Simplified textual network command structure

MessageClient.cpp

@@ -136,7 +136,15 @@ void MessageClient::impl::parse_message (QByteArray const& msg)
 {
   try
     {
-        qDebug() << "incoming udp message" << msg;
+        QList<QByteArray> segments = msg.split('|');
+        if(segments.isEmpty()){
+            return;
+        }
+
+        QString type(segments.first());
+        QString message(segments.mid(1).join('|'));
+        qDebug() << "MessageClient: Incoming" << type << message;
+        Q_EMIT self_->message_received(type, message);
     }
   catch (std::exception const& e)
     {
@@ -152,8 +160,7 @@ void MessageClient::impl::heartbeat ()
 {
    if (server_port_ && !server_.isNull ())
     {
-      QByteArray message;
+      QByteArray message("PING|");
-      qDebug() << "outgoing udp heartbeat message" << message;
       writeDatagram (message, server_, server_port_);
     }
 }
@@ -162,8 +169,7 @@ void MessageClient::impl::closedown ()
 {
    if (server_port_ && !server_.isNull ())
     {
-      QByteArray message;
+      QByteArray message("EXIT|");
-      qDebug() << "outgoing udp closedown message" << message;
       writeDatagram (message, server_, server_port_);
     }
 }
@@ -265,6 +271,14 @@ void MessageClient::set_server_port (port_type server_port)
   m_->server_port_ = server_port;
 }
 
+void MessageClient::send_message(QString const &type, QString const &message){
+  QByteArray b;
+  b.append(type);
+  b.append('|');
+  b.append(message);
+  m_->send_message(b);
+}
+
 void MessageClient::send_raw_datagram (QByteArray const& message, QHostAddress const& dest_address
                                        , port_type dest_port)
 {

MessageClient.hpp

@@ -47,6 +47,9 @@ public:
   // change the server port messages are sent to
   Q_SLOT void set_server_port (port_type server_port = 0u);
 
+  // this slot is used to send an arbitrary message
+  Q_SLOT void send_message(QString const &type, QString const &message);
+
   // this slot may be used to send arbitrary UDP datagrams to and
   // destination allowing the underlying socket to be used for general
   // UDP messaging if desired
@@ -56,6 +59,10 @@ public:
   // with send_raw_datagram() above)
   Q_SLOT void add_blocked_destination (QHostAddress const&);
 
+
+  // this signal is emitted when the a reply a message is received
+  Q_SIGNAL void message_received(QString const &type, QString const &message);
+
   // this signal is emitted when network errors occur or if a host
   // lookup fails
   Q_SIGNAL void error (QString const&) const;

udp.py

@@ -11,10 +11,15 @@ def main():
         while True:
             content, addr = sock.recvfrom(65500)
             print("from:", ":".join(map(str, addr)))
-            print("->", repr(content))
+
-            print("sending test reply...", end="")
+            typ, msg = content.split('|')
-            sock.sendto("test", addr)
+            print("->", typ)
-            print("done")
+            print("->", msg)
+
+            if typ == "PING":
+                print("sending pong reply...", end="")
+                sock.sendto("PONG|hello world|asdf", addr)
+                print("done")
     finally:
         sock.close()