WSJT-X/MessageClient.cpp
Bill Somerville b74788ea89 Implement schema negotiation for the UDP protocol
The MessageClient and MessageServer classes now agree a maximum common
schema number  for the protocol described  in NetworkMessage.hpp. this
is achieved by  the client sending a Heartbeat  message specifying the
highest  schema number  supported, the  server responds  with messages
using  the minimum  of its  highest  supported schema  number and  the
highest  schema number  sent by  the client  in its  initial Heartbeat
message.   This  mechanism  enables  clients and  servers  built  with
different  generations  of the  message  schema  to interoperate  with
minimum loss of functionality.

It should  be noted that messages  may be extended with  new fields on
the  end of  the current  definition  so long  as the  meaning of  the
original fields  are unchanged.  Such  an extension does not  need the
schema number  to be  incremented. On  the other  hand, using  a newer
version  of  the  underlying  Qt  QDataStream::Version  should  always
increment  the schema  number  since  the NetworkMessage::Builder  and
NetworkMessage::Reader classes need to know which QDataStream::Version
to use.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@5991 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2015-10-21 18:56:29 +00:00

384 lines
10 KiB
C++

#include "MessageClient.hpp"
#include <stdexcept>
#include <QUdpSocket>
#include <QHostInfo>
#include <QTimer>
#include <QQueue>
#include <QByteArray>
#include <QHostAddress>
#include "NetworkMessage.hpp"
#include "pimpl_impl.hpp"
#include "moc_MessageClient.cpp"
class MessageClient::impl
: public QUdpSocket
{
Q_OBJECT;
public:
impl (QString const& id, port_type server_port, MessageClient * self)
: self_ {self}
, id_ {id}
, server_port_ {server_port}
, schema_ {2} // use 2 prior to negotiation not 1 which is broken
, heartbeat_timer_ {new QTimer {this}}
{
connect (heartbeat_timer_, &QTimer::timeout, this, &impl::heartbeat);
connect (this, &QIODevice::readyRead, this, &impl::pending_datagrams);
heartbeat_timer_->start (NetworkMessage::pulse * 1000);
// bind to an ephemeral port
bind ();
}
~impl ()
{
closedown ();
}
enum StreamStatus {Fail, Short, OK};
void parse_message (QByteArray const& msg);
void pending_datagrams ();
void heartbeat ();
void closedown ();
StreamStatus check_status (QDataStream const&) const;
void send_message (QByteArray const&);
Q_SLOT void host_info_results (QHostInfo);
MessageClient * self_;
QString id_;
QString server_string_;
port_type server_port_;
QHostAddress server_;
quint32 schema_;
QTimer * heartbeat_timer_;
// hold messages sent before host lookup completes asynchronously
QQueue<QByteArray> pending_messages_;
};
#include "MessageClient.moc"
void MessageClient::impl::host_info_results (QHostInfo host_info)
{
if (QHostInfo::NoError != host_info.error ())
{
Q_EMIT self_->error ("UDP server lookup failed:\n" + host_info.errorString ());
pending_messages_.clear (); // discard
}
else if (host_info.addresses ().size ())
{
server_ = host_info.addresses ()[0];
// send initial heartbeat which allows schema negotiation
heartbeat ();
// clear any backlog
while (pending_messages_.size ())
{
send_message (pending_messages_.dequeue ());
}
}
}
void MessageClient::impl::pending_datagrams ()
{
while (hasPendingDatagrams ())
{
QByteArray datagram;
datagram.resize (pendingDatagramSize ());
QHostAddress sender_address;
port_type sender_port;
if (0 <= readDatagram (datagram.data (), datagram.size (), &sender_address, &sender_port))
{
parse_message (datagram);
}
}
}
void MessageClient::impl::parse_message (QByteArray const& msg)
{
try
{
//
// message format is described in NetworkMessage.hpp
//
NetworkMessage::Reader in {msg};
if (OK == check_status (in) && id_ == in.id ()) // OK and for us
{
if (schema_ < in.schema ()) // one time record of server's
// negotiated schema
{
schema_ = in.schema ();
}
//
// message format is described in NetworkMessage.hpp
//
switch (in.type ())
{
case NetworkMessage::Reply:
{
// unpack message
QTime time;
qint32 snr;
float delta_time;
quint32 delta_frequency;
QByteArray mode;
QByteArray message;
in >> time >> snr >> delta_time >> delta_frequency >> mode >> message;
if (check_status (in) != Fail)
{
Q_EMIT self_->reply (time, snr, delta_time, delta_frequency
, QString::fromUtf8 (mode), QString::fromUtf8 (message));
}
}
break;
case NetworkMessage::Replay:
if (check_status (in) != Fail)
{
Q_EMIT self_->replay ();
}
break;
case NetworkMessage::HaltTx:
{
bool auto_only {false};
in >> auto_only;
if (check_status (in) != Fail)
{
Q_EMIT self_->halt_tx (auto_only);
}
}
break;
case NetworkMessage::FreeText:
{
QByteArray message;
bool send {true};
in >> message >> send;
if (check_status (in) != Fail)
{
Q_EMIT self_->free_text (QString::fromUtf8 (message), send);
}
}
break;
default:
// Ignore
break;
}
}
}
catch (std::exception const& e)
{
Q_EMIT self_->error (QString {"MessageClient exception: %1"}.arg (e.what ()));
}
catch (...)
{
Q_EMIT self_->error ("Unexpected exception in MessageClient");
}
}
void MessageClient::impl::heartbeat ()
{
if (server_port_ && !server_.isNull ())
{
QByteArray message;
NetworkMessage::Builder hb {&message, NetworkMessage::Heartbeat, id_, schema_};
hb << NetworkMessage::Builder::schema_number; // maximum schema number accepted
if (OK == check_status (hb))
{
writeDatagram (message, server_, server_port_);
}
}
}
void MessageClient::impl::closedown ()
{
if (server_port_ && !server_.isNull ())
{
QByteArray message;
NetworkMessage::Builder out {&message, NetworkMessage::Close, id_, schema_};
if (OK == check_status (out))
{
writeDatagram (message, server_, server_port_);
}
}
}
void MessageClient::impl::send_message (QByteArray const& message)
{
if (server_port_)
{
if (!server_.isNull ())
{
writeDatagram (message, server_, server_port_);
}
else
{
pending_messages_.enqueue (message);
}
}
}
auto MessageClient::impl::check_status (QDataStream const& stream) const -> StreamStatus
{
auto stat = stream.status ();
StreamStatus result {Fail};
switch (stat)
{
case QDataStream::ReadPastEnd:
result = Short;
break;
case QDataStream::ReadCorruptData:
Q_EMIT self_->error ("Message serialization error: read corrupt data");
break;
case QDataStream::WriteFailed:
Q_EMIT self_->error ("Message serialization error: write error");
break;
default:
result = OK;
break;
}
return result;
}
MessageClient::MessageClient (QString const& id, QString const& server, port_type server_port, QObject * self)
: QObject {self}
, m_ {id, server_port, this}
{
connect (&*m_, static_cast<void (impl::*) (impl::SocketError)> (&impl::error)
, [this] (impl::SocketError /* e */)
{
Q_EMIT error (m_->errorString ());
});
set_server (server);
}
QHostAddress MessageClient::server_address () const
{
return m_->server_;
}
auto MessageClient::server_port () const -> port_type
{
return m_->server_port_;
}
void MessageClient::set_server (QString const& server)
{
m_->server_.clear ();
m_->server_string_ = server;
if (!server.isEmpty ())
{
// queue a host address lookup
QHostInfo::lookupHost (server, &*m_, SLOT (host_info_results (QHostInfo)));
}
}
void MessageClient::set_server_port (port_type server_port)
{
m_->server_port_ = server_port;
}
void MessageClient::send_raw_datagram (QByteArray const& message, QHostAddress const& dest_address
, port_type dest_port)
{
if (dest_port && !dest_address.isNull ())
{
m_->writeDatagram (message, dest_address, dest_port);
}
}
void MessageClient::status_update (Frequency f, QString const& mode, QString const& dx_call
, QString const& report, QString const& tx_mode
, bool tx_enabled, bool transmitting)
{
if (m_->server_port_ && !m_->server_string_.isEmpty ())
{
QByteArray message;
NetworkMessage::Builder out {&message, NetworkMessage::Status, m_->id_, m_->schema_};
out << f << mode.toUtf8 () << dx_call.toUtf8 () << report.toUtf8 () << tx_mode.toUtf8 ()
<< tx_enabled << transmitting;
if (impl::OK == m_->check_status (out))
{
m_->send_message (message);
}
else
{
Q_EMIT error ("Error creating UDP message");
}
}
}
void MessageClient::decode (bool is_new, QTime time, qint32 snr, float delta_time, quint32 delta_frequency
, QString const& mode, QString const& message_text)
{
if (m_->server_port_ && !m_->server_string_.isEmpty ())
{
QByteArray message;
NetworkMessage::Builder out {&message, NetworkMessage::Decode, m_->id_, m_->schema_};
out << is_new << time << snr << delta_time << delta_frequency << mode.toUtf8 () << message_text.toUtf8 ();
if (impl::OK == m_->check_status (out))
{
m_->send_message (message);
}
else
{
Q_EMIT error ("Error creating UDP message");
}
}
}
void MessageClient::clear_decodes ()
{
if (m_->server_port_ && !m_->server_string_.isEmpty ())
{
QByteArray message;
NetworkMessage::Builder out {&message, NetworkMessage::Clear, m_->id_, m_->schema_};
if (impl::OK == m_->check_status (out))
{
m_->send_message (message);
}
else
{
Q_EMIT error ("Error creating UDP message");
}
}
}
void MessageClient::qso_logged (QDateTime time, QString const& dx_call, QString const& dx_grid
, Frequency dial_frequency, QString const& mode, QString const& report_sent
, QString const& report_received, QString const& tx_power
, QString const& comments, QString const& name)
{
if (m_->server_port_ && !m_->server_string_.isEmpty ())
{
QByteArray message;
NetworkMessage::Builder out {&message, NetworkMessage::QSOLogged, m_->id_, m_->schema_};
out << time << dx_call.toUtf8 () << dx_grid.toUtf8 () << dial_frequency << mode.toUtf8 ()
<< report_sent.toUtf8 () << report_received.toUtf8 () << tx_power.toUtf8 () << comments.toUtf8 () << name.toUtf8 ();
if (impl::OK == m_->check_status (out))
{
m_->send_message (message);
}
else
{
Q_EMIT error ("Error creating UDP message");
}
}
}