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
29 namespace beast = boost::beast; // from <boost/beast.hpp>
30 namespace http = beast::http; // from <boost/beast/http.hpp>
31 namespace websocket = beast::websocket; // from <boost/beast/websocket.hpp>
32 namespace net = boost::asio; // from <boost/asio.hpp>
33 namespace ssl = boost::asio::ssl; // from <boost/asio/ssl.hpp>
34 using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
35
36 //------------------------------------------------------------------------------
37
38 // Report a failure
39 void
fail(beast::error_code ec,char const * what)40 fail(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
46 class 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
55 public:
56 // Resolver and socket require an io_context
57 explicit
session(net::io_context & ioc,ssl::context & ctx)58 session(net::io_context& ioc, ssl::context& ctx)
59 : resolver_(net::make_strand(ioc))
60 , ws_(net::make_strand(ioc), ctx)
61 {
62 }
63
64 // Start the asynchronous operation
65 void
run(char const * host,char const * port,char const * text)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 port,
79 beast::bind_front_handler(
80 &session::on_resolve,
81 shared_from_this()));
82 }
83
84 void
on_resolve(beast::error_code ec,tcp::resolver::results_type results)85 on_resolve(
86 beast::error_code ec,
87 tcp::resolver::results_type results)
88 {
89 if(ec)
90 return fail(ec, "resolve");
91
92 // Set a timeout on the operation
93 beast::get_lowest_layer(ws_).expires_after(std::chrono::seconds(30));
94
95 // Make the connection on the IP address we get from a lookup
96 beast::get_lowest_layer(ws_).async_connect(
97 results,
98 beast::bind_front_handler(
99 &session::on_connect,
100 shared_from_this()));
101 }
102
103 void
on_connect(beast::error_code ec,tcp::resolver::results_type::endpoint_type ep)104 on_connect(beast::error_code ec, tcp::resolver::results_type::endpoint_type ep)
105 {
106 if(ec)
107 return fail(ec, "connect");
108
109 // Update the host_ string. This will provide the value of the
110 // Host HTTP header during the WebSocket handshake.
111 // See https://tools.ietf.org/html/rfc7230#section-5.4
112 host_ += ':' + std::to_string(ep.port());
113
114 // Set a timeout on the operation
115 beast::get_lowest_layer(ws_).expires_after(std::chrono::seconds(30));
116
117 // Perform the SSL handshake
118 ws_.next_layer().async_handshake(
119 ssl::stream_base::client,
120 beast::bind_front_handler(
121 &session::on_ssl_handshake,
122 shared_from_this()));
123 }
124
125 void
on_ssl_handshake(beast::error_code ec)126 on_ssl_handshake(beast::error_code ec)
127 {
128 if(ec)
129 return fail(ec, "ssl_handshake");
130
131 // Turn off the timeout on the tcp_stream, because
132 // the websocket stream has its own timeout system.
133 beast::get_lowest_layer(ws_).expires_never();
134
135 // Set suggested timeout settings for the websocket
136 ws_.set_option(
137 websocket::stream_base::timeout::suggested(
138 beast::role_type::client));
139
140 // Set a decorator to change the User-Agent of the handshake
141 ws_.set_option(websocket::stream_base::decorator(
142 [](websocket::request_type& req)
143 {
144 req.set(http::field::user_agent,
145 std::string(BOOST_BEAST_VERSION_STRING) +
146 " websocket-client-async-ssl");
147 }));
148
149 // Perform the websocket handshake
150 ws_.async_handshake(host_, "/",
151 beast::bind_front_handler(
152 &session::on_handshake,
153 shared_from_this()));
154 }
155
156 void
on_handshake(beast::error_code ec)157 on_handshake(beast::error_code ec)
158 {
159 if(ec)
160 return fail(ec, "handshake");
161
162 // Send the message
163 ws_.async_write(
164 net::buffer(text_),
165 beast::bind_front_handler(
166 &session::on_write,
167 shared_from_this()));
168 }
169
170 void
on_write(beast::error_code ec,std::size_t bytes_transferred)171 on_write(
172 beast::error_code ec,
173 std::size_t bytes_transferred)
174 {
175 boost::ignore_unused(bytes_transferred);
176
177 if(ec)
178 return fail(ec, "write");
179
180 // Read a message into our buffer
181 ws_.async_read(
182 buffer_,
183 beast::bind_front_handler(
184 &session::on_read,
185 shared_from_this()));
186 }
187
188 void
on_read(beast::error_code ec,std::size_t bytes_transferred)189 on_read(
190 beast::error_code ec,
191 std::size_t bytes_transferred)
192 {
193 boost::ignore_unused(bytes_transferred);
194
195 if(ec)
196 return fail(ec, "read");
197
198 // Close the WebSocket connection
199 ws_.async_close(websocket::close_code::normal,
200 beast::bind_front_handler(
201 &session::on_close,
202 shared_from_this()));
203 }
204
205 void
on_close(beast::error_code ec)206 on_close(beast::error_code ec)
207 {
208 if(ec)
209 return fail(ec, "close");
210
211 // If we get here then the connection is closed gracefully
212
213 // The make_printable() function helps print a ConstBufferSequence
214 std::cout << beast::make_printable(buffer_.data()) << std::endl;
215 }
216 };
217
218 //------------------------------------------------------------------------------
219
main(int argc,char ** argv)220 int main(int argc, char** argv)
221 {
222 // Check command line arguments.
223 if(argc != 4)
224 {
225 std::cerr <<
226 "Usage: websocket-client-async-ssl <host> <port> <text>\n" <<
227 "Example:\n" <<
228 " websocket-client-async-ssl echo.websocket.org 443 \"Hello, world!\"\n";
229 return EXIT_FAILURE;
230 }
231 auto const host = argv[1];
232 auto const port = argv[2];
233 auto const text = argv[3];
234
235 // The io_context is required for all I/O
236 net::io_context ioc;
237
238 // The SSL context is required, and holds certificates
239 ssl::context ctx{ssl::context::tlsv12_client};
240
241 // This holds the root certificate used for verification
242 load_root_certificates(ctx);
243
244 // Launch the asynchronous operation
245 std::make_shared<session>(ioc, ctx)->run(host, port, text);
246
247 // Run the I/O service. The call will return when
248 // the socket is closed.
249 ioc.run();
250
251 return EXIT_SUCCESS;
252 }
253