ceph/src/boost/libs/beast/example/advanced/server/advanced_server.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: Advanced server
  13 //
  14 //------------------------------------------------------------------------------
  15
  16 #include <boost/beast/core.hpp>
  17 #include <boost/beast/http.hpp>
  18 #include <boost/beast/websocket.hpp>
  19 #include <boost/beast/version.hpp>
  20 #include <boost/asio/bind_executor.hpp>
  21 #include <boost/asio/signal_set.hpp>
  22 #include <boost/asio/strand.hpp>
  23 #include <boost/make_unique.hpp>
  24 #include <boost/optional.hpp>
  25 #include <algorithm>
  26 #include <cstdlib>
  27 #include <functional>
  28 #include <iostream>
  29 #include <memory>
  30 #include <string>
  31 #include <thread>
  32 #include <vector>
  33
  34 namespace beast = boost::beast;                 // from <boost/beast.hpp>
  35 namespace http = beast::http;                   // from <boost/beast/http.hpp>
  36 namespace websocket = beast::websocket;         // from <boost/beast/websocket.hpp>
  37 namespace net = boost::asio;                    // from <boost/asio.hpp>
  38 using tcp = boost::asio::ip::tcp;               // from <boost/asio/ip/tcp.hpp>
  39
  40 // Return a reasonable mime type based on the extension of a file.
  41 beast::string_view
  42 mime_type(beast::string_view path)
  43 {
  44     using beast::iequals;
  45     auto const ext = [&path]
  46     {
  47         auto const pos = path.rfind(".");
  48         if(pos == beast::string_view::npos)
  49             return beast::string_view{};
  50         return path.substr(pos);
  51     }();
  52     if(iequals(ext, ".htm"))  return "text/html";
  53     if(iequals(ext, ".html")) return "text/html";
  54     if(iequals(ext, ".php"))  return "text/html";
  55     if(iequals(ext, ".css"))  return "text/css";
  56     if(iequals(ext, ".txt"))  return "text/plain";
  57     if(iequals(ext, ".js"))   return "application/javascript";
  58     if(iequals(ext, ".json")) return "application/json";
  59     if(iequals(ext, ".xml"))  return "application/xml";
  60     if(iequals(ext, ".swf"))  return "application/x-shockwave-flash";
  61     if(iequals(ext, ".flv"))  return "video/x-flv";
  62     if(iequals(ext, ".png"))  return "image/png";
  63     if(iequals(ext, ".jpe"))  return "image/jpeg";
  64     if(iequals(ext, ".jpeg")) return "image/jpeg";
  65     if(iequals(ext, ".jpg"))  return "image/jpeg";
  66     if(iequals(ext, ".gif"))  return "image/gif";
  67     if(iequals(ext, ".bmp"))  return "image/bmp";
  68     if(iequals(ext, ".ico"))  return "image/vnd.microsoft.icon";
  69     if(iequals(ext, ".tiff")) return "image/tiff";
  70     if(iequals(ext, ".tif"))  return "image/tiff";
  71     if(iequals(ext, ".svg"))  return "image/svg+xml";
  72     if(iequals(ext, ".svgz")) return "image/svg+xml";
  73     return "application/text";
  74 }
  75
  76 // Append an HTTP rel-path to a local filesystem path.
  77 // The returned path is normalized for the platform.
  78 std::string
  79 path_cat(
  80     beast::string_view base,
  81     beast::string_view path)
  82 {
  83     if(base.empty())
  84         return std::string(path);
  85     std::string result(base);
  86 #ifdef BOOST_MSVC
  87     char constexpr path_separator = '\\';
  88     if(result.back() == path_separator)
  89         result.resize(result.size() - 1);
  90     result.append(path.data(), path.size());
  91     for(auto& c : result)
  92         if(c == '/')
  93             c = path_separator;
  94 #else
  95     char constexpr path_separator = '/';
  96     if(result.back() == path_separator)
  97         result.resize(result.size() - 1);
  98     result.append(path.data(), path.size());
  99 #endif
 100     return result;
 101 }
 102
 103 // This function produces an HTTP response for the given
 104 // request. The type of the response object depends on the
 105 // contents of the request, so the interface requires the
 106 // caller to pass a generic lambda for receiving the response.
 107 template<
 108     class Body, class Allocator,
 109     class Send>
 110 void
 111 handle_request(
 112     beast::string_view doc_root,
 113     http::request<Body, http::basic_fields<Allocator>>&& req,
 114     Send&& send)
 115 {
 116     // Returns a bad request response
 117     auto const bad_request =
 118     [&req](beast::string_view why)
 119     {
 120         http::response<http::string_body> res{http::status::bad_request, req.version()};
 121         res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
 122         res.set(http::field::content_type, "text/html");
 123         res.keep_alive(req.keep_alive());
 124         res.body() = std::string(why);
 125         res.prepare_payload();
 126         return res;
 127     };
 128
 129     // Returns a not found response
 130     auto const not_found =
 131     [&req](beast::string_view target)
 132     {
 133         http::response<http::string_body> res{http::status::not_found, req.version()};
 134         res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
 135         res.set(http::field::content_type, "text/html");
 136         res.keep_alive(req.keep_alive());
 137         res.body() = "The resource '" + std::string(target) + "' was not found.";
 138         res.prepare_payload();
 139         return res;
 140     };
 141
 142     // Returns a server error response
 143     auto const server_error =
 144     [&req](beast::string_view what)
 145     {
 146         http::response<http::string_body> res{http::status::internal_server_error, req.version()};
 147         res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
 148         res.set(http::field::content_type, "text/html");
 149         res.keep_alive(req.keep_alive());
 150         res.body() = "An error occurred: '" + std::string(what) + "'";
 151         res.prepare_payload();
 152         return res;
 153     };
 154
 155     // Make sure we can handle the method
 156     if( req.method() != http::verb::get &&
 157         req.method() != http::verb::head)
 158         return send(bad_request("Unknown HTTP-method"));
 159
 160     // Request path must be absolute and not contain "..".
 161     if( req.target().empty() ||
 162         req.target()[0] != '/' ||
 163         req.target().find("..") != beast::string_view::npos)
 164         return send(bad_request("Illegal request-target"));
 165
 166     // Build the path to the requested file
 167     std::string path = path_cat(doc_root, req.target());
 168     if(req.target().back() == '/')
 169         path.append("index.html");
 170
 171     // Attempt to open the file
 172     beast::error_code ec;
 173     http::file_body::value_type body;
 174     body.open(path.c_str(), beast::file_mode::scan, ec);
 175
 176     // Handle the case where the file doesn't exist
 177     if(ec == beast::errc::no_such_file_or_directory)
 178         return send(not_found(req.target()));
 179
 180     // Handle an unknown error
 181     if(ec)
 182         return send(server_error(ec.message()));
 183
 184     // Cache the size since we need it after the move
 185     auto const size = body.size();
 186
 187     // Respond to HEAD request
 188     if(req.method() == http::verb::head)
 189     {
 190         http::response<http::empty_body> res{http::status::ok, req.version()};
 191         res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
 192         res.set(http::field::content_type, mime_type(path));
 193         res.content_length(size);
 194         res.keep_alive(req.keep_alive());
 195         return send(std::move(res));
 196     }
 197
 198     // Respond to GET request
 199     http::response<http::file_body> res{
 200         std::piecewise_construct,
 201         std::make_tuple(std::move(body)),
 202         std::make_tuple(http::status::ok, req.version())};
 203     res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
 204     res.set(http::field::content_type, mime_type(path));
 205     res.content_length(size);
 206     res.keep_alive(req.keep_alive());
 207     return send(std::move(res));
 208 }
 209
 210 //------------------------------------------------------------------------------
 211
 212 // Report a failure
 213 void
 214 fail(beast::error_code ec, char const* what)
 215 {
 216     std::cerr << what << ": " << ec.message() << "\n";
 217 }
 218
 219 // Echoes back all received WebSocket messages
 220 class websocket_session : public std::enable_shared_from_this<websocket_session>
 221 {
 222     websocket::stream<beast::tcp_stream> ws_;
 223     beast::flat_buffer buffer_;
 224
 225 public:
 226     // Take ownership of the socket
 227     explicit
 228     websocket_session(tcp::socket&& socket)
 229         : ws_(std::move(socket))
 230     {
 231     }
 232
 233     // Start the asynchronous accept operation
 234     template<class Body, class Allocator>
 235     void
 236     do_accept(http::request<Body, http::basic_fields<Allocator>> req)
 237     {
 238         // Set suggested timeout settings for the websocket
 239         ws_.set_option(
 240             websocket::stream_base::timeout::suggested(
 241                 beast::role_type::server));
 242
 243         // Set a decorator to change the Server of the handshake
 244         ws_.set_option(websocket::stream_base::decorator(
 245             [](websocket::response_type& res)
 246             {
 247                 res.set(http::field::server,
 248                     std::string(BOOST_BEAST_VERSION_STRING) +
 249                         " advanced-server");
 250             }));
 251
 252         // Accept the websocket handshake
 253         ws_.async_accept(
 254             req,
 255             beast::bind_front_handler(
 256                 &websocket_session::on_accept,
 257                 shared_from_this()));
 258     }
 259
 260 private:
 261     void
 262     on_accept(beast::error_code ec)
 263     {
 264         if(ec)
 265             return fail(ec, "accept");
 266
 267         // Read a message
 268         do_read();
 269     }
 270
 271     void
 272     do_read()
 273     {
 274         // Read a message into our buffer
 275         ws_.async_read(
 276             buffer_,
 277             beast::bind_front_handler(
 278                 &websocket_session::on_read,
 279                 shared_from_this()));
 280     }
 281
 282     void
 283     on_read(
 284         beast::error_code ec,
 285         std::size_t bytes_transferred)
 286     {
 287         boost::ignore_unused(bytes_transferred);
 288
 289         // This indicates that the websocket_session was closed
 290         if(ec == websocket::error::closed)
 291             return;
 292
 293         if(ec)
 294             fail(ec, "read");
 295
 296         // Echo the message
 297         ws_.text(ws_.got_text());
 298         ws_.async_write(
 299             buffer_.data(),
 300             beast::bind_front_handler(
 301                 &websocket_session::on_write,
 302                 shared_from_this()));
 303     }
 304
 305     void
 306     on_write(
 307         beast::error_code ec,
 308         std::size_t bytes_transferred)
 309     {
 310         boost::ignore_unused(bytes_transferred);
 311
 312         if(ec)
 313             return fail(ec, "write");
 314
 315         // Clear the buffer
 316         buffer_.consume(buffer_.size());
 317
 318         // Do another read
 319         do_read();
 320     }
 321 };
 322
 323 //------------------------------------------------------------------------------
 324
 325 // Handles an HTTP server connection
 326 class http_session : public std::enable_shared_from_this<http_session>
 327 {
 328     // This queue is used for HTTP pipelining.
 329     class queue
 330     {
 331         enum
 332         {
 333             // Maximum number of responses we will queue
 334             limit = 8
 335         };
 336
 337         // The type-erased, saved work item
 338         struct work
 339         {
 340             virtual ~work() = default;
 341             virtual void operator()() = 0;
 342         };
 343
 344         http_session& self_;
 345         std::vector<std::unique_ptr<work>> items_;
 346
 347     public:
 348         explicit
 349         queue(http_session& self)
 350             : self_(self)
 351         {
 352             static_assert(limit > 0, "queue limit must be positive");
 353             items_.reserve(limit);
 354         }
 355
 356         // Returns `true` if we have reached the queue limit
 357         bool
 358         is_full() const
 359         {
 360             return items_.size() >= limit;
 361         }
 362
 363         // Called when a message finishes sending
 364         // Returns `true` if the caller should initiate a read
 365         bool
 366         on_write()
 367         {
 368             BOOST_ASSERT(! items_.empty());
 369             auto const was_full = is_full();
 370             items_.erase(items_.begin());
 371             if(! items_.empty())
 372                 (*items_.front())();
 373             return was_full;
 374         }
 375
 376         // Called by the HTTP handler to send a response.
 377         template<bool isRequest, class Body, class Fields>
 378         void
 379         operator()(http::message<isRequest, Body, Fields>&& msg)
 380         {
 381             // This holds a work item
 382             struct work_impl : work
 383             {
 384                 http_session& self_;
 385                 http::message<isRequest, Body, Fields> msg_;
 386
 387                 work_impl(
 388                     http_session& self,
 389                     http::message<isRequest, Body, Fields>&& msg)
 390                     : self_(self)
 391                     , msg_(std::move(msg))
 392                 {
 393                 }
 394
 395                 void
 396                 operator()()
 397                 {
 398                     http::async_write(
 399                         self_.stream_,
 400                         msg_,
 401                         beast::bind_front_handler(
 402                             &http_session::on_write,
 403                             self_.shared_from_this(),
 404                             msg_.need_eof()));
 405                 }
 406             };
 407
 408             // Allocate and store the work
 409             items_.push_back(
 410                 boost::make_unique<work_impl>(self_, std::move(msg)));
 411
 412             // If there was no previous work, start this one
 413             if(items_.size() == 1)
 414                 (*items_.front())();
 415         }
 416     };
 417
 418     beast::tcp_stream stream_;
 419     beast::flat_buffer buffer_;
 420     std::shared_ptr<std::string const> doc_root_;
 421     queue queue_;
 422
 423     // The parser is stored in an optional container so we can
 424     // construct it from scratch it at the beginning of each new message.
 425     boost::optional<http::request_parser<http::string_body>> parser_;
 426
 427 public:
 428     // Take ownership of the socket
 429     http_session(
 430         tcp::socket&& socket,
 431         std::shared_ptr<std::string const> const& doc_root)
 432         : stream_(std::move(socket))
 433         , doc_root_(doc_root)
 434         , queue_(*this)
 435     {
 436     }
 437
 438     // Start the session
 439     void
 440     run()
 441     {
 442         do_read();
 443     }
 444
 445 private:
 446     void
 447     do_read()
 448     {
 449         // Construct a new parser for each message
 450         parser_.emplace();
 451
 452         // Apply a reasonable limit to the allowed size
 453         // of the body in bytes to prevent abuse.
 454         parser_->body_limit(10000);
 455
 456         // Set the timeout.
 457         stream_.expires_after(std::chrono::seconds(30));
 458
 459         // Read a request using the parser-oriented interface
 460         http::async_read(
 461             stream_,
 462             buffer_,
 463             *parser_,
 464             beast::bind_front_handler(
 465                 &http_session::on_read,
 466                 shared_from_this()));
 467     }
 468
 469     void
 470     on_read(beast::error_code ec, std::size_t bytes_transferred)
 471     {
 472         boost::ignore_unused(bytes_transferred);
 473
 474         // This means they closed the connection
 475         if(ec == http::error::end_of_stream)
 476             return do_close();
 477
 478         if(ec)
 479             return fail(ec, "read");
 480
 481         // See if it is a WebSocket Upgrade
 482         if(websocket::is_upgrade(parser_->get()))
 483         {
 484             // Create a websocket session, transferring ownership
 485             // of both the socket and the HTTP request.
 486             std::make_shared<websocket_session>(
 487                 stream_.release_socket())->do_accept(parser_->release());
 488             return;
 489         }
 490
 491         // Send the response
 492         handle_request(*doc_root_, parser_->release(), queue_);
 493
 494         // If we aren't at the queue limit, try to pipeline another request
 495         if(! queue_.is_full())
 496             do_read();
 497     }
 498
 499     void
 500     on_write(bool close, beast::error_code ec, std::size_t bytes_transferred)
 501     {
 502         boost::ignore_unused(bytes_transferred);
 503
 504         if(ec)
 505             return fail(ec, "write");
 506
 507         if(close)
 508         {
 509             // This means we should close the connection, usually because
 510             // the response indicated the "Connection: close" semantic.
 511             return do_close();
 512         }
 513
 514         // Inform the queue that a write completed
 515         if(queue_.on_write())
 516         {
 517             // Read another request
 518             do_read();
 519         }
 520     }
 521
 522     void
 523     do_close()
 524     {
 525         // Send a TCP shutdown
 526         beast::error_code ec;
 527         stream_.socket().shutdown(tcp::socket::shutdown_send, ec);
 528
 529         // At this point the connection is closed gracefully
 530     }
 531 };
 532
 533 //------------------------------------------------------------------------------
 534
 535 // Accepts incoming connections and launches the sessions
 536 class listener : public std::enable_shared_from_this<listener>
 537 {
 538     net::io_context& ioc_;
 539     tcp::acceptor acceptor_;
 540     std::shared_ptr<std::string const> doc_root_;
 541
 542 public:
 543     listener(
 544         net::io_context& ioc,
 545         tcp::endpoint endpoint,
 546         std::shared_ptr<std::string const> const& doc_root)
 547         : ioc_(ioc)
 548         , acceptor_(net::make_strand(ioc))
 549         , doc_root_(doc_root)
 550     {
 551         beast::error_code ec;
 552
 553         // Open the acceptor
 554         acceptor_.open(endpoint.protocol(), ec);
 555         if(ec)
 556         {
 557             fail(ec, "open");
 558             return;
 559         }
 560
 561         // Allow address reuse
 562         acceptor_.set_option(net::socket_base::reuse_address(true), ec);
 563         if(ec)
 564         {
 565             fail(ec, "set_option");
 566             return;
 567         }
 568
 569         // Bind to the server address
 570         acceptor_.bind(endpoint, ec);
 571         if(ec)
 572         {
 573             fail(ec, "bind");
 574             return;
 575         }
 576
 577         // Start listening for connections
 578         acceptor_.listen(
 579             net::socket_base::max_listen_connections, ec);
 580         if(ec)
 581         {
 582             fail(ec, "listen");
 583             return;
 584         }
 585     }
 586
 587     // Start accepting incoming connections
 588     void
 589     run()
 590     {
 591         do_accept();
 592     }
 593
 594 private:
 595     void
 596     do_accept()
 597     {
 598         // The new connection gets its own strand
 599         acceptor_.async_accept(
 600             net::make_strand(ioc_),
 601             beast::bind_front_handler(
 602                 &listener::on_accept,
 603                 shared_from_this()));
 604     }
 605
 606     void
 607     on_accept(beast::error_code ec, tcp::socket socket)
 608     {
 609         if(ec)
 610         {
 611             fail(ec, "accept");
 612         }
 613         else
 614         {
 615             // Create the http session and run it
 616             std::make_shared<http_session>(
 617                 std::move(socket),
 618                 doc_root_)->run();
 619         }
 620
 621         // Accept another connection
 622         do_accept();
 623     }
 624 };
 625
 626 //------------------------------------------------------------------------------
 627
 628 int main(int argc, char* argv[])
 629 {
 630     // Check command line arguments.
 631     if (argc != 5)
 632     {
 633         std::cerr <<
 634             "Usage: advanced-server <address> <port> <doc_root> <threads>\n" <<
 635             "Example:\n" <<
 636             "    advanced-server 0.0.0.0 8080 . 1\n";
 637         return EXIT_FAILURE;
 638     }
 639     auto const address = net::ip::make_address(argv[1]);
 640     auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
 641     auto const doc_root = std::make_shared<std::string>(argv[3]);
 642     auto const threads = std::max<int>(1, std::atoi(argv[4]));
 643
 644     // The io_context is required for all I/O
 645     net::io_context ioc{threads};
 646
 647     // Create and launch a listening port
 648     std::make_shared<listener>(
 649         ioc,
 650         tcp::endpoint{address, port},
 651         doc_root)->run();
 652
 653     // Capture SIGINT and SIGTERM to perform a clean shutdown
 654     net::signal_set signals(ioc, SIGINT, SIGTERM);
 655     signals.async_wait(
 656         [&](beast::error_code const&, int)
 657         {
 658             // Stop the `io_context`. This will cause `run()`
 659             // to return immediately, eventually destroying the
 660             // `io_context` and all of the sockets in it.
 661             ioc.stop();
 662         });
 663
 664     // Run the I/O service on the requested number of threads
 665     std::vector<std::thread> v;
 666     v.reserve(threads - 1);
 667     for(auto i = threads - 1; i > 0; --i)
 668         v.emplace_back(
 669         [&ioc]
 670         {
 671             ioc.run();
 672         });
 673     ioc.run();
 674
 675     // (If we get here, it means we got a SIGINT or SIGTERM)
 676
 677     // Block until all the threads exit
 678     for(auto& t : v)
 679         t.join();
 680
 681     return EXIT_SUCCESS;
 682 }