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 server, asynchronous
13 //
14 //------------------------------------------------------------------------------
15
16 #include "example/common/server_certificate.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 <boost/asio/dispatch.hpp>
24 #include <algorithm>
25 #include <cstdlib>
26 #include <functional>
27 #include <iostream>
28 #include <memory>
29 #include <string>
30 #include <thread>
31 #include <vector>
32
33 namespace beast = boost::beast; // from <boost/beast.hpp>
34 namespace http = beast::http; // from <boost/beast/http.hpp>
35 namespace websocket = beast::websocket; // from <boost/beast/websocket.hpp>
36 namespace net = boost::asio; // from <boost/asio.hpp>
37 namespace ssl = boost::asio::ssl; // from <boost/asio/ssl.hpp>
38 using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
39
40 //------------------------------------------------------------------------------
41
42 // Report a failure
43 void
fail(beast::error_code ec,char const * what)44 fail(beast::error_code ec, char const* what)
45 {
46 std::cerr << what << ": " << ec.message() << "\n";
47 }
48
49 // Echoes back all received WebSocket messages
50 class session : public std::enable_shared_from_this<session>
51 {
52 websocket::stream<
53 beast::ssl_stream<beast::tcp_stream>> ws_;
54 beast::flat_buffer buffer_;
55
56 public:
57 // Take ownership of the socket
session(tcp::socket && socket,ssl::context & ctx)58 session(tcp::socket&& socket, ssl::context& ctx)
59 : ws_(std::move(socket), ctx)
60 {
61 }
62
63 // Get on the correct executor
64 void
run()65 run()
66 {
67 // We need to be executing within a strand to perform async operations
68 // on the I/O objects in this session. Although not strictly necessary
69 // for single-threaded contexts, this example code is written to be
70 // thread-safe by default.
71 net::dispatch(ws_.get_executor(),
72 beast::bind_front_handler(
73 &session::on_run,
74 shared_from_this()));
75 }
76
77 // Start the asynchronous operation
78 void
on_run()79 on_run()
80 {
81 // Set the timeout.
82 beast::get_lowest_layer(ws_).expires_after(std::chrono::seconds(30));
83
84 // Perform the SSL handshake
85 ws_.next_layer().async_handshake(
86 ssl::stream_base::server,
87 beast::bind_front_handler(
88 &session::on_handshake,
89 shared_from_this()));
90 }
91
92 void
on_handshake(beast::error_code ec)93 on_handshake(beast::error_code ec)
94 {
95 if(ec)
96 return fail(ec, "handshake");
97
98 // Turn off the timeout on the tcp_stream, because
99 // the websocket stream has its own timeout system.
100 beast::get_lowest_layer(ws_).expires_never();
101
102 // Set suggested timeout settings for the websocket
103 ws_.set_option(
104 websocket::stream_base::timeout::suggested(
105 beast::role_type::server));
106
107 // Set a decorator to change the Server of the handshake
108 ws_.set_option(websocket::stream_base::decorator(
109 [](websocket::response_type& res)
110 {
111 res.set(http::field::server,
112 std::string(BOOST_BEAST_VERSION_STRING) +
113 " websocket-server-async-ssl");
114 }));
115
116 // Accept the websocket handshake
117 ws_.async_accept(
118 beast::bind_front_handler(
119 &session::on_accept,
120 shared_from_this()));
121 }
122
123 void
on_accept(beast::error_code ec)124 on_accept(beast::error_code ec)
125 {
126 if(ec)
127 return fail(ec, "accept");
128
129 // Read a message
130 do_read();
131 }
132
133 void
do_read()134 do_read()
135 {
136 // Read a message into our buffer
137 ws_.async_read(
138 buffer_,
139 beast::bind_front_handler(
140 &session::on_read,
141 shared_from_this()));
142 }
143
144 void
on_read(beast::error_code ec,std::size_t bytes_transferred)145 on_read(
146 beast::error_code ec,
147 std::size_t bytes_transferred)
148 {
149 boost::ignore_unused(bytes_transferred);
150
151 // This indicates that the session was closed
152 if(ec == websocket::error::closed)
153 return;
154
155 if(ec)
156 fail(ec, "read");
157
158 // Echo the message
159 ws_.text(ws_.got_text());
160 ws_.async_write(
161 buffer_.data(),
162 beast::bind_front_handler(
163 &session::on_write,
164 shared_from_this()));
165 }
166
167 void
on_write(beast::error_code ec,std::size_t bytes_transferred)168 on_write(
169 beast::error_code ec,
170 std::size_t bytes_transferred)
171 {
172 boost::ignore_unused(bytes_transferred);
173
174 if(ec)
175 return fail(ec, "write");
176
177 // Clear the buffer
178 buffer_.consume(buffer_.size());
179
180 // Do another read
181 do_read();
182 }
183 };
184
185 //------------------------------------------------------------------------------
186
187 // Accepts incoming connections and launches the sessions
188 class listener : public std::enable_shared_from_this<listener>
189 {
190 net::io_context& ioc_;
191 ssl::context& ctx_;
192 tcp::acceptor acceptor_;
193
194 public:
listener(net::io_context & ioc,ssl::context & ctx,tcp::endpoint endpoint)195 listener(
196 net::io_context& ioc,
197 ssl::context& ctx,
198 tcp::endpoint endpoint)
199 : ioc_(ioc)
200 , ctx_(ctx)
201 , acceptor_(net::make_strand(ioc))
202 {
203 beast::error_code ec;
204
205 // Open the acceptor
206 acceptor_.open(endpoint.protocol(), ec);
207 if(ec)
208 {
209 fail(ec, "open");
210 return;
211 }
212
213 // Allow address reuse
214 acceptor_.set_option(net::socket_base::reuse_address(true), ec);
215 if(ec)
216 {
217 fail(ec, "set_option");
218 return;
219 }
220
221 // Bind to the server address
222 acceptor_.bind(endpoint, ec);
223 if(ec)
224 {
225 fail(ec, "bind");
226 return;
227 }
228
229 // Start listening for connections
230 acceptor_.listen(
231 net::socket_base::max_listen_connections, ec);
232 if(ec)
233 {
234 fail(ec, "listen");
235 return;
236 }
237 }
238
239 // Start accepting incoming connections
240 void
run()241 run()
242 {
243 do_accept();
244 }
245
246 private:
247 void
do_accept()248 do_accept()
249 {
250 // The new connection gets its own strand
251 acceptor_.async_accept(
252 net::make_strand(ioc_),
253 beast::bind_front_handler(
254 &listener::on_accept,
255 shared_from_this()));
256 }
257
258 void
on_accept(beast::error_code ec,tcp::socket socket)259 on_accept(beast::error_code ec, tcp::socket socket)
260 {
261 if(ec)
262 {
263 fail(ec, "accept");
264 }
265 else
266 {
267 // Create the session and run it
268 std::make_shared<session>(std::move(socket), ctx_)->run();
269 }
270
271 // Accept another connection
272 do_accept();
273 }
274 };
275
276 //------------------------------------------------------------------------------
277
main(int argc,char * argv[])278 int main(int argc, char* argv[])
279 {
280 // Check command line arguments.
281 if (argc != 4)
282 {
283 std::cerr <<
284 "Usage: websocket-server-async-ssl <address> <port> <threads>\n" <<
285 "Example:\n" <<
286 " websocket-server-async-ssl 0.0.0.0 8080 1\n";
287 return EXIT_FAILURE;
288 }
289 auto const address = net::ip::make_address(argv[1]);
290 auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
291 auto const threads = std::max<int>(1, std::atoi(argv[3]));
292
293 // The io_context is required for all I/O
294 net::io_context ioc{threads};
295
296 // The SSL context is required, and holds certificates
297 ssl::context ctx{ssl::context::tlsv12};
298
299 // This holds the self-signed certificate used by the server
300 load_server_certificate(ctx);
301
302 // Create and launch a listening port
303 std::make_shared<listener>(ioc, ctx, tcp::endpoint{address, port})->run();
304
305 // Run the I/O service on the requested number of threads
306 std::vector<std::thread> v;
307 v.reserve(threads - 1);
308 for(auto i = threads - 1; i > 0; --i)
309 v.emplace_back(
310 [&ioc]
311 {
312 ioc.run();
313 });
314 ioc.run();
315
316 return EXIT_SUCCESS;
317 }
318