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1 | // | |
2 | // posix_chat_client.cpp | |
3 | // ~~~~~~~~~~~~~~~~~~~~~ | |
4 | // | |
5 | // Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com) | |
6 | // | |
7 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
8 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
9 | // | |
10 | ||
11 | #include <cstdlib> | |
12 | #include <cstring> | |
13 | #include <iostream> | |
14 | #include <boost/array.hpp> | |
15 | #include <boost/bind.hpp> | |
16 | #include <boost/asio.hpp> | |
17 | #include "chat_message.hpp" | |
18 | ||
19 | #if defined(BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR) | |
20 | ||
21 | using boost::asio::ip::tcp; | |
22 | namespace posix = boost::asio::posix; | |
23 | ||
24 | class posix_chat_client | |
25 | { | |
26 | public: | |
27 | posix_chat_client(boost::asio::io_context& io_context, | |
28 | const tcp::resolver::results_type& endpoints) | |
29 | : socket_(io_context), | |
30 | input_(io_context, ::dup(STDIN_FILENO)), | |
31 | output_(io_context, ::dup(STDOUT_FILENO)), | |
32 | input_buffer_(chat_message::max_body_length) | |
33 | { | |
34 | boost::asio::async_connect(socket_, endpoints, | |
35 | boost::bind(&posix_chat_client::handle_connect, this, | |
36 | boost::asio::placeholders::error)); | |
37 | } | |
38 | ||
39 | private: | |
40 | ||
41 | void handle_connect(const boost::system::error_code& error) | |
42 | { | |
43 | if (!error) | |
44 | { | |
45 | // Read the fixed-length header of the next message from the server. | |
46 | boost::asio::async_read(socket_, | |
47 | boost::asio::buffer(read_msg_.data(), chat_message::header_length), | |
48 | boost::bind(&posix_chat_client::handle_read_header, this, | |
49 | boost::asio::placeholders::error)); | |
50 | ||
51 | // Read a line of input entered by the user. | |
52 | boost::asio::async_read_until(input_, input_buffer_, '\n', | |
53 | boost::bind(&posix_chat_client::handle_read_input, this, | |
54 | boost::asio::placeholders::error, | |
55 | boost::asio::placeholders::bytes_transferred)); | |
56 | } | |
57 | } | |
58 | ||
59 | void handle_read_header(const boost::system::error_code& error) | |
60 | { | |
61 | if (!error && read_msg_.decode_header()) | |
62 | { | |
63 | // Read the variable-length body of the message from the server. | |
64 | boost::asio::async_read(socket_, | |
65 | boost::asio::buffer(read_msg_.body(), read_msg_.body_length()), | |
66 | boost::bind(&posix_chat_client::handle_read_body, this, | |
67 | boost::asio::placeholders::error)); | |
68 | } | |
69 | else | |
70 | { | |
71 | close(); | |
72 | } | |
73 | } | |
74 | ||
75 | void handle_read_body(const boost::system::error_code& error) | |
76 | { | |
77 | if (!error) | |
78 | { | |
79 | // Write out the message we just received, terminated by a newline. | |
80 | static char eol[] = { '\n' }; | |
81 | boost::array<boost::asio::const_buffer, 2> buffers = {{ | |
82 | boost::asio::buffer(read_msg_.body(), read_msg_.body_length()), | |
83 | boost::asio::buffer(eol) }}; | |
84 | boost::asio::async_write(output_, buffers, | |
85 | boost::bind(&posix_chat_client::handle_write_output, this, | |
86 | boost::asio::placeholders::error)); | |
87 | } | |
88 | else | |
89 | { | |
90 | close(); | |
91 | } | |
92 | } | |
93 | ||
94 | void handle_write_output(const boost::system::error_code& error) | |
95 | { | |
96 | if (!error) | |
97 | { | |
98 | // Read the fixed-length header of the next message from the server. | |
99 | boost::asio::async_read(socket_, | |
100 | boost::asio::buffer(read_msg_.data(), chat_message::header_length), | |
101 | boost::bind(&posix_chat_client::handle_read_header, this, | |
102 | boost::asio::placeholders::error)); | |
103 | } | |
104 | else | |
105 | { | |
106 | close(); | |
107 | } | |
108 | } | |
109 | ||
110 | void handle_read_input(const boost::system::error_code& error, | |
111 | std::size_t length) | |
112 | { | |
113 | if (!error) | |
114 | { | |
115 | // Write the message (minus the newline) to the server. | |
116 | write_msg_.body_length(length - 1); | |
117 | input_buffer_.sgetn(write_msg_.body(), length - 1); | |
118 | input_buffer_.consume(1); // Remove newline from input. | |
119 | write_msg_.encode_header(); | |
120 | boost::asio::async_write(socket_, | |
121 | boost::asio::buffer(write_msg_.data(), write_msg_.length()), | |
122 | boost::bind(&posix_chat_client::handle_write, this, | |
123 | boost::asio::placeholders::error)); | |
124 | } | |
125 | else if (error == boost::asio::error::not_found) | |
126 | { | |
127 | // Didn't get a newline. Send whatever we have. | |
128 | write_msg_.body_length(input_buffer_.size()); | |
129 | input_buffer_.sgetn(write_msg_.body(), input_buffer_.size()); | |
130 | write_msg_.encode_header(); | |
131 | boost::asio::async_write(socket_, | |
132 | boost::asio::buffer(write_msg_.data(), write_msg_.length()), | |
133 | boost::bind(&posix_chat_client::handle_write, this, | |
134 | boost::asio::placeholders::error)); | |
135 | } | |
136 | else | |
137 | { | |
138 | close(); | |
139 | } | |
140 | } | |
141 | ||
142 | void handle_write(const boost::system::error_code& error) | |
143 | { | |
144 | if (!error) | |
145 | { | |
146 | // Read a line of input entered by the user. | |
147 | boost::asio::async_read_until(input_, input_buffer_, '\n', | |
148 | boost::bind(&posix_chat_client::handle_read_input, this, | |
149 | boost::asio::placeholders::error, | |
150 | boost::asio::placeholders::bytes_transferred)); | |
151 | } | |
152 | else | |
153 | { | |
154 | close(); | |
155 | } | |
156 | } | |
157 | ||
158 | void close() | |
159 | { | |
160 | // Cancel all outstanding asynchronous operations. | |
161 | socket_.close(); | |
162 | input_.close(); | |
163 | output_.close(); | |
164 | } | |
165 | ||
166 | private: | |
167 | tcp::socket socket_; | |
168 | posix::stream_descriptor input_; | |
169 | posix::stream_descriptor output_; | |
170 | chat_message read_msg_; | |
171 | chat_message write_msg_; | |
172 | boost::asio::streambuf input_buffer_; | |
173 | }; | |
174 | ||
175 | int main(int argc, char* argv[]) | |
176 | { | |
177 | try | |
178 | { | |
179 | if (argc != 3) | |
180 | { | |
181 | std::cerr << "Usage: posix_chat_client <host> <port>\n"; | |
182 | return 1; | |
183 | } | |
184 | ||
185 | boost::asio::io_context io_context; | |
186 | ||
187 | tcp::resolver resolver(io_context); | |
188 | tcp::resolver::results_type endpoints = resolver.resolve(argv[1], argv[2]); | |
189 | ||
190 | posix_chat_client c(io_context, endpoints); | |
191 | ||
192 | io_context.run(); | |
193 | } | |
194 | catch (std::exception& e) | |
195 | { | |
196 | std::cerr << "Exception: " << e.what() << "\n"; | |
197 | } | |
198 | ||
199 | return 0; | |
200 | } | |
201 | ||
202 | #else // defined(BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR) | |
203 | int main() {} | |
204 | #endif // defined(BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR) |