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1 | // |
2 | // Copyright (c) 2016-2017 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: HTTP server, synchronous | |
13 | // | |
14 | //------------------------------------------------------------------------------ | |
15 | ||
16 | #include <boost/beast/core.hpp> | |
17 | #include <boost/beast/http.hpp> | |
18 | #include <boost/beast/version.hpp> | |
19 | #include <boost/asio/ip/tcp.hpp> | |
20 | #include <boost/config.hpp> | |
21 | #include <cstdlib> | |
22 | #include <iostream> | |
23 | #include <memory> | |
24 | #include <string> | |
25 | #include <thread> | |
26 | ||
27 | using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp> | |
28 | namespace http = boost::beast::http; // from <boost/beast/http.hpp> | |
29 | ||
30 | //------------------------------------------------------------------------------ | |
31 | ||
32 | // Return a reasonable mime type based on the extension of a file. | |
33 | boost::beast::string_view | |
34 | mime_type(boost::beast::string_view path) | |
35 | { | |
36 | using boost::beast::iequals; | |
37 | auto const ext = [&path] | |
38 | { | |
39 | auto const pos = path.rfind("."); | |
40 | if(pos == boost::beast::string_view::npos) | |
41 | return boost::beast::string_view{}; | |
42 | return path.substr(pos); | |
43 | }(); | |
44 | if(iequals(ext, ".htm")) return "text/html"; | |
45 | if(iequals(ext, ".html")) return "text/html"; | |
46 | if(iequals(ext, ".php")) return "text/html"; | |
47 | if(iequals(ext, ".css")) return "text/css"; | |
48 | if(iequals(ext, ".txt")) return "text/plain"; | |
49 | if(iequals(ext, ".js")) return "application/javascript"; | |
50 | if(iequals(ext, ".json")) return "application/json"; | |
51 | if(iequals(ext, ".xml")) return "application/xml"; | |
52 | if(iequals(ext, ".swf")) return "application/x-shockwave-flash"; | |
53 | if(iequals(ext, ".flv")) return "video/x-flv"; | |
54 | if(iequals(ext, ".png")) return "image/png"; | |
55 | if(iequals(ext, ".jpe")) return "image/jpeg"; | |
56 | if(iequals(ext, ".jpeg")) return "image/jpeg"; | |
57 | if(iequals(ext, ".jpg")) return "image/jpeg"; | |
58 | if(iequals(ext, ".gif")) return "image/gif"; | |
59 | if(iequals(ext, ".bmp")) return "image/bmp"; | |
60 | if(iequals(ext, ".ico")) return "image/vnd.microsoft.icon"; | |
61 | if(iequals(ext, ".tiff")) return "image/tiff"; | |
62 | if(iequals(ext, ".tif")) return "image/tiff"; | |
63 | if(iequals(ext, ".svg")) return "image/svg+xml"; | |
64 | if(iequals(ext, ".svgz")) return "image/svg+xml"; | |
65 | return "application/text"; | |
66 | } | |
67 | ||
68 | // Append an HTTP rel-path to a local filesystem path. | |
69 | // The returned path is normalized for the platform. | |
70 | std::string | |
71 | path_cat( | |
72 | boost::beast::string_view base, | |
73 | boost::beast::string_view path) | |
74 | { | |
75 | if(base.empty()) | |
76 | return path.to_string(); | |
77 | std::string result = base.to_string(); | |
78 | #if BOOST_MSVC | |
79 | char constexpr path_separator = '\\'; | |
80 | if(result.back() == path_separator) | |
81 | result.resize(result.size() - 1); | |
82 | result.append(path.data(), path.size()); | |
83 | for(auto& c : result) | |
84 | if(c == '/') | |
85 | c = path_separator; | |
86 | #else | |
87 | char constexpr path_separator = '/'; | |
88 | if(result.back() == path_separator) | |
89 | result.resize(result.size() - 1); | |
90 | result.append(path.data(), path.size()); | |
91 | #endif | |
92 | return result; | |
93 | } | |
94 | ||
95 | // This function produces an HTTP response for the given | |
96 | // request. The type of the response object depends on the | |
97 | // contents of the request, so the interface requires the | |
98 | // caller to pass a generic lambda for receiving the response. | |
99 | template< | |
100 | class Body, class Allocator, | |
101 | class Send> | |
102 | void | |
103 | handle_request( | |
104 | boost::beast::string_view doc_root, | |
105 | http::request<Body, http::basic_fields<Allocator>>&& req, | |
106 | Send&& send) | |
107 | { | |
108 | // Returns a bad request response | |
109 | auto const bad_request = | |
110 | [&req](boost::beast::string_view why) | |
111 | { | |
112 | http::response<http::string_body> res{http::status::bad_request, req.version()}; | |
113 | res.set(http::field::server, BOOST_BEAST_VERSION_STRING); | |
114 | res.set(http::field::content_type, "text/html"); | |
115 | res.keep_alive(req.keep_alive()); | |
116 | res.body() = why.to_string(); | |
117 | res.prepare_payload(); | |
118 | return res; | |
119 | }; | |
120 | ||
121 | // Returns a not found response | |
122 | auto const not_found = | |
123 | [&req](boost::beast::string_view target) | |
124 | { | |
125 | http::response<http::string_body> res{http::status::not_found, req.version()}; | |
126 | res.set(http::field::server, BOOST_BEAST_VERSION_STRING); | |
127 | res.set(http::field::content_type, "text/html"); | |
128 | res.keep_alive(req.keep_alive()); | |
129 | res.body() = "The resource '" + target.to_string() + "' was not found."; | |
130 | res.prepare_payload(); | |
131 | return res; | |
132 | }; | |
133 | ||
134 | // Returns a server error response | |
135 | auto const server_error = | |
136 | [&req](boost::beast::string_view what) | |
137 | { | |
138 | http::response<http::string_body> res{http::status::internal_server_error, req.version()}; | |
139 | res.set(http::field::server, BOOST_BEAST_VERSION_STRING); | |
140 | res.set(http::field::content_type, "text/html"); | |
141 | res.keep_alive(req.keep_alive()); | |
142 | res.body() = "An error occurred: '" + what.to_string() + "'"; | |
143 | res.prepare_payload(); | |
144 | return res; | |
145 | }; | |
146 | ||
147 | // Make sure we can handle the method | |
148 | if( req.method() != http::verb::get && | |
149 | req.method() != http::verb::head) | |
150 | return send(bad_request("Unknown HTTP-method")); | |
151 | ||
152 | // Request path must be absolute and not contain "..". | |
153 | if( req.target().empty() || | |
154 | req.target()[0] != '/' || | |
155 | req.target().find("..") != boost::beast::string_view::npos) | |
156 | return send(bad_request("Illegal request-target")); | |
157 | ||
158 | // Build the path to the requested file | |
159 | std::string path = path_cat(doc_root, req.target()); | |
160 | if(req.target().back() == '/') | |
161 | path.append("index.html"); | |
162 | ||
163 | // Attempt to open the file | |
164 | boost::beast::error_code ec; | |
165 | http::file_body::value_type body; | |
166 | body.open(path.c_str(), boost::beast::file_mode::scan, ec); | |
167 | ||
168 | // Handle the case where the file doesn't exist | |
169 | if(ec == boost::system::errc::no_such_file_or_directory) | |
170 | return send(not_found(req.target())); | |
171 | ||
172 | // Handle an unknown error | |
173 | if(ec) | |
174 | return send(server_error(ec.message())); | |
175 | ||
176 | // Respond to HEAD request | |
177 | if(req.method() == http::verb::head) | |
178 | { | |
179 | http::response<http::empty_body> res{http::status::ok, req.version()}; | |
180 | res.set(http::field::server, BOOST_BEAST_VERSION_STRING); | |
181 | res.set(http::field::content_type, mime_type(path)); | |
182 | res.content_length(body.size()); | |
183 | res.keep_alive(req.keep_alive()); | |
184 | return send(std::move(res)); | |
185 | } | |
186 | ||
187 | // Respond to GET request | |
188 | http::response<http::file_body> res{ | |
189 | std::piecewise_construct, | |
190 | std::make_tuple(std::move(body)), | |
191 | std::make_tuple(http::status::ok, req.version())}; | |
192 | res.set(http::field::server, BOOST_BEAST_VERSION_STRING); | |
193 | res.set(http::field::content_type, mime_type(path)); | |
194 | res.content_length(body.size()); | |
195 | res.keep_alive(req.keep_alive()); | |
196 | return send(std::move(res)); | |
197 | } | |
198 | ||
199 | //------------------------------------------------------------------------------ | |
200 | ||
201 | // Report a failure | |
202 | void | |
203 | fail(boost::system::error_code ec, char const* what) | |
204 | { | |
205 | std::cerr << what << ": " << ec.message() << "\n"; | |
206 | } | |
207 | ||
208 | // This is the C++11 equivalent of a generic lambda. | |
209 | // The function object is used to send an HTTP message. | |
210 | template<class Stream> | |
211 | struct send_lambda | |
212 | { | |
213 | Stream& stream_; | |
214 | bool& close_; | |
215 | boost::system::error_code& ec_; | |
216 | ||
217 | explicit | |
218 | send_lambda( | |
219 | Stream& stream, | |
220 | bool& close, | |
221 | boost::system::error_code& ec) | |
222 | : stream_(stream) | |
223 | , close_(close) | |
224 | , ec_(ec) | |
225 | { | |
226 | } | |
227 | ||
228 | template<bool isRequest, class Body, class Fields> | |
229 | void | |
230 | operator()(http::message<isRequest, Body, Fields>&& msg) const | |
231 | { | |
232 | // Determine if we should close the connection after | |
233 | close_ = msg.need_eof(); | |
234 | ||
235 | // We need the serializer here because the serializer requires | |
236 | // a non-const file_body, and the message oriented version of | |
237 | // http::write only works with const messages. | |
238 | http::serializer<isRequest, Body, Fields> sr{msg}; | |
239 | http::write(stream_, sr, ec_); | |
240 | } | |
241 | }; | |
242 | ||
243 | // Handles an HTTP server connection | |
244 | void | |
245 | do_session( | |
246 | tcp::socket& socket, | |
247 | std::string const& doc_root) | |
248 | { | |
249 | bool close = false; | |
250 | boost::system::error_code ec; | |
251 | ||
252 | // This buffer is required to persist across reads | |
253 | boost::beast::flat_buffer buffer; | |
254 | ||
255 | // This lambda is used to send messages | |
256 | send_lambda<tcp::socket> lambda{socket, close, ec}; | |
257 | ||
258 | for(;;) | |
259 | { | |
260 | // Read a request | |
261 | http::request<http::string_body> req; | |
262 | http::read(socket, buffer, req, ec); | |
263 | if(ec == http::error::end_of_stream) | |
264 | break; | |
265 | if(ec) | |
266 | return fail(ec, "read"); | |
267 | ||
268 | // Send the response | |
269 | handle_request(doc_root, std::move(req), lambda); | |
270 | if(ec) | |
271 | return fail(ec, "write"); | |
272 | if(close) | |
273 | { | |
274 | // This means we should close the connection, usually because | |
275 | // the response indicated the "Connection: close" semantic. | |
276 | break; | |
277 | } | |
278 | } | |
279 | ||
280 | // Send a TCP shutdown | |
281 | socket.shutdown(tcp::socket::shutdown_send, ec); | |
282 | ||
283 | // At this point the connection is closed gracefully | |
284 | } | |
285 | ||
286 | //------------------------------------------------------------------------------ | |
287 | ||
288 | int main(int argc, char* argv[]) | |
289 | { | |
290 | try | |
291 | { | |
292 | // Check command line arguments. | |
293 | if (argc != 4) | |
294 | { | |
295 | std::cerr << | |
296 | "Usage: http-server-sync <address> <port> <doc_root>\n" << | |
297 | "Example:\n" << | |
298 | " http-server-sync 0.0.0.0 8080 .\n"; | |
299 | return EXIT_FAILURE; | |
300 | } | |
301 | auto const address = boost::asio::ip::make_address(argv[1]); | |
302 | auto const port = static_cast<unsigned short>(std::atoi(argv[2])); | |
303 | std::string const doc_root = argv[3]; | |
304 | ||
305 | // The io_context is required for all I/O | |
306 | boost::asio::io_context ioc{1}; | |
307 | ||
308 | // The acceptor receives incoming connections | |
309 | tcp::acceptor acceptor{ioc, {address, port}}; | |
310 | for(;;) | |
311 | { | |
312 | // This will receive the new connection | |
313 | tcp::socket socket{ioc}; | |
314 | ||
315 | // Block until we get a connection | |
316 | acceptor.accept(socket); | |
317 | ||
318 | // Launch the session, transferring ownership of the socket | |
319 | std::thread{std::bind( | |
320 | &do_session, | |
321 | std::move(socket), | |
322 | doc_root)}.detach(); | |
323 | } | |
324 | } | |
325 | catch (const std::exception& e) | |
326 | { | |
327 | std::cerr << "Error: " << e.what() << std::endl; | |
328 | return EXIT_FAILURE; | |
329 | } | |
330 | } |