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 client, synchronous
13//
14//------------------------------------------------------------------------------
15
16//[example_websocket_client
17
18#include <boost/beast/core.hpp>
19#include <boost/beast/websocket.hpp>
20#include <boost/asio/connect.hpp>
21#include <boost/asio/ip/tcp.hpp>
22#include <cstdlib>
23#include <iostream>
24#include <string>
25
26namespace beast = boost::beast; // from <boost/beast.hpp>
27namespace http = beast::http; // from <boost/beast/http.hpp>
28namespace websocket = beast::websocket; // from <boost/beast/websocket.hpp>
29namespace net = boost::asio; // from <boost/asio.hpp>
30using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
31
32// Sends a WebSocket message and prints the response
33int main(int argc, char** argv)
34{
35 try
36 {
37 // Check command line arguments.
38 if(argc != 4)
39 {
40 std::cerr <<
41 "Usage: websocket-client-sync <host> <port> <text>\n" <<
42 "Example:\n" <<
43 " websocket-client-sync echo.websocket.org 80 \"Hello, world!\"\n";
44 return EXIT_FAILURE;
45 }
46 std::string host = argv[1];
47 auto const port = argv[2];
48 auto const text = argv[3];
49
50 // The io_context is required for all I/O
51 net::io_context ioc;
52
53 // These objects perform our I/O
54 tcp::resolver resolver{ioc};
55 websocket::stream<tcp::socket> ws{ioc};
56
57 // Look up the domain name
58 auto const results = resolver.resolve(host, service: port);
59
60 // Make the connection on the IP address we get from a lookup
61 auto ep = net::connect(s&: ws.next_layer(), endpoints: results);
62
63 // Update the host_ string. This will provide the value of the
64 // Host HTTP header during the WebSocket handshake.
65 // See https://tools.ietf.org/html/rfc7230#section-5.4
66 host += ':' + std::to_string(val: ep.port());
67
68 // Set a decorator to change the User-Agent of the handshake
69 ws.set_option(websocket::stream_base::decorator(
70 [](websocket::request_type& req)
71 {
72 req.set(name: http::field::user_agent,
73 value: std::string(BOOST_BEAST_VERSION_STRING) +
74 " websocket-client-coro");
75 }));
76
77 // Perform the websocket handshake
78 ws.handshake(host, target: "/");
79
80 // Send the message
81 ws.write(buffers: net::buffer(data: std::string(text)));
82
83 // This buffer will hold the incoming message
84 beast::flat_buffer buffer;
85
86 // Read a message into our buffer
87 ws.read(buffer);
88
89 // Close the WebSocket connection
90 ws.close(cr: websocket::close_code::normal);
91
92 // If we get here then the connection is closed gracefully
93
94 // The make_printable() function helps print a ConstBufferSequence
95 std::cout << beast::make_printable(buffers: buffer.data()) << std::endl;
96 }
97 catch(std::exception const& e)
98 {
99 std::cerr << "Error: " << e.what() << std::endl;
100 return EXIT_FAILURE;
101 }
102 return EXIT_SUCCESS;
103}
104
105//]
106

source code of boost/libs/beast/example/websocket/client/sync/websocket_client_sync.cpp