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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, asynchronous | |
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/bind_executor.hpp> | |
20 | #include <boost/asio/ip/tcp.hpp> | |
21 | #include <boost/asio/strand.hpp> | |
22 | #include <boost/config.hpp> | |
23 | #include <algorithm> | |
24 | #include <cstdlib> | |
25 | #include <functional> | |
26 | #include <iostream> | |
27 | #include <memory> | |
28 | #include <string> | |
29 | #include <thread> | |
30 | #include <vector> | |
31 | ||
32 | using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp> | |
33 | namespace http = boost::beast::http; // from <boost/beast/http.hpp> | |
34 | ||
35 | // Return a reasonable mime type based on the extension of a file. | |
36 | boost::beast::string_view | |
37 | mime_type(boost::beast::string_view path) | |
38 | { | |
39 | using boost::beast::iequals; | |
40 | auto const ext = [&path] | |
41 | { | |
42 | auto const pos = path.rfind("."); | |
43 | if(pos == boost::beast::string_view::npos) | |
44 | return boost::beast::string_view{}; | |
45 | return path.substr(pos); | |
46 | }(); | |
47 | if(iequals(ext, ".htm")) return "text/html"; | |
48 | if(iequals(ext, ".html")) return "text/html"; | |
49 | if(iequals(ext, ".php")) return "text/html"; | |
50 | if(iequals(ext, ".css")) return "text/css"; | |
51 | if(iequals(ext, ".txt")) return "text/plain"; | |
52 | if(iequals(ext, ".js")) return "application/javascript"; | |
53 | if(iequals(ext, ".json")) return "application/json"; | |
54 | if(iequals(ext, ".xml")) return "application/xml"; | |
55 | if(iequals(ext, ".swf")) return "application/x-shockwave-flash"; | |
56 | if(iequals(ext, ".flv")) return "video/x-flv"; | |
57 | if(iequals(ext, ".png")) return "image/png"; | |
58 | if(iequals(ext, ".jpe")) return "image/jpeg"; | |
59 | if(iequals(ext, ".jpeg")) return "image/jpeg"; | |
60 | if(iequals(ext, ".jpg")) return "image/jpeg"; | |
61 | if(iequals(ext, ".gif")) return "image/gif"; | |
62 | if(iequals(ext, ".bmp")) return "image/bmp"; | |
63 | if(iequals(ext, ".ico")) return "image/vnd.microsoft.icon"; | |
64 | if(iequals(ext, ".tiff")) return "image/tiff"; | |
65 | if(iequals(ext, ".tif")) return "image/tiff"; | |
66 | if(iequals(ext, ".svg")) return "image/svg+xml"; | |
67 | if(iequals(ext, ".svgz")) return "image/svg+xml"; | |
68 | return "application/text"; | |
69 | } | |
70 | ||
71 | // Append an HTTP rel-path to a local filesystem path. | |
72 | // The returned path is normalized for the platform. | |
73 | std::string | |
74 | path_cat( | |
75 | boost::beast::string_view base, | |
76 | boost::beast::string_view path) | |
77 | { | |
78 | if(base.empty()) | |
79 | return path.to_string(); | |
80 | std::string result = base.to_string(); | |
81 | #if BOOST_MSVC | |
82 | char constexpr path_separator = '\\'; | |
83 | if(result.back() == path_separator) | |
84 | result.resize(result.size() - 1); | |
85 | result.append(path.data(), path.size()); | |
86 | for(auto& c : result) | |
87 | if(c == '/') | |
88 | c = path_separator; | |
89 | #else | |
90 | char constexpr path_separator = '/'; | |
91 | if(result.back() == path_separator) | |
92 | result.resize(result.size() - 1); | |
93 | result.append(path.data(), path.size()); | |
94 | #endif | |
95 | return result; | |
96 | } | |
97 | ||
98 | // This function produces an HTTP response for the given | |
99 | // request. The type of the response object depends on the | |
100 | // contents of the request, so the interface requires the | |
101 | // caller to pass a generic lambda for receiving the response. | |
102 | template< | |
103 | class Body, class Allocator, | |
104 | class Send> | |
105 | void | |
106 | handle_request( | |
107 | boost::beast::string_view doc_root, | |
108 | http::request<Body, http::basic_fields<Allocator>>&& req, | |
109 | Send&& send) | |
110 | { | |
111 | // Returns a bad request response | |
112 | auto const bad_request = | |
113 | [&req](boost::beast::string_view why) | |
114 | { | |
115 | http::response<http::string_body> res{http::status::bad_request, req.version()}; | |
116 | res.set(http::field::server, BOOST_BEAST_VERSION_STRING); | |
117 | res.set(http::field::content_type, "text/html"); | |
118 | res.keep_alive(req.keep_alive()); | |
119 | res.body() = why.to_string(); | |
120 | res.prepare_payload(); | |
121 | return res; | |
122 | }; | |
123 | ||
124 | // Returns a not found response | |
125 | auto const not_found = | |
126 | [&req](boost::beast::string_view target) | |
127 | { | |
128 | http::response<http::string_body> res{http::status::not_found, req.version()}; | |
129 | res.set(http::field::server, BOOST_BEAST_VERSION_STRING); | |
130 | res.set(http::field::content_type, "text/html"); | |
131 | res.keep_alive(req.keep_alive()); | |
132 | res.body() = "The resource '" + target.to_string() + "' was not found."; | |
133 | res.prepare_payload(); | |
134 | return res; | |
135 | }; | |
136 | ||
137 | // Returns a server error response | |
138 | auto const server_error = | |
139 | [&req](boost::beast::string_view what) | |
140 | { | |
141 | http::response<http::string_body> res{http::status::internal_server_error, req.version()}; | |
142 | res.set(http::field::server, BOOST_BEAST_VERSION_STRING); | |
143 | res.set(http::field::content_type, "text/html"); | |
144 | res.keep_alive(req.keep_alive()); | |
145 | res.body() = "An error occurred: '" + what.to_string() + "'"; | |
146 | res.prepare_payload(); | |
147 | return res; | |
148 | }; | |
149 | ||
150 | // Make sure we can handle the method | |
151 | if( req.method() != http::verb::get && | |
152 | req.method() != http::verb::head) | |
153 | return send(bad_request("Unknown HTTP-method")); | |
154 | ||
155 | // Request path must be absolute and not contain "..". | |
156 | if( req.target().empty() || | |
157 | req.target()[0] != '/' || | |
158 | req.target().find("..") != boost::beast::string_view::npos) | |
159 | return send(bad_request("Illegal request-target")); | |
160 | ||
161 | // Build the path to the requested file | |
162 | std::string path = path_cat(doc_root, req.target()); | |
163 | if(req.target().back() == '/') | |
164 | path.append("index.html"); | |
165 | ||
166 | // Attempt to open the file | |
167 | boost::beast::error_code ec; | |
168 | http::file_body::value_type body; | |
169 | body.open(path.c_str(), boost::beast::file_mode::scan, ec); | |
170 | ||
171 | // Handle the case where the file doesn't exist | |
172 | if(ec == boost::system::errc::no_such_file_or_directory) | |
173 | return send(not_found(req.target())); | |
174 | ||
175 | // Handle an unknown error | |
176 | if(ec) | |
177 | return send(server_error(ec.message())); | |
178 | ||
179 | // Respond to HEAD request | |
180 | if(req.method() == http::verb::head) | |
181 | { | |
182 | http::response<http::empty_body> res{http::status::ok, req.version()}; | |
183 | res.set(http::field::server, BOOST_BEAST_VERSION_STRING); | |
184 | res.set(http::field::content_type, mime_type(path)); | |
185 | res.content_length(body.size()); | |
186 | res.keep_alive(req.keep_alive()); | |
187 | return send(std::move(res)); | |
188 | } | |
189 | ||
190 | // Respond to GET request | |
191 | http::response<http::file_body> res{ | |
192 | std::piecewise_construct, | |
193 | std::make_tuple(std::move(body)), | |
194 | std::make_tuple(http::status::ok, req.version())}; | |
195 | res.set(http::field::server, BOOST_BEAST_VERSION_STRING); | |
196 | res.set(http::field::content_type, mime_type(path)); | |
197 | res.content_length(body.size()); | |
198 | res.keep_alive(req.keep_alive()); | |
199 | return send(std::move(res)); | |
200 | } | |
201 | ||
202 | //------------------------------------------------------------------------------ | |
203 | ||
204 | // Report a failure | |
205 | void | |
206 | fail(boost::system::error_code ec, char const* what) | |
207 | { | |
208 | std::cerr << what << ": " << ec.message() << "\n"; | |
209 | } | |
210 | ||
211 | // Handles an HTTP server connection | |
212 | class session : public std::enable_shared_from_this<session> | |
213 | { | |
214 | // This is the C++11 equivalent of a generic lambda. | |
215 | // The function object is used to send an HTTP message. | |
216 | struct send_lambda | |
217 | { | |
218 | session& self_; | |
219 | ||
220 | explicit | |
221 | send_lambda(session& self) | |
222 | : self_(self) | |
223 | { | |
224 | } | |
225 | ||
226 | template<bool isRequest, class Body, class Fields> | |
227 | void | |
228 | operator()(http::message<isRequest, Body, Fields>&& msg) const | |
229 | { | |
230 | // The lifetime of the message has to extend | |
231 | // for the duration of the async operation so | |
232 | // we use a shared_ptr to manage it. | |
233 | auto sp = std::make_shared< | |
234 | http::message<isRequest, Body, Fields>>(std::move(msg)); | |
235 | ||
236 | // Store a type-erased version of the shared | |
237 | // pointer in the class to keep it alive. | |
238 | self_.res_ = sp; | |
239 | ||
240 | // Write the response | |
241 | http::async_write( | |
242 | self_.socket_, | |
243 | *sp, | |
244 | boost::asio::bind_executor( | |
245 | self_.strand_, | |
246 | std::bind( | |
247 | &session::on_write, | |
248 | self_.shared_from_this(), | |
249 | std::placeholders::_1, | |
250 | std::placeholders::_2, | |
251 | sp->need_eof()))); | |
252 | } | |
253 | }; | |
254 | ||
255 | tcp::socket socket_; | |
256 | boost::asio::strand< | |
257 | boost::asio::io_context::executor_type> strand_; | |
258 | boost::beast::flat_buffer buffer_; | |
259 | std::string const& doc_root_; | |
260 | http::request<http::string_body> req_; | |
261 | std::shared_ptr<void> res_; | |
262 | send_lambda lambda_; | |
263 | ||
264 | public: | |
265 | // Take ownership of the socket | |
266 | explicit | |
267 | session( | |
268 | tcp::socket socket, | |
269 | std::string const& doc_root) | |
270 | : socket_(std::move(socket)) | |
271 | , strand_(socket_.get_executor()) | |
272 | , doc_root_(doc_root) | |
273 | , lambda_(*this) | |
274 | { | |
275 | } | |
276 | ||
277 | // Start the asynchronous operation | |
278 | void | |
279 | run() | |
280 | { | |
281 | do_read(); | |
282 | } | |
283 | ||
284 | void | |
285 | do_read() | |
286 | { | |
287 | // Read a request | |
288 | http::async_read(socket_, buffer_, req_, | |
289 | boost::asio::bind_executor( | |
290 | strand_, | |
291 | std::bind( | |
292 | &session::on_read, | |
293 | shared_from_this(), | |
294 | std::placeholders::_1, | |
295 | std::placeholders::_2))); | |
296 | } | |
297 | ||
298 | void | |
299 | on_read( | |
300 | boost::system::error_code ec, | |
301 | std::size_t bytes_transferred) | |
302 | { | |
303 | boost::ignore_unused(bytes_transferred); | |
304 | ||
305 | // This means they closed the connection | |
306 | if(ec == http::error::end_of_stream) | |
307 | return do_close(); | |
308 | ||
309 | if(ec) | |
310 | return fail(ec, "read"); | |
311 | ||
312 | // Send the response | |
313 | handle_request(doc_root_, std::move(req_), lambda_); | |
314 | } | |
315 | ||
316 | void | |
317 | on_write( | |
318 | boost::system::error_code ec, | |
319 | std::size_t bytes_transferred, | |
320 | bool close) | |
321 | { | |
322 | boost::ignore_unused(bytes_transferred); | |
323 | ||
324 | if(ec) | |
325 | return fail(ec, "write"); | |
326 | ||
327 | if(close) | |
328 | { | |
329 | // This means we should close the connection, usually because | |
330 | // the response indicated the "Connection: close" semantic. | |
331 | return do_close(); | |
332 | } | |
333 | ||
334 | // We're done with the response so delete it | |
335 | res_ = nullptr; | |
336 | ||
337 | // Read another request | |
338 | do_read(); | |
339 | } | |
340 | ||
341 | void | |
342 | do_close() | |
343 | { | |
344 | // Send a TCP shutdown | |
345 | boost::system::error_code ec; | |
346 | socket_.shutdown(tcp::socket::shutdown_send, ec); | |
347 | ||
348 | // At this point the connection is closed gracefully | |
349 | } | |
350 | }; | |
351 | ||
352 | //------------------------------------------------------------------------------ | |
353 | ||
354 | // Accepts incoming connections and launches the sessions | |
355 | class listener : public std::enable_shared_from_this<listener> | |
356 | { | |
357 | tcp::acceptor acceptor_; | |
358 | tcp::socket socket_; | |
359 | std::string const& doc_root_; | |
360 | ||
361 | public: | |
362 | listener( | |
363 | boost::asio::io_context& ioc, | |
364 | tcp::endpoint endpoint, | |
365 | std::string const& doc_root) | |
366 | : acceptor_(ioc) | |
367 | , socket_(ioc) | |
368 | , doc_root_(doc_root) | |
369 | { | |
370 | boost::system::error_code ec; | |
371 | ||
372 | // Open the acceptor | |
373 | acceptor_.open(endpoint.protocol(), ec); | |
374 | if(ec) | |
375 | { | |
376 | fail(ec, "open"); | |
377 | return; | |
378 | } | |
379 | ||
380 | // Bind to the server address | |
381 | acceptor_.bind(endpoint, ec); | |
382 | if(ec) | |
383 | { | |
384 | fail(ec, "bind"); | |
385 | return; | |
386 | } | |
387 | ||
388 | // Start listening for connections | |
389 | acceptor_.listen( | |
390 | boost::asio::socket_base::max_listen_connections, ec); | |
391 | if(ec) | |
392 | { | |
393 | fail(ec, "listen"); | |
394 | return; | |
395 | } | |
396 | } | |
397 | ||
398 | // Start accepting incoming connections | |
399 | void | |
400 | run() | |
401 | { | |
402 | if(! acceptor_.is_open()) | |
403 | return; | |
404 | do_accept(); | |
405 | } | |
406 | ||
407 | void | |
408 | do_accept() | |
409 | { | |
410 | acceptor_.async_accept( | |
411 | socket_, | |
412 | std::bind( | |
413 | &listener::on_accept, | |
414 | shared_from_this(), | |
415 | std::placeholders::_1)); | |
416 | } | |
417 | ||
418 | void | |
419 | on_accept(boost::system::error_code ec) | |
420 | { | |
421 | if(ec) | |
422 | { | |
423 | fail(ec, "accept"); | |
424 | } | |
425 | else | |
426 | { | |
427 | // Create the session and run it | |
428 | std::make_shared<session>( | |
429 | std::move(socket_), | |
430 | doc_root_)->run(); | |
431 | } | |
432 | ||
433 | // Accept another connection | |
434 | do_accept(); | |
435 | } | |
436 | }; | |
437 | ||
438 | //------------------------------------------------------------------------------ | |
439 | ||
440 | int main(int argc, char* argv[]) | |
441 | { | |
442 | // Check command line arguments. | |
443 | if (argc != 5) | |
444 | { | |
445 | std::cerr << | |
446 | "Usage: http-server-async <address> <port> <doc_root> <threads>\n" << | |
447 | "Example:\n" << | |
448 | " http-server-async 0.0.0.0 8080 . 1\n"; | |
449 | return EXIT_FAILURE; | |
450 | } | |
451 | auto const address = boost::asio::ip::make_address(argv[1]); | |
452 | auto const port = static_cast<unsigned short>(std::atoi(argv[2])); | |
453 | std::string const doc_root = argv[3]; | |
454 | auto const threads = std::max<int>(1, std::atoi(argv[4])); | |
455 | ||
456 | // The io_context is required for all I/O | |
457 | boost::asio::io_context ioc{threads}; | |
458 | ||
459 | // Create and launch a listening port | |
460 | std::make_shared<listener>( | |
461 | ioc, | |
462 | tcp::endpoint{address, port}, | |
463 | doc_root)->run(); | |
464 | ||
465 | // Run the I/O service on the requested number of threads | |
466 | std::vector<std::thread> v; | |
467 | v.reserve(threads - 1); | |
468 | for(auto i = threads - 1; i > 0; --i) | |
469 | v.emplace_back( | |
470 | [&ioc] | |
471 | { | |
472 | ioc.run(); | |
473 | }); | |
474 | ioc.run(); | |
475 | ||
476 | return EXIT_SUCCESS; | |
477 | } |