_code ec, size_t /*bytes*/) {
if (ec)
std::cerr << "read failed: " << ec.message() << "\n";
else {
std::istream is(buf.get());
std::string line;
while (getline(is, line)) // FIXME being sloppy with partially read lines
{
async_write(*s, boost::asio::buffer("Ack\n", 4), [&,s,buf](error_code ec, size_t) {
if (ec) std::cerr << "write failed: " << ec.message() << "\n";
});
if (line == "Exit") {
std::cout << "Exit received\n";
return;
}
if (line == "Shutdown") {
std::cout << "Server shutdown requested\n";
a.close();
return;
}
}
do_session(s); // full duplex, can read while writing, using a second buffer
}
});
};
do_accept = [&] {
auto s = std::make_shared<session::element_type>(svc);
a.async_accept(*s, [&,s](error_code ec) {
if (ec)
std::cerr << "accept failed: " << ec.message() << "\n";
else {
do_session(s);
do_accept(); // accept the next
}
});
};
do_accept(); // kick-off
svc.run(); // wait for shutdown (Ctrl-C or failure)
}
注意示例会话
echo -en "hello world\nExit\n" | netcat 127.0.0.1 6767
echo -en "hello world\nShutdown\n" | netcat 127.0.0.1 6767
印刷
Ack
Ack
Ack
Ack
Exit received
Server shutdown requested
accept failed: Operation canceled
终止命令
如果你想要一个主动关闭所有打开的会话并关闭服务器的“终止”命令,你必须
您可以在此处查看这两种方法的代码:Boost ASIO: Send message to all connected clients
与当前示例集成的最简单方法:
Live On Coliru
#include <boost/asio.hpp>
#include <iostream>
#include <list>
using boost::asio::ip::tcp;
using boost::system::error_code;
using boost::asio::streambuf;
int main() {
boost::asio::io_service svc;
tcp::acceptor a(svc);
a.open(tcp::v4());
a.set_option(tcp::acceptor::reuse_address(true));
a.bind({{}, 6767}); // bind to port 6767 on localhost
a.listen(5);
using session = std::shared_ptr<tcp::socket>;
using sessref = std::weak_ptr<tcp::socket>;
std::function<void()> do_accept;
std::function<void(session)> do_session;
std::list<sessref> session_list;
auto garbage_collect_sessions = [&session_list] {
session_list.remove_if(std::mem_fn(&sessref::expired));
};
do_session = [&](session s) {
// do a read
auto buf = std::make_shared<boost::asio::streambuf>();
async_read_until(*s, *buf, "\n", [&,s,buf](error_code ec, size_t /*bytes*/) {
if (ec)
std::cerr << "read failed: " << ec.message() << "\n";
else {
std::istream is(buf.get());
std::string line;
while (getline(is, line)) // FIXME being sloppy with partially read lines
{
async_write(*s, boost::asio::buffer("Ack\n", 4), [&,s,buf](error_code ec, size_t) {
if (ec) std::cerr << "write failed: " << ec.message() << "\n";
});
if (line == "Exit") {
std::cout << "Exit received\n";
return;
}
if (line == "Shutdown") {
std::cout << "Server shutdown requested\n";
a.close();
return;
}
if (line == "Terminate") {
std::cout << "Server termination requested\n";
a.close();
for (auto wp : session_list) {
if (auto session = wp.lock())
session->close();
}
return;
}
}
do_session(s); // full duplex, can read while writing, using a second buffer
}
});
};
do_accept = [&] {
auto s = std::make_shared<session::element_type>(svc);
a.async_accept(*s, [&,s](error_code ec) {
if (ec)
std::cerr << "accept failed: " << ec.message() << "\n";
else {
garbage_collect_sessions();
session_list.push_back(s);
do_session(s);
do_accept(); // accept the next
}
});
};
do_accept(); // kick-off
svc.run(); // wait for shutdown (Ctrl-C or failure)
}
其中显然使用 asession_list
来实现"Terminate"
命令:
if (line == "Terminate") {
std::cout << "Server termination requested\n";
a.close();
for (auto wp : session_list) {
if (auto session = wp.lock())
session->close();
}
return;
}