683 lines
19 KiB
C++
683 lines
19 KiB
C++
//
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// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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// Official repository: https://github.com/boostorg/beast
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//
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//------------------------------------------------------------------------------
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//
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// Example: Advanced server
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//
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//------------------------------------------------------------------------------
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#include <boost/beast/core.hpp>
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#include <boost/beast/http.hpp>
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#include <boost/beast/websocket.hpp>
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#include <boost/beast/version.hpp>
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#include <boost/asio/bind_executor.hpp>
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#include <boost/asio/signal_set.hpp>
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#include <boost/asio/strand.hpp>
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#include <boost/make_unique.hpp>
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#include <boost/optional.hpp>
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#include <algorithm>
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#include <cstdlib>
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#include <functional>
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#include <iostream>
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#include <memory>
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#include <string>
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#include <thread>
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#include <vector>
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namespace beast = boost::beast; // from <boost/beast.hpp>
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namespace http = beast::http; // from <boost/beast/http.hpp>
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namespace websocket = beast::websocket; // from <boost/beast/websocket.hpp>
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namespace net = boost::asio; // from <boost/asio.hpp>
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using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
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// Return a reasonable mime type based on the extension of a file.
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beast::string_view
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mime_type(beast::string_view path)
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{
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using beast::iequals;
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auto const ext = [&path]
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{
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auto const pos = path.rfind(".");
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if(pos == beast::string_view::npos)
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return beast::string_view{};
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return path.substr(pos);
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}();
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if(iequals(ext, ".htm")) return "text/html";
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if(iequals(ext, ".html")) return "text/html";
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if(iequals(ext, ".php")) return "text/html";
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if(iequals(ext, ".css")) return "text/css";
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if(iequals(ext, ".txt")) return "text/plain";
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if(iequals(ext, ".js")) return "application/javascript";
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if(iequals(ext, ".json")) return "application/json";
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if(iequals(ext, ".xml")) return "application/xml";
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if(iequals(ext, ".swf")) return "application/x-shockwave-flash";
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if(iequals(ext, ".flv")) return "video/x-flv";
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if(iequals(ext, ".png")) return "image/png";
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if(iequals(ext, ".jpe")) return "image/jpeg";
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if(iequals(ext, ".jpeg")) return "image/jpeg";
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if(iequals(ext, ".jpg")) return "image/jpeg";
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if(iequals(ext, ".gif")) return "image/gif";
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if(iequals(ext, ".bmp")) return "image/bmp";
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if(iequals(ext, ".ico")) return "image/vnd.microsoft.icon";
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if(iequals(ext, ".tiff")) return "image/tiff";
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if(iequals(ext, ".tif")) return "image/tiff";
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if(iequals(ext, ".svg")) return "image/svg+xml";
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if(iequals(ext, ".svgz")) return "image/svg+xml";
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return "application/text";
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}
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// Append an HTTP rel-path to a local filesystem path.
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// The returned path is normalized for the platform.
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std::string
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path_cat(
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beast::string_view base,
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beast::string_view path)
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{
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if(base.empty())
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return std::string(path);
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std::string result(base);
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#ifdef BOOST_MSVC
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char constexpr path_separator = '\\';
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if(result.back() == path_separator)
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result.resize(result.size() - 1);
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result.append(path.data(), path.size());
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for(auto& c : result)
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if(c == '/')
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c = path_separator;
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#else
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char constexpr path_separator = '/';
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if(result.back() == path_separator)
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result.resize(result.size() - 1);
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result.append(path.data(), path.size());
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#endif
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return result;
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}
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// This function produces an HTTP response for the given
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// request. The type of the response object depends on the
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// contents of the request, so the interface requires the
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// caller to pass a generic lambda for receiving the response.
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template<
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class Body, class Allocator,
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class Send>
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void
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handle_request(
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beast::string_view doc_root,
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http::request<Body, http::basic_fields<Allocator>>&& req,
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Send&& send)
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{
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// Returns a bad request response
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auto const bad_request =
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[&req](beast::string_view why)
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{
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http::response<http::string_body> res{http::status::bad_request, req.version()};
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res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
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res.set(http::field::content_type, "text/html");
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res.keep_alive(req.keep_alive());
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res.body() = std::string(why);
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res.prepare_payload();
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return res;
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};
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// Returns a not found response
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auto const not_found =
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[&req](beast::string_view target)
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{
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http::response<http::string_body> res{http::status::not_found, req.version()};
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res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
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res.set(http::field::content_type, "text/html");
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res.keep_alive(req.keep_alive());
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res.body() = "The resource '" + std::string(target) + "' was not found.";
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res.prepare_payload();
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return res;
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};
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// Returns a server error response
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auto const server_error =
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[&req](beast::string_view what)
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{
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http::response<http::string_body> res{http::status::internal_server_error, req.version()};
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res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
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res.set(http::field::content_type, "text/html");
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res.keep_alive(req.keep_alive());
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res.body() = "An error occurred: '" + std::string(what) + "'";
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res.prepare_payload();
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return res;
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};
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// Make sure we can handle the method
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if( req.method() != http::verb::get &&
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req.method() != http::verb::head)
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return send(bad_request("Unknown HTTP-method"));
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// Request path must be absolute and not contain "..".
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if( req.target().empty() ||
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req.target()[0] != '/' ||
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req.target().find("..") != beast::string_view::npos)
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return send(bad_request("Illegal request-target"));
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// Build the path to the requested file
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std::string path = path_cat(doc_root, req.target());
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if(req.target().back() == '/')
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path.append("index.html");
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// Attempt to open the file
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beast::error_code ec;
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http::file_body::value_type body;
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body.open(path.c_str(), beast::file_mode::scan, ec);
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// Handle the case where the file doesn't exist
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if(ec == beast::errc::no_such_file_or_directory)
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return send(not_found(req.target()));
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// Handle an unknown error
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if(ec)
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return send(server_error(ec.message()));
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// Cache the size since we need it after the move
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auto const size = body.size();
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// Respond to HEAD request
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if(req.method() == http::verb::head)
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{
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http::response<http::empty_body> res{http::status::ok, req.version()};
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res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
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res.set(http::field::content_type, mime_type(path));
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res.content_length(size);
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res.keep_alive(req.keep_alive());
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return send(std::move(res));
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}
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// Respond to GET request
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http::response<http::file_body> res{
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std::piecewise_construct,
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std::make_tuple(std::move(body)),
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std::make_tuple(http::status::ok, req.version())};
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res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
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res.set(http::field::content_type, mime_type(path));
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res.content_length(size);
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res.keep_alive(req.keep_alive());
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return send(std::move(res));
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}
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//------------------------------------------------------------------------------
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// Report a failure
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void
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fail(beast::error_code ec, char const* what)
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{
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std::cerr << what << ": " << ec.message() << "\n";
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}
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// Echoes back all received WebSocket messages
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class websocket_session : public std::enable_shared_from_this<websocket_session>
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{
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websocket::stream<beast::tcp_stream> ws_;
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beast::flat_buffer buffer_;
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public:
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// Take ownership of the socket
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explicit
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websocket_session(tcp::socket&& socket)
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: ws_(std::move(socket))
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{
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}
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// Start the asynchronous accept operation
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template<class Body, class Allocator>
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void
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do_accept(http::request<Body, http::basic_fields<Allocator>> req)
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{
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// Set suggested timeout settings for the websocket
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ws_.set_option(
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websocket::stream_base::timeout::suggested(
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beast::role_type::server));
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// Set a decorator to change the Server of the handshake
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ws_.set_option(websocket::stream_base::decorator(
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[](websocket::response_type& res)
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{
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res.set(http::field::server,
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std::string(BOOST_BEAST_VERSION_STRING) +
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" advanced-server");
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}));
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// Accept the websocket handshake
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ws_.async_accept(
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req,
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beast::bind_front_handler(
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&websocket_session::on_accept,
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shared_from_this()));
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}
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private:
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void
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on_accept(beast::error_code ec)
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{
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if(ec)
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return fail(ec, "accept");
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// Read a message
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do_read();
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}
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void
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do_read()
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{
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// Read a message into our buffer
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ws_.async_read(
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buffer_,
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beast::bind_front_handler(
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&websocket_session::on_read,
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shared_from_this()));
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}
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void
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on_read(
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beast::error_code ec,
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std::size_t bytes_transferred)
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{
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boost::ignore_unused(bytes_transferred);
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// This indicates that the websocket_session was closed
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if(ec == websocket::error::closed)
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return;
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if(ec)
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fail(ec, "read");
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// Echo the message
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ws_.text(ws_.got_text());
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ws_.async_write(
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buffer_.data(),
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beast::bind_front_handler(
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&websocket_session::on_write,
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shared_from_this()));
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}
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void
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on_write(
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beast::error_code ec,
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std::size_t bytes_transferred)
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{
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boost::ignore_unused(bytes_transferred);
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if(ec)
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return fail(ec, "write");
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// Clear the buffer
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buffer_.consume(buffer_.size());
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// Do another read
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do_read();
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}
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};
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//------------------------------------------------------------------------------
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// Handles an HTTP server connection
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class http_session : public std::enable_shared_from_this<http_session>
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{
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// This queue is used for HTTP pipelining.
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class queue
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{
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enum
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{
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// Maximum number of responses we will queue
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limit = 8
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};
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// The type-erased, saved work item
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struct work
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{
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virtual ~work() = default;
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virtual void operator()() = 0;
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};
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http_session& self_;
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std::vector<std::unique_ptr<work>> items_;
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public:
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explicit
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queue(http_session& self)
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: self_(self)
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{
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static_assert(limit > 0, "queue limit must be positive");
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items_.reserve(limit);
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}
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// Returns `true` if we have reached the queue limit
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bool
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is_full() const
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{
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return items_.size() >= limit;
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}
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// Called when a message finishes sending
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// Returns `true` if the caller should initiate a read
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bool
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on_write()
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{
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BOOST_ASSERT(! items_.empty());
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auto const was_full = is_full();
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items_.erase(items_.begin());
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if(! items_.empty())
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(*items_.front())();
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return was_full;
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}
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// Called by the HTTP handler to send a response.
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template<bool isRequest, class Body, class Fields>
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void
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operator()(http::message<isRequest, Body, Fields>&& msg)
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{
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// This holds a work item
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struct work_impl : work
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{
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http_session& self_;
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http::message<isRequest, Body, Fields> msg_;
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work_impl(
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http_session& self,
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http::message<isRequest, Body, Fields>&& msg)
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: self_(self)
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, msg_(std::move(msg))
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{
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}
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void
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operator()()
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{
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http::async_write(
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self_.stream_,
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msg_,
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beast::bind_front_handler(
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&http_session::on_write,
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self_.shared_from_this(),
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msg_.need_eof()));
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}
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};
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// Allocate and store the work
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items_.push_back(
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boost::make_unique<work_impl>(self_, std::move(msg)));
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// If there was no previous work, start this one
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if(items_.size() == 1)
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(*items_.front())();
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}
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};
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beast::tcp_stream stream_;
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beast::flat_buffer buffer_;
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std::shared_ptr<std::string const> doc_root_;
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queue queue_;
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// The parser is stored in an optional container so we can
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// construct it from scratch it at the beginning of each new message.
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boost::optional<http::request_parser<http::string_body>> parser_;
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public:
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// Take ownership of the socket
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http_session(
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tcp::socket&& socket,
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std::shared_ptr<std::string const> const& doc_root)
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: stream_(std::move(socket))
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, doc_root_(doc_root)
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, queue_(*this)
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{
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}
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// Start the session
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void
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run()
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{
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do_read();
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}
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private:
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void
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do_read()
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{
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// Construct a new parser for each message
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parser_.emplace();
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// Apply a reasonable limit to the allowed size
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// of the body in bytes to prevent abuse.
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parser_->body_limit(10000);
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// Set the timeout.
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stream_.expires_after(std::chrono::seconds(30));
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// Read a request using the parser-oriented interface
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http::async_read(
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stream_,
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buffer_,
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*parser_,
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beast::bind_front_handler(
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&http_session::on_read,
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shared_from_this()));
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}
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void
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on_read(beast::error_code ec, std::size_t bytes_transferred)
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{
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boost::ignore_unused(bytes_transferred);
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// This means they closed the connection
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if(ec == http::error::end_of_stream)
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return do_close();
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if(ec)
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return fail(ec, "read");
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// See if it is a WebSocket Upgrade
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if(websocket::is_upgrade(parser_->get()))
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{
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// Create a websocket session, transferring ownership
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// of both the socket and the HTTP request.
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std::make_shared<websocket_session>(
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stream_.release_socket())->do_accept(parser_->release());
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return;
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}
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// Send the response
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handle_request(*doc_root_, parser_->release(), queue_);
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// If we aren't at the queue limit, try to pipeline another request
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if(! queue_.is_full())
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do_read();
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}
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void
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on_write(bool close, beast::error_code ec, std::size_t bytes_transferred)
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{
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boost::ignore_unused(bytes_transferred);
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if(ec)
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return fail(ec, "write");
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if(close)
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{
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// This means we should close the connection, usually because
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// the response indicated the "Connection: close" semantic.
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return do_close();
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}
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// Inform the queue that a write completed
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if(queue_.on_write())
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{
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// Read another request
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do_read();
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}
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}
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void
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do_close()
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{
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// Send a TCP shutdown
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beast::error_code ec;
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stream_.socket().shutdown(tcp::socket::shutdown_send, ec);
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// At this point the connection is closed gracefully
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}
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};
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//------------------------------------------------------------------------------
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// Accepts incoming connections and launches the sessions
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class listener : public std::enable_shared_from_this<listener>
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{
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net::io_context& ioc_;
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tcp::acceptor acceptor_;
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std::shared_ptr<std::string const> doc_root_;
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public:
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listener(
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net::io_context& ioc,
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tcp::endpoint endpoint,
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std::shared_ptr<std::string const> const& doc_root)
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: ioc_(ioc)
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, acceptor_(net::make_strand(ioc))
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, doc_root_(doc_root)
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{
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beast::error_code ec;
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// Open the acceptor
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acceptor_.open(endpoint.protocol(), ec);
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if(ec)
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{
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fail(ec, "open");
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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(ioc_),
|
|
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();
|
|
}
|
|
|
|
// 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>(1, std::atoi(argv[4]));
|
|
|
|
// The io_context is required for all I/O
|
|
net::io_context ioc{threads};
|
|
|
|
// Create and launch a listening port
|
|
std::make_shared<listener>(
|
|
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.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;
|
|
}
|