libs/beast/example/websocket/client/async-ssl/websocket_client_async_ssl.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: WebSocket SSL client, asynchronous
//
//------------------------------------------------------------------------------
#include "example/common/root_certificates.hpp"
#include <boost/beast/core.hpp>
#include <boost/beast/ssl.hpp>
#include <boost/beast/websocket.hpp>
#include <boost/beast/websocket/ssl.hpp>
#include <boost/asio/strand.hpp>
#include <cstdlib>
#include <functional>
#include <iostream>
#include <memory>
#include <string>
namespace beast = boost::beast; // from <boost/beast.hpp>
namespace http = beast::http; // from <boost/beast/http.hpp>
namespace websocket = beast::websocket; // from <boost/beast/websocket.hpp>
namespace net = boost::asio; // from <boost/asio.hpp>
namespace ssl = boost::asio::ssl; // from <boost/asio/ssl.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";
}
// Sends a WebSocket message and prints the response
class session : public std::enable_shared_from_this<session>
{
tcp::resolver resolver_;
websocket::stream<
beast::ssl_stream<beast::tcp_stream>> ws_;
beast::flat_buffer buffer_;
std::string host_;
std::string text_;
public:
// Resolver and socket require an io_context
explicit
session(net::io_context& ioc, ssl::context& ctx)
: resolver_(net::make_strand(ioc))
, ws_(net::make_strand(ioc), ctx)
{
}
// Start the asynchronous operation
void
run(
char const* host,
char const* port,
char const* text)
{
// Save these for later
host_ = host;
text_ = text;
// Look up the domain name
resolver_.async_resolve(
host,
port,
beast::bind_front_handler(
&session::on_resolve,
shared_from_this()));
}
void
on_resolve(
beast::error_code ec,
tcp::resolver::results_type results)
{
if(ec)
return fail(ec, "resolve");
// Set a timeout on the operation
beast::get_lowest_layer(ws_).expires_after(std::chrono::seconds(30));
// Make the connection on the IP address we get from a lookup
beast::get_lowest_layer(ws_).async_connect(
results,
beast::bind_front_handler(
&session::on_connect,
shared_from_this()));
}
void
on_connect(beast::error_code ec, tcp::resolver::results_type::endpoint_type ep)
{
if(ec)
return fail(ec, "connect");
// Set a timeout on the operation
beast::get_lowest_layer(ws_).expires_after(std::chrono::seconds(30));
// Set SNI Hostname (many hosts need this to handshake successfully)
if(! SSL_set_tlsext_host_name(
ws_.next_layer().native_handle(),
host_.c_str()))
{
ec = beast::error_code(static_cast<int>(::ERR_get_error()),
net::error::get_ssl_category());
return fail(ec, "connect");
}
// Update the host_ string. This will provide the value of the
// Host HTTP header during the WebSocket handshake.
// See https://tools.ietf.org/html/rfc7230#section-5.4
host_ += ':' + std::to_string(ep.port());
// Perform the SSL handshake
ws_.next_layer().async_handshake(
ssl::stream_base::client,
beast::bind_front_handler(
&session::on_ssl_handshake,
shared_from_this()));
}
void
on_ssl_handshake(beast::error_code ec)
{
if(ec)
return fail(ec, "ssl_handshake");
// Turn off the timeout on the tcp_stream, because
// the websocket stream has its own timeout system.
beast::get_lowest_layer(ws_).expires_never();
// Set suggested timeout settings for the websocket
ws_.set_option(
websocket::stream_base::timeout::suggested(
beast::role_type::client));
// Set a decorator to change the User-Agent of the handshake
ws_.set_option(websocket::stream_base::decorator(
[](websocket::request_type& req)
{
req.set(http::field::user_agent,
std::string(BOOST_BEAST_VERSION_STRING) +
" websocket-client-async-ssl");
}));
// Perform the websocket handshake
ws_.async_handshake(host_, "/",
beast::bind_front_handler(
&session::on_handshake,
shared_from_this()));
}
void
on_handshake(beast::error_code ec)
{
if(ec)
return fail(ec, "handshake");
// Send the message
ws_.async_write(
net::buffer(text_),
beast::bind_front_handler(
&session::on_write,
shared_from_this()));
}
void
on_write(
beast::error_code ec,
std::size_t bytes_transferred)
{
boost::ignore_unused(bytes_transferred);
if(ec)
return fail(ec, "write");
// Read a message into our buffer
ws_.async_read(
buffer_,
beast::bind_front_handler(
&session::on_read,
shared_from_this()));
}
void
on_read(
beast::error_code ec,
std::size_t bytes_transferred)
{
boost::ignore_unused(bytes_transferred);
if(ec)
return fail(ec, "read");
// Close the WebSocket connection
ws_.async_close(websocket::close_code::normal,
beast::bind_front_handler(
&session::on_close,
shared_from_this()));
}
void
on_close(beast::error_code ec)
{
if(ec)
return fail(ec, "close");
// If we get here then the connection is closed gracefully
// The make_printable() function helps print a ConstBufferSequence
std::cout << beast::make_printable(buffer_.data()) << std::endl;
}
};
//------------------------------------------------------------------------------
int main(int argc, char** argv)
{
// Check command line arguments.
if(argc != 4)
{
std::cerr <<
"Usage: websocket-client-async-ssl <host> <port> <text>\n" <<
"Example:\n" <<
" websocket-client-async-ssl echo.websocket.org 443 \"Hello, world!\"\n";
return EXIT_FAILURE;
}
auto const host = argv[1];
auto const port = argv[2];
auto const text = argv[3];
// The io_context is required for all I/O
net::io_context ioc;
// The SSL context is required, and holds certificates
ssl::context ctx{ssl::context::tlsv12_client};
// This holds the root certificate used for verification
load_root_certificates(ctx);
// Launch the asynchronous operation
std::make_shared<session>(ioc, ctx)->run(host, port, text);
// Run the I/O service. The call will return when
// the socket is closed.
ioc.run();
return EXIT_SUCCESS;
}