372 lines
11 KiB
C++
372 lines
11 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/vinniefalco/CppCon2018
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//
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#include "http_session.hpp"
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#include "websocket_session.hpp"
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#include <boost/config.hpp>
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#include <iostream>
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#define BOOST_NO_CXX14_GENERIC_LAMBDAS
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//------------------------------------------------------------------------------
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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 == 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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// 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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struct http_session::send_lambda
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{
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http_session& self_;
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explicit
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send_lambda(http_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 = boost::make_shared<
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http::message<isRequest, Body, Fields>>(std::move(msg));
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// Write the response
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auto self = self_.shared_from_this();
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http::async_write(
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self_.stream_,
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*sp,
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[self, sp](beast::error_code ec, std::size_t bytes)
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{
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self->on_write(ec, bytes, sp->need_eof());
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});
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}
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};
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//------------------------------------------------------------------------------
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http_session::
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http_session(
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tcp::socket&& socket,
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boost::shared_ptr<shared_state> const& state)
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: stream_(std::move(socket))
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, state_(state)
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{
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}
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void
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http_session::
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run()
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{
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do_read();
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}
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// Report a failure
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void
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http_session::
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fail(beast::error_code ec, char const* what)
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{
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// Don't report on canceled operations
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if(ec == net::error::operation_aborted)
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return;
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std::cerr << what << ": " << ec.message() << "\n";
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}
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void
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http_session::
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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
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http::async_read(
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stream_,
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buffer_,
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parser_->get(),
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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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http_session::
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on_read(beast::error_code ec, std::size_t)
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{
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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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{
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stream_.socket().shutdown(tcp::socket::shutdown_send, ec);
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return;
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}
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// Handle the error, if any
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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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boost::make_shared<websocket_session>(
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stream_.release_socket(),
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state_)->run(parser_->release());
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return;
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}
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// Send the response
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#ifndef BOOST_NO_CXX14_GENERIC_LAMBDAS
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//
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// The following code requires generic
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// lambdas, available in C++14 and later.
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//
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handle_request(
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state_->doc_root(),
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std::move(req_),
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[this](auto&& response)
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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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using response_type = typename std::decay<decltype(response)>::type;
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auto sp = boost::make_shared<response_type>(std::forward<decltype(response)>(response));
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#if 0
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// NOTE This causes an ICE in gcc 7.3
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// Write the response
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http::async_write(this->stream_, *sp,
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[self = shared_from_this(), sp](
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beast::error_code ec, std::size_t bytes)
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{
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self->on_write(ec, bytes, sp->need_eof());
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});
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#else
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// Write the response
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auto self = shared_from_this();
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http::async_write(stream_, *sp,
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[self, sp](
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beast::error_code ec, std::size_t bytes)
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{
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self->on_write(ec, bytes, sp->need_eof());
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});
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#endif
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});
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#else
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//
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// This code uses the function object type send_lambda in
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// place of a generic lambda which is not available in C++11
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//
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handle_request(
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state_->doc_root(),
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parser_->release(),
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send_lambda(*this));
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#endif
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}
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void
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http_session::
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on_write(beast::error_code ec, std::size_t, bool close)
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{
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// Handle the error, if any
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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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stream_.socket().shutdown(tcp::socket::shutdown_send, ec);
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return;
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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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