Files
boost_beast/examples/websocket_sync_echo_server.hpp
2017-07-20 08:12:14 -07:00

327 lines
8.0 KiB
C++

//
// Copyright (c) 2013-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef WEBSOCKET_SYNC_ECHO_SERVER_HPP
#define WEBSOCKET_SYNC_ECHO_SERVER_HPP
#include <beast/core/placeholders.hpp>
#include <beast/core/streambuf.hpp>
#include <beast/websocket.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/optional.hpp>
#include <atomic>
#include <functional>
#include <memory>
#include <mutex>
#include <ostream>
#include <string>
#include <thread>
#include <type_traits>
#include <typeindex>
#include <unordered_map>
#include <utility>
namespace websocket {
/** Synchronous WebSocket echo client/server
*/
class sync_echo_server
{
public:
using error_code = beast::error_code;
using endpoint_type = boost::asio::ip::tcp::endpoint;
using address_type = boost::asio::ip::address;
using socket_type = boost::asio::ip::tcp::socket;
private:
struct identity
{
template<class Body, class Fields>
void
operator()(beast::http::message<
true, Body, Fields>& req) const
{
req.fields.replace("User-Agent", "sync_echo_client");
}
template<class Body, class Fields>
void
operator()(beast::http::message<
false, Body, Fields>& resp) const
{
resp.fields.replace("Server", "sync_echo_server");
}
};
/** A container of type-erased option setters.
*/
template<class NextLayer>
class options_set
{
// workaround for std::function bug in msvc
struct callable
{
virtual ~callable() = default;
virtual void operator()(
beast::websocket::stream<NextLayer>&) = 0;
};
template<class T>
class callable_impl : public callable
{
T t_;
public:
template<class U>
callable_impl(U&& u)
: t_(std::forward<U>(u))
{
}
void
operator()(beast::websocket::stream<NextLayer>& ws)
{
t_(ws);
}
};
template<class Opt>
class lambda
{
Opt opt_;
public:
lambda(lambda&&) = default;
lambda(lambda const&) = default;
lambda(Opt const& opt)
: opt_(opt)
{
}
void
operator()(beast::websocket::stream<NextLayer>& ws) const
{
ws.set_option(opt_);
}
};
std::unordered_map<std::type_index,
std::unique_ptr<callable>> list_;
public:
template<class Opt>
void
set_option(Opt const& opt)
{
std::unique_ptr<callable> p;
p.reset(new callable_impl<lambda<Opt>>{opt});
list_[std::type_index{
typeid(Opt)}] = std::move(p);
}
void
set_options(beast::websocket::stream<NextLayer>& ws)
{
for(auto const& op : list_)
(*op.second)(ws);
}
};
std::ostream* log_;
boost::asio::io_service ios_;
socket_type sock_;
endpoint_type ep_;
boost::asio::ip::tcp::acceptor acceptor_;
std::thread thread_;
options_set<socket_type> opts_;
public:
/** Constructor.
@param log A pointer to a stream to log to, or `nullptr`
to disable logging.
*/
sync_echo_server(std::ostream* log)
: log_(log)
, sock_(ios_)
, acceptor_(ios_)
{
opts_.set_option(
beast::websocket::decorate(identity{}));
}
/** Destructor.
*/
~sync_echo_server()
{
if(thread_.joinable())
{
error_code ec;
ios_.dispatch(
[&]{ acceptor_.close(ec); });
thread_.join();
}
}
/** Return the listening endpoint.
*/
endpoint_type
local_endpoint() const
{
return acceptor_.local_endpoint();
}
/** Set a websocket option.
The option will be applied to all new connections.
@param opt The option to apply.
*/
template<class Opt>
void
set_option(Opt const& opt)
{
opts_.set_option(opt);
}
/** Open a listening port.
@param ep The address and port to bind to.
@param ec Set to the error, if any occurred.
*/
void
open(endpoint_type const& ep, error_code& ec)
{
acceptor_.open(ep.protocol(), ec);
if(ec)
return fail("open", ec);
acceptor_.set_option(
boost::asio::socket_base::reuse_address{true});
acceptor_.bind(ep, ec);
if(ec)
return fail("bind", ec);
acceptor_.listen(
boost::asio::socket_base::max_connections, ec);
if(ec)
return fail("listen", ec);
acceptor_.async_accept(sock_, ep_,
std::bind(&sync_echo_server::on_accept, this,
beast::asio::placeholders::error));
thread_ = std::thread{[&]{ ios_.run(); }};
}
private:
void
fail(std::string what, error_code ec)
{
if(log_)
{
static std::mutex m;
std::lock_guard<std::mutex> lock{m};
(*log_) << what << ": " <<
ec.message() << std::endl;
}
}
void
fail(std::string what, error_code ec,
int id, endpoint_type const& ep)
{
if(log_)
if(ec != beast::websocket::error::closed)
fail("[#" + std::to_string(id) + " " +
boost::lexical_cast<std::string>(ep) +
"] " + what, ec);
}
void
on_accept(error_code ec)
{
if(ec == boost::asio::error::operation_aborted)
return;
if(ec)
return fail("accept", ec);
struct lambda
{
std::size_t id;
endpoint_type ep;
sync_echo_server& self;
boost::asio::io_service::work work;
// Must be destroyed before work otherwise the
// io_service could be destroyed before the socket.
socket_type sock;
lambda(sync_echo_server& self_,
endpoint_type const& ep_,
socket_type&& sock_)
: id([]
{
static std::atomic<std::size_t> n{0};
return ++n;
}())
, ep(ep_)
, self(self_)
, work(sock_.get_io_service())
, sock(std::move(sock_))
{
}
void operator()()
{
self.do_peer(id, ep, std::move(sock));
}
};
std::thread{lambda{*this, ep_, std::move(sock_)}}.detach();
acceptor_.async_accept(sock_, ep_,
std::bind(&sync_echo_server::on_accept, this,
beast::asio::placeholders::error));
}
void
do_peer(std::size_t id,
endpoint_type const& ep, socket_type&& sock)
{
using boost::asio::buffer;
using boost::asio::buffer_copy;
beast::websocket::stream<
socket_type> ws{std::move(sock)};
opts_.set_options(ws);
error_code ec;
ws.accept(ec);
if(ec)
{
fail("accept", ec, id, ep);
return;
}
for(;;)
{
beast::websocket::opcode op;
beast::streambuf sb;
ws.read(op, sb, ec);
if(ec)
{
auto const s = ec.message();
break;
}
ws.set_option(beast::websocket::message_type{op});
ws.write(sb.data(), ec);
if(ec)
break;
}
if(ec && ec != beast::websocket::error::closed)
{
fail("read", ec, id, ep);
}
}
};
} // websocket
#endif