libs/beast/example/websocket/server/chat-multi/http_session.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/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 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 == 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)); } //------------------------------------------------------------------------------ struct http_session::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 { // 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_.stream_, *sp, [self, sp](beast::error_code ec, std::size_t bytes) { self->on_write(ec, bytes, sp->need_eof()); }); } }; //------------------------------------------------------------------------------ http_session:: http_session( tcp::socket&& socket, boost::shared_ptr<shared_state> const& state) : stream_(std::move(socket)) , state_(state) { } void http_session:: run() { do_read(); } // 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"; } void http_session:: 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 http::async_read( stream_, buffer_, parser_->get(), beast::bind_front_handler( &http_session::on_read, shared_from_this())); } 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) { 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(parser_->get())) { // Create a websocket session, transferring ownership // of both the socket and the HTTP request. boost::make_shared<websocket_session>( stream_.release_socket(), state_)->run(parser_->release()); 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->stream_, *sp, [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(stream_, *sp, [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(), parser_->release(), 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. stream_.socket().shutdown(tcp::socket::shutdown_send, ec); return; } // Read another request do_read(); }