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Examples

s11n_example::connection Class Reference

Collaboration diagram for s11n_example::connection:

Collaboration graph

List of all members.


Detailed Description

The connection class provides serialization primitives on top of a socket.

Each message sent using this class consists of:

Definition at line 34 of file connection.hpp.


Public Member Functions

 connection (asio::io_service &io_service)
 Constructor.
asio::ip::tcp::socketsocket ()
 Get the underlying socket. Used for making a connection or for accepting an incoming connection.
template<typename T, typename Handler>
void async_write (const T &t, Handler handler)
 Asynchronously write a data structure to the socket.
template<typename T, typename Handler>
void async_read (T &t, Handler handler)
 Asynchronously read a data structure from the socket.
template<typename T, typename Handler>
void handle_read_header (const asio::error_code &e, T &t, boost::tuple< Handler > handler)
 Handle a completed read of a message header. The handler is passed using a tuple since boost::bind seems to have trouble binding a function object created using boost::bind as a parameter.
template<typename T, typename Handler>
void handle_read_data (const asio::error_code &e, T &t, boost::tuple< Handler > handler)
 Handle a completed read of message data.

Private Types

enum  { header_length = 8 }
 The size of a fixed length header. More...

Private Attributes

asio::ip::tcp::socket socket_
 The underlying socket.
std::string outbound_header_
 Holds an outbound header.
std::string outbound_data_
 Holds the outbound data.
char inbound_header_ [header_length]
 Holds an inbound header.
std::vector< char > inbound_data_
 Holds the inbound data.

Member Enumeration Documentation

anonymous enum [private]

The size of a fixed length header.

Enumerator:
header_length 

Definition at line 166 of file connection.hpp.

00169 { header_length = 8 };


Constructor & Destructor Documentation

s11n_example::connection::connection ( asio::io_service io_service  ) 

Constructor.

Definition at line 38 of file connection.hpp.

00039     : socket_(io_service)
00040   {
00041   }


Member Function Documentation

asio::ip::tcp::socket& s11n_example::connection::socket (  ) 

Get the underlying socket. Used for making a connection or for accepting an incoming connection.

Definition at line 44 of file connection.hpp.

Referenced by s11n_example::client::client(), and s11n_example::client::handle_connect().

00046   {
00047     return socket_;

template<typename T, typename Handler>
void s11n_example::connection::async_write ( const T &  t,
Handler  handler 
)

Asynchronously write a data structure to the socket.

Definition at line 51 of file connection.hpp.

00053   {
00054     // Serialize the data first so we know how large it is.
00055     std::ostringstream archive_stream;
00056     boost::archive::text_oarchive archive(archive_stream);
00057     archive << t;
00058     outbound_data_ = archive_stream.str();
00059 
00060     // Format the header.
00061     std::ostringstream header_stream;
00062     header_stream << std::setw(header_length)
00063       << std::hex << outbound_data_.size();
00064     if (!header_stream || header_stream.str().size() != header_length)
00065     {
00066       // Something went wrong, inform the caller.
00067       asio::error_code error(asio::error::invalid_argument);
00068       socket_.io_service().post(boost::bind(handler, error));
00069       return;
00070     }
00071     outbound_header_ = header_stream.str();
00072 
00073     // Write the serialized data to the socket. We use "gather-write" to send
00074     // both the header and the data in a single write operation.
00075     std::vector<asio::const_buffer> buffers;
00076     buffers.push_back(asio::buffer(outbound_header_));
00077     buffers.push_back(asio::buffer(outbound_data_));
00078     asio::async_write(socket_, buffers, handler);

template<typename T, typename Handler>
void s11n_example::connection::async_read ( T &  t,
Handler  handler 
)

Asynchronously read a data structure from the socket.

Definition at line 82 of file connection.hpp.

Referenced by s11n_example::client::handle_connect().

00084   {
00085     // Issue a read operation to read exactly the number of bytes in a header.
00086     void (connection::*f)(
00087         const asio::error_code&,
00088         T&, boost::tuple<Handler>)
00089       = &connection::handle_read_header<T, Handler>;
00090     asio::async_read(socket_, asio::buffer(inbound_header_),
00091         boost::bind(f,
00092           this, asio::placeholders::error, boost::ref(t),
00093           boost::make_tuple(handler)));

template<typename T, typename Handler>
void s11n_example::connection::handle_read_header ( const asio::error_code e,
T &  t,
boost::tuple< Handler >  handler 
)

Handle a completed read of a message header. The handler is passed using a tuple since boost::bind seems to have trouble binding a function object created using boost::bind as a parameter.

Definition at line 97 of file connection.hpp.

00102   {
00103     if (e)
00104     {
00105       boost::get<0>(handler)(e);
00106     }
00107     else
00108     {
00109       // Determine the length of the serialized data.
00110       std::istringstream is(std::string(inbound_header_, header_length));
00111       std::size_t inbound_data_size = 0;
00112       if (!(is >> std::hex >> inbound_data_size))
00113       {
00114         // Header doesn't seem to be valid. Inform the caller.
00115         asio::error_code error(asio::error::invalid_argument);
00116         boost::get<0>(handler)(error);
00117         return;
00118       }
00119 
00120       // Start an asynchronous call to receive the data.
00121       inbound_data_.resize(inbound_data_size);
00122       void (connection::*f)(
00123           const asio::error_code&,
00124           T&, boost::tuple<Handler>)
00125         = &connection::handle_read_data<T, Handler>;
00126       asio::async_read(socket_, asio::buffer(inbound_data_),
00127         boost::bind(f, this,

template<typename T, typename Handler>
void s11n_example::connection::handle_read_data ( const asio::error_code e,
T &  t,
boost::tuple< Handler >  handler 
)

Handle a completed read of message data.

Definition at line 131 of file connection.hpp.

00136   {
00137     if (e)
00138     {
00139       boost::get<0>(handler)(e);
00140     }
00141     else
00142     {
00143       // Extract the data structure from the data just received.
00144       try
00145       {
00146         std::string archive_data(&inbound_data_[0], inbound_data_.size());
00147         std::istringstream archive_stream(archive_data);
00148         boost::archive::text_iarchive archive(archive_stream);
00149         archive >> t;
00150       }
00151       catch (std::exception& e)
00152       {
00153         // Unable to decode data.
00154         asio::error_code error(asio::error::invalid_argument);
00155         boost::get<0>(handler)(error);
00156         return;
00157       }
00158 
00159       // Inform caller that data has been received ok.


Member Data Documentation

asio::ip::tcp::socket s11n_example::connection::socket_ [private]

The underlying socket.

Definition at line 163 of file connection.hpp.

Referenced by async_read(), and async_write().

std::string s11n_example::connection::outbound_header_ [private]

Holds an outbound header.

Definition at line 169 of file connection.hpp.

Referenced by async_write().

std::string s11n_example::connection::outbound_data_ [private]

Holds the outbound data.

Definition at line 172 of file connection.hpp.

Referenced by async_write().

char s11n_example::connection::inbound_header_[header_length] [private]

Holds an inbound header.

Definition at line 175 of file connection.hpp.

Referenced by async_read().

std::vector<char> s11n_example::connection::inbound_data_ [private]

Holds the inbound data.

Definition at line 178 of file connection.hpp.

Referenced by handle_read_data().


The documentation for this class was generated from the following file:
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