libs/beast/example/http/server/stackless-ssl/http_server_stackless_ssl.cpp

   1 //
   2 // Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
   3 //
   4 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   5 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // Official repository: https://github.com/boostorg/beast
   8 //
   9
  10 //------------------------------------------------------------------------------
  11 //
  12 // Example: HTTP SSL server, stackless coroutine
  13 //
  14 //------------------------------------------------------------------------------
  15
  16 #include "example/common/server_certificate.hpp"
  17
  18 #include <boost/beast/core.hpp>
  19 #include <boost/beast/http.hpp>
  20 #include <boost/beast/ssl.hpp>
  21 #include <boost/beast/version.hpp>
  22 #include <boost/asio/coroutine.hpp>
  23 #include <boost/asio/dispatch.hpp>
  24 #include <boost/asio/strand.hpp>
  25 #include <boost/config.hpp>
  26 #include <algorithm>
  27 #include <cstdlib>
  28 #include <functional>
  29 #include <iostream>
  30 #include <memory>
  31 #include <string>
  32 #include <thread>
  33 #include <vector>
  34
  35 namespace beast = boost::beast;         // from <boost/beast.hpp>
  36 namespace http = beast::http;           // from <boost/beast/http.hpp>
  37 namespace net = boost::asio;            // from <boost/asio.hpp>
  38 namespace ssl = boost::asio::ssl;       // from <boost/asio/ssl.hpp>
  39 using tcp = boost::asio::ip::tcp;       // from <boost/asio/ip/tcp.hpp>
  40
  41 // Return a reasonable mime type based on the extension of a file.
  42 beast::string_view
  43 mime_type(beast::string_view path)
  44 {
  45     using beast::iequals;
  46     auto const ext = [&path]
  47     {
  48         auto const pos = path.rfind(".");
  49         if(pos == beast::string_view::npos)
  50             return beast::string_view{};
  51         return path.substr(pos);
  52     }();
  53     if(iequals(ext, ".htm"))  return "text/html";
  54     if(iequals(ext, ".html")) return "text/html";
  55     if(iequals(ext, ".php"))  return "text/html";
  56     if(iequals(ext, ".css"))  return "text/css";
  57     if(iequals(ext, ".txt"))  return "text/plain";
  58     if(iequals(ext, ".js"))   return "application/javascript";
  59     if(iequals(ext, ".json")) return "application/json";
  60     if(iequals(ext, ".xml"))  return "application/xml";
  61     if(iequals(ext, ".swf"))  return "application/x-shockwave-flash";
  62     if(iequals(ext, ".flv"))  return "video/x-flv";
  63     if(iequals(ext, ".png"))  return "image/png";
  64     if(iequals(ext, ".jpe"))  return "image/jpeg";
  65     if(iequals(ext, ".jpeg")) return "image/jpeg";
  66     if(iequals(ext, ".jpg"))  return "image/jpeg";
  67     if(iequals(ext, ".gif"))  return "image/gif";
  68     if(iequals(ext, ".bmp"))  return "image/bmp";
  69     if(iequals(ext, ".ico"))  return "image/vnd.microsoft.icon";
  70     if(iequals(ext, ".tiff")) return "image/tiff";
  71     if(iequals(ext, ".tif"))  return "image/tiff";
  72     if(iequals(ext, ".svg"))  return "image/svg+xml";
  73     if(iequals(ext, ".svgz")) return "image/svg+xml";
  74     return "application/text";
  75 }
  76
  77 // Append an HTTP rel-path to a local filesystem path.
  78 // The returned path is normalized for the platform.
  79 std::string
  80 path_cat(
  81     beast::string_view base,
  82     beast::string_view path)
  83 {
  84     if(base.empty())
  85         return std::string(path);
  86     std::string result(base);
  87 #ifdef BOOST_MSVC
  88     char constexpr path_separator = '\\';
  89     if(result.back() == path_separator)
  90         result.resize(result.size() - 1);
  91     result.append(path.data(), path.size());
  92     for(auto& c : result)
  93         if(c == '/')
  94             c = path_separator;
  95 #else
  96     char constexpr path_separator = '/';
  97     if(result.back() == path_separator)
  98         result.resize(result.size() - 1);
  99     result.append(path.data(), path.size());
 100 #endif
 101     return result;
 102 }
 103
 104 // This function produces an HTTP response for the given
 105 // request. The type of the response object depends on the
 106 // contents of the request, so the interface requires the
 107 // caller to pass a generic lambda for receiving the response.
 108 template<
 109     class Body, class Allocator,
 110     class Send>
 111 void
 112 handle_request(
 113     beast::string_view doc_root,
 114     http::request<Body, http::basic_fields<Allocator>>&& req,
 115     Send&& send)
 116 {
 117     // Returns a bad request response
 118     auto const bad_request =
 119     [&req](beast::string_view why)
 120     {
 121         http::response<http::string_body> res{http::status::bad_request, req.version()};
 122         res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
 123         res.set(http::field::content_type, "text/html");
 124         res.keep_alive(req.keep_alive());
 125         res.body() = std::string(why);
 126         res.prepare_payload();
 127         return res;
 128     };
 129
 130     // Returns a not found response
 131     auto const not_found =
 132     [&req](beast::string_view target)
 133     {
 134         http::response<http::string_body> res{http::status::not_found, req.version()};
 135         res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
 136         res.set(http::field::content_type, "text/html");
 137         res.keep_alive(req.keep_alive());
 138         res.body() = "The resource '" + std::string(target) + "' was not found.";
 139         res.prepare_payload();
 140         return res;
 141     };
 142
 143     // Returns a server error response
 144     auto const server_error =
 145     [&req](beast::string_view what)
 146     {
 147         http::response<http::string_body> res{http::status::internal_server_error, req.version()};
 148         res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
 149         res.set(http::field::content_type, "text/html");
 150         res.keep_alive(req.keep_alive());
 151         res.body() = "An error occurred: '" + std::string(what) + "'";
 152         res.prepare_payload();
 153         return res;
 154     };
 155
 156     // Make sure we can handle the method
 157     if( req.method() != http::verb::get &&
 158         req.method() != http::verb::head)
 159         return send(bad_request("Unknown HTTP-method"));
 160
 161     // Request path must be absolute and not contain "..".
 162     if( req.target().empty() ||
 163         req.target()[0] != '/' ||
 164         req.target().find("..") != beast::string_view::npos)
 165         return send(bad_request("Illegal request-target"));
 166
 167     // Build the path to the requested file
 168     std::string path = path_cat(doc_root, req.target());
 169     if(req.target().back() == '/')
 170         path.append("index.html");
 171
 172     // Attempt to open the file
 173     beast::error_code ec;
 174     http::file_body::value_type body;
 175     body.open(path.c_str(), beast::file_mode::scan, ec);
 176
 177     // Handle the case where the file doesn't exist
 178     if(ec == beast::errc::no_such_file_or_directory)
 179         return send(not_found(req.target()));
 180
 181     // Handle an unknown error
 182     if(ec)
 183         return send(server_error(ec.message()));
 184
 185     // Cache the size since we need it after the move
 186     auto const size = body.size();
 187
 188     // Respond to HEAD request
 189     if(req.method() == http::verb::head)
 190     {
 191         http::response<http::empty_body> res{http::status::ok, req.version()};
 192         res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
 193         res.set(http::field::content_type, mime_type(path));
 194         res.content_length(size);
 195         res.keep_alive(req.keep_alive());
 196         return send(std::move(res));
 197     }
 198
 199     // Respond to GET request
 200     http::response<http::file_body> res{
 201         std::piecewise_construct,
 202         std::make_tuple(std::move(body)),
 203         std::make_tuple(http::status::ok, req.version())};
 204     res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
 205     res.set(http::field::content_type, mime_type(path));
 206     res.content_length(size);
 207     res.keep_alive(req.keep_alive());
 208     return send(std::move(res));
 209 }
 210
 211 //------------------------------------------------------------------------------
 212
 213 // Report a failure
 214 void
 215 fail(beast::error_code ec, char const* what)
 216 {
 217     // ssl::error::stream_truncated, also known as an SSL "short read",
 218     // indicates the peer closed the connection without performing the
 219     // required closing handshake (for example, Google does this to
 220     // improve performance). Generally this can be a security issue,
 221     // but if your communication protocol is self-terminated (as
 222     // it is with both HTTP and WebSocket) then you may simply
 223     // ignore the lack of close_notify.
 224     //
 225     // https://github.com/boostorg/beast/issues/38
 226     //
 227     // https://security.stackexchange.com/questions/91435/how-to-handle-a-malicious-ssl-tls-shutdown
 228     //
 229     // When a short read would cut off the end of an HTTP message,
 230     // Beast returns the error beast::http::error::partial_message.
 231     // Therefore, if we see a short read here, it has occurred
 232     // after the message has been completed, so it is safe to ignore it.
 233
 234     if(ec == net::ssl::error::stream_truncated)
 235         return;
 236
 237     std::cerr << what << ": " << ec.message() << "\n";
 238 }
 239
 240 // Handles an HTTP server connection
 241 class session
 242     : public boost::asio::coroutine
 243     , public std::enable_shared_from_this<session>
 244 {
 245     // This is the C++11 equivalent of a generic lambda.
 246     // The function object is used to send an HTTP message.
 247     struct send_lambda
 248     {
 249         session& self_;
 250
 251         explicit
 252         send_lambda(session& self)
 253             : self_(self)
 254         {
 255         }
 256
 257         template<bool isRequest, class Body, class Fields>
 258         void
 259         operator()(http::message<isRequest, Body, Fields>&& msg) const
 260         {
 261             // The lifetime of the message has to extend
 262             // for the duration of the async operation so
 263             // we use a shared_ptr to manage it.
 264             auto sp = std::make_shared<
 265                 http::message<isRequest, Body, Fields>>(std::move(msg));
 266
 267             // Store a type-erased version of the shared
 268             // pointer in the class to keep it alive.
 269             self_.res_ = sp;
 270
 271             // Write the response
 272             http::async_write(
 273                 self_.stream_,
 274                 *sp,
 275                 std::bind(
 276                     &session::loop,
 277                     self_.shared_from_this(),
 278                     std::placeholders::_1,
 279                     std::placeholders::_2,
 280                     sp->need_eof()));
 281         }
 282     };
 283
 284     beast::ssl_stream<beast::tcp_stream> stream_;
 285     beast::flat_buffer buffer_;
 286     std::shared_ptr<std::string const> doc_root_;
 287     http::request<http::string_body> req_;
 288     std::shared_ptr<void> res_;
 289     send_lambda lambda_;
 290
 291 public:
 292     // Take ownership of the socket
 293     explicit
 294     session(
 295         tcp::socket&& socket,
 296         ssl::context& ctx,
 297         std::shared_ptr<std::string const> const& doc_root)
 298         : stream_(std::move(socket), ctx)
 299         , doc_root_(doc_root)
 300         , lambda_(*this)
 301     {
 302     }
 303
 304     // Start the asynchronous operation
 305     void
 306     run()
 307     {
 308         // We need to be executing within a strand to perform async operations
 309         // on the I/O objects in this session.Although not strictly necessary
 310         // for single-threaded contexts, this example code is written to be
 311         // thread-safe by default.
 312         net::dispatch(stream_.get_executor(),
 313                       beast::bind_front_handler(&session::loop,
 314                                                 shared_from_this(),
 315                                                 beast::error_code{},
 316                                                 0,
 317                                                 false));
 318     }
 319
 320     #include <boost/asio/yield.hpp>
 321
 322     void
 323     loop(
 324         beast::error_code ec,
 325         std::size_t bytes_transferred,
 326         bool close)
 327     {
 328         boost::ignore_unused(bytes_transferred);
 329         reenter(*this)
 330         {
 331             // Set the timeout.
 332             beast::get_lowest_layer(stream_).expires_after(std::chrono::seconds(30));
 333
 334             // Perform the SSL handshake
 335             yield stream_.async_handshake(
 336                 ssl::stream_base::server,
 337                 std::bind(
 338                     &session::loop,
 339                     shared_from_this(),
 340                     std::placeholders::_1,
 341                     0,
 342                     false));
 343             if(ec)
 344                 return fail(ec, "handshake");
 345
 346             for(;;)
 347             {
 348                 // Set the timeout.
 349                 beast::get_lowest_layer(stream_).expires_after(std::chrono::seconds(30));
 350
 351                 // Make the request empty before reading,
 352                 // otherwise the operation behavior is undefined.
 353                 req_ = {};
 354
 355                 // Read a request
 356                 yield http::async_read(stream_, buffer_, req_,
 357                     std::bind(
 358                         &session::loop,
 359                         shared_from_this(),
 360                         std::placeholders::_1,
 361                         std::placeholders::_2,
 362                         false));
 363                 if(ec == http::error::end_of_stream)
 364                 {
 365                     // The remote host closed the connection
 366                     break;
 367                 }
 368                 if(ec)
 369                     return fail(ec, "read");
 370
 371                 // Send the response
 372                 yield handle_request(*doc_root_, std::move(req_), lambda_);
 373                 if(ec)
 374                     return fail(ec, "write");
 375                 if(close)
 376                 {
 377                     // This means we should close the connection, usually because
 378                     // the response indicated the "Connection: close" semantic.
 379                     break;
 380                 }
 381
 382                 // We're done with the response so delete it
 383                 res_ = nullptr;
 384             }
 385
 386             // Set the timeout.
 387             beast::get_lowest_layer(stream_).expires_after(std::chrono::seconds(30));
 388
 389             // Perform the SSL shutdown
 390             yield stream_.async_shutdown(
 391                 std::bind(
 392                     &session::loop,
 393                     shared_from_this(),
 394                     std::placeholders::_1,
 395                     0,
 396                     false));
 397             if(ec)
 398                 return fail(ec, "shutdown");
 399
 400             // At this point the connection is closed gracefully
 401         }
 402     }
 403
 404     #include <boost/asio/unyield.hpp>
 405 };
 406
 407 //------------------------------------------------------------------------------
 408
 409 // Accepts incoming connections and launches the sessions
 410 class listener
 411     : public boost::asio::coroutine
 412     , public std::enable_shared_from_this<listener>
 413 {
 414     net::io_context& ioc_;
 415     ssl::context& ctx_;
 416     tcp::acceptor acceptor_;
 417     tcp::socket socket_;
 418     std::shared_ptr<std::string const> doc_root_;
 419
 420 public:
 421     listener(
 422         net::io_context& ioc,
 423         ssl::context& ctx,
 424         tcp::endpoint endpoint,
 425         std::shared_ptr<std::string const> const& doc_root)
 426         : ioc_(ioc)
 427         , ctx_(ctx)
 428         , acceptor_(net::make_strand(ioc))
 429         , socket_(net::make_strand(ioc))
 430         , doc_root_(doc_root)
 431     {
 432         beast::error_code ec;
 433
 434         // Open the acceptor
 435         acceptor_.open(endpoint.protocol(), ec);
 436         if(ec)
 437         {
 438             fail(ec, "open");
 439             return;
 440         }
 441
 442         // Allow address reuse
 443         acceptor_.set_option(net::socket_base::reuse_address(true), ec);
 444         if(ec)
 445         {
 446             fail(ec, "set_option");
 447             return;
 448         }
 449
 450         // Bind to the server address
 451         acceptor_.bind(endpoint, ec);
 452         if(ec)
 453         {
 454             fail(ec, "bind");
 455             return;
 456         }
 457
 458         // Start listening for connections
 459         acceptor_.listen(
 460             net::socket_base::max_listen_connections, ec);
 461         if(ec)
 462         {
 463             fail(ec, "listen");
 464             return;
 465         }
 466     }
 467
 468     // Start accepting incoming connections
 469     void
 470     run()
 471     {
 472         loop();
 473     }
 474
 475 private:
 476
 477     #include <boost/asio/yield.hpp>
 478
 479     void
 480     loop(beast::error_code ec = {})
 481     {
 482         reenter(*this)
 483         {
 484             for(;;)
 485             {
 486                 yield acceptor_.async_accept(
 487                     socket_,
 488                     std::bind(
 489                         &listener::loop,
 490                         shared_from_this(),
 491                         std::placeholders::_1));
 492                 if(ec)
 493                 {
 494                     fail(ec, "accept");
 495                 }
 496                 else
 497                 {
 498                     // Create the session and run it
 499                     std::make_shared<session>(
 500                         std::move(socket_),
 501                         ctx_,
 502                         doc_root_)->run();
 503                 }
 504
 505                 // Make sure each session gets its own strand
 506                 socket_ = tcp::socket(net::make_strand(ioc_));
 507             }
 508         }
 509     }
 510
 511     #include <boost/asio/unyield.hpp>
 512 };
 513
 514 //------------------------------------------------------------------------------
 515
 516 int main(int argc, char* argv[])
 517 {
 518     // Check command line arguments.
 519     if (argc != 5)
 520     {
 521         std::cerr <<
 522             "Usage: http-server-stackless-ssl <address> <port> <doc_root> <threads>\n" <<
 523             "Example:\n" <<
 524             "    http-server-stackless-ssl 0.0.0.0 8080 . 1\n";
 525         return EXIT_FAILURE;
 526     }
 527     auto const address = net::ip::make_address(argv[1]);
 528     auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
 529     auto const doc_root = std::make_shared<std::string>(argv[3]);
 530     auto const threads = std::max<int>(1, std::atoi(argv[4]));
 531
 532     // The io_context is required for all I/O
 533     net::io_context ioc{threads};
 534
 535     // The SSL context is required, and holds certificates
 536     ssl::context ctx{ssl::context::tlsv12};
 537
 538     // This holds the self-signed certificate used by the server
 539     load_server_certificate(ctx);
 540
 541     // Create and launch a listening port
 542     std::make_shared<listener>(
 543         ioc,
 544         ctx,
 545         tcp::endpoint{address, port},
 546         doc_root)->run();
 547
 548     // Run the I/O service on the requested number of threads
 549     std::vector<std::thread> v;
 550     v.reserve(threads - 1);
 551     for(auto i = threads - 1; i > 0; --i)
 552         v.emplace_back(
 553         [&ioc]
 554         {
 555             ioc.run();
 556         });
 557     ioc.run();
 558
 559     return EXIT_SUCCESS;
 560 }