1//
2// Copyright (c) 2016-2019 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 SSL client, coroutine
13//
14//------------------------------------------------------------------------------
15
16#include "example/common/root_certificates.hpp"
17
18#include <boost/beast/core.hpp>
19#include <boost/beast/ssl.hpp>
20#include <boost/beast/websocket.hpp>
21#include <boost/beast/websocket/ssl.hpp>
22#include <boost/asio/spawn.hpp>
23#include <cstdlib>
24#include <functional>
25#include <iostream>
26#include <string>
27
28namespace beast = boost::beast; // from <boost/beast.hpp>
29namespace http = beast::http; // from <boost/beast/http.hpp>
30namespace websocket = beast::websocket; // from <boost/beast/websocket.hpp>
31namespace net = boost::asio; // from <boost/asio.hpp>
32namespace ssl = boost::asio::ssl; // from <boost/asio/ssl.hpp>
33using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
34
35//------------------------------------------------------------------------------
36
37// Report a failure
38void
39fail(beast::error_code ec, char const* what)
40{
41 std::cerr << what << ": " << ec.message() << "\n";
42}
43
44// Sends a WebSocket message and prints the response
45void
46do_session(
47 std::string host,
48 std::string const& port,
49 std::string const& text,
50 net::io_context& ioc,
51 ssl::context& ctx,
52 net::yield_context yield)
53{
54 beast::error_code ec;
55
56 // These objects perform our I/O
57 tcp::resolver resolver(ioc);
58 websocket::stream<
59 beast::ssl_stream<beast::tcp_stream>> ws(ioc, ctx);
60
61 // Look up the domain name
62 auto const results = resolver.async_resolve(host, service: port, token: yield[ec]);
63 if(ec)
64 return fail(ec, what: "resolve");
65
66 // Set a timeout on the operation
67 beast::get_lowest_layer(t&: ws).expires_after(expiry_time: std::chrono::seconds(30));
68
69 // Make the connection on the IP address we get from a lookup
70 auto ep = beast::get_lowest_layer(t&: ws).async_connect(endpoints: results, handler: yield[ec]);
71 if(ec)
72 return fail(ec, what: "connect");
73
74 // Set SNI Hostname (many hosts need this to handshake successfully)
75 if(! SSL_set_tlsext_host_name(
76 ws.next_layer().native_handle(),
77 host.c_str()))
78 {
79 ec = beast::error_code(static_cast<int>(::ERR_get_error()),
80 net::error::get_ssl_category());
81 return fail(ec, what: "connect");
82 }
83
84 // Update the host string. This will provide the value of the
85 // Host HTTP header during the WebSocket handshake.
86 // See https://tools.ietf.org/html/rfc7230#section-5.4
87 host += ':' + std::to_string(val: ep.port());
88
89 // Set a timeout on the operation
90 beast::get_lowest_layer(t&: ws).expires_after(expiry_time: std::chrono::seconds(30));
91
92 // Set a decorator to change the User-Agent of the handshake
93 ws.set_option(websocket::stream_base::decorator(
94 [](websocket::request_type& req)
95 {
96 req.set(name: http::field::user_agent,
97 value: std::string(BOOST_BEAST_VERSION_STRING) +
98 " websocket-client-coro");
99 }));
100
101 // Perform the SSL handshake
102 ws.next_layer().async_handshake(type: ssl::stream_base::client, handler: yield[ec]);
103 if(ec)
104 return fail(ec, what: "ssl_handshake");
105
106 // Turn off the timeout on the tcp_stream, because
107 // the websocket stream has its own timeout system.
108 beast::get_lowest_layer(t&: ws).expires_never();
109
110 // Set suggested timeout settings for the websocket
111 ws.set_option(
112 websocket::stream_base::timeout::suggested(
113 role: beast::role_type::client));
114
115 // Perform the websocket handshake
116 ws.async_handshake(host, target: "/", handler: yield[ec]);
117 if(ec)
118 return fail(ec, what: "handshake");
119
120 // Send the message
121 ws.async_write(bs: net::buffer(data: std::string(text)), handler: yield[ec]);
122 if(ec)
123 return fail(ec, what: "write");
124
125 // This buffer will hold the incoming message
126 beast::flat_buffer buffer;
127
128 // Read a message into our buffer
129 ws.async_read(buffer, handler: yield[ec]);
130 if(ec)
131 return fail(ec, what: "read");
132
133 // Close the WebSocket connection
134 ws.async_close(cr: websocket::close_code::normal, handler: yield[ec]);
135 if(ec)
136 return fail(ec, what: "close");
137
138 // If we get here then the connection is closed gracefully
139
140 // The make_printable() function helps print a ConstBufferSequence
141 std::cout << beast::make_printable(buffers: buffer.data()) << std::endl;
142}
143
144//------------------------------------------------------------------------------
145
146int main(int argc, char** argv)
147{
148 // Check command line arguments.
149 if(argc != 4)
150 {
151 std::cerr <<
152 "Usage: websocket-client-coro-ssl <host> <port> <text>\n" <<
153 "Example:\n" <<
154 " websocket-client-coro-ssl echo.websocket.org 443 \"Hello, world!\"\n";
155 return EXIT_FAILURE;
156 }
157 auto const host = argv[1];
158 auto const port = argv[2];
159 auto const text = argv[3];
160
161 // The io_context is required for all I/O
162 net::io_context ioc;
163
164 // The SSL context is required, and holds certificates
165 ssl::context ctx{ssl::context::tlsv12_client};
166
167 // This holds the root certificate used for verification
168 load_root_certificates(ctx);
169
170 // Launch the asynchronous operation
171 boost::asio::spawn(ctx&: ioc, function: std::bind(
172 f: &do_session,
173 args: std::string(host),
174 args: std::string(port),
175 args: std::string(text),
176 args: std::ref(t&: ioc),
177 args: std::ref(t&: ctx),
178 args: std::placeholders::_1),
179 // on completion, spawn will call this function
180 token: [](std::exception_ptr ex)
181 {
182 // if an exception occurred in the coroutine,
183 // it's something critical, e.g. out of memory
184 // we capture normal errors in the ec
185 // so we just rethrow the exception here,
186 // which will cause `ioc.run()` to throw
187 if (ex)
188 std::rethrow_exception(ex);
189 });
190
191 // Run the I/O service. The call will return when
192 // the socket is closed.
193 ioc.run();
194
195 return EXIT_SUCCESS;
196}
197

source code of boost/libs/beast/example/websocket/client/coro-ssl/websocket_client_coro_ssl.cpp