diff --git a/CHANGELOG.md b/CHANGELOG.md index 9a29059a..50720440 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -1,3 +1,18 @@ +Version 189: + +* Add CppCon2018 chat server example and video + +-------------------------------------------------------------------------------- + +Version 188: + +* Remove extraneous strand from example +* Add missing include in http/read.ipp +* Test for gcc warning bug +* Fix a spurious gcc warning + +-------------------------------------------------------------------------------- + Version 187: * Add experimental timeout_socket diff --git a/README.md b/README.md index d56ad696..23d5b620 100644 --- a/README.md +++ b/README.md @@ -43,11 +43,11 @@ This library is designed for: ## Appearances -| Bishop Fox 2018 | -| ------------ | -| Beast Security Review | +| CppCon 2018 | Bishop Fox 2018 | +| ------------ | ------------ | +| Beast | Beast Security Review | -| CppCon 2017 | CppCast 2017 | CppCon 2016 | +| CppCon 2017 | CppCast 2017 | CppCon 2016 | | ------------ | ------------ | ----------- | | Beast | Vinnie Falco | Beast | diff --git a/doc/qbk/02_examples.qbk b/doc/qbk/02_examples.qbk index 55363bd9..03eca696 100644 --- a/doc/qbk/02_examples.qbk +++ b/doc/qbk/02_examples.qbk @@ -201,6 +201,28 @@ and illustrate the implementation of advanced features. +[section CppCon 2018] + +This talk was given at [@https://cppcon.org CppCon 2018]. In this +presentation, we develop a multi-user chat server written in C++ using +Beast WebSocket, which uses a provided chat client written in HTML and +JavaScript. The source files for this example are located at +[source_file example/cppcon2018]. + + +[block''' + + + + + +'''] + +[endsect] + + + [section Common Files] Some of the examples use one or more shared header files, they are diff --git a/doc/qbk/06_websocket.qbk b/doc/qbk/06_websocket.qbk index a5413a8d..5d00e645 100644 --- a/doc/qbk/06_websocket.qbk +++ b/doc/qbk/06_websocket.qbk @@ -29,13 +29,13 @@ Boost.Asio with a consistent asynchronous model using a modern C++ approach. [ws_snippet_1] ] -[include 06_websocket/1_streams.qbk] -[include 06_websocket/2_connect.qbk] -[include 06_websocket/3_client.qbk] -[include 06_websocket/4_server.qbk] -[include 06_websocket/5_messages.qbk] -[include 06_websocket/6_control.qbk] -[include 06_websocket/7_teardown.qbk] -[include 06_websocket/8_notes.qbk] +[include 06_websocket/01_streams.qbk] +[include 06_websocket/02_connect.qbk] +[include 06_websocket/03_client.qbk] +[include 06_websocket/04_server.qbk] +[include 06_websocket/05_messages.qbk] +[include 06_websocket/06_control.qbk] +[include 06_websocket/07_teardown.qbk] +[include 06_websocket/08_notes.qbk] [endsect] diff --git a/doc/qbk/06_websocket/1_streams.qbk b/doc/qbk/06_websocket/01_streams.qbk similarity index 100% rename from doc/qbk/06_websocket/1_streams.qbk rename to doc/qbk/06_websocket/01_streams.qbk diff --git a/doc/qbk/06_websocket/2_connect.qbk b/doc/qbk/06_websocket/02_connect.qbk similarity index 100% rename from doc/qbk/06_websocket/2_connect.qbk rename to doc/qbk/06_websocket/02_connect.qbk diff --git a/doc/qbk/06_websocket/3_client.qbk b/doc/qbk/06_websocket/03_client.qbk similarity index 100% rename from doc/qbk/06_websocket/3_client.qbk rename to doc/qbk/06_websocket/03_client.qbk diff --git a/doc/qbk/06_websocket/4_server.qbk b/doc/qbk/06_websocket/04_server.qbk similarity index 100% rename from doc/qbk/06_websocket/4_server.qbk rename to doc/qbk/06_websocket/04_server.qbk diff --git a/doc/qbk/06_websocket/5_messages.qbk b/doc/qbk/06_websocket/05_messages.qbk similarity index 100% rename from doc/qbk/06_websocket/5_messages.qbk rename to doc/qbk/06_websocket/05_messages.qbk diff --git a/doc/qbk/06_websocket/6_control.qbk b/doc/qbk/06_websocket/06_control.qbk similarity index 100% rename from doc/qbk/06_websocket/6_control.qbk rename to doc/qbk/06_websocket/06_control.qbk diff --git a/doc/qbk/06_websocket/7_teardown.qbk b/doc/qbk/06_websocket/07_teardown.qbk similarity index 100% rename from doc/qbk/06_websocket/7_teardown.qbk rename to doc/qbk/06_websocket/07_teardown.qbk diff --git a/doc/qbk/06_websocket/8_notes.qbk b/doc/qbk/06_websocket/08_notes.qbk similarity index 100% rename from doc/qbk/06_websocket/8_notes.qbk rename to doc/qbk/06_websocket/08_notes.qbk diff --git a/doc/qbk/09_releases.qbk b/doc/qbk/09_releases.qbk index 0684b18e..8dbba163 100644 --- a/doc/qbk/09_releases.qbk +++ b/doc/qbk/09_releases.qbk @@ -9,14 +9,27 @@ [section Release Notes] - - [heading Boost 1.69] +[* New Videos] + +[block''' + + + + + +'''] + [* New Features] * ([issue 1133]) Add `BOOST_BEAST_USE_STD_STRING_VIEW` +[* Examples] + +* New WebSocket server and browser-based client: [source_file example/cppcon2018] + [*Fixes] * ([issue 1245]) Fix a rare case of incorrect UTF8 validation diff --git a/example/CMakeLists.txt b/example/CMakeLists.txt index 950c29db..c2704007 100644 --- a/example/CMakeLists.txt +++ b/example/CMakeLists.txt @@ -8,6 +8,7 @@ # add_subdirectory (advanced) +add_subdirectory (cppcon2018) add_subdirectory (http) add_subdirectory (websocket) diff --git a/example/Jamfile b/example/Jamfile index cccbfe4b..be63be5f 100644 --- a/example/Jamfile +++ b/example/Jamfile @@ -8,6 +8,7 @@ # build-project advanced ; +build-project cppcon2018 ; build-project http ; build-project websocket ; diff --git a/example/cppcon2018/CMakeLists.txt b/example/cppcon2018/CMakeLists.txt new file mode 100644 index 00000000..c4d938e8 --- /dev/null +++ b/example/cppcon2018/CMakeLists.txt @@ -0,0 +1,37 @@ +# +# Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com) +# +# Distributed under the Boost Software License, Version 1.0. (See accompanying +# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) +# +# Official repository: https://github.com/boostorg/beast +# + +GroupSources(include/boost/beast beast) +GroupSources(example/cppcon2018 "/") + +file (GLOB APP_FILES + beast.hpp + http_session.cpp + http_session.hpp + Jamfile + listener.cpp + listener.hpp + main.cpp + net.hpp + shared_state.cpp + shared_state.hpp + websocket_session.cpp + websocket_session.hpp + chat_client.html + README.md +) + +source_group ("" FILES ${APP_FILES}) + +add_executable (websocket-chat-server + ${APP_FILES} + ${BOOST_BEAST_FILES} +) + +set_property(TARGET websocket-chat-server PROPERTY FOLDER "example-cppcon2018") diff --git a/example/cppcon2018/Jamfile b/example/cppcon2018/Jamfile new file mode 100644 index 00000000..a22014e9 --- /dev/null +++ b/example/cppcon2018/Jamfile @@ -0,0 +1,19 @@ +# +# Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com) +# +# Distributed under the Boost Software License, Version 1.0. (See accompanying +# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) +# +# Official repository: https://github.com/boostorg/beast +# + +exe websocket-chat-server : + http_session.cpp + listener.cpp + main.cpp + shared_state.cpp + websocket_session.cpp + : + coverage:no + ubasan:no + ; diff --git a/example/cppcon2018/README.md b/example/cppcon2018/README.md new file mode 100644 index 00000000..4e62b87a --- /dev/null +++ b/example/cppcon2018/README.md @@ -0,0 +1,23 @@ +*This repository contains the presentation file and compiling +source code for the CppCon2018 talk.* + +# Get Rich Quick! Using Boost.Beast WebSockets and Networking TS + +Do you want to make a lot of money? You'll see some examples of free +browser and server based WebSocket programs which have earned their +respective individual authors tens of millions of dollars in no time +at all. Perhaps after seeing this talk in person, you'll write the +next massively successful WebSocket app! + +The WebSocket protocol powers the interactive web by enabling two-way +messaging between the browser and the web server. The Boost.Beast +library implements this protocol on top of the industry standard +Boost.Asio library which models the Networking Technical Specification +proposed for the ISO C++ Standard. + +This presentation introduces Networking TS concepts and algorithms, +how to read their requirements, and how to use them in your programs. +We will build from scratch a multi-user chat server in C++11 using +Beast, and the corresponding browser-based chat client in HTML and +JavaScript. No prior knowledge or understanding of Beast or Asio is +required, the talk is suited for everyone. diff --git a/example/cppcon2018/beast.hpp b/example/cppcon2018/beast.hpp new file mode 100644 index 00000000..d24e24a5 --- /dev/null +++ b/example/cppcon2018/beast.hpp @@ -0,0 +1,19 @@ +// +// Copyright (c) 2018 Vinnie Falco (vinnie dot falco at gmail dot com) +// +// Distributed under the Boost Software License, Version 1.0. (See accompanying +// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) +// +// Official repository: https://github.com/vinniefalco/CppCon2018 +// + +#ifndef CPPCON2018_BEAST_HPP +#define CPPCON2018_BEAST_HPP + +#include + +namespace beast = boost::beast; +namespace http = boost::beast::http; // from +namespace websocket = boost::beast::websocket; // from + +#endif diff --git a/example/cppcon2018/chat_client.html b/example/cppcon2018/chat_client.html new file mode 100644 index 00000000..3913a069 --- /dev/null +++ b/example/cppcon2018/chat_client.html @@ -0,0 +1,57 @@ + + + + + WebSocket Chat - CppCon2018 + + +

WebSocket Chat

+

Source code: https://github.com/vinniefalco/CppCon2018

+ + Server URI: + +
+ Your Name:
+ + 

+
+  

+    Message

+    
+    
+  

+  
+
+
diff --git a/example/cppcon2018/http_session.cpp b/example/cppcon2018/http_session.cpp
new file mode 100644
index 00000000..2c554b60
--- /dev/null
+++ b/example/cppcon2018/http_session.cpp
@@ -0,0 +1,349 @@
+//
+// Copyright (c) 2018 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/vinniefalco/CppCon2018
+//
+
+#include "http_session.hpp"
+#include "websocket_session.hpp"
+#include 
+#include 
+
+#define BOOST_NO_CXX14_GENERIC_LAMBDAS
+
+//------------------------------------------------------------------------------
+
+// Return a reasonable mime type based on the extension of a file.
+boost::beast::string_view
+mime_type(boost::beast::string_view path)
+{
+    using boost::beast::iequals;
+    auto const ext = [&path]
+    {
+        auto const pos = path.rfind(".");
+        if(pos == boost::beast::string_view::npos)
+            return boost::beast::string_view{};
+        return path.substr(pos);
+    }();
+    if(iequals(ext, ".htm"))  return "text/html";
+    if(iequals(ext, ".html")) return "text/html";
+    if(iequals(ext, ".php"))  return "text/html";
+    if(iequals(ext, ".css"))  return "text/css";
+    if(iequals(ext, ".txt"))  return "text/plain";
+    if(iequals(ext, ".js"))   return "application/javascript";
+    if(iequals(ext, ".json")) return "application/json";
+    if(iequals(ext, ".xml"))  return "application/xml";
+    if(iequals(ext, ".swf"))  return "application/x-shockwave-flash";
+    if(iequals(ext, ".flv"))  return "video/x-flv";
+    if(iequals(ext, ".png"))  return "image/png";
+    if(iequals(ext, ".jpe"))  return "image/jpeg";
+    if(iequals(ext, ".jpeg")) return "image/jpeg";
+    if(iequals(ext, ".jpg"))  return "image/jpeg";
+    if(iequals(ext, ".gif"))  return "image/gif";
+    if(iequals(ext, ".bmp"))  return "image/bmp";
+    if(iequals(ext, ".ico"))  return "image/vnd.microsoft.icon";
+    if(iequals(ext, ".tiff")) return "image/tiff";
+    if(iequals(ext, ".tif"))  return "image/tiff";
+    if(iequals(ext, ".svg"))  return "image/svg+xml";
+    if(iequals(ext, ".svgz")) return "image/svg+xml";
+    return "application/text";
+}
+
+// Append an HTTP rel-path to a local filesystem path.
+// The returned path is normalized for the platform.
+std::string
+path_cat(
+    boost::beast::string_view base,
+    boost::beast::string_view path)
+{
+    if(base.empty())
+        return path.to_string();
+    std::string result = base.to_string();
+#if BOOST_MSVC
+    char constexpr path_separator = '\\';
+    if(result.back() == path_separator)
+        result.resize(result.size() - 1);
+    result.append(path.data(), path.size());
+    for(auto& c : result)
+        if(c == '/')
+            c = path_separator;
+#else
+    char constexpr path_separator = '/';
+    if(result.back() == path_separator)
+        result.resize(result.size() - 1);
+    result.append(path.data(), path.size());
+#endif
+    return result;
+}
+
+// This function produces an HTTP response for the given
+// request. The type of the response object depends on the
+// contents of the request, so the interface requires the
+// caller to pass a generic lambda for receiving the response.
+template<
+    class Body, class Allocator,
+    class Send>
+void
+handle_request(
+    boost::beast::string_view doc_root,
+    http::request>&& req,
+    Send&& send)
+{
+    // Returns a bad request response
+    auto const bad_request =
+    [&req](boost::beast::string_view why)
+    {
+        http::response res{http::status::bad_request, req.version()};
+        res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
+        res.set(http::field::content_type, "text/html");
+        res.keep_alive(req.keep_alive());
+        res.body() = why.to_string();
+        res.prepare_payload();
+        return res;
+    };
+
+    // Returns a not found response
+    auto const not_found =
+    [&req](boost::beast::string_view target)
+    {
+        http::response res{http::status::not_found, req.version()};
+        res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
+        res.set(http::field::content_type, "text/html");
+        res.keep_alive(req.keep_alive());
+        res.body() = "The resource '" + target.to_string() + "' was not found.";
+        res.prepare_payload();
+        return res;
+    };
+
+    // Returns a server error response
+    auto const server_error =
+    [&req](boost::beast::string_view what)
+    {
+        http::response res{http::status::internal_server_error, req.version()};
+        res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
+        res.set(http::field::content_type, "text/html");
+        res.keep_alive(req.keep_alive());
+        res.body() = "An error occurred: '" + what.to_string() + "'";
+        res.prepare_payload();
+        return res;
+    };
+
+    // Make sure we can handle the method
+    if( req.method() != http::verb::get &&
+        req.method() != http::verb::head)
+        return send(bad_request("Unknown HTTP-method"));
+
+    // Request path must be absolute and not contain "..".
+    if( req.target().empty() ||
+        req.target()[0] != '/' ||
+        req.target().find("..") != boost::beast::string_view::npos)
+        return send(bad_request("Illegal request-target"));
+
+    // Build the path to the requested file
+    std::string path = path_cat(doc_root, req.target());
+    if(req.target().back() == '/')
+        path.append("index.html");
+
+    // Attempt to open the file
+    boost::beast::error_code ec;
+    http::file_body::value_type body;
+    body.open(path.c_str(), boost::beast::file_mode::scan, ec);
+
+    // Handle the case where the file doesn't exist
+    if(ec == boost::system::errc::no_such_file_or_directory)
+        return send(not_found(req.target()));
+
+    // Handle an unknown error
+    if(ec)
+        return send(server_error(ec.message()));
+
+    // Cache the size since we need it after the move
+    auto const size = body.size();
+
+    // Respond to HEAD request
+    if(req.method() == http::verb::head)
+    {
+        http::response res{http::status::ok, req.version()};
+        res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
+        res.set(http::field::content_type, mime_type(path));
+        res.content_length(size);
+        res.keep_alive(req.keep_alive());
+        return send(std::move(res));
+    }
+
+    // Respond to GET request
+    http::response res{
+        std::piecewise_construct,
+        std::make_tuple(std::move(body)),
+        std::make_tuple(http::status::ok, req.version())};
+    res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
+    res.set(http::field::content_type, mime_type(path));
+    res.content_length(size);
+    res.keep_alive(req.keep_alive());
+    return send(std::move(res));
+}
+
+//------------------------------------------------------------------------------
+
+http_session::
+http_session(
+    tcp::socket socket,
+    std::shared_ptr const& state)
+    : socket_(std::move(socket))
+    , state_(state)
+{
+}
+
+void
+http_session::
+run()
+{
+    // Read a request
+    http::async_read(socket_, buffer_, req_,
+        [self = shared_from_this()]
+            (error_code ec, std::size_t bytes)
+        {
+            self->on_read(ec, bytes);
+        });
+}
+
+// Report a failure
+void
+http_session::
+fail(error_code ec, char const* what)
+{
+    // Don't report on canceled operations
+    if(ec == net::error::operation_aborted)
+        return;
+
+    std::cerr << what << ": " << ec.message() << "\n";
+}
+
+template
+void
+http_session::
+send_lambda::
+operator()(http::message&& msg) const
+{
+    // The lifetime of the message has to extend
+    // for the duration of the async operation so
+    // we use a shared_ptr to manage it.
+    auto sp = std::make_shared<
+        http::message>(std::move(msg));
+
+    // Write the response
+    auto self = self_.shared_from_this();
+    http::async_write(
+        self_.socket_,
+        *sp,
+        [self, sp](error_code ec, std::size_t bytes)
+        {
+            self->on_write(ec, bytes, sp->need_eof());
+        });
+}
+
+void
+http_session::
+on_read(error_code ec, std::size_t)
+{
+    // This means they closed the connection
+    if(ec == http::error::end_of_stream)
+    {
+        socket_.shutdown(tcp::socket::shutdown_send, ec);
+        return;
+    }
+
+    // Handle the error, if any
+    if(ec)
+        return fail(ec, "read");
+
+    // See if it is a WebSocket Upgrade
+    if(websocket::is_upgrade(req_))
+    {
+        // Create a WebSocket session by transferring the socket
+        std::make_shared(
+            std::move(socket_), state_)->run(std::move(req_));
+        return;
+    }
+
+    // Send the response
+#ifndef BOOST_NO_CXX14_GENERIC_LAMBDAS
+    //
+    // The following code requires generic
+    // lambdas, available in C++14 and later.
+    //
+    handle_request(
+        state_->doc_root(),
+        std::move(req_),
+        [this](auto&& response)
+        {
+            // The lifetime of the message has to extend
+            // for the duration of the async operation so
+            // we use a shared_ptr to manage it.
+            using response_type = typename std::decay::type;
+            auto sp = std::make_shared(std::forward(response));
+
+        #if 0
+            // NOTE This causes an ICE in gcc 7.3
+            // Write the response
+            http::async_write(this->socket_, *sp,
+				[self = shared_from_this(), sp](
+					error_code ec, std::size_t bytes)
+				{
+					self->on_write(ec, bytes, sp->need_eof()); 
+				});
+        #else
+            // Write the response
+            auto self = shared_from_this();
+            http::async_write(this->socket_, *sp,
+				[self, sp](
+					error_code ec, std::size_t bytes)
+				{
+					self->on_write(ec, bytes, sp->need_eof()); 
+				});
+        #endif
+        });
+#else
+    //
+    // This code uses the function object type send_lambda in
+    // place of a generic lambda which is not available in C++11
+    //
+    handle_request(
+        state_->doc_root(),
+        std::move(req_),
+        send_lambda(*this));
+
+#endif
+}
+
+void
+http_session::
+on_write(error_code ec, std::size_t, bool close)
+{
+    // Handle the error, if any
+    if(ec)
+        return fail(ec, "write");
+
+    if(close)
+    {
+        // This means we should close the connection, usually because
+        // the response indicated the "Connection: close" semantic.
+        socket_.shutdown(tcp::socket::shutdown_send, ec);
+        return;
+    }
+
+    // Clear contents of the request message,
+    // otherwise the read behavior is undefined.
+    req_ = {};
+
+    // Read another request
+    http::async_read(socket_, buffer_, req_,
+        [self = shared_from_this()]
+            (error_code ec, std::size_t bytes)
+        {
+            self->on_read(ec, bytes);
+        });
+}
diff --git a/example/cppcon2018/http_session.hpp b/example/cppcon2018/http_session.hpp
new file mode 100644
index 00000000..530d2fa8
--- /dev/null
+++ b/example/cppcon2018/http_session.hpp
@@ -0,0 +1,56 @@
+//
+// Copyright (c) 2018 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/vinniefalco/CppCon2018
+//
+
+#ifndef CPPCON2018_HTTP_SESSION_HPP
+#define CPPCON2018_HTTP_SESSION_HPP
+
+#include "net.hpp"
+#include "beast.hpp"
+#include "shared_state.hpp"
+#include 
+#include 
+
+/** Represents an established HTTP connection
+*/
+class http_session : public std::enable_shared_from_this
+{
+    tcp::socket socket_;
+    beast::flat_buffer buffer_;
+    std::shared_ptr state_;
+    http::request req_;
+
+    struct send_lambda
+    {
+        http_session& self_;
+
+        explicit
+        send_lambda(http_session& self)
+            : self_(self)
+        {
+        }
+
+        template
+        void
+        operator()(http::message&& msg) const;
+    };
+
+    void fail(error_code ec, char const* what);
+    void on_read(error_code ec, std::size_t);
+    void on_write(
+        error_code ec, std::size_t, bool close);
+
+public:
+    http_session(
+        tcp::socket socket,
+        std::shared_ptr const& state);
+
+    void run();
+};
+
+#endif
diff --git a/example/cppcon2018/listener.cpp b/example/cppcon2018/listener.cpp
new file mode 100644
index 00000000..a6087260
--- /dev/null
+++ b/example/cppcon2018/listener.cpp
@@ -0,0 +1,103 @@
+//
+// Copyright (c) 2018 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/vinniefalco/CppCon2018
+//
+
+#include "listener.hpp"
+#include "http_session.hpp"
+#include 
+
+listener::
+listener(
+    net::io_context& ioc,
+    tcp::endpoint endpoint,
+    std::shared_ptr const& state)
+    : acceptor_(ioc)
+    , socket_(ioc)
+    , state_(state)
+{
+    error_code ec;
+
+    // Open the acceptor
+    acceptor_.open(endpoint.protocol(), ec);
+    if(ec)
+    {
+        fail(ec, "open");
+        return;
+    }
+
+    // Allow address reuse
+    acceptor_.set_option(net::socket_base::reuse_address(true));
+    if(ec)
+    {
+        fail(ec, "set_option");
+        return;
+    }
+
+    // Bind to the server address
+    acceptor_.bind(endpoint, ec);
+    if(ec)
+    {
+        fail(ec, "bind");
+        return;
+    }
+
+    // Start listening for connections
+    acceptor_.listen(
+        net::socket_base::max_listen_connections, ec);
+    if(ec)
+    {
+        fail(ec, "listen");
+        return;
+    }
+}
+
+void
+listener::
+run()
+{
+    // Start accepting a connection
+    acceptor_.async_accept(
+        socket_,
+        [self = shared_from_this()](error_code ec)
+        {
+            self->on_accept(ec);
+        });
+}
+
+// Report a failure
+void
+listener::
+fail(error_code ec, char const* what)
+{
+    // Don't report on canceled operations
+    if(ec == net::error::operation_aborted)
+        return;
+    std::cerr << what << ": " << ec.message() << "\n";
+}
+
+// Handle a connection
+void
+listener::
+on_accept(error_code ec)
+{
+    if(ec)
+        return fail(ec, "accept");
+    else
+        // Launch a new session for this connection
+        std::make_shared(
+            std::move(socket_),
+            state_)->run();
+
+    // Accept another connection
+    acceptor_.async_accept(
+        socket_,
+        [self = shared_from_this()](error_code ec)
+        {
+            self->on_accept(ec);
+        });
+}
diff --git a/example/cppcon2018/listener.hpp b/example/cppcon2018/listener.hpp
new file mode 100644
index 00000000..3ee1a898
--- /dev/null
+++ b/example/cppcon2018/listener.hpp
@@ -0,0 +1,40 @@
+//
+// Copyright (c) 2018 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/vinniefalco/CppCon2018
+//
+
+#ifndef CPPCON2018_LISTENER_HPP
+#define CPPCON2018_LISTENER_HPP
+
+#include "net.hpp"
+#include 
+#include 
+
+// Forward declaration
+class shared_state;
+
+// Accepts incoming connections and launches the sessions
+class listener : public std::enable_shared_from_this
+{
+    tcp::acceptor acceptor_;
+    tcp::socket socket_;
+    std::shared_ptr state_;
+
+    void fail(error_code ec, char const* what);
+    void on_accept(error_code ec);
+
+public:
+    listener(
+        net::io_context& ioc,
+        tcp::endpoint endpoint,
+        std::shared_ptr const& state);
+
+    // Start accepting incoming connections
+    void run();
+};
+
+#endif
diff --git a/example/cppcon2018/main.cpp b/example/cppcon2018/main.cpp
new file mode 100644
index 00000000..79c4d9de
--- /dev/null
+++ b/example/cppcon2018/main.cpp
@@ -0,0 +1,65 @@
+//
+// Copyright (c) 2018 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/vinniefalco/CppCon2018
+//
+
+//------------------------------------------------------------------------------
+/*
+    WebSocket chat server
+
+    This implements a multi-user chat room using WebSocket.
+*/
+//------------------------------------------------------------------------------
+
+#include "listener.hpp"
+#include "shared_state.hpp"
+#include 
+#include 
+
+int
+main(int argc, char* argv[])
+{
+    // Check command line arguments.
+    if (argc != 4)
+    {
+        std::cerr <<
+            "Usage: websocket-chat-server 
  \n" <<
+            "Example:\n" <<
+            "    websocket-chat-server 0.0.0.0 8080 .\n";
+        return EXIT_FAILURE;
+    }
+    auto address = net::ip::make_address(argv[1]);
+    auto port = static_cast(std::atoi(argv[2]));
+    auto doc_root = argv[3];
+
+    // The io_context is required for all I/O
+    net::io_context ioc;
+
+    // Create and launch a listening port
+    std::make_shared(
+        ioc,
+        tcp::endpoint{address, port},
+        std::make_shared(doc_root))->run();
+
+    // Capture SIGINT and SIGTERM to perform a clean shutdown
+    net::signal_set signals(ioc, SIGINT, SIGTERM);
+    signals.async_wait(
+        [&ioc](boost::system::error_code const&, int)
+        {
+            // Stop the io_context. This will cause run()
+            // to return immediately, eventually destroying the
+            // io_context and any remaining handlers in it.
+            ioc.stop();
+        });
+
+    // Run the I/O service on the main thread
+    ioc.run();
+
+    // (If we get here, it means we got a SIGINT or SIGTERM)
+
+    return EXIT_SUCCESS;
+}
diff --git a/example/cppcon2018/net.hpp b/example/cppcon2018/net.hpp
new file mode 100644
index 00000000..4c925d05
--- /dev/null
+++ b/example/cppcon2018/net.hpp
@@ -0,0 +1,19 @@
+//
+// Copyright (c) 2018 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/vinniefalco/CppCon2018
+//
+
+#ifndef CPPCON2018_ASIO_HPP
+#define CPPCON2018_ASIO_HPP
+
+#include 
+
+namespace net = boost::asio;                    // namespace asio
+using tcp = net::ip::tcp;                       // from 
+using error_code = boost::system::error_code;   // from 
+
+#endif
diff --git a/example/cppcon2018/shared_state.cpp b/example/cppcon2018/shared_state.cpp
new file mode 100644
index 00000000..a31d0e1a
--- /dev/null
+++ b/example/cppcon2018/shared_state.cpp
@@ -0,0 +1,41 @@
+//
+// Copyright (c) 2018 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/vinniefalco/CppCon2018
+//
+
+#include "shared_state.hpp"
+#include "websocket_session.hpp"
+
+shared_state::
+shared_state(std::string doc_root)
+    : doc_root_(std::move(doc_root))
+{
+}
+
+void
+shared_state::
+join(websocket_session& session)
+{
+    sessions_.insert(&session);
+}
+
+void
+shared_state::
+leave(websocket_session& session)
+{
+    sessions_.erase(&session);
+}
+
+void
+shared_state::
+send(std::string message)
+{
+    auto const ss = std::make_shared(std::move(message));
+
+    for(auto session : sessions_)
+        session->send(ss);
+}
diff --git a/example/cppcon2018/shared_state.hpp b/example/cppcon2018/shared_state.hpp
new file mode 100644
index 00000000..b00bf11a
--- /dev/null
+++ b/example/cppcon2018/shared_state.hpp
@@ -0,0 +1,45 @@
+//
+// Copyright (c) 2018 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/vinniefalco/CppCon2018
+//
+
+#ifndef CPPCON2018_SHARED_STATE_HPP
+#define CPPCON2018_SHARED_STATE_HPP
+
+#include 
+#include 
+#include 
+
+// Forward declaration
+class websocket_session;
+
+// Represents the shared server state
+class shared_state
+{
+    std::string doc_root_;
+
+    // This simple method of tracking
+    // sessions only works with an implicit
+    // strand (i.e. a single-threaded server)
+    std::unordered_set sessions_;
+
+public:
+    explicit
+    shared_state(std::string doc_root);
+
+    std::string const&
+    doc_root() const noexcept
+    {
+        return doc_root_;
+    }
+
+    void join  (websocket_session& session);
+    void leave (websocket_session& session);
+    void send  (std::string message);
+};
+
+#endif
diff --git a/example/cppcon2018/websocket_session.cpp b/example/cppcon2018/websocket_session.cpp
new file mode 100644
index 00000000..e87cee58
--- /dev/null
+++ b/example/cppcon2018/websocket_session.cpp
@@ -0,0 +1,126 @@
+//
+// Copyright (c) 2018 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/vinniefalco/CppCon2018
+//
+
+#include "websocket_session.hpp"
+
+websocket_session::
+websocket_session(
+    tcp::socket socket,
+    std::shared_ptr const& state)
+    : ws_(std::move(socket))
+    , state_(state)
+{
+}
+
+websocket_session::
+~websocket_session()
+{
+    // Remove this session from the list of active sessions
+    state_->leave(*this);
+}
+
+void
+websocket_session::
+fail(error_code ec, char const* what)
+{
+    // Don't report these
+    if( ec == net::error::operation_aborted ||
+        ec == websocket::error::closed)
+        return;
+
+    std::cerr << what << ": " << ec.message() << "\n";
+}
+
+void
+websocket_session::
+on_accept(error_code ec)
+{
+    // Handle the error, if any
+    if(ec)
+        return fail(ec, "accept");
+
+    // Add this session to the list of active sessions
+    state_->join(*this);
+
+    // Read a message
+    ws_.async_read(
+        buffer_,
+        [sp = shared_from_this()](
+            error_code ec, std::size_t bytes)
+        {
+            sp->on_read(ec, bytes);
+        });
+}
+
+void
+websocket_session::
+on_read(error_code ec, std::size_t)
+{
+    // Handle the error, if any
+    if(ec)
+        return fail(ec, "read");
+
+    // Send to all connections
+    state_->send(beast::buffers_to_string(buffer_.data()));
+
+    // Clear the buffer
+    buffer_.consume(buffer_.size());
+
+    // Read another message
+    ws_.async_read(
+        buffer_,
+        [sp = shared_from_this()](
+            error_code ec, std::size_t bytes)
+        {
+            sp->on_read(ec, bytes);
+        });
+}
+
+void
+websocket_session::
+send(std::shared_ptr const& ss)
+{
+    // Always add to queue
+    queue_.push_back(ss);
+
+    // Are we already writing?
+    if(queue_.size() > 1)
+        return;
+
+    // We are not currently writing, so send this immediately
+    ws_.async_write(
+        net::buffer(*queue_.front()),
+        [sp = shared_from_this()](
+            error_code ec, std::size_t bytes)
+        {
+            sp->on_write(ec, bytes);
+        });
+}
+
+void
+websocket_session::
+on_write(error_code ec, std::size_t)
+{
+    // Handle the error, if any
+    if(ec)
+        return fail(ec, "write");
+
+    // Remove the string from the queue
+    queue_.erase(queue_.begin());
+
+    // Send the next message if any
+    if(! queue_.empty())
+        ws_.async_write(
+            net::buffer(*queue_.front()),
+            [sp = shared_from_this()](
+                error_code ec, std::size_t bytes)
+            {
+                sp->on_write(ec, bytes);
+            });
+}
diff --git a/example/cppcon2018/websocket_session.hpp b/example/cppcon2018/websocket_session.hpp
new file mode 100644
index 00000000..a8cd5be9
--- /dev/null
+++ b/example/cppcon2018/websocket_session.hpp
@@ -0,0 +1,69 @@
+//
+// Copyright (c) 2018 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/vinniefalco/CppCon2018
+//
+
+#ifndef CPPCON2018_WEBSOCKET_SESSION_HPP
+#define CPPCON2018_WEBSOCKET_SESSION_HPP
+
+#include "net.hpp"
+#include "beast.hpp"
+#include "shared_state.hpp"
+
+#include 
+#include 
+#include 
+#include 
+
+// Forward declaration
+class shared_state;
+
+/** Represents an active WebSocket connection to the server
+*/
+class websocket_session : public std::enable_shared_from_this
+{
+    beast::flat_buffer buffer_;
+    websocket::stream ws_;
+    std::shared_ptr state_;
+    std::vector> queue_;
+
+    void fail(error_code ec, char const* what);
+    void on_accept(error_code ec);
+    void on_read(error_code ec, std::size_t bytes_transferred);
+    void on_write(error_code ec, std::size_t bytes_transferred);
+
+public:
+    websocket_session(
+        tcp::socket socket,
+        std::shared_ptr const& state);
+
+    ~websocket_session();
+
+    template
+    void
+    run(http::request> req);
+
+    // Send a message
+    void
+    send(std::shared_ptr const& ss);
+};
+
+template
+void
+websocket_session::
+run(http::request> req)
+{
+    // Accept the websocket handshake
+    ws_.async_accept(
+        req,
+        std::bind(
+            &websocket_session::on_accept,
+            shared_from_this(),
+            std::placeholders::_1));
+}
+
+#endif