LP-269 StreamService plugin which enables a TCP/IP stream whereby any connection to 7891 port gets served with all asynchronous changes on UAV data objects in JSON format.

ground/gcs/src/plugins/plugins.pro

@@ -238,3 +238,10 @@ plugin_usagetracker.depends += plugin_uavobjects
 plugin_usagetracker.depends += plugin_uavtalk
 plugin_setupwizard.depends += plugin_uavobjectutil
 SUBDIRS += plugin_usagetracker
+
+# Stream Service Plugin
+plugin_streamservice.subdir = streamservice
+plugin_streamservice.depends = plugin_coreplugin
+plugin_streamservice.depends += plugin_uavobjects
+plugin_streamservice.depends += plugin_uavtalk
+SUBDIRS += plugin_streamservice

ground/gcs/src/plugins/streamservice/StreamServicePlugin.pluginspec

@@ -0,0 +1,12 @@
+<plugin name="StreamServicePlugin" version="1.0.0" compatVersion="1.0.0">
+    <vendor>The LibrePilot Project</vendor>
+    <copyright>(C) 2016 LibrePilot Project; (C) 2010 OpenPilot Project and Nokia</copyright>
+    <license>The GNU Public License (GPL) Version 3</license>
+    <description>UAV Objects listener publishing changes in socket</description>
+    <url>http://www.librepilot.org</url>
+    <dependencyList>
+        <dependency name="Core" version="1.0.0"/>
+        <dependency name="UAVTalk" version="1.0.0"/>
+        <dependency name="UAVObjects" version="1.0.0"/>
+    </dependencyList>
+</plugin>

ground/gcs/src/plugins/streamservice/streamservice.pro

@@ -0,0 +1,18 @@
+TEMPLATE = lib
+TARGET = StreamServicePlugin
+
+QT       += network widgets
+
+include(../../plugin.pri)
+include(../../plugins/coreplugin/coreplugin.pri)
+include(../../plugins/uavtalk/uavtalk.pri)
+include(../../plugins/uavobjects/uavobjects.pri)
+
+SOURCES += streamserviceplugin.cpp
+
+HEADERS += streamserviceplugin.h
+
+OTHER_FILES +=
+
+DISTFILES += \
+    StreamServicePlugin.pluginspec

ground/gcs/src/plugins/streamservice/streamserviceplugin.cpp

@@ -0,0 +1,155 @@
+/**
+ ******************************************************************************
+ *
+ * @file       streamserviceplugin.h
+ * @author     The LibrePilot Project, http://www.librepilot.org Copyright (C) 2016.
+ * @addtogroup GCSPlugins GCS Plugins
+ * @{
+ * @addtogroup StreamServicePlugin Plugin
+ * @{
+ * @brief Data UAV Data objects TCP/IP stream service
+ *****************************************************************************/
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+#include "streamserviceplugin.h"
+
+#include <QJsonObject>
+#include <QJsonDocument>
+#include <QMessageBox>
+#include <QDateTime>
+#include <QTcpServer>
+#include <QTcpSocket>
+
+#include "extensionsystem/pluginmanager.h"
+#include "../uavobjects/uavobjectmanager.h"
+#include "../uavobjects/uavdataobject.h"
+
+StreamServicePlugin::StreamServicePlugin() :
+    port(7891),
+    isSubscribed(false) {}
+
+StreamServicePlugin::~StreamServicePlugin()
+{
+    if (pServer == Q_NULLPTR) {
+        return;
+    }
+    if (pServer->isListening()) {
+        foreach(QTcpSocket * client, activeClients) {
+            /* Disconnect the client discarding pending
+             * bytes */
+            if (client->isOpen()) {
+                client->close();
+            }
+        }
+        pServer->close();
+    }
+}
+
+bool StreamServicePlugin::initialize(const QStringList &arguments, QString *errorString)
+{
+    Q_UNUSED(arguments);
+    Q_UNUSED(errorString);
+
+    pServer = new QTcpServer();
+
+    if (!pServer->listen(QHostAddress::Any, port)) {
+        *errorString = tr("Couldn't start StreamService: ") + pServer->errorString();
+        return false;
+    }
+
+    connect(pServer, &QTcpServer::newConnection, this, &StreamServicePlugin::clientConnected);
+
+    return true;
+}
+
+void StreamServicePlugin::extensionsInitialized()
+{
+    if (pServer == Q_NULLPTR) {
+        return;
+    }
+
+    pServer->resumeAccepting();
+}
+
+void StreamServicePlugin::shutdown()
+{
+    if (pServer != Q_NULLPTR) {
+        pServer->pauseAccepting();
+    }
+
+    foreach(QTcpSocket * pClient, activeClients) {
+        pClient->disconnectFromHost();
+    }
+}
+
+void StreamServicePlugin::objectUpdated(UAVObject *pObj)
+{
+    QJsonObject qtjson;
+
+    pObj->toJson(qtjson);
+
+    // Adds timestamp: Milliseconds from epoch
+    qtjson.insert("gcs_timestamp_ms", QJsonValue(QDateTime::currentMSecsSinceEpoch()));
+
+    QJsonDocument jsonDoc(qtjson);
+    QString strJson = QString(jsonDoc.toJson(QJsonDocument::Compact)) + "\n";
+
+    foreach(QTcpSocket * pClient, activeClients) {
+        if (pClient->isOpen()) {
+            if (pClient->write(strJson.toUtf8().constData(), strJson.length())) {
+                pClient->flush();
+            }
+        }
+    }
+}
+
+void StreamServicePlugin::clientConnected()
+{
+    QTcpSocket *pending = pServer->nextPendingConnection();
+
+    if (pending == Q_NULLPTR) {
+        return;
+    }
+    makeSureIsSubscribed();
+
+    connect(pending, &QTcpSocket::disconnected, this, &StreamServicePlugin::clientDisconnected);
+    activeClients.append(pending);
+}
+
+void StreamServicePlugin::clientDisconnected()
+{
+    disconnect(sender());
+    activeClients.removeAll((QTcpSocket *)sender());
+}
+
+inline void StreamServicePlugin::makeSureIsSubscribed()
+{
+    if (isSubscribed) {
+        return;
+    }
+
+    ExtensionSystem::PluginManager *pm = ExtensionSystem::PluginManager::instance();
+    UAVObjectManager *objManager = pm->getObject<UAVObjectManager>();
+    Q_ASSERT(objManager);
+
+    QList< QList<UAVDataObject *> > objList = objManager->getDataObjects();
+    foreach(QList<UAVDataObject *> list, objList) {
+        foreach(UAVDataObject * obj, list) {
+            connect(obj, &UAVDataObject::objectUpdated, this, &StreamServicePlugin::objectUpdated);
+        }
+    }
+    isSubscribed = true;
+}

ground/gcs/src/plugins/streamservice/streamserviceplugin.h

@@ -0,0 +1,67 @@
+/**
+ ******************************************************************************
+ *
+ * @file       streamserviceplugin.h
+ * @author     The LibrePilot Project, http://www.librepilot.org Copyright (C) 2016.
+ * @addtogroup GCSPlugins GCS Plugins
+ * @{
+ * @addtogroup StreamServicePlugin Plugin
+ * @{
+ * @brief Data UAV Data objects TCP/IP stream service
+ *****************************************************************************/
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+#ifndef STREAMSERVICEPLUGIN_H
+#define STREAMSERVICEPLUGIN_H
+
+#include <extensionsystem/iplugin.h>
+#include "../uavobjects/uavobject.h"
+
+#include <QtPlugin>
+
+class QTcpServer;
+class QTcpSocket;
+
+class StreamServicePlugin : public ExtensionSystem::IPlugin {
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID "Openpilot.StreamService")
+
+public:
+    StreamServicePlugin();
+    ~StreamServicePlugin();
+
+    bool initialize(const QStringList &arguments, QString *errorString);
+    void extensionsInitialized();
+    void shutdown();
+
+public slots:
+    void objectUpdated(UAVObject *pObj);
+
+private slots:
+    void clientConnected();
+    void clientDisconnected();
+
+private:
+    quint16 port;
+
+    QTcpServer *pServer;
+    QList<QTcpSocket *> activeClients;
+    bool isSubscribed;
+
+    inline void makeSureIsSubscribed();
+};
+
+#endif // STREAMSERVICEPLUGIN_H