2 // Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
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)
7 // Official repository: https://github.com/boostorg/beast
10 //------------------------------------------------------------------------------
12 // Example: HTTP server, asynchronous
14 //------------------------------------------------------------------------------
16 #include <boost/beast/core.hpp>
17 #include <boost/beast/http.hpp>
18 #include <boost/beast/version.hpp>
19 #include <boost/asio/dispatch.hpp>
20 #include <boost/asio/strand.hpp>
21 #include <boost/config.hpp>
31 namespace beast = boost::beast; // from <boost/beast.hpp>
32 namespace http = beast::http; // from <boost/beast/http.hpp>
33 namespace net = boost::asio; // from <boost/asio.hpp>
34 using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
36 // Return a reasonable mime type based on the extension of a file.
38 mime_type(beast::string_view path)
41 auto const ext = [&path]
43 auto const pos = path.rfind(".");
44 if(pos == beast::string_view::npos)
45 return beast::string_view{};
46 return path.substr(pos);
48 if(iequals(ext, ".htm")) return "text/html";
49 if(iequals(ext, ".html")) return "text/html";
50 if(iequals(ext, ".php")) return "text/html";
51 if(iequals(ext, ".css")) return "text/css";
52 if(iequals(ext, ".txt")) return "text/plain";
53 if(iequals(ext, ".js")) return "application/javascript";
54 if(iequals(ext, ".json")) return "application/json";
55 if(iequals(ext, ".xml")) return "application/xml";
56 if(iequals(ext, ".swf")) return "application/x-shockwave-flash";
57 if(iequals(ext, ".flv")) return "video/x-flv";
58 if(iequals(ext, ".png")) return "image/png";
59 if(iequals(ext, ".jpe")) return "image/jpeg";
60 if(iequals(ext, ".jpeg")) return "image/jpeg";
61 if(iequals(ext, ".jpg")) return "image/jpeg";
62 if(iequals(ext, ".gif")) return "image/gif";
63 if(iequals(ext, ".bmp")) return "image/bmp";
64 if(iequals(ext, ".ico")) return "image/vnd.microsoft.icon";
65 if(iequals(ext, ".tiff")) return "image/tiff";
66 if(iequals(ext, ".tif")) return "image/tiff";
67 if(iequals(ext, ".svg")) return "image/svg+xml";
68 if(iequals(ext, ".svgz")) return "image/svg+xml";
69 return "application/text";
72 // Append an HTTP rel-path to a local filesystem path.
73 // The returned path is normalized for the platform.
76 beast::string_view base,
77 beast::string_view path)
80 return std::string(path);
81 std::string result(base);
83 char constexpr path_separator = '\\';
84 if(result.back() == path_separator)
85 result.resize(result.size() - 1);
86 result.append(path.data(), path.size());
91 char constexpr path_separator = '/';
92 if(result.back() == path_separator)
93 result.resize(result.size() - 1);
94 result.append(path.data(), path.size());
99 // This function produces an HTTP response for the given
100 // request. The type of the response object depends on the
101 // contents of the request, so the interface requires the
102 // caller to pass a generic lambda for receiving the response.
104 class Body, class Allocator,
108 beast::string_view doc_root,
109 http::request<Body, http::basic_fields<Allocator>>&& req,
112 // Returns a bad request response
113 auto const bad_request =
114 [&req](beast::string_view why)
116 http::response<http::string_body> res{http::status::bad_request, req.version()};
117 res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
118 res.set(http::field::content_type, "text/html");
119 res.keep_alive(req.keep_alive());
120 res.body() = std::string(why);
121 res.prepare_payload();
125 // Returns a not found response
126 auto const not_found =
127 [&req](beast::string_view target)
129 http::response<http::string_body> res{http::status::not_found, req.version()};
130 res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
131 res.set(http::field::content_type, "text/html");
132 res.keep_alive(req.keep_alive());
133 res.body() = "The resource '" + std::string(target) + "' was not found.";
134 res.prepare_payload();
138 // Returns a server error response
139 auto const server_error =
140 [&req](beast::string_view what)
142 http::response<http::string_body> res{http::status::internal_server_error, req.version()};
143 res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
144 res.set(http::field::content_type, "text/html");
145 res.keep_alive(req.keep_alive());
146 res.body() = "An error occurred: '" + std::string(what) + "'";
147 res.prepare_payload();
151 // Make sure we can handle the method
152 if( req.method() != http::verb::get &&
153 req.method() != http::verb::head)
154 return send(bad_request("Unknown HTTP-method"));
156 // Request path must be absolute and not contain "..".
157 if( req.target().empty() ||
158 req.target()[0] != '/' ||
159 req.target().find("..") != beast::string_view::npos)
160 return send(bad_request("Illegal request-target"));
162 // Build the path to the requested file
163 std::string path = path_cat(doc_root, req.target());
164 if(req.target().back() == '/')
165 path.append("index.html");
167 // Attempt to open the file
168 beast::error_code ec;
169 http::file_body::value_type body;
170 body.open(path.c_str(), beast::file_mode::scan, ec);
172 // Handle the case where the file doesn't exist
173 if(ec == beast::errc::no_such_file_or_directory)
174 return send(not_found(req.target()));
176 // Handle an unknown error
178 return send(server_error(ec.message()));
180 // Cache the size since we need it after the move
181 auto const size = body.size();
183 // Respond to HEAD request
184 if(req.method() == http::verb::head)
186 http::response<http::empty_body> res{http::status::ok, req.version()};
187 res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
188 res.set(http::field::content_type, mime_type(path));
189 res.content_length(size);
190 res.keep_alive(req.keep_alive());
191 return send(std::move(res));
194 // Respond to GET request
195 http::response<http::file_body> res{
196 std::piecewise_construct,
197 std::make_tuple(std::move(body)),
198 std::make_tuple(http::status::ok, req.version())};
199 res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
200 res.set(http::field::content_type, mime_type(path));
201 res.content_length(size);
202 res.keep_alive(req.keep_alive());
203 return send(std::move(res));
206 //------------------------------------------------------------------------------
210 fail(beast::error_code ec, char const* what)
212 std::cerr << what << ": " << ec.message() << "\n";
215 // Handles an HTTP server connection
216 class session : public std::enable_shared_from_this<session>
218 // This is the C++11 equivalent of a generic lambda.
219 // The function object is used to send an HTTP message.
225 send_lambda(session& self)
230 template<bool isRequest, class Body, class Fields>
232 operator()(http::message<isRequest, Body, Fields>&& msg) const
234 // The lifetime of the message has to extend
235 // for the duration of the async operation so
236 // we use a shared_ptr to manage it.
237 auto sp = std::make_shared<
238 http::message<isRequest, Body, Fields>>(std::move(msg));
240 // Store a type-erased version of the shared
241 // pointer in the class to keep it alive.
244 // Write the response
248 beast::bind_front_handler(
250 self_.shared_from_this(),
255 beast::tcp_stream stream_;
256 beast::flat_buffer buffer_;
257 std::shared_ptr<std::string const> doc_root_;
258 http::request<http::string_body> req_;
259 std::shared_ptr<void> res_;
263 // Take ownership of the stream
265 tcp::socket&& socket,
266 std::shared_ptr<std::string const> const& doc_root)
267 : stream_(std::move(socket))
268 , doc_root_(doc_root)
273 // Start the asynchronous operation
277 // We need to be executing within a strand to perform async operations
278 // on the I/O objects in this session. Although not strictly necessary
279 // for single-threaded contexts, this example code is written to be
280 // thread-safe by default.
281 net::dispatch(stream_.get_executor(),
282 beast::bind_front_handler(
284 shared_from_this()));
290 // Make the request empty before reading,
291 // otherwise the operation behavior is undefined.
295 stream_.expires_after(std::chrono::seconds(30));
298 http::async_read(stream_, buffer_, req_,
299 beast::bind_front_handler(
301 shared_from_this()));
306 beast::error_code ec,
307 std::size_t bytes_transferred)
309 boost::ignore_unused(bytes_transferred);
311 // This means they closed the connection
312 if(ec == http::error::end_of_stream)
316 return fail(ec, "read");
319 handle_request(*doc_root_, std::move(req_), lambda_);
325 beast::error_code ec,
326 std::size_t bytes_transferred)
328 boost::ignore_unused(bytes_transferred);
331 return fail(ec, "write");
335 // This means we should close the connection, usually because
336 // the response indicated the "Connection: close" semantic.
340 // We're done with the response so delete it
343 // Read another request
350 // Send a TCP shutdown
351 beast::error_code ec;
352 stream_.socket().shutdown(tcp::socket::shutdown_send, ec);
354 // At this point the connection is closed gracefully
358 //------------------------------------------------------------------------------
360 // Accepts incoming connections and launches the sessions
361 class listener : public std::enable_shared_from_this<listener>
363 net::io_context& ioc_;
364 tcp::acceptor acceptor_;
365 std::shared_ptr<std::string const> doc_root_;
369 net::io_context& ioc,
370 tcp::endpoint endpoint,
371 std::shared_ptr<std::string const> const& doc_root)
373 , acceptor_(net::make_strand(ioc))
374 , doc_root_(doc_root)
376 beast::error_code ec;
379 acceptor_.open(endpoint.protocol(), ec);
386 // Allow address reuse
387 acceptor_.set_option(net::socket_base::reuse_address(true), ec);
390 fail(ec, "set_option");
394 // Bind to the server address
395 acceptor_.bind(endpoint, ec);
402 // Start listening for connections
404 net::socket_base::max_listen_connections, ec);
412 // Start accepting incoming connections
423 // The new connection gets its own strand
424 acceptor_.async_accept(
425 net::make_strand(ioc_),
426 beast::bind_front_handler(
427 &listener::on_accept,
428 shared_from_this()));
432 on_accept(beast::error_code ec, tcp::socket socket)
440 // Create the session and run it
441 std::make_shared<session>(
446 // Accept another connection
451 //------------------------------------------------------------------------------
453 int main(int argc, char* argv[])
455 // Check command line arguments.
459 "Usage: http-server-async <address> <port> <doc_root> <threads>\n" <<
461 " http-server-async 0.0.0.0 8080 . 1\n";
464 auto const address = net::ip::make_address(argv[1]);
465 auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
466 auto const doc_root = std::make_shared<std::string>(argv[3]);
467 auto const threads = std::max<int>(1, std::atoi(argv[4]));
469 // The io_context is required for all I/O
470 net::io_context ioc{threads};
472 // Create and launch a listening port
473 std::make_shared<listener>(
475 tcp::endpoint{address, port},
478 // Run the I/O service on the requested number of threads
479 std::vector<std::thread> v;
480 v.reserve(threads - 1);
481 for(auto i = threads - 1; i > 0; --i)