ceph/src/boost/libs/beast/example/websocket/server/coro/websocket_server_coro.cpp

   1 //
   2 // Copyright (c) 2016-2017 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: WebSocket server, coroutine
  13 //
  14 //------------------------------------------------------------------------------
  15
  16 #include <boost/beast/core.hpp>
  17 #include <boost/beast/websocket.hpp>
  18 #include <boost/asio/ip/tcp.hpp>
  19 #include <boost/asio/spawn.hpp>
  20 #include <algorithm>
  21 #include <cstdlib>
  22 #include <functional>
  23 #include <iostream>
  24 #include <memory>
  25 #include <string>
  26 #include <thread>
  27 #include <vector>
  28
  29 using tcp = boost::asio::ip::tcp;               // from <boost/asio/ip/tcp.hpp>
  30 namespace websocket = boost::beast::websocket;  // from <boost/beast/websocket.hpp>
  31
  32 //------------------------------------------------------------------------------
  33
  34 // Report a failure
  35 void
  36 fail(boost::system::error_code ec, char const* what)
  37 {
  38     std::cerr << what << ": " << ec.message() << "\n";
  39 }
  40
  41 // Echoes back all received WebSocket messages
  42 void
  43 do_session(tcp::socket& socket, boost::asio::yield_context yield)
  44 {
  45     boost::system::error_code ec;
  46
  47     // Construct the stream by moving in the socket
  48     websocket::stream<tcp::socket> ws{std::move(socket)};
  49
  50     // Accept the websocket handshake
  51     ws.async_accept(yield[ec]);
  52     if(ec)
  53         return fail(ec, "accept");
  54
  55     for(;;)
  56     {
  57         // This buffer will hold the incoming message
  58         boost::beast::multi_buffer buffer;
  59
  60         // Read a message
  61         ws.async_read(buffer, yield[ec]);
  62
  63         // This indicates that the session was closed
  64         if(ec == websocket::error::closed)
  65             break;
  66
  67         if(ec)
  68             return fail(ec, "read");
  69
  70         // Echo the message back
  71         ws.text(ws.got_text());
  72         ws.async_write(buffer.data(), yield[ec]);
  73         if(ec)
  74             return fail(ec, "write");
  75     }
  76 }
  77
  78 //------------------------------------------------------------------------------
  79
  80 // Accepts incoming connections and launches the sessions
  81 void
  82 do_listen(
  83     boost::asio::io_context& ioc,
  84     tcp::endpoint endpoint,
  85     boost::asio::yield_context yield)
  86 {
  87     boost::system::error_code ec;
  88
  89     // Open the acceptor
  90     tcp::acceptor acceptor(ioc);
  91     acceptor.open(endpoint.protocol(), ec);
  92     if(ec)
  93         return fail(ec, "open");
  94
  95     // Bind to the server address
  96     acceptor.bind(endpoint, ec);
  97     if(ec)
  98         return fail(ec, "bind");
  99
 100     // Start listening for connections
 101     acceptor.listen(boost::asio::socket_base::max_listen_connections, ec);
 102     if(ec)
 103         return fail(ec, "listen");
 104
 105     for(;;)
 106     {
 107         tcp::socket socket(ioc);
 108         acceptor.async_accept(socket, yield[ec]);
 109         if(ec)
 110             fail(ec, "accept");
 111         else
 112             boost::asio::spawn(
 113                 acceptor.get_executor().context(),
 114                 std::bind(
 115                     &do_session,
 116                     std::move(socket),
 117                     std::placeholders::_1));
 118     }
 119 }
 120
 121 int main(int argc, char* argv[])
 122 {
 123     // Check command line arguments.
 124     if (argc != 4)
 125     {
 126         std::cerr <<
 127             "Usage: websocket-server-coro <address> <port> <threads>\n" <<
 128             "Example:\n" <<
 129             "    websocket-server-coro 0.0.0.0 8080 1\n";
 130         return EXIT_FAILURE;
 131     }
 132     auto const address = boost::asio::ip::make_address(argv[1]);
 133     auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
 134     auto const threads = std::max<int>(1, std::atoi(argv[3]));
 135
 136     // The io_context is required for all I/O
 137     boost::asio::io_context ioc{threads};
 138
 139     // Spawn a listening port
 140     boost::asio::spawn(ioc,
 141         std::bind(
 142             &do_listen,
 143             std::ref(ioc),
 144             tcp::endpoint{address, port},
 145             std::placeholders::_1));
 146
 147     // Run the I/O service on the requested number of threads
 148     std::vector<std::thread> v;
 149     v.reserve(threads - 1);
 150     for(auto i = threads - 1; i > 0; --i)
 151         v.emplace_back(
 152         [&ioc]
 153         {
 154             ioc.run();
 155         });
 156     ioc.run();
 157
 158     return EXIT_SUCCESS;
 159 }