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benstadin/MultiIoContext.hpp

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Boost Beast Multi Context Test
Raw
main.cpp
//
// Copyright (c) 2016-2019 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
//
//------------------------------------------------------------------------------
//
// Example: Advanced server
//
//------------------------------------------------------------------------------
#include <boost/beast/core.hpp>
#include <boost/beast/http.hpp>
#include <boost/beast/websocket.hpp>
#include <boost/beast/version.hpp>
#include <boost/asio/bind_executor.hpp>
#include <boost/asio/signal_set.hpp>
#include <boost/asio/strand.hpp>
#include <boost/make_unique.hpp>
#include <boost/optional.hpp>
#include <algorithm>
#include <cstdlib>
#include <functional>
#include <iostream>
#include <memory>
#include <string>
#include <thread>
#include <vector>
#include "MultiIoContext.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>
namespace net = boost::asio; // from <boost/asio.hpp>
using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
// 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 std::string(path);
std::string result(base);
#ifdef 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() = std::string(why);
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 '" + std::string(target) + "' 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: '" + std::string(what) + "'";
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 == beast::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));
}
//------------------------------------------------------------------------------
// Report a failure
void
fail(beast::error_code ec, char const* what)
{
std::cerr << what << ": " << ec.message() << "\n";
}
// Echoes back all received WebSocket messages
class websocket_session : public std::enable_shared_from_this<websocket_session>
{
websocket::stream<beast::tcp_stream> ws_;
beast::flat_buffer buffer_;
public:
// Take ownership of the socket
explicit
websocket_session(tcp::socket&& socket)
: ws_(std::move(socket))
{
}
// Start the asynchronous accept operation
template<class Body, class Allocator>
void
do_accept(http::request<Body, http::basic_fields<Allocator>> req)
{
// Set suggested timeout settings for the websocket
ws_.set_option(
websocket::stream_base::timeout::suggested(
beast::role_type::server));
// Set a decorator to change the Server of the handshake
ws_.set_option(websocket::stream_base::decorator(
[](websocket::response_type& res)
{
res.set(http::field::server,
std::string(BOOST_BEAST_VERSION_STRING) +
" advanced-server");
}));
// Accept the websocket handshake
ws_.async_accept(
req,
beast::bind_front_handler(
&websocket_session::on_accept,
shared_from_this()));
}
private:
void
on_accept(beast::error_code ec)
{
if(ec)
return fail(ec, "accept");
// Read a message
do_read();
}
void
do_read()
{
// Read a message into our buffer
ws_.async_read(
buffer_,
beast::bind_front_handler(
&websocket_session::on_read,
shared_from_this()));
}
void
on_read(
beast::error_code ec,
std::size_t bytes_transferred)
{
boost::ignore_unused(bytes_transferred);
// This indicates that the websocket_session was closed
if(ec == websocket::error::closed)
return;
if(ec)
fail(ec, "read");
// Echo the message
ws_.text(ws_.got_text());
ws_.async_write(
buffer_.data(),
beast::bind_front_handler(
&websocket_session::on_write,
shared_from_this()));
}
void
on_write(
beast::error_code ec,
std::size_t bytes_transferred)
{
boost::ignore_unused(bytes_transferred);
if(ec)
return fail(ec, "write");
// Clear the buffer
buffer_.consume(buffer_.size());
// Do another read
do_read();
}
};
//------------------------------------------------------------------------------
// Handles an HTTP server connection
class http_session : public std::enable_shared_from_this<http_session>
{
// This queue is used for HTTP pipelining.
class queue
{
enum
{
// Maximum number of responses we will queue
limit = 8
};
// The type-erased, saved work item
struct work
{
virtual ~work() = default;
virtual void operator()() = 0;
};
http_session& self_;
std::vector<std::unique_ptr<work>> items_;
public:
explicit
queue(http_session& self)
: self_(self)
{
static_assert(limit > 0, "queue limit must be positive");
items_.reserve(limit);
}
// Returns `true` if we have reached the queue limit
bool
is_full() const
{
return items_.size() >= limit;
}
// Called when a message finishes sending
// Returns `true` if the caller should initiate a read
bool
on_write()
{
BOOST_ASSERT(! items_.empty());
auto const was_full = is_full();
items_.erase(items_.begin());
if(! items_.empty())
(*items_.front())();
return was_full;
}
// Called by the HTTP handler to send a response.
template<bool isRequest, class Body, class Fields>
void
operator()(http::message<isRequest, Body, Fields>&& msg)
{
// This holds a work item
struct work_impl : work
{
http_session& self_;
http::message<isRequest, Body, Fields> msg_;
work_impl(
http_session& self,
http::message<isRequest, Body, Fields>&& msg)
: self_(self)
, msg_(std::move(msg))
{
}
void
operator()()
{
http::async_write(
self_.stream_,
msg_,
beast::bind_front_handler(
&http_session::on_write,
self_.shared_from_this(),
msg_.need_eof()));
}
};
// Allocate and store the work
items_.push_back(
boost::make_unique<work_impl>(self_, std::move(msg)));
// If there was no previous work, start this one
if(items_.size() == 1)
(*items_.front())();
}
};
beast::tcp_stream stream_;
beast::flat_buffer buffer_;
std::shared_ptr<std::string const> doc_root_;
queue queue_;
// The parser is stored in an optional container so we can
// construct it from scratch it at the beginning of each new message.
boost::optional<http::request_parser<http::string_body>> parser_;
public:
// Take ownership of the socket
http_session(
tcp::socket&& socket,
std::shared_ptr<std::string const> const& doc_root)
: stream_(std::move(socket))
, doc_root_(doc_root)
, queue_(*this)
{
}
// Start the session
void
run()
{
do_read();
}
private:
void
do_read()
{
// Construct a new parser for each message
parser_.emplace();
// Apply a reasonable limit to the allowed size
// of the body in bytes to prevent abuse.
parser_->body_limit(10000);
// Set the timeout.
stream_.expires_after(std::chrono::seconds(30));
// Read a request using the parser-oriented interface
http::async_read(
stream_,
buffer_,
*parser_,
beast::bind_front_handler(
&http_session::on_read,
shared_from_this()));
}
void
on_read(beast::error_code ec, std::size_t bytes_transferred)
{
boost::ignore_unused(bytes_transferred);
// This means they closed the connection
if(ec == http::error::end_of_stream)
return do_close();
if(ec)
return fail(ec, "read");
// See if it is a WebSocket Upgrade
if(websocket::is_upgrade(parser_->get()))
{
// Create a websocket session, transferring ownership
// of both the socket and the HTTP request.
std::make_shared<websocket_session>(
stream_.release_socket())->do_accept(parser_->release());
return;
}
// Send the response
handle_request(*doc_root_, parser_->release(), queue_);
// If we aren't at the queue limit, try to pipeline another request
if(! queue_.is_full())
do_read();
}
void
on_write(bool close, beast::error_code ec, std::size_t bytes_transferred)
{
boost::ignore_unused(bytes_transferred);
if(ec)
return fail(ec, "write");
if(close)
{
// This means we should close the connection, usually because
// the response indicated the "Connection: close" semantic.
return do_close();
}
// Inform the queue that a write completed
if(queue_.on_write())
{
// Read another request
do_read();
}
}
void
do_close()
{
// Send a TCP shutdown
beast::error_code ec;
stream_.socket().shutdown(tcp::socket::shutdown_send, ec);
// At this point the connection is closed gracefully
}
};
//------------------------------------------------------------------------------
// Accepts incoming connections and launches the sessions
class listener : public std::enable_shared_from_this<listener>
{
net::io_context& ioc_;
multi_io_context& multi_io_context_;
tcp::acceptor acceptor_;
boost::asio::io_context *socket_;
std::shared_ptr<std::string const> doc_root_;
public:
listener(
net::io_context& ioc,
multi_io_context& multi_io_context,
tcp::endpoint endpoint,
std::shared_ptr<std::string const> const& doc_root)
: ioc_(ioc)
, acceptor_(ioc)
, multi_io_context_(multi_io_context)
, socket_(multi_io_context.bump_context())
, doc_root_(doc_root)
{
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;
}
}
// Start accepting incoming connections
void
run()
{
do_accept();
}
private:
void
do_accept()
{
// The new connection gets its own strand
acceptor_.async_accept(
net::make_strand(*socket_),
beast::bind_front_handler(
&listener::on_accept,
shared_from_this()));
}
void
on_accept(beast::error_code ec, tcp::socket socket)
{
if(ec)
{
fail(ec, "accept");
}
else
{
// Create the http session and run it
std::make_shared<http_session>(
std::move(socket),
doc_root_)->run();
}
// Reset the socket with the next io_context
socket_ = multi_io_context_.bump_context();
// Accept another connection
do_accept();
}
};
//------------------------------------------------------------------------------
int main(int argc, char* argv[])
{
// Check command line arguments.
if (argc != 5)
{
std::cerr <<
"Usage: advanced-server <address> <port> <doc_root> <threads>\n" <<
"Example:\n" <<
" advanced-server 0.0.0.0 8080 . 1\n";
return EXIT_FAILURE;
}
auto const address = net::ip::make_address(argv[1]);
auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
auto const doc_root = std::make_shared<std::string>(argv[3]);
auto const threads = std::max<int>(2, std::atoi(argv[4]));
// The io_context is required for all I/O
multi_io_context ioc{static_cast<size_t>(threads)};
net::io_context &listener_ioc = *ioc.get_listener_context();
// Create and launch a listening port
std::make_shared<listener>(
listener_ioc,
ioc,
tcp::endpoint{address, port},
doc_root)->run();
// Capture SIGINT and SIGTERM to perform a clean shutdown
// net::signal_set signals(ioc, SIGINT, SIGTERM);
// signals.async_wait(
// [&](beast::error_code const&, int)
// {
// // Stop the `io_context`. This will cause `run()`
// // to return immediately, eventually destroying the
// // `io_context` and all of the sockets 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.bump_context()->run();
});
listener_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;
}
Raw
MultiIoContext.hpp
#ifndef MultiIoContext_h
#define MultiIoContext_h
#include <boost/asio/io_context.hpp>
#include <boost/asio/executor_work_guard.hpp>
#include <deque>
#include <vector>
#include <algorithm>
class multi_io_context
{
class io_context
{
boost::asio::io_context ioc_;
boost::asio::executor_work_guard<
boost::asio::io_context::executor_type> work_;
public:
explicit
io_context(int concurrency_hint = -1)
: ioc_{concurrency_hint}
, work_{boost::asio::make_work_guard(ioc_)}
{
}
io_context(io_context const&) = delete;
io_context& operator=(io_context const&) = delete;
~io_context() = default;
boost::asio::io_context&
get()
{
return ioc_;
}
};
int const concurrency_hint_{2};
std::size_t index_{0};
std::deque<io_context> io_contexts_;
std::vector<boost::asio::io_context*> ptr_io_contexts_;
public:
explicit
multi_io_context(std::size_t num_contexts = 2)
{
num_contexts = std::max<std::size_t>(2, num_contexts);
for(std::size_t i = 0; i < num_contexts; ++i)
{
io_contexts_.emplace_back(concurrency_hint_);
ptr_io_contexts_.emplace_back(&io_contexts_.back().get());
}
}
multi_io_context(multi_io_context const&) = delete;
multi_io_context& operator=(multi_io_context const&) = delete;
multi_io_context(multi_io_context&&) = default;
~multi_io_context() = default;
std::size_t
size() const
{
return io_contexts_.size();
}
// Returns a vector of non-owning pointers to the io_contexts
std::vector<boost::asio::io_context*> const
contexts()
{
return ptr_io_contexts_;
}
// Returns the current io_context, without advancing the index
boost::asio::io_context*
get_context()
{
if (!io_contexts_.size()) {
return nullptr;
}
return ptr_io_contexts_[index_];
}
boost::asio::io_context*
get_listener_context()
{
if (!io_contexts_.size()) {
return nullptr;
}
// // naively set to be at index 0
auto& ioc = io_contexts_.at(0).get();
return &ioc;
}
// Returns the current io_context, and advances the index
// returns all contexts but the listener's
boost::asio::io_context*
bump_context()
{
// if (io_contexts_.size() < 2) {
// return nullptr;
// }
//
// if(++index_ == io_contexts_.size() || index_ == 0)
// index_ = 1;
//
// return ptr_io_contexts_[index_];
auto& ioc = io_contexts_.at(index_).get();
if(++index_ == io_contexts_.size())
index_ = 0;
return &ioc;
}
};
#endif /* MultiIoContext_h */
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