libs/beast/example/websocket/client/async-ssl-system-executor/websocket_client_async_ssl_system_executor.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, using system_executor // //------------------------------------------------------------------------------ #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 <boost/asio/system_executor.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_; // Objects are constructed with a strand to // ensure that handlers do not execute concurrently. session(net::strand<net::system_executor> ex, ssl::context& ctx) : resolver_(ex) , ws_(ex, ctx) { } public: // Delegate construction to a prive constructor to be able to use // the same strand for both I/O objects. explicit session(ssl::context& ctx) : session(net::make_strand(net::system_executor{}), 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 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>(ctx)->run(host, port, text); // The async operations will run on the system_executor. // Because the main thread has nothing to do in this example, we just wait // for the system_executor to run out of work. net::query(net::system_executor(), net::execution::context).join(); return EXIT_SUCCESS; }