469 lines
14 KiB
C++
469 lines
14 KiB
C++
//
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// Copyright (c) 2016-2017 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: HTTP server, stackless coroutine
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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/version.hpp>
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#include <boost/asio/bind_executor.hpp>
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#include <boost/asio/coroutine.hpp>
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#include <boost/asio/ip/tcp.hpp>
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#include <boost/asio/strand.hpp>
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#include <boost/config.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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using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
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namespace http = boost::beast::http; // from <boost/beast/http.hpp>
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// Return a reasonable mime type based on the extension of a file.
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boost::beast::string_view
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mime_type(boost::beast::string_view path)
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{
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using boost::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 == boost::beast::string_view::npos)
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return boost::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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boost::beast::string_view base,
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boost::beast::string_view path)
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{
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if(base.empty())
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return path.to_string();
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std::string result = base.to_string();
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#if 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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boost::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](boost::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() = why.to_string();
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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](boost::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 '" + target.to_string() + "' 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](boost::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: '" + what.to_string() + "'";
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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("..") != boost::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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boost::beast::error_code ec;
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http::file_body::value_type body;
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body.open(path.c_str(), boost::beast::file_mode::scan, ec);
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// Handle the case where the file doesn't exist
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if(ec == boost::system::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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// 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(body.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(body.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(boost::system::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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// Handles an HTTP server connection
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class session
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: public boost::asio::coroutine
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, public std::enable_shared_from_this<session>
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{
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// This is the C++11 equivalent of a generic lambda.
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// The function object is used to send an HTTP message.
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struct send_lambda
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{
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session& self_;
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std::shared_ptr<void> res_;
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explicit
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send_lambda(session& self)
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: self_(self)
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{
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}
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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) const
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{
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// The lifetime of the message has to extend
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// for the duration of the async operation so
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// we use a shared_ptr to manage it.
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auto sp = std::make_shared<
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http::message<isRequest, Body, Fields>>(std::move(msg));
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// Store a type-erased version of the shared
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// pointer in the class to keep it alive.
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self_.res_ = sp;
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// Write the response
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http::async_write(
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self_.socket_,
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*sp,
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boost::asio::bind_executor(
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self_.strand_,
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std::bind(
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&session::loop,
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self_.shared_from_this(),
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std::placeholders::_1,
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std::placeholders::_2,
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sp->need_eof())));
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}
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};
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tcp::socket socket_;
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boost::asio::strand<
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boost::asio::io_context::executor_type> strand_;
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boost::beast::flat_buffer buffer_;
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std::string const& doc_root_;
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http::request<http::string_body> req_;
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std::shared_ptr<void> res_;
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send_lambda lambda_;
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public:
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// Take ownership of the socket
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explicit
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session(
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tcp::socket socket,
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std::string const& doc_root)
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: socket_(std::move(socket))
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, strand_(socket_.get_executor())
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, doc_root_(doc_root)
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, lambda_(*this)
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{
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}
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// Start the asynchronous operation
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void
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run()
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{
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loop({}, 0, false);
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}
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#include <boost/asio/yield.hpp>
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void
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loop(
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boost::system::error_code ec,
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std::size_t bytes_transferred,
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bool close)
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{
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boost::ignore_unused(bytes_transferred);
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reenter(*this)
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{
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for(;;)
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{
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// Read a request
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yield http::async_read(socket_, buffer_, req_,
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boost::asio::bind_executor(
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strand_,
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std::bind(
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&session::loop,
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shared_from_this(),
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std::placeholders::_1,
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std::placeholders::_2,
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false)));
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if(ec == http::error::end_of_stream)
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{
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// The remote host closed the connection
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break;
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}
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if(ec)
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return fail(ec, "read");
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// Send the response
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yield handle_request(doc_root_, std::move(req_), lambda_);
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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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break;
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}
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// We're done with the response so delete it
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res_ = nullptr;
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}
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// Send a TCP shutdown
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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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#include <boost/asio/unyield.hpp>
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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
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: public boost::asio::coroutine
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, public std::enable_shared_from_this<listener>
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{
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tcp::acceptor acceptor_;
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tcp::socket socket_;
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std::string const& doc_root_;
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public:
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listener(
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boost::asio::io_context& ioc,
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tcp::endpoint endpoint,
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std::string const& doc_root)
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: acceptor_(ioc)
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, socket_(ioc)
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, doc_root_(doc_root)
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{
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boost::system::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;
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}
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// Bind to the server address
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acceptor_.bind(endpoint, ec);
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if(ec)
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{
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fail(ec, "bind");
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return;
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}
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// Start listening for connections
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acceptor_.listen(boost::asio::socket_base::max_listen_connections, ec);
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if(ec)
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{
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fail(ec, "listen");
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return;
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}
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}
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// Start accepting incoming connections
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void
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run()
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{
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if(! acceptor_.is_open())
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return;
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loop();
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}
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#include <boost/asio/yield.hpp>
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void
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loop(boost::system::error_code ec = {})
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{
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reenter(*this)
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{
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for(;;)
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{
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yield acceptor_.async_accept(
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socket_,
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std::bind(
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&listener::loop,
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shared_from_this(),
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std::placeholders::_1));
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if(ec)
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{
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fail(ec, "accept");
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}
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else
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{
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// Create the session and run it
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std::make_shared<session>(
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std::move(socket_),
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doc_root_)->run();
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}
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}
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}
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}
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#include <boost/asio/unyield.hpp>
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};
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//------------------------------------------------------------------------------
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int main(int argc, char* argv[])
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{
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// Check command line arguments.
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if (argc != 5)
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{
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std::cerr <<
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"Usage: http-server-stackless <address> <port> <doc_root> <threads>\n" <<
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"Example:\n" <<
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" http-server-stackless 0.0.0.0 8080 . 1\n";
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return EXIT_FAILURE;
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}
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auto const address = boost::asio::ip::make_address(argv[1]);
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auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
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std::string const doc_root = argv[3];
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auto const threads = std::max<int>(1, std::atoi(argv[4]));
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// The io_context is required for all I/O
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boost::asio::io_context ioc{threads};
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// Create and launch a listening port
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std::make_shared<listener>(
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ioc,
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tcp::endpoint{address, port},
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doc_root)->run();
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// Run the I/O service on the requested number of threads
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std::vector<std::thread> v;
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v.reserve(threads - 1);
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for(auto i = threads - 1; i > 0; --i)
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v.emplace_back(
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[&ioc]
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{
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ioc.run();
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});
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ioc.run();
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return EXIT_SUCCESS;
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}
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