ceph/src/boost/libs/beast/example/http/client/coro/http_client_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: HTTP client, coroutine
  13 //
  14 //------------------------------------------------------------------------------
  15
  16 #include <boost/beast/core.hpp>
  17 #include <boost/beast/http.hpp>
  18 #include <boost/beast/version.hpp>
  19 #include <boost/asio/connect.hpp>
  20 #include <boost/asio/spawn.hpp>
  21 #include <boost/asio/ip/tcp.hpp>
  22 #include <cstdlib>
  23 #include <functional>
  24 #include <iostream>
  25 #include <string>
  26
  27 using tcp = boost::asio::ip::tcp;       // from <boost/asio/ip/tcp.hpp>
  28 namespace http = boost::beast::http;    // from <boost/beast/http.hpp>
  29
  30 //------------------------------------------------------------------------------
  31
  32 // Report a failure
  33 void
  34 fail(boost::system::error_code ec, char const* what)
  35 {
  36     std::cerr << what << ": " << ec.message() << "\n";
  37 }
  38
  39 // Performs an HTTP GET and prints the response
  40 void
  41 do_session(
  42     std::string const& host,
  43     std::string const& port,
  44     std::string const& target,
  45     int version,
  46     boost::asio::io_context& ioc,
  47     boost::asio::yield_context yield)
  48 {
  49     boost::system::error_code ec;
  50
  51     // These objects perform our I/O
  52     tcp::resolver resolver{ioc};
  53     tcp::socket socket{ioc};
  54
  55     // Look up the domain name
  56     auto const results = resolver.async_resolve(host, port, yield[ec]);
  57     if(ec)
  58         return fail(ec, "resolve");
  59
  60     // Make the connection on the IP address we get from a lookup
  61     boost::asio::async_connect(socket, results.begin(), results.end(), yield[ec]);
  62     if(ec)
  63         return fail(ec, "connect");
  64
  65     // Set up an HTTP GET request message
  66     http::request<http::string_body> req{http::verb::get, target, version};
  67     req.set(http::field::host, host);
  68     req.set(http::field::user_agent, BOOST_BEAST_VERSION_STRING);
  69
  70     // Send the HTTP request to the remote host
  71     http::async_write(socket, req, yield[ec]);
  72     if(ec)
  73         return fail(ec, "write");
  74
  75     // This buffer is used for reading and must be persisted
  76     boost::beast::flat_buffer b;
  77
  78     // Declare a container to hold the response
  79     http::response<http::dynamic_body> res;
  80
  81     // Receive the HTTP response
  82     http::async_read(socket, b, res, yield[ec]);
  83     if(ec)
  84         return fail(ec, "read");
  85
  86     // Write the message to standard out
  87     std::cout << res << std::endl;
  88
  89     // Gracefully close the socket
  90     socket.shutdown(tcp::socket::shutdown_both, ec);
  91
  92     // not_connected happens sometimes
  93     // so don't bother reporting it.
  94     //
  95     if(ec && ec != boost::system::errc::not_connected)
  96         return fail(ec, "shutdown");
  97
  98     // If we get here then the connection is closed gracefully
  99 }
 100
 101 //------------------------------------------------------------------------------
 102
 103 int main(int argc, char** argv)
 104 {
 105     // Check command line arguments.
 106     if(argc != 4 && argc != 5)
 107     {
 108         std::cerr <<
 109             "Usage: http-client-coro <host> <port> <target> [<HTTP version: 1.0 or 1.1(default)>]\n" <<
 110             "Example:\n" <<
 111             "    http-client-coro www.example.com 80 /\n" <<
 112             "    http-client-coro www.example.com 80 / 1.0\n";
 113         return EXIT_FAILURE;
 114     }
 115     auto const host = argv[1];
 116     auto const port = argv[2];
 117     auto const target = argv[3];
 118     int version = argc == 5 && !std::strcmp("1.0", argv[4]) ? 10 : 11;
 119
 120     // The io_context is required for all I/O
 121     boost::asio::io_context ioc;
 122
 123     // Launch the asynchronous operation
 124     boost::asio::spawn(ioc, std::bind(
 125         &do_session,
 126         std::string(host),
 127         std::string(port),
 128         std::string(target),
 129         version,
 130         std::ref(ioc),
 131         std::placeholders::_1));
 132
 133     // Run the I/O service. The call will return when
 134     // the get operation is complete.
 135     ioc.run();
 136
 137     return EXIT_SUCCESS;
 138 }