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, asynchronous
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/strand.hpp>
23#include <cstdlib>
24#include <functional>
25#include <iostream>
26#include <memory>
27#include <string>
28
29namespace beast = boost::beast; // from <boost/beast.hpp>
30namespace http = beast::http; // from <boost/beast/http.hpp>
31namespace websocket = beast::websocket; // from <boost/beast/websocket.hpp>
32namespace net = boost::asio; // from <boost/asio.hpp>
33namespace ssl = boost::asio::ssl; // from <boost/asio/ssl.hpp>
34using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
35
36//------------------------------------------------------------------------------
37
38// Report a failure
39void
40fail(beast::error_code ec, char const* what)
41{
42 std::cerr << what << ": " << ec.message() << "\n";
43}
44
45// Sends a WebSocket message and prints the response
46class session : public std::enable_shared_from_this<session>
47{
48 tcp::resolver resolver_;
49 websocket::stream<
50 beast::ssl_stream<beast::tcp_stream>> ws_;
51 beast::flat_buffer buffer_;
52 std::string host_;
53 std::string text_;
54
55public:
56 // Resolver and socket require an io_context
57 explicit
58 session(net::io_context& ioc, ssl::context& ctx)
59 : resolver_(net::make_strand(ctx&: ioc))
60 , ws_(net::make_strand(ctx&: ioc), ctx)
61 {
62 }
63
64 // Start the asynchronous operation
65 void
66 run(
67 char const* host,
68 char const* port,
69 char const* text)
70 {
71 // Save these for later
72 host_ = host;
73 text_ = text;
74
75 // Look up the domain name
76 resolver_.async_resolve(
77 host,
78 service: port,
79 token: beast::bind_front_handler(
80 handler: &session::on_resolve,
81 args: shared_from_this()));
82 }
83
84 void
85 on_resolve(
86 beast::error_code ec,
87 tcp::resolver::results_type results)
88 {
89 if(ec)
90 return fail(ec, what: "resolve");
91
92 // Set a timeout on the operation
93 beast::get_lowest_layer(t&: ws_).expires_after(expiry_time: std::chrono::seconds(30));
94
95 // Make the connection on the IP address we get from a lookup
96 beast::get_lowest_layer(t&: ws_).async_connect(
97 endpoints: results,
98 handler: beast::bind_front_handler(
99 handler: &session::on_connect,
100 args: shared_from_this()));
101 }
102
103 void
104 on_connect(beast::error_code ec, tcp::resolver::results_type::endpoint_type ep)
105 {
106 if(ec)
107 return fail(ec, what: "connect");
108
109 // Set a timeout on the operation
110 beast::get_lowest_layer(t&: ws_).expires_after(expiry_time: std::chrono::seconds(30));
111
112 // Set SNI Hostname (many hosts need this to handshake successfully)
113 if(! SSL_set_tlsext_host_name(
114 ws_.next_layer().native_handle(),
115 host_.c_str()))
116 {
117 ec = beast::error_code(static_cast<int>(::ERR_get_error()),
118 net::error::get_ssl_category());
119 return fail(ec, what: "connect");
120 }
121
122 // Update the host_ string. This will provide the value of the
123 // Host HTTP header during the WebSocket handshake.
124 // See https://tools.ietf.org/html/rfc7230#section-5.4
125 host_ += ':' + std::to_string(val: ep.port());
126
127 // Perform the SSL handshake
128 ws_.next_layer().async_handshake(
129 type: ssl::stream_base::client,
130 handler: beast::bind_front_handler(
131 handler: &session::on_ssl_handshake,
132 args: shared_from_this()));
133 }
134
135 void
136 on_ssl_handshake(beast::error_code ec)
137 {
138 if(ec)
139 return fail(ec, what: "ssl_handshake");
140
141 // Turn off the timeout on the tcp_stream, because
142 // the websocket stream has its own timeout system.
143 beast::get_lowest_layer(t&: ws_).expires_never();
144
145 // Set suggested timeout settings for the websocket
146 ws_.set_option(
147 websocket::stream_base::timeout::suggested(
148 role: beast::role_type::client));
149
150 // Set a decorator to change the User-Agent of the handshake
151 ws_.set_option(websocket::stream_base::decorator(
152 [](websocket::request_type& req)
153 {
154 req.set(name: http::field::user_agent,
155 value: std::string(BOOST_BEAST_VERSION_STRING) +
156 " websocket-client-async-ssl");
157 }));
158
159 // Perform the websocket handshake
160 ws_.async_handshake(host: host_, target: "/",
161 handler: beast::bind_front_handler(
162 handler: &session::on_handshake,
163 args: shared_from_this()));
164 }
165
166 void
167 on_handshake(beast::error_code ec)
168 {
169 if(ec)
170 return fail(ec, what: "handshake");
171
172 // Send the message
173 ws_.async_write(
174 bs: net::buffer(data&: text_),
175 handler: beast::bind_front_handler(
176 handler: &session::on_write,
177 args: shared_from_this()));
178 }
179
180 void
181 on_write(
182 beast::error_code ec,
183 std::size_t bytes_transferred)
184 {
185 boost::ignore_unused(bytes_transferred);
186
187 if(ec)
188 return fail(ec, what: "write");
189
190 // Read a message into our buffer
191 ws_.async_read(
192 buffer&: buffer_,
193 handler: beast::bind_front_handler(
194 handler: &session::on_read,
195 args: shared_from_this()));
196 }
197
198 void
199 on_read(
200 beast::error_code ec,
201 std::size_t bytes_transferred)
202 {
203 boost::ignore_unused(bytes_transferred);
204
205 if(ec)
206 return fail(ec, what: "read");
207
208 // Close the WebSocket connection
209 ws_.async_close(cr: websocket::close_code::normal,
210 handler: beast::bind_front_handler(
211 handler: &session::on_close,
212 args: shared_from_this()));
213 }
214
215 void
216 on_close(beast::error_code ec)
217 {
218 if(ec)
219 return fail(ec, what: "close");
220
221 // If we get here then the connection is closed gracefully
222
223 // The make_printable() function helps print a ConstBufferSequence
224 std::cout << beast::make_printable(buffers: buffer_.data()) << std::endl;
225 }
226};
227
228//------------------------------------------------------------------------------
229
230int main(int argc, char** argv)
231{
232 // Check command line arguments.
233 if(argc != 4)
234 {
235 std::cerr <<
236 "Usage: websocket-client-async-ssl <host> <port> <text>\n" <<
237 "Example:\n" <<
238 " websocket-client-async-ssl echo.websocket.org 443 \"Hello, world!\"\n";
239 return EXIT_FAILURE;
240 }
241 auto const host = argv[1];
242 auto const port = argv[2];
243 auto const text = argv[3];
244
245 // The io_context is required for all I/O
246 net::io_context ioc;
247
248 // The SSL context is required, and holds certificates
249 ssl::context ctx{ssl::context::tlsv12_client};
250
251 // This holds the root certificate used for verification
252 load_root_certificates(ctx);
253
254 // Launch the asynchronous operation
255 std::make_shared<session>(args&: ioc, args&: ctx)->run(host, port, text);
256
257 // Run the I/O service. The call will return when
258 // the socket is closed.
259 ioc.run();
260
261 return EXIT_SUCCESS;
262}
263

source code of boost/libs/beast/example/websocket/client/async-ssl/websocket_client_async_ssl.cpp