increased stability of connection and added basic error handling

headers/buzzerconn.h

@@ -29,6 +29,8 @@ public:
     int connection_progress;
     QString ip;
     int port;
+    int errors;
+    int errors_until_disconnect = 4;
 
 
 
@@ -43,7 +45,16 @@ signals:
 public slots:
     ReturnData_t senddata(QNetworkAccessManager * NetMan, QUrl serviceUrl, int timeout);
         //function to communicate with the buzzer
-    unsigned long sendCommand(QString command);
+    signed long sendCommand(QString command, int timeout);
+        //function to send commands to the sensor
+        //Can be:
+        //command - return
+        //GET_TIMESTAMP - timestamp of the sensor
+        //GET_LASTPRESSED - timestamp of the sensor when it was triggered the last time
+        //
+        //error codes:
+        //(-1) : timeout
+        //(-2) : invalid data was recieved
     Q_INVOKABLE QList<double> gettimes(int timeout);
         //function to get the times from the buzzer as a list with the normal network manager
     Q_INVOKABLE bool connect();

sources/buzzerconn.cpp

@@ -50,6 +50,11 @@ bool BuzzerConn::connect()
     loop.exec();
     timer.stop();
 
+    if(timer.remainingTime() == 0){
+        //the time has been triggered -> timeout
+        return(false);
+    }
+
 
     QList<double> times = gettimes(1000);
     qDebug() << times[0];
@@ -119,19 +124,25 @@ QList<double> BuzzerConn::gettimes(int timeout)
     //    }
 
     QList<double> times;
-    unsigned long ret;
+    signed long ret;
-    ret = this->sendCommand("GET_TIMESTAMP");
+    ret = this->sendCommand("GET_TIMESTAMP", timeout);
-    if(ret){
+    if(ret >= 0){
         times.append(double(200));
         times.append(double(ret));
-        ret = this->sendCommand("GET_LASTPRESSED");
+        ret = this->sendCommand("GET_LASTPRESSED", timeout);
+        if(ret >= 0){
             times.append(double(ret));
             return(times);
         }
         else {
-        times.append(444);
+            times[0] = ret;
         }
 
+    }
+    else {
+        times.append(ret);
+    }
+    return(times);
 
 }
 
@@ -224,8 +235,20 @@ bool BuzzerConn::refresh()
 //        //this->connected = false;
 //        return(false);
 //    }
+    QList<double> ret = this->gettimes(800);
+    if(ret[0] >= 0){
+        this->errors = 0;
+        return(this->calcoffset(ret));
+    }
+    else {
+        this->errors ++;
+        if(this->errors > errors_until_disconnect){
+            this->socket->disconnectFromHost();
+            this->connected = false;
+        }
+        return(false);
+    }
 
-    return(this->calcoffset(this->gettimes(1000)));
 }
 
 ReturnData_t BuzzerConn::senddata(QNetworkAccessManager * NetMan, QUrl serviceUrl, int timeout)
@@ -269,7 +292,13 @@ ReturnData_t BuzzerConn::senddata(QNetworkAccessManager * NetMan, QUrl serviceUr
     return(ret);
 }
 
-unsigned long BuzzerConn::sendCommand(QString command){
+signed long BuzzerConn::sendCommand(QString command, int timeout){
+
+    //if there is any data in the storage, clear it
+    if(this->socket->bytesAvailable() > 0){
+        this->socket->readAll();
+    }
+
     //send request to the socket server
     QByteArray arrBlock;
     QDataStream out(&arrBlock, QIODevice::WriteOnly);
@@ -288,22 +317,26 @@ unsigned long BuzzerConn::sendCommand(QString command){
     timer.setSingleShot(true);
     loop.connect(&timer, SIGNAL(timeout()), &loop, SLOT(quit()));
     loop.connect(socket, SIGNAL(readyRead()), &loop, SLOT(quit()));
-    timer.start(3000);
+    timer.start(timeout);
     loop.exec();
 
     //loop finished
     timer.stop();
+    if(timer.remainingTime() == 0){
+        //the time has been triggered -> timeout
+        return(-1);
+    }
 
-    qDebug() << "ready read";
+    //if the data is not 4 bites long if is invalid -> clear and terminate
-    qDebug() << this->socket->bytesAvailable();
     if(this->socket->bytesAvailable() != 4){
         this->socket->readAll();
+        return(-2);
     }
-    unsigned long data = 0;
+    long data = 0;
     this->socket->read((char*)&data,4);
 
     qDebug() << data;
     qDebug() << this->socket->bytesAvailable();
-    qDebug() << "end read";
+
     return data;
 }

sources/main.cpp

@@ -106,7 +106,7 @@ int main(int argc, char *argv[])
 
     connectToDatabase();
     BuzzerConn * pBuzzerConn = new BuzzerConn(nullptr, "192.168.4.1", 80);
-    BuzzerConn * pStartpadConn = new BuzzerConn(nullptr, "192.168.4.2", 80);
+    BuzzerConn * pStartpadConn = new BuzzerConn(nullptr, "192.168.4.3", 80);
     AppSettings * pAppSettings = new AppSettings();
 
     //setup the sql storage model as a qml model