From: chris_at_[hidden]
Date: 2008-04-21 01:43:43
Author: chris_kohlhoff
Date: 2008-04-21 01:43:42 EDT (Mon, 21 Apr 2008)
New Revision: 44678
URL: http://svn.boost.org/trac/boost/changeset/44678
Log:
Add porthopper example to demonstrate applications that mix synchronous and
asynchronous operations.
Added:
trunk/libs/asio/example/porthopper/
trunk/libs/asio/example/porthopper/Jamfile (contents, props changed)
trunk/libs/asio/example/porthopper/Jamfile.v2 (contents, props changed)
trunk/libs/asio/example/porthopper/client.cpp (contents, props changed)
trunk/libs/asio/example/porthopper/protocol.hpp (contents, props changed)
trunk/libs/asio/example/porthopper/server.cpp (contents, props changed)
Added: trunk/libs/asio/example/porthopper/Jamfile
==============================================================================
--- (empty file)
+++ trunk/libs/asio/example/porthopper/Jamfile 2008-04-21 01:43:42 EDT (Mon, 21 Apr 2008)
@@ -0,0 +1,45 @@
+#
+# Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff 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)
+#
+
+subproject libs/asio/example/porthopper ;
+
+project boost : $(BOOST_ROOT) ;
+
+if $(UNIX)
+{
+ switch $(JAMUNAME)
+ {
+ case SunOS* :
+ {
+ SOCKET_LIBS = <find-library>socket <find-library>nsl ;
+ }
+ }
+}
+
+exe client
+ : <lib>@boost/libs/system/build/boost_system
+ client.cpp
+ : <include>$(BOOST_ROOT)
+ <include>../../../..
+ <define>BOOST_ALL_NO_LIB=1
+ <threading>multi
+ <mingw><*><find-library>ws2_32
+ <mingw><*><find-library>mswsock
+ $(SOCKET_LIBS)
+ ;
+
+exe server
+ : <lib>@boost/libs/system/build/boost_system
+ server.cpp
+ : <include>$(BOOST_ROOT)
+ <include>../../../..
+ <define>BOOST_ALL_NO_LIB=1
+ <threading>multi
+ <mingw><*><find-library>ws2_32
+ <mingw><*><find-library>mswsock
+ $(SOCKET_LIBS)
+ ;
Added: trunk/libs/asio/example/porthopper/Jamfile.v2
==============================================================================
--- (empty file)
+++ trunk/libs/asio/example/porthopper/Jamfile.v2 2008-04-21 01:43:42 EDT (Mon, 21 Apr 2008)
@@ -0,0 +1,41 @@
+#
+# Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff 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)
+#
+
+import os ;
+
+if [ os.name ] = SOLARIS
+{
+ lib socket ;
+ lib nsl ;
+}
+else if [ os.name ] = NT
+{
+ lib ws2_32 ;
+ lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+ lib ipv6 ;
+}
+
+project
+ : requirements
+ <library>/boost/system//boost_system
+ <define>BOOST_ALL_NO_LIB=1
+ <threading>multi
+ <os>SOLARIS:<library>socket
+ <os>SOLARIS:<library>nsl
+ <os>NT:<define>_WIN32_WINNT=0x0501
+ <os>NT,<toolset>gcc:<library>ws2_32
+ <os>NT,<toolset>gcc:<library>mswsock
+ <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+ <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+ <os>HPUX:<library>ipv6
+ ;
+
+exe client : client.cpp ;
+exe server : server.cpp ;
Added: trunk/libs/asio/example/porthopper/client.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/asio/example/porthopper/client.cpp 2008-04-21 01:43:42 EDT (Mon, 21 Apr 2008)
@@ -0,0 +1,183 @@
+#include <boost/asio.hpp>
+#include <boost/lambda/lambda.hpp>
+#include <boost/lambda/bind.hpp>
+#include <boost/lambda/if.hpp>
+#include <boost/shared_ptr.hpp>
+#include <algorithm>
+#include <cstdlib>
+#include <exception>
+#include <iostream>
+#include <string>
+#include "protocol.hpp"
+
+using namespace boost;
+using boost::asio::ip::tcp;
+using boost::asio::ip::udp;
+
+int main(int argc, char* argv[])
+{
+ try
+ {
+ if (argc != 3)
+ {
+ std::cerr << "Usage: client <host> <port>\n";
+ return 1;
+ }
+ using namespace std; // For atoi.
+ std::string host_name = argv[1];
+ std::string port = argv[2];
+
+ boost::asio::io_service io_service;
+
+ // Determine the location of the server.
+ tcp::resolver resolver(io_service);
+ tcp::resolver::query query(host_name, port);
+ tcp::endpoint remote_endpoint = *resolver.resolve(query);
+
+ // Establish the control connection to the server.
+ tcp::socket control_socket(io_service);
+ control_socket.connect(remote_endpoint);
+
+ // Create a datagram socket to receive data from the server.
+ shared_ptr<udp::socket> data_socket(
+ new udp::socket(io_service, udp::endpoint(udp::v4(), 0)));
+
+ // Determine what port we will receive data on.
+ udp::endpoint data_endpoint = data_socket->local_endpoint();
+
+ // Ask the server to start sending us data.
+ control_request start = control_request::start(data_endpoint.port());
+ boost::asio::write(control_socket, start.to_buffers());
+
+ unsigned long last_frame_number = 0;
+ for (;;)
+ {
+ // Receive 50 messages on the current data socket.
+ for (int i = 0; i < 50; ++i)
+ {
+ // Receive a frame from the server.
+ frame f;
+ data_socket->receive(f.to_buffers(), 0);
+ if (f.number() > last_frame_number)
+ {
+ last_frame_number = f.number();
+ std::cout << "\n" << f.payload();
+ }
+ }
+
+ // Time to switch to a new socket. To ensure seamless handover we will
+ // continue to receive packets using the old socket until data arrives on
+ // the new one.
+ std::cout << " Starting renegotiation";
+
+ // Create the new data socket.
+ shared_ptr<udp::socket> new_data_socket(
+ new udp::socket(io_service, udp::endpoint(udp::v4(), 0)));
+
+ // Determine the new port we will use to receive data.
+ udp::endpoint new_data_endpoint = new_data_socket->local_endpoint();
+
+ // Ask the server to switch over to the new port.
+ control_request change = control_request::change(
+ data_endpoint.port(), new_data_endpoint.port());
+ boost::system::error_code control_result;
+ boost::asio::async_write(control_socket, change.to_buffers(),
+ lambda::unlambda((
+ lambda::var(control_result) = lambda::_1
+ )));
+
+ // Try to receive a frame from the server on the new data socket. If we
+ // successfully receive a frame on this new data socket we can consider
+ // the renegotation complete. In that case we will close the old data
+ // socket, which will cause any outstanding receive operation on it to be
+ // cancelled.
+ frame f1;
+ boost::system::error_code new_data_socket_result;
+ new_data_socket->async_receive(f1.to_buffers(),
+ lambda::unlambda((
+ // Note: lambda::_1 is the first argument to the callback handler,
+ // which in this case is the error code for the operation.
+ lambda::var(new_data_socket_result) = lambda::_1,
+ lambda::if_(!lambda::_1)
+ [
+ // We have successfully received a frame on the new data socket,
+ // so we can close the old data socket. This will cancel any
+ // outstanding receive operation on the old data socket.
+ lambda::var(data_socket) = shared_ptr<udp::socket>()
+ ]
+ )));
+
+ // This loop will continue until we have successfully completed the
+ // renegotiation (i.e. received a frame on the new data socket), or some
+ // unrecoverable error occurs.
+ bool done = false;
+ while (!done)
+ {
+ // Even though we're performing a renegotation, we want to continue
+ // receiving data as smoothly as possible. Therefore we will continue to
+ // try to receive a frame from the server on the old data socket. If we
+ // receive a frame on this socket we will interrupt the io_service,
+ // print the frame, and resume waiting for the other operations to
+ // complete.
+ frame f2;
+ done = true; // Let's be optimistic.
+ if (data_socket) // Might have been closed by new_data_socket's handler.
+ {
+ data_socket->async_receive(f2.to_buffers(), 0,
+ lambda::unlambda((
+ lambda::if_(!lambda::_1)
+ [
+ // We have successfully received a frame on the old data
+ // socket. Stop the io_service so that we can print it.
+ lambda::bind(&boost::asio::io_service::stop, &io_service),
+ lambda::var(done) = false
+ ]
+ )));
+ }
+
+ // Run the operations in parallel. This will block until all operations
+ // have finished, or until the io_service is interrupted. (No threads!)
+ io_service.reset();
+ io_service.run();
+
+ // If the io_service.run() was interrupted then we have received a frame
+ // on the old data socket. We need to keep waiting for the renegotation
+ // operations to complete.
+ if (!done)
+ {
+ if (f2.number() > last_frame_number)
+ {
+ last_frame_number = f2.number();
+ std::cout << "\n" << f2.payload();
+ }
+ }
+ }
+
+ // Since the loop has finished, we have either successfully completed
+ // the renegotation, or an error has occurred. First we'll check for
+ // errors.
+ if (control_result)
+ throw boost::system::system_error(control_result);
+ if (new_data_socket_result)
+ throw boost::system::system_error(new_data_socket_result);
+
+ // If we get here it means we have successfully started receiving data on
+ // the new data socket. This new data socket will be used from now on
+ // (until the next time we renegotiate).
+ std::cout << " Renegotiation complete";
+ data_socket = new_data_socket;
+ data_endpoint = new_data_endpoint;
+ if (f1.number() > last_frame_number)
+ {
+ last_frame_number = f1.number();
+ std::cout << "\n" << f1.payload();
+ }
+ }
+ }
+ catch (std::exception& e)
+ {
+ std::cerr << "Exception: " << e.what() << std::endl;
+ }
+
+ return 0;
+}
Added: trunk/libs/asio/example/porthopper/protocol.hpp
==============================================================================
--- (empty file)
+++ trunk/libs/asio/example/porthopper/protocol.hpp 2008-04-21 01:43:42 EDT (Mon, 21 Apr 2008)
@@ -0,0 +1,145 @@
+#ifndef PORTHOPPER_PROTOCOL_HPP
+#define PORTHOPPER_PROTOCOL_HPP
+
+#include <boost/array.hpp>
+#include <boost/asio.hpp>
+#include <cstring>
+#include <iomanip>
+#include <string>
+#include <strstream>
+
+// This request is sent by the client to the server over a TCP connection.
+// The client uses it to perform three functions:
+// - To request that data start being sent to a given port.
+// - To request that data is no longer sent to a given port.
+// - To change the target port to another.
+class control_request
+{
+public:
+ // Construct an empty request. Used when receiving.
+ control_request()
+ {
+ }
+
+ // Create a request to start sending data to a given port.
+ static const control_request start(unsigned short port)
+ {
+ return control_request(0, port);
+ }
+
+ // Create a request to stop sending data to a given port.
+ static const control_request stop(unsigned short port)
+ {
+ return control_request(port, 0);
+ }
+
+ // Create a request to change the port that data is sent to.
+ static const control_request change(
+ unsigned short old_port, unsigned short new_port)
+ {
+ return control_request(old_port, new_port);
+ }
+
+ // Get the old port. Returns 0 for start requests.
+ unsigned short old_port() const
+ {
+ std::istrstream is(data_, encoded_port_size);
+ unsigned short port = 0;
+ is >> std::setw(encoded_port_size) >> std::hex >> port;
+ return port;
+ }
+
+ // Get the new port. Returns 0 for stop requests.
+ unsigned short new_port() const
+ {
+ std::istrstream is(data_ + encoded_port_size, encoded_port_size);
+ unsigned short port = 0;
+ is >> std::setw(encoded_port_size) >> std::hex >> port;
+ return port;
+ }
+
+ // Obtain buffers for reading from or writing to a socket.
+ boost::array<boost::asio::mutable_buffer, 1> to_buffers()
+ {
+ boost::array<boost::asio::mutable_buffer, 1> buffers
+ = { { boost::asio::buffer(data_) } };
+ return buffers;
+ }
+
+private:
+ // Construct with specified old and new ports.
+ control_request(unsigned short old_port, unsigned short new_port)
+ {
+ std::ostrstream os(data_, control_request_size);
+ os << std::setw(encoded_port_size) << std::hex << old_port;
+ os << std::setw(encoded_port_size) << std::hex << new_port;
+ }
+
+ // The length in bytes of a control_request and its components.
+ enum
+ {
+ encoded_port_size = 4, // 16-bit port in hex.
+ control_request_size = encoded_port_size * 2
+ };
+
+ // The encoded request data.
+ char data_[control_request_size];
+};
+
+// This frame is sent from the server to subscribed clients over UDP.
+class frame
+{
+public:
+ // The maximum allowable length of the payload.
+ enum { payload_size = 32 };
+
+ // Construct an empty frame. Used when receiving.
+ frame()
+ {
+ }
+
+ // Construct a frame with specified frame number and payload.
+ frame(unsigned long number, const std::string& payload)
+ {
+ std::ostrstream os(data_, frame_size);
+ os << std::setw(encoded_number_size) << std::hex << number;
+ os << std::setw(payload_size)
+ << std::setfill(' ') << payload.substr(0, payload_size);
+ }
+
+ // Get the frame number.
+ unsigned long number() const
+ {
+ std::istrstream is(data_, encoded_number_size);
+ unsigned long number = 0;
+ is >> std::setw(encoded_number_size) >> std::hex >> number;
+ return number;
+ }
+
+ // Get the payload data.
+ const std::string payload() const
+ {
+ return std::string(data_ + encoded_number_size, payload_size);
+ }
+
+ // Obtain buffers for reading from or writing to a socket.
+ boost::array<boost::asio::mutable_buffer, 1> to_buffers()
+ {
+ boost::array<boost::asio::mutable_buffer, 1> buffers
+ = { { boost::asio::buffer(data_) } };
+ return buffers;
+ }
+
+private:
+ // The length in bytes of a frame and its components.
+ enum
+ {
+ encoded_number_size = 8, // Frame number in hex.
+ frame_size = encoded_number_size + payload_size
+ };
+
+ // The encoded frame data.
+ char data_[frame_size];
+};
+
+#endif // PORTHOPPER_PROTOCOL_HPP
Added: trunk/libs/asio/example/porthopper/server.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/asio/example/porthopper/server.cpp 2008-04-21 01:43:42 EDT (Mon, 21 Apr 2008)
@@ -0,0 +1,177 @@
+#include <boost/asio.hpp>
+#include <boost/bind.hpp>
+#include <boost/shared_ptr.hpp>
+#include <cmath>
+#include <cstdlib>
+#include <exception>
+#include <iostream>
+#include <set>
+#include "protocol.hpp"
+
+using boost::asio::ip::tcp;
+using boost::asio::ip::udp;
+
+typedef boost::shared_ptr<tcp::socket> tcp_socket_ptr;
+typedef boost::shared_ptr<boost::asio::deadline_timer> timer_ptr;
+typedef boost::shared_ptr<control_request> control_request_ptr;
+
+class server
+{
+public:
+ // Construct the server to wait for incoming control connections.
+ server(boost::asio::io_service& io_service, unsigned short port)
+ : acceptor_(io_service, tcp::endpoint(tcp::v4(), port)),
+ timer_(io_service),
+ udp_socket_(io_service, udp::endpoint(udp::v4(), 0)),
+ next_frame_number_(1)
+ {
+ // Start waiting for a new control connection.
+ tcp_socket_ptr new_socket(new tcp::socket(acceptor_.get_io_service()));
+ acceptor_.async_accept(*new_socket,
+ boost::bind(&server::handle_accept, this,
+ boost::asio::placeholders::error, new_socket));
+
+ // Start the timer used to generate outgoing frames.
+ timer_.expires_from_now(boost::posix_time::milliseconds(100));
+ timer_.async_wait(boost::bind(&server::handle_timer, this));
+ }
+
+ // Handle a new control connection.
+ void handle_accept(const boost::system::error_code& ec, tcp_socket_ptr socket)
+ {
+ if (!ec)
+ {
+ // Start receiving control requests on the connection.
+ control_request_ptr request(new control_request);
+ boost::asio::async_read(*socket, request->to_buffers(),
+ boost::bind(&server::handle_control_request, this,
+ boost::asio::placeholders::error, socket, request));
+
+ // Start waiting for a new control connection.
+ tcp_socket_ptr new_socket(new tcp::socket(acceptor_.get_io_service()));
+ acceptor_.async_accept(*new_socket,
+ boost::bind(&server::handle_accept, this,
+ boost::asio::placeholders::error, new_socket));
+ }
+ }
+
+ // Handle a new control request.
+ void handle_control_request(const boost::system::error_code& ec,
+ tcp_socket_ptr socket, control_request_ptr request)
+ {
+ if (!ec)
+ {
+ // Delay handling of the control request to simulate network latency.
+ timer_ptr delay_timer(
+ new boost::asio::deadline_timer(acceptor_.get_io_service()));
+ delay_timer->expires_from_now(boost::posix_time::seconds(2));
+ delay_timer->async_wait(
+ boost::bind(&server::handle_control_request_timer, this,
+ socket, request, delay_timer));
+ }
+ }
+
+ void handle_control_request_timer(tcp_socket_ptr socket,
+ control_request_ptr request, timer_ptr delay_timer)
+ {
+ // Determine what address this client is connected from, since
+ // subscriptions must be stored on the server as a complete endpoint, not
+ // just a port. We use the non-throwing overload of remote_endpoint() since
+ // it may fail if the socket is no longer connected.
+ boost::system::error_code ec;
+ tcp::endpoint remote_endpoint = socket->remote_endpoint(ec);
+ if (!ec)
+ {
+ // Remove old port subscription, if any.
+ if (unsigned short old_port = request->old_port())
+ {
+ udp::endpoint old_endpoint(remote_endpoint.address(), old_port);
+ subscribers_.erase(old_endpoint);
+ std::cout << "Removing subscription " << old_endpoint << std::endl;
+ }
+
+ // Add new port subscription, if any.
+ if (unsigned short new_port = request->new_port())
+ {
+ udp::endpoint new_endpoint(remote_endpoint.address(), new_port);
+ subscribers_.insert(new_endpoint);
+ std::cout << "Adding subscription " << new_endpoint << std::endl;
+ }
+ }
+
+ // Wait for next control request on this connection.
+ boost::asio::async_read(*socket, request->to_buffers(),
+ boost::bind(&server::handle_control_request, this,
+ boost::asio::placeholders::error, socket, request));
+ }
+
+ // Every time the timer fires we will generate a new frame and send it to all
+ // subscribers.
+ void handle_timer()
+ {
+ // Generate payload.
+ double x = next_frame_number_ * 0.2;
+ double y = std::sin(x);
+ int char_index = static_cast<int>((y + 1.0) * (frame::payload_size / 2));
+ std::string payload;
+ for (int i = 0; i < frame::payload_size; ++i)
+ payload += (i == char_index ? '*' : '.');
+
+ // Create the frame to be sent to all subscribers.
+ frame f(next_frame_number_++, payload);
+
+ // Send frame to all subscribers. We can use synchronous calls here since
+ // UDP send operations typically do not block.
+ std::set<udp::endpoint>::iterator j;
+ for (j = subscribers_.begin(); j != subscribers_.end(); ++j)
+ {
+ boost::system::error_code ec;
+ udp_socket_.send_to(f.to_buffers(), *j, 0, ec);
+ }
+
+ // Wait for next timeout.
+ timer_.expires_from_now(boost::posix_time::milliseconds(100));
+ timer_.async_wait(boost::bind(&server::handle_timer, this));
+ }
+
+private:
+ // The acceptor used to accept incoming control connections.
+ tcp::acceptor acceptor_;
+
+ // The timer used for generating data.
+ boost::asio::deadline_timer timer_;
+
+ // The socket used to send data to subscribers.
+ udp::socket udp_socket_;
+
+ // The next frame number.
+ unsigned long next_frame_number_;
+
+ // The set of endpoints that are subscribed.
+ std::set<udp::endpoint> subscribers_;
+};
+
+int main(int argc, char* argv[])
+{
+ try
+ {
+ if (argc != 2)
+ {
+ std::cerr << "Usage: server <port>\n";
+ return 1;
+ }
+
+ boost::asio::io_service io_service;
+
+ using namespace std; // For atoi.
+ server s(io_service, atoi(argv[1]));
+
+ io_service.run();
+ }
+ catch (std::exception& e)
+ {
+ std::cerr << "Exception: " << e.what() << std::endl;
+ }
+
+ return 0;
+}