AirMapManager: subscribe to traffic alerts when a flight is created using MQTT

src/MissionManager/AirMapManager.cc

@@ -817,9 +817,66 @@ void AirMapTelemetry::stopTelemetryStream()
     _state = State::EndCommunication;
 }
 
+void AirMapTrafficAlertClient::startConnection(const QString& flightID, const QString& password)
+{
+    _flightID = flightID;
+
+    setClientId("qgc-client-id"); // TODO: random?
+    setUsername(flightID);
+    setPassword(password);
+    connectToHost();
+}
+
+void AirMapTrafficAlertClient::onError(const QMQTT::ClientError error)
+{
+    // TODO: user-facing warning
+    qWarning() << "QMQTT error" << (int)error;
+}
+
+void AirMapTrafficAlertClient::onConnected()
+{
+    // see https://developers.airmap.com/v2.0/docs/traffic-alerts
+    subscribe("uav/traffic/sa/" + _flightID, 0); // situational awareness topic
+}
+
+void AirMapTrafficAlertClient::onSubscribed(const QString& topic)
+{
+    qCDebug(AirMapManagerLog) << "subscribed" << topic;
+}
+
+void AirMapTrafficAlertClient::onReceived(const QMQTT::Message& message)
+{
+    qCDebug(AirMapManagerLog) << "traffic publish received:" << QString::fromUtf8(message.payload());
+    // looks like this:
+    // "{"traffic":[{"id":"OAW380-1501565193-airline-0081","direction":-41.20024491976423,"altitude":"5675",
+    // "latitude":"47.50335","longitude":"8.40912","recorded_time":"1501774066","ground_speed_kts":"199",
+    // "true_heading":"241","properties":{"aircraft_id":"OAW380"},"timestamp":1501774079064}]}"
+
+    QJsonParseError parseError;
+    QJsonDocument responseJson = QJsonDocument::fromJson(message.payload(), &parseError);
+    if (parseError.error != QJsonParseError::NoError) {
+        qWarning() << "QMQTT JSON parsing error" << parseError.errorString();
+        return;
+    }
+    QJsonObject rootObject = responseJson.object();
+    const QJsonArray& trafficArray = rootObject["traffic"].toArray();
+    for (int i = 0; i < trafficArray.count(); i++) {
+        const QJsonObject& trafficObject = trafficArray[i].toObject();
+        QString traffic_id = trafficObject["id"].toString();
+        float altitude = trafficObject["altitude"].toString().toFloat() * 0.3048f; // feet to meters
+        double lat = trafficObject["latitude"].toString().toDouble();
+        double lon = trafficObject["longitude"].toString().toDouble();
+        float heading = trafficObject["true_heading"].toString().toDouble(); // in deg
+        QString vehicle_id = trafficObject["properties"].toObject()["aircraft_id"].toString();
+        emit trafficUpdate(traffic_id, vehicle_id, QGeoCoordinate(lat, lon, altitude), heading);
+
+    }
+}
+
+
 AirMapManager::AirMapManager(QGCApplication* app, QGCToolbox* toolbox)
     : QGCTool(app, toolbox), _airspaceRestrictionManager(_networkingData), _flightManager(_networkingData),
-      _telemetry(_networkingData)
+      _telemetry(_networkingData), _trafficAlerts("mqtt-prod.airmap.io", 8883)
 {
     _updateTimer.setInterval(2000);
     _updateTimer.setSingleShot(true);
@@ -829,7 +886,9 @@ AirMapManager::AirMapManager(QGCApplication* app, QGCToolbox* toolbox)
     connect(&_flightManager, &AirMapFlightManager::networkError, this, &AirMapManager::_networkError);
     connect(&_telemetry, &AirMapTelemetry::networkError, this, &AirMapManager::_networkError);
 
-    connect(&_flightManager, &AirMapFlightManager::flightPermitStatusChanged, this, &AirMapManager::flightPermitStatusChanged);
+    connect(&_flightManager, &AirMapFlightManager::flightPermitStatusChanged, this, &AirMapManager::_flightPermitStatusChanged);
+
+    connect(&_trafficAlerts, &AirMapTrafficAlertClient::trafficUpdate, this, &AirMapManager::trafficUpdate);
 
     qmlRegisterUncreatableType<AirspaceAuthorization>("QGroundControl", 1, 0, "AirspaceAuthorization", "Reference only");
 
@@ -840,6 +899,18 @@ AirMapManager::AirMapManager(QGCApplication* app, QGCToolbox* toolbox)
     GOOGLE_PROTOBUF_VERIFY_VERSION;
 }
 
+void AirMapManager::_flightPermitStatusChanged()
+{
+    // activate traffic alerts
+    if (_flightManager.flightPermitStatus() == AirspaceAuthorization::PermitAccepted) {
+        qCDebug(AirMapManagerLog) << "Subscribing to Traffic Alerts";
+        // since we already created the flight, we know that we have a valid login token
+        _trafficAlerts.startConnection(_flightManager.flightID(), _networkingData.login.JWTToken());
+    }
+
+    emit flightPermitStatusChanged();
+}
+
 AirMapManager::~AirMapManager()
 {
 
@@ -885,6 +956,7 @@ void AirMapManager::_vehicleArmedChanged(bool armed)
         // end the flight if we were in mission mode during arming or disarming
         // TODO: needs to be improved. for instance if we do RTL and then want to continue the mission...
         if (_vehicleWasInMissionMode || _vehicle->flightMode() == _vehicle->missionFlightMode()) {
+            _trafficAlerts.disconnectFromHost();
             _flightManager.endFlight();
         }
     }

src/MissionManager/AirMapManager.h

@@ -16,6 +16,8 @@
 #include "MissionItem.h"
 #include "MultiVehicleManager.h"
 
+#include <qmqtt.h>
+
 #include <QGeoCoordinate>
 #include <QList>
 #include <QNetworkAccessManager>
@@ -319,6 +321,43 @@ private:
     float                   _lastHdop = 1.f;
 };
 
+
+class AirMapTrafficAlertClient : public QMQTT::Client
+{
+    Q_OBJECT
+public:
+    AirMapTrafficAlertClient(const QString& host, const quint16 port, QObject* parent = NULL)
+        : QMQTT::Client(host, port, QSslConfiguration::defaultConfiguration(), true, parent)
+    {
+        connect(this, &AirMapTrafficAlertClient::connected, this, &AirMapTrafficAlertClient::onConnected);
+        connect(this, &AirMapTrafficAlertClient::subscribed, this, &AirMapTrafficAlertClient::onSubscribed);
+        connect(this, &AirMapTrafficAlertClient::received, this, &AirMapTrafficAlertClient::onReceived);
+        connect(this, &AirMapTrafficAlertClient::error, this, &AirMapTrafficAlertClient::onError);
+    }
+    virtual ~AirMapTrafficAlertClient() = default;
+
+    void startConnection(const QString& flightID, const QString& password);
+
+signals:
+    void trafficUpdate(QString traffic_id, QString vehicle_id, QGeoCoordinate location, float heading);
+
+private slots:
+
+    void onError(const QMQTT::ClientError error);
+
+    void onConnected();
+
+    void onSubscribed(const QString& topic);
+
+    void onReceived(const QMQTT::Message& message);
+
+private:
+    QString _flightID;
+};
+
+
+
+
 /// AirMap server communication support.
 class AirMapManager : public QGCTool
 {
@@ -347,6 +386,8 @@ public:
 signals:
     void flightPermitStatusChanged();
 
+    void trafficUpdate(QString traffic_id, QString vehicle_id, QGeoCoordinate location, float heading);
+
 private slots:
     void _updateToROI(void);
     void _networkError(QNetworkReply::NetworkError code, const QString& errorString, const QString& serverErrorMessage);
@@ -354,6 +395,8 @@ private slots:
     void _activeVehicleChanged(Vehicle* activeVehicle);
     void _vehicleArmedChanged(bool armed);
 
+    void _flightPermitStatusChanged();
+
 private:
     bool _hasAPIKey() const { return _networkingData.airmapAPIKey != ""; }
 
@@ -366,6 +409,7 @@ private:
     AirspaceRestrictionManager   _airspaceRestrictionManager;
     AirMapFlightManager          _flightManager;
     AirMapTelemetry              _telemetry;
+    AirMapTrafficAlertClient     _trafficAlerts;
 
     QGeoCoordinate          _roiCenter;
     double                  _roiRadius;