Refactor all examples:

fix #575, fix #604, fix #608, fix #634, fix #712

All examples are rewritten:

* Using Best Practices
* Mostly self-contained
* New examples to complete the feature matrix
* The server-framework example is removed

example/websocket/server/async-ssl/websocket_server_async_ssl.cpp

@@ -0,0 +1,273 @@
+//
+// 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
+//
+
+//------------------------------------------------------------------------------
+//
+// Example: WebSocket SSL server, asynchronous
+//
+//------------------------------------------------------------------------------
+
+#include "example/common/server_certificate.hpp"
+
+#include <boost/beast/core.hpp>
+#include <boost/beast/websocket.hpp>
+#include <boost/beast/websocket/ssl.hpp>
+#include <boost/asio/strand.hpp>
+#include <boost/asio/ip/tcp.hpp>
+#include <boost/asio/ssl/stream.hpp>
+#include <algorithm>
+#include <cstdlib>
+#include <functional>
+#include <iostream>
+#include <memory>
+#include <string>
+#include <thread>
+#include <vector>
+
+using tcp = boost::asio::ip::tcp;               // from <boost/asio/ip/tcp.hpp>
+namespace ssl = boost::asio::ssl;               // from <boost/asio/ssl.hpp>
+namespace websocket = boost::beast::websocket;  // from <boost/beast/websocket.hpp>
+
+//------------------------------------------------------------------------------
+
+// Report a failure
+void
+fail(boost::system::error_code ec, char const* what)
+{
+    std::cerr << what << ": " << ec.message() << "\n";
+}
+
+// Echoes back all received WebSocket messages
+class session : public std::enable_shared_from_this<session>
+{
+    tcp::socket socket_;
+    websocket::stream<ssl::stream<tcp::socket&>> ws_;
+    boost::asio::io_service::strand strand_;
+    boost::beast::multi_buffer buffer_;
+
+public:
+    // Take ownership of the socket
+    session(tcp::socket socket, ssl::context& ctx)
+        : socket_(std::move(socket))
+        , ws_(socket_, ctx)
+        , strand_(ws_.get_io_service())
+    {
+    }
+
+    // Start the asynchronous operation
+    void
+    run()
+    {
+        // Perform the SSL handshake
+        ws_.next_layer().async_handshake(
+            ssl::stream_base::server,
+            strand_.wrap(std::bind(
+                &session::on_handshake,
+                shared_from_this(),
+                std::placeholders::_1)));
+    }
+
+    void
+    on_handshake(boost::system::error_code ec)
+    {
+        if(ec)
+            return fail(ec, "handshake");
+
+        // Accept the websocket handshake
+        ws_.async_accept(
+            strand_.wrap(std::bind(
+                &session::on_accept,
+                shared_from_this(),
+                std::placeholders::_1)));
+    }
+
+    void
+    on_accept(boost::system::error_code ec)
+    {
+        if(ec)
+            return fail(ec, "accept");
+
+        // Read a message
+        do_read();
+    }
+
+    void
+    do_read()
+    {
+        // Read a message into our buffer
+        ws_.async_read(
+            buffer_,
+            strand_.wrap(std::bind(
+                &session::on_read,
+                shared_from_this(),
+                std::placeholders::_1)));
+    }
+
+    void
+    on_read(boost::system::error_code ec)
+    {
+        // This indicates that the session was closed
+        if(ec == websocket::error::closed)
+            return;
+
+        if(ec)
+            fail(ec, "read");
+
+        // Echo the message
+        ws_.text(ws_.got_text());
+        ws_.async_write(
+            buffer_.data(),
+            strand_.wrap(std::bind(
+                &session::on_write,
+                shared_from_this(),
+                std::placeholders::_1)));
+    }
+
+    void
+    on_write(boost::system::error_code ec)
+    {
+        if(ec)
+            return fail(ec, "write");
+
+        // Clear the buffer
+        buffer_.consume(buffer_.size());
+
+        // Do another read
+        do_read();
+    }
+};
+
+//------------------------------------------------------------------------------
+
+// Accepts incoming connections and launches the sessions
+class listener : public std::enable_shared_from_this<listener>
+{
+    ssl::context& ctx_;
+    boost::asio::io_service::strand strand_;
+    tcp::acceptor acceptor_;
+    tcp::socket socket_;
+
+public:
+    listener(
+        boost::asio::io_service& ios,
+        ssl::context& ctx,
+        tcp::endpoint endpoint)
+        : ctx_(ctx)
+        , strand_(ios)
+        , acceptor_(ios)
+        , socket_(ios)
+    {
+        boost::system::error_code ec;
+
+        // Open the acceptor
+        acceptor_.open(endpoint.protocol(), ec);
+        if(ec)
+        {
+            fail(ec, "open");
+            return;
+        }
+
+        // Bind to the server address
+        acceptor_.bind(endpoint, ec);
+        if(ec)
+        {
+            fail(ec, "bind");
+            return;
+        }
+
+        // Start listening for connections
+        acceptor_.listen(
+            boost::asio::socket_base::max_connections, ec);
+        if(ec)
+        {
+            fail(ec, "listen");
+            return;
+        }
+    }
+
+    // Start accepting incoming connections
+    void
+    run()
+    {
+        if(! acceptor_.is_open())
+            return;
+        do_accept();
+    }
+
+    void
+    do_accept()
+    {
+        acceptor_.async_accept(
+            socket_,
+            std::bind(
+                &listener::on_accept,
+                shared_from_this(),
+                std::placeholders::_1));
+    }
+
+    void
+    on_accept(boost::system::error_code ec)
+    {
+        if(ec)
+        {
+            fail(ec, "accept");
+        }
+        else
+        {
+            // Create the session and run it
+            std::make_shared<session>(std::move(socket_), ctx_)->run();
+        }
+
+        // Accept another connection
+        do_accept();
+    }
+};
+
+//------------------------------------------------------------------------------
+
+int main(int argc, char* argv[])
+{
+    // Check command line arguments.
+    if (argc != 4)
+    {
+        std::cerr <<
+            "Usage: websocket-server-async-ssl <address> <port> <threads>\n" <<
+            "Example:\n" <<
+            "    websocket-server-async-ssl 0.0.0.0 8080 1\n";
+        return EXIT_FAILURE;
+    }
+    auto const address = boost::asio::ip::address::from_string(argv[1]);
+    auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
+    auto const threads = std::max<std::size_t>(1, std::atoi(argv[3]));
+
+    // The io_service is required for all I/O
+    boost::asio::io_service ios{threads};
+    
+    // The SSL context is required, and holds certificates
+    ssl::context ctx{ssl::context::sslv23};
+
+    // This holds the self-signed certificate used by the server
+    load_server_certificate(ctx);
+
+    // Create and launch a listening port
+    std::make_shared<listener>(ios, ctx, tcp::endpoint{address, port})->run();
+
+    // Run the I/O service on the requested number of threads
+    std::vector<std::thread> v;
+    v.reserve(threads - 1);
+    for(auto i = threads - 1; i > 0; --i)
+        v.emplace_back(
+        [&ios]
+        {
+            ios.run();
+        });
+    ios.run();
+
+    return EXIT_SUCCESS;
+}