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Add websocket-chat-multi example:

Browse Source 
This is the multi-threaded io_context version of the
CppCon2018 WebSocket chat server and client example.
This commit is contained in:
Vinnie Falco
2019-01-21 10:18:45 -08:00
parent 9a8e22950f
commit 3081f52ad5
18 changed files with 1112 additions and 1 deletions
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1
CHANGELOG.md
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@ -2,6 +2,7 @@ Version 206
* Clear error codes idiomatically * Clear error codes idiomatically
* websocket stream uses shared_ptr<impl_type> * websocket stream uses shared_ptr<impl_type>
* Add websocket-chat-multi example
-------------------------------------------------------------------------------- --------------------------------------------------------------------------------

11
doc/qbk/02_examples.qbk
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@ -173,7 +173,7 @@ These servers offer both HTTP and WebSocket services on the same port,
and illustrate the implementation of advanced features. and illustrate the implementation of advanced features.
[table [table
[[Description] [Features] [Source File]] [[Description] [Features] [Sources]]
[ [
[Advanced] [Advanced]
[[itemized_list [[itemized_list
@ -195,6 +195,15 @@ and illustrate the implementation of advanced features.
[Clean exit via SIGINT (CTRL+C) or SIGTERM (kill)] [Clean exit via SIGINT (CTRL+C) or SIGTERM (kill)]
]] ]]
[[example_src example/advanced/server-flex/advanced_server_flex.cpp advanced_server_flex.cpp]] [[example_src example/advanced/server-flex/advanced_server_flex.cpp advanced_server_flex.cpp]]
][
[Chat Server, multi-threaded]
[[itemized_list
[Multi-user Chat]
[Broadcasting Messages]
[Dual protocols: HTTP and WebSocket]
[Clean exit via SIGINT (CTRL+C) or SIGTERM (kill)]
]]
[[source_file example/websocket/server/chat-multi]]
]] ]]
[endsect] [endsect]

1
example/websocket/server/CMakeLists.txt
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@ -8,6 +8,7 @@
# #
add_subdirectory (async) add_subdirectory (async)
add_subdirectory (chat-multi)
add_subdirectory (coro) add_subdirectory (coro)
add_subdirectory (fast) add_subdirectory (fast)
add_subdirectory (stackless) add_subdirectory (stackless)

1
example/websocket/server/Jamfile
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@ -8,6 +8,7 @@
# #
build-project async ; build-project async ;
build-project chat-multi ;
build-project coro ; build-project coro ;
build-project fast ; build-project fast ;
build-project stackless ; build-project stackless ;

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example/websocket/server/chat-multi/CMakeLists.txt Normal file
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@ -0,0 +1,37 @@
#
# Copyright (c) 2016-2017 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)
#
# Official repository: https://github.com/boostorg/beast
#
GroupSources(include/boost/beast beast)
GroupSources(example/cppcon2018 "/")
file (GLOB APP_FILES
beast.hpp
http_session.cpp
http_session.hpp
Jamfile
listener.cpp
listener.hpp
main.cpp
net.hpp
shared_state.cpp
shared_state.hpp
websocket_session.cpp
websocket_session.hpp
chat_client.html
README.md
)
source_group ("" FILES ${APP_FILES})
add_executable (websocket-chat-multi
${APP_FILES}
${BOOST_BEAST_FILES}
)
set_property(TARGET websocket-chat-multi PROPERTY FOLDER "example-websocket-server")

19
example/websocket/server/chat-multi/Jamfile Normal file
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@ -0,0 +1,19 @@
#
# Copyright (c) 2016-2017 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)
#
# Official repository: https://github.com/boostorg/beast
#
exe websocket-chat-multi :
http_session.cpp
listener.cpp
main.cpp
shared_state.cpp
websocket_session.cpp
:
<variant>coverage:<build>no
<variant>ubasan:<build>no
;

19
example/websocket/server/chat-multi/beast.hpp Normal file
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@ -0,0 +1,19 @@
//
// Copyright (c) 2018 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)
//
// Official repository: https://github.com/vinniefalco/CppCon2018
//
#ifndef BOOST_BEAST_EXAMPLE_WEBSOCKET_CHAT_MULTI_BEAST_HPP
#define BOOST_BEAST_EXAMPLE_WEBSOCKET_CHAT_MULTI_BEAST_HPP
#include <boost/beast.hpp>
namespace beast = boost::beast; // from <boost/beast.hpp>
namespace http = beast::http; // from <boost/beast/http.hpp>
namespace websocket = beast::websocket; // from <boost/beast/websocket.hpp>
#endif

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example/websocket/server/chat-multi/chat_client.html Normal file
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@ -0,0 +1,57 @@
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>WebSocket Chat - CppCon2018</title>
</head>
<body>
<h1>WebSocket Chat</h1>
<p>Source code: <a href="https://github.com/vinniefalco/CppCon2018">https://github.com/vinniefalco/CppCon2018</a></p>
Server URI: <input class="draw-border" id="uri" size="47" value="ws://localhost:8080" style="margin-bottom: 5px;">
<button class="echo-button" id="connect">Connect</button>
<button class="echo-button" id="disconnect">Disconnect</button><br>
Your Name: <input class="draw-border" id="userName" size=47 style="margin-bottom: 5px;"><br>
<pre id="messages" style="width: 600px; height: 400px; border: solid 1px #cccccc; margin-bottom: 5px;"></pre>
<div style="margin-bottom: 5px;">
Message<br>
<input class="draw-border" id="sendMessage" size="74" value="">
<button class="echo-button" id="send">Send</button>
</div>
<script>
var ws = null;
connect.onclick = function() {
ws = new WebSocket(uri.value);
ws.onopen = function(ev) {
messages.innerText += "[connection opened]\n";
};
ws.onclose = function(ev) {
messages.innerText += "[connection closed]\n";
};
ws.onmessage = function(ev) {
messages.innerText += ev.data + "\n";
};
ws.onerror = function(ev) {
messages.innerText += "[error]\n";
console.log(ev);
};
};
disconnect.onclick = function() {
ws.close();
};
send.onclick = function() {
ws.send(userName.value + ": " + sendMessage.value);
sendMessage.value = "";
};
sendMessage.onkeyup = function(ev) {
ev.preventDefault();
if (event.keyCode === 13) {
send.click();
}
}
</script>
</body>
</html>

354
example/websocket/server/chat-multi/http_session.cpp Normal file
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@ -0,0 +1,354 @@
//
// Copyright (c) 2018 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)
//
// Official repository: https://github.com/vinniefalco/CppCon2018
//
#include "http_session.hpp"
#include "websocket_session.hpp"
#include <boost/config.hpp>
#include <iostream>
#define BOOST_NO_CXX14_GENERIC_LAMBDAS
//------------------------------------------------------------------------------
// Return a reasonable mime type based on the extension of a file.
beast::string_view
mime_type(beast::string_view path)
{
using beast::iequals;
auto const ext = [&path]
{
auto const pos = path.rfind(".");
if(pos == beast::string_view::npos)
return beast::string_view{};
return path.substr(pos);
}();
if(iequals(ext, ".htm")) return "text/html";
if(iequals(ext, ".html")) return "text/html";
if(iequals(ext, ".php")) return "text/html";
if(iequals(ext, ".css")) return "text/css";
if(iequals(ext, ".txt")) return "text/plain";
if(iequals(ext, ".js")) return "application/javascript";
if(iequals(ext, ".json")) return "application/json";
if(iequals(ext, ".xml")) return "application/xml";
if(iequals(ext, ".swf")) return "application/x-shockwave-flash";
if(iequals(ext, ".flv")) return "video/x-flv";
if(iequals(ext, ".png")) return "image/png";
if(iequals(ext, ".jpe")) return "image/jpeg";
if(iequals(ext, ".jpeg")) return "image/jpeg";
if(iequals(ext, ".jpg")) return "image/jpeg";
if(iequals(ext, ".gif")) return "image/gif";
if(iequals(ext, ".bmp")) return "image/bmp";
if(iequals(ext, ".ico")) return "image/vnd.microsoft.icon";
if(iequals(ext, ".tiff")) return "image/tiff";
if(iequals(ext, ".tif")) return "image/tiff";
if(iequals(ext, ".svg")) return "image/svg+xml";
if(iequals(ext, ".svgz")) return "image/svg+xml";
return "application/text";
}
// Append an HTTP rel-path to a local filesystem path.
// The returned path is normalized for the platform.
std::string
path_cat(
beast::string_view base,
beast::string_view path)
{
if(base.empty())
return path.to_string();
std::string result = base.to_string();
#if BOOST_MSVC
char constexpr path_separator = '\\';
if(result.back() == path_separator)
result.resize(result.size() - 1);
result.append(path.data(), path.size());
for(auto& c : result)
if(c == '/')
c = path_separator;
#else
char constexpr path_separator = '/';
if(result.back() == path_separator)
result.resize(result.size() - 1);
result.append(path.data(), path.size());
#endif
return result;
}
// This function produces an HTTP response for the given
// request. The type of the response object depends on the
// contents of the request, so the interface requires the
// caller to pass a generic lambda for receiving the response.
template<
class Body, class Allocator,
class Send>
void
handle_request(
beast::string_view doc_root,
http::request<Body, http::basic_fields<Allocator>>&& req,
Send&& send)
{
// Returns a bad request response
auto const bad_request =
[&req](beast::string_view why)
{
http::response<http::string_body> res{http::status::bad_request, req.version()};
res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
res.set(http::field::content_type, "text/html");
res.keep_alive(req.keep_alive());
res.body() = why.to_string();
res.prepare_payload();
return res;
};
// Returns a not found response
auto const not_found =
[&req](beast::string_view target)
{
http::response<http::string_body> res{http::status::not_found, req.version()};
res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
res.set(http::field::content_type, "text/html");
res.keep_alive(req.keep_alive());
res.body() = "The resource '" + target.to_string() + "' was not found.";
res.prepare_payload();
return res;
};
// Returns a server error response
auto const server_error =
[&req](beast::string_view what)
{
http::response<http::string_body> res{http::status::internal_server_error, req.version()};
res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
res.set(http::field::content_type, "text/html");
res.keep_alive(req.keep_alive());
res.body() = "An error occurred: '" + what.to_string() + "'";
res.prepare_payload();
return res;
};
// Make sure we can handle the method
if( req.method() != http::verb::get &&
req.method() != http::verb::head)
return send(bad_request("Unknown HTTP-method"));
// Request path must be absolute and not contain "..".
if( req.target().empty() ||
req.target()[0] != '/' ||
req.target().find("..") != beast::string_view::npos)
return send(bad_request("Illegal request-target"));
// Build the path to the requested file
std::string path = path_cat(doc_root, req.target());
if(req.target().back() == '/')
path.append("index.html");
// Attempt to open the file
beast::error_code ec;
http::file_body::value_type body;
body.open(path.c_str(), beast::file_mode::scan, ec);
// Handle the case where the file doesn't exist
if(ec == boost::system::errc::no_such_file_or_directory)
return send(not_found(req.target()));
// Handle an unknown error
if(ec)
return send(server_error(ec.message()));
// Cache the size since we need it after the move
auto const size = body.size();
// Respond to HEAD request
if(req.method() == http::verb::head)
{
http::response<http::empty_body> res{http::status::ok, req.version()};
res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
res.set(http::field::content_type, mime_type(path));
res.content_length(size);
res.keep_alive(req.keep_alive());
return send(std::move(res));
}
// Respond to GET request
http::response<http::file_body> res{
std::piecewise_construct,
std::make_tuple(std::move(body)),
std::make_tuple(http::status::ok, req.version())};
res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
res.set(http::field::content_type, mime_type(path));
res.content_length(size);
res.keep_alive(req.keep_alive());
return send(std::move(res));
}
//------------------------------------------------------------------------------
http_session::
http_session(
tcp::socket socket,
boost::shared_ptr<shared_state> const& state)
: socket_(std::move(socket))
, state_(state)
, strand_(socket_.get_executor())
{
}
void
http_session::
run()
{
// Read a request
http::async_read(socket_, buffer_, req_,
net::bind_executor(strand_,
std::bind(
&http_session::on_read,
shared_from_this(),
std::placeholders::_1,
std::placeholders::_2)));
}
// Report a failure
void
http_session::
fail(beast::error_code ec, char const* what)
{
// Don't report on canceled operations
if(ec == net::error::operation_aborted)
return;
std::cerr << what << ": " << ec.message() << "\n";
}
template<bool isRequest, class Body, class Fields>
void
http_session::
send_lambda::
operator()(http::message<isRequest, Body, Fields>&& msg) const
{
// The lifetime of the message has to extend
// for the duration of the async operation so
// we use a shared_ptr to manage it.
auto sp = boost::make_shared<
http::message<isRequest, Body, Fields>>(std::move(msg));
// Write the response
auto self = self_.shared_from_this();
http::async_write(
self_.socket_,
*sp,
net::bind_executor(self_.strand_,
[self, sp](beast::error_code ec, std::size_t bytes)
{
self->on_write(ec, bytes, sp->need_eof());
}));
}
void
http_session::
on_read(beast::error_code ec, std::size_t)
{
// This means they closed the connection
if(ec == http::error::end_of_stream)
{
socket_.shutdown(tcp::socket::shutdown_send, ec);
return;
}
// Handle the error, if any
if(ec)
return fail(ec, "read");
// See if it is a WebSocket Upgrade
if(websocket::is_upgrade(req_))
{
// Create a WebSocket session by transferring the socket
boost::make_shared<websocket_session>(
std::move(socket_), state_)->run(std::move(req_));
return;
}
// Send the response
#ifndef BOOST_NO_CXX14_GENERIC_LAMBDAS
//
// The following code requires generic
// lambdas, available in C++14 and later.
//
handle_request(
state_->doc_root(),
std::move(req_),
[this](auto&& response)
{
// The lifetime of the message has to extend
// for the duration of the async operation so
// we use a shared_ptr to manage it.
using response_type = typename std::decay<decltype(response)>::type;
auto sp = boost::make_shared<response_type>(std::forward<decltype(response)>(response));
#if 0
// NOTE This causes an ICE in gcc 7.3
// Write the response
http::async_write(this->socket_, *sp,
net::bind_executor(strand_,
[self = shared_from_this(), sp](
beast::error_code ec, std::size_t bytes)
{
self->on_write(ec, bytes, sp->need_eof());
}));
#else
// Write the response
auto self = shared_from_this();
http::async_write(this->socket_, *sp,
net::bind_executor(strand_,
[self, sp](
beast::error_code ec, std::size_t bytes)
{
self->on_write(ec, bytes, sp->need_eof());
}));
#endif
});
#else
//
// This code uses the function object type send_lambda in
// place of a generic lambda which is not available in C++11
//
handle_request(
state_->doc_root(),
std::move(req_),
send_lambda(*this));
#endif
}
void
http_session::
on_write(beast::error_code ec, std::size_t, bool close)
{
// Handle the error, if any
if(ec)
return fail(ec, "write");
if(close)
{
// This means we should close the connection, usually because
// the response indicated the "Connection: close" semantic.
socket_.shutdown(tcp::socket::shutdown_send, ec);
return;
}
// Clear contents of the request message,
// otherwise the read behavior is undefined.
req_ = {};
// Read another request
http::async_read(socket_, buffer_, req_,
std::bind(
&http_session::on_read,
shared_from_this(),
std::placeholders::_1,
std::placeholders::_2));
}

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example/websocket/server/chat-multi/http_session.hpp Normal file
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//
// Copyright (c) 2018 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)
//
// Official repository: https://github.com/vinniefalco/CppCon2018
//
#ifndef BOOST_BEAST_EXAMPLE_WEBSOCKET_CHAT_MULTI_HTTP_SESSION_HPP
#define BOOST_BEAST_EXAMPLE_WEBSOCKET_CHAT_MULTI_HTTP_SESSION_HPP
#include "net.hpp"
#include "beast.hpp"
#include "shared_state.hpp"
#include <boost/smart_ptr.hpp>
#include <cstdlib>
#include <memory>
/** Represents an established HTTP connection
*/
class http_session : public boost::enable_shared_from_this<http_session>
{
tcp::socket socket_;
beast::flat_buffer buffer_;
boost::shared_ptr<shared_state> state_;
http::request<http::string_body> req_;
net::strand<net::io_context::executor_type> strand_;
struct send_lambda
{
http_session& self_;
explicit
send_lambda(http_session& self)
: self_(self)
{
}
template<bool isRequest, class Body, class Fields>
void
operator()(http::message<isRequest, Body, Fields>&& msg) const;
};
void fail(beast::error_code ec, char const* what);
void on_read(beast::error_code ec, std::size_t);
void on_write(beast::error_code ec, std::size_t, bool close);
public:
http_session(
tcp::socket socket,
boost::shared_ptr<shared_state> const& state);
void run();
};
#endif

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example/websocket/server/chat-multi/listener.cpp Normal file
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//
// Copyright (c) 2018 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)
//
// Official repository: https://github.com/vinniefalco/CppCon2018
//
#include "listener.hpp"
#include "http_session.hpp"
#include <iostream>
listener::
listener(
net::io_context& ioc,
tcp::endpoint endpoint,
boost::shared_ptr<shared_state> const& state)
: acceptor_(ioc)
, socket_(ioc)
, state_(state)
{
beast::error_code ec;
// Open the acceptor
acceptor_.open(endpoint.protocol(), ec);
if(ec)
{
fail(ec, "open");
return;
}
// Allow address reuse
acceptor_.set_option(net::socket_base::reuse_address(true), ec);
if(ec)
{
fail(ec, "set_option");
return;
}
// Bind to the server address
acceptor_.bind(endpoint, ec);
if(ec)
{
fail(ec, "bind");
return;
}
// Start listening for connections
acceptor_.listen(
net::socket_base::max_listen_connections, ec);
if(ec)
{
fail(ec, "listen");
return;
}
}
void
listener::
run()
{
// Start accepting a connection
acceptor_.async_accept(
socket_,
std::bind(
&listener::on_accept,
shared_from_this(),
std::placeholders::_1));
}
// Report a failure
void
listener::
fail(beast::error_code ec, char const* what)
{
// Don't report on canceled operations
if(ec == net::error::operation_aborted)
return;
std::cerr << what << ": " << ec.message() << "\n";
}
// Handle a connection
void
listener::
on_accept(beast::error_code ec)
{
if(ec)
return fail(ec, "accept");
else
// Launch a new session for this connection
boost::make_shared<http_session>(
std::move(socket_),
state_)->run();
// Accept another connection
acceptor_.async_accept(
socket_,
std::bind(
&listener::on_accept,
shared_from_this(),
std::placeholders::_1));
}

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//
// Copyright (c) 2018 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)
//
// Official repository: https://github.com/vinniefalco/CppCon2018
//
#ifndef BOOST_BEAST_EXAMPLE_WEBSOCKET_CHAT_MULTI_LISTENER_HPP
#define BOOST_BEAST_EXAMPLE_WEBSOCKET_CHAT_MULTI_LISTENER_HPP
#include "beast.hpp"
#include "net.hpp"
#include <boost/smart_ptr.hpp>
#include <memory>
#include <string>
// Forward declaration
class shared_state;
// Accepts incoming connections and launches the sessions
class listener : public boost::enable_shared_from_this<listener>
{
tcp::acceptor acceptor_;
tcp::socket socket_;
boost::shared_ptr<shared_state> state_;
void fail(beast::error_code ec, char const* what);
void on_accept(beast::error_code ec);
public:
listener(
net::io_context& ioc,
tcp::endpoint endpoint,
boost::shared_ptr<shared_state> const& state);
// Start accepting incoming connections
void run();
};
#endif

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//
// Copyright (c) 2018 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)
//
// Official repository: https://github.com/vinniefalco/CppCon2018
//
//------------------------------------------------------------------------------
/*
WebSocket chat server, multi-threaded
This implements a multi-user chat room using WebSocket. The
`io_context` runs on any number of threads, specified at
the command line.
*/
//------------------------------------------------------------------------------
#include "listener.hpp"
#include "shared_state.hpp"
#include <boost/asio/signal_set.hpp>
#include <boost/smart_ptr.hpp>
#include <iostream>
#include <vector>
int
main(int argc, char* argv[])
{
// Check command line arguments.
if (argc != 5)
{
std::cerr <<
"Usage: websocket-chat-multi <address> <port> <doc_root> <threads>\n" <<
"Example:\n" <<
" websocket-chat-server 0.0.0.0 8080 .\n";
return EXIT_FAILURE;
}
auto address = net::ip::make_address(argv[1]);
auto port = static_cast<unsigned short>(std::atoi(argv[2]));
auto doc_root = argv[3];
auto const threads = std::max<int>(1, std::atoi(argv[4]));
// The io_context is required for all I/O
net::io_context ioc;
// Create and launch a listening port
boost::make_shared<listener>(
ioc,
tcp::endpoint{address, port},
boost::make_shared<shared_state>(doc_root))->run();
// Capture SIGINT and SIGTERM to perform a clean shutdown
net::signal_set signals(ioc, SIGINT, SIGTERM);
signals.async_wait(
[&ioc](boost::system::error_code const&, int)
{
// Stop the io_context. This will cause run()
// to return immediately, eventually destroying the
// io_context and any remaining handlers in it.
ioc.stop();
});
// Run the I/O service on the requested number of threads
std::vector<std::thread> v;
v.reserve(threads - 1);
for(auto i = threads - 1; i > 0; --i)
v.emplace_back(
[&ioc]
{
ioc.run();
});
ioc.run();
// (If we get here, it means we got a SIGINT or SIGTERM)
// Block until all the threads exit
for(auto& t : v)
t.join();
return EXIT_SUCCESS;
}

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//
// Copyright (c) 2018 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)
//
// Official repository: https://github.com/vinniefalco/CppCon2018
//
#ifndef BOOST_BEAST_EXAMPLE_WEBSOCKET_CHAT_MULTI_NET_HPP
#define BOOST_BEAST_EXAMPLE_WEBSOCKET_CHAT_MULTI_NET_HPP
#include <boost/asio.hpp>
namespace net = boost::asio; // from <boost/asio.hpp>
using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
#endif

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//
// Copyright (c) 2018 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)
//
// Official repository: https://github.com/vinniefalco/CppCon2018
//
#include "shared_state.hpp"
#include "websocket_session.hpp"
shared_state::
shared_state(std::string doc_root)
: doc_root_(std::move(doc_root))
{
}
void
shared_state::
join(websocket_session* session)
{
std::lock_guard<std::mutex> lock(mutex_);
sessions_.insert(session);
}
void
shared_state::
leave(websocket_session* session)
{
std::lock_guard<std::mutex> lock(mutex_);
sessions_.erase(session);
}
// Broadcast a message to all websocket client sessions
void
shared_state::
send(std::string message)
{
// Put the message in a shared pointer so we can re-use it for each client
auto const ss = boost::make_shared<std::string const>(std::move(message));
// Make a local list of all the weak pointers representing
// the sessions, so we can do the actual sending without
// holding the mutex:
std::vector<boost::weak_ptr<websocket_session>> v;
{
std::lock_guard<std::mutex> lock(mutex_);
v.reserve(sessions_.size());
for(auto p : sessions_)
v.emplace_back(p->weak_from_this());
}
// For each session in our local list, try to acquire a strong
// pointer. If successful, then send the message on that session.
for(auto const& wp : v)
if(auto sp = wp.lock())
sp->send(ss);
}

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//
// Copyright (c) 2018 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)
//
// Official repository: https://github.com/vinniefalco/CppCon2018
//
#ifndef BOOST_BEAST_EXAMPLE_WEBSOCKET_CHAT_MULTI_SHARED_STATE_HPP
#define BOOST_BEAST_EXAMPLE_WEBSOCKET_CHAT_MULTI_SHARED_STATE_HPP
#include <boost/smart_ptr.hpp>
#include <memory>
#include <mutex>
#include <string>
#include <unordered_set>
// Forward declaration
class websocket_session;
// Represents the shared server state
class shared_state
{
std::string const doc_root_;
// This mutex synchronizes all access to sessions_
std::mutex mutex_;
// Keep a list of all the connected clients
std::unordered_set<websocket_session*> sessions_;
public:
explicit
shared_state(std::string doc_root);
std::string const&
doc_root() const noexcept
{
return doc_root_;
}
void join (websocket_session* session);
void leave (websocket_session* session);
void send (std::string message);
};
#endif

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//
// Copyright (c) 2018 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)
//
// Official repository: https://github.com/vinniefalco/CppCon2018
//
#include "websocket_session.hpp"
#include <iostream>
websocket_session::
websocket_session(
tcp::socket socket,
boost::shared_ptr<shared_state> const& state)
: ws_(std::move(socket))
, state_(state)
, strand_(ws_.get_executor())
{
}
websocket_session::
~websocket_session()
{
// Remove this session from the list of active sessions
state_->leave(this);
}
void
websocket_session::
fail(beast::error_code ec, char const* what)
{
// Don't report these
if( ec == net::error::operation_aborted ||
ec == websocket::error::closed)
return;
std::cerr << what << ": " << ec.message() << "\n";
}
void
websocket_session::
on_accept(beast::error_code ec)
{
// Handle the error, if any
if(ec)
return fail(ec, "accept");
// Add this session to the list of active sessions
state_->join(this);
// Read a message
ws_.async_read(
buffer_,
net::bind_executor(strand_,
std::bind(
&websocket_session::on_read,
shared_from_this(),
std::placeholders::_1,
std::placeholders::_2)));
}
void
websocket_session::
on_read(beast::error_code ec, std::size_t)
{
// Handle the error, if any
if(ec)
return fail(ec, "read");
// Send to all connections
state_->send(beast::buffers_to_string(buffer_.data()));
// Clear the buffer
buffer_.consume(buffer_.size());
// Read another message
ws_.async_read(
buffer_,
net::bind_executor(strand_,
std::bind(
&websocket_session::on_read,
shared_from_this(),
std::placeholders::_1,
std::placeholders::_2)));
}
void
websocket_session::
send(boost::shared_ptr<std::string const> const& ss)
{
// Always add to queue
queue_.push_back(ss);
// Are we already writing?
if(queue_.size() > 1)
return;
// We are not currently writing, so send this immediately
ws_.async_write(
net::buffer(*queue_.front()),
net::bind_executor(strand_,
std::bind(
&websocket_session::on_write,
shared_from_this(),
std::placeholders::_1,
std::placeholders::_2)));
}
void
websocket_session::
on_write(beast::error_code ec, std::size_t)
{
// Handle the error, if any
if(ec)
return fail(ec, "write");
// Remove the string from the queue
queue_.erase(queue_.begin());
// Send the next message if any
if(! queue_.empty())
ws_.async_write(
net::buffer(*queue_.front()),
net::bind_executor(strand_,
std::bind(
&websocket_session::on_write,
shared_from_this(),
std::placeholders::_1,
std::placeholders::_2)));
}

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//
// Copyright (c) 2018 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)
//
// Official repository: https://github.com/vinniefalco/CppCon2018
//
#ifndef BOOST_BEAST_EXAMPLE_WEBSOCKET_CHAT_MULTI_WEBSOCKET_SESSION_HPP
#define BOOST_BEAST_EXAMPLE_WEBSOCKET_CHAT_MULTI_WEBSOCKET_SESSION_HPP
#include "net.hpp"
#include "beast.hpp"
#include "shared_state.hpp"
#include <cstdlib>
#include <memory>
#include <string>
#include <vector>
// Forward declaration
class shared_state;
/** Represents an active WebSocket connection to the server
*/
class websocket_session : public boost::enable_shared_from_this<websocket_session>
{
beast::flat_buffer buffer_;
websocket::stream<tcp::socket> ws_;
boost::shared_ptr<shared_state> state_;
std::vector<boost::shared_ptr<std::string const>> queue_;
net::strand<net::io_context::executor_type> strand_;
void fail(beast::error_code ec, char const* what);
void on_accept(beast::error_code ec);
void on_read(beast::error_code ec, std::size_t bytes_transferred);
void on_write(beast::error_code ec, std::size_t bytes_transferred);
public:
websocket_session(
tcp::socket socket,
boost::shared_ptr<shared_state> const& state);
~websocket_session();
template<class Body, class Allocator>
void
run(http::request<Body, http::basic_fields<Allocator>> req);
// Send a message
void
send(boost::shared_ptr<std::string const> const& ss);
};
template<class Body, class Allocator>
void
websocket_session::
run(http::request<Body, http::basic_fields<Allocator>> req)
{
// Accept the websocket handshake
ws_.async_accept(
req,
std::bind(
&websocket_session::on_accept,
shared_from_this(),
std::placeholders::_1));
}
#endif