libs/beast/example/http/client/coro/http_client_coro.cpp
//
// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// Official repository: https://github.com/boostorg/beast
//
//------------------------------------------------------------------------------
//
// Example: HTTP client, coroutine
//
//------------------------------------------------------------------------------
#include <boost/beast/core.hpp>
#include <boost/beast/http.hpp>
#include <boost/beast/version.hpp>
#include <boost/asio/spawn.hpp>
#include <cstdlib>
#include <functional>
#include <iostream>
#include <string>
namespace beast = boost::beast; // from <boost/beast.hpp>
namespace http = beast::http; // from <boost/beast/http.hpp>
namespace net = boost::asio; // from <boost/asio.hpp>
using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
//------------------------------------------------------------------------------
// Report a failure
void
fail(beast::error_code ec, char const* what)
{
std::cerr << what << ": " << ec.message() << "\n";
}
// Performs an HTTP GET and prints the response
void
do_session(
std::string const& host,
std::string const& port,
std::string const& target,
int version,
net::io_context& ioc,
net::yield_context yield)
{
beast::error_code ec;
// These objects perform our I/O
tcp::resolver resolver(ioc);
beast::tcp_stream stream(ioc);
// Look up the domain name
auto const results = resolver.async_resolve(host, port, yield[ec]);
if(ec)
return fail(ec, "resolve");
// Set the timeout.
stream.expires_after(std::chrono::seconds(30));
// Make the connection on the IP address we get from a lookup
stream.async_connect(results, yield[ec]);
if(ec)
return fail(ec, "connect");
// Set up an HTTP GET request message
http::request<http::string_body> req{http::verb::get, target, version};
req.set(http::field::host, host);
req.set(http::field::user_agent, BOOST_BEAST_VERSION_STRING);
// Set the timeout.
stream.expires_after(std::chrono::seconds(30));
// Send the HTTP request to the remote host
http::async_write(stream, req, yield[ec]);
if(ec)
return fail(ec, "write");
// This buffer is used for reading and must be persisted
beast::flat_buffer b;
// Declare a container to hold the response
http::response<http::dynamic_body> res;
// Receive the HTTP response
http::async_read(stream, b, res, yield[ec]);
if(ec)
return fail(ec, "read");
// Write the message to standard out
std::cout << res << std::endl;
// Gracefully close the socket
stream.socket().shutdown(tcp::socket::shutdown_both, ec);
// not_connected happens sometimes
// so don't bother reporting it.
//
if(ec && ec != beast::errc::not_connected)
return fail(ec, "shutdown");
// If we get here then the connection is closed gracefully
}
//------------------------------------------------------------------------------
int main(int argc, char** argv)
{
// Check command line arguments.
if(argc != 4 && argc != 5)
{
std::cerr <<
"Usage: http-client-coro <host> <port> <target> [<HTTP version: 1.0 or 1.1(default)>]\n" <<
"Example:\n" <<
" http-client-coro www.example.com 80 /\n" <<
" http-client-coro www.example.com 80 / 1.0\n";
return EXIT_FAILURE;
}
auto const host = argv[1];
auto const port = argv[2];
auto const target = argv[3];
int version = argc == 5 && !std::strcmp("1.0", argv[4]) ? 10 : 11;
// The io_context is required for all I/O
net::io_context ioc;
// Launch the asynchronous operation
boost::asio::spawn(ioc, std::bind(
&do_session,
std::string(host),
std::string(port),
std::string(target),
version,
std::ref(ioc),
std::placeholders::_1));
// Run the I/O service. The call will return when
// the get operation is complete.
ioc.run();
return EXIT_SUCCESS;
}