[GUI] Add connection loss detection and reestablishment

programs/light_client/ClientDataModel.cpp

@@ -156,6 +156,7 @@ void GrapheneApplication::start( QString apiurl, QString user, QString pass )
       m_client = std::make_shared<fc::http::websocket_client>();
       ilog( "connecting...${s}", ("s",apiurl.toStdString()) );
       auto con  = m_client->connect( apiurl.toStdString() );
+      m_connectionClosed = con->closed.connect([this]{queueExecute([this]{setIsConnected(false);});});
       auto apic = std::make_shared<fc::rpc::websocket_api_connection>(*con);
       auto remote_api = apic->get_remote_api< login_api >(1);
       auto db_api = apic->get_remote_api< database_api >(0);

programs/light_client/ClientDataModel.hpp

@@ -129,6 +129,8 @@ class GrapheneApplication : public QObject {
    ChainDataModel*             m_model       = nullptr;
    bool                        m_isConnected = false;
 
+   boost::signals2::scoped_connection m_connectionClosed;
+
    std::shared_ptr<fc::http::websocket_client>  m_client;
    fc::future<void>                        m_done;
 

programs/light_client/qml/main.qml

@@ -14,10 +14,6 @@ ApplicationWindow {
    height: 480
    title: qsTr("Hello World")
 
-   Component.onCompleted: {
-      app.start("ws://localhost:8090", "user", "pass")
-   }
-
    menuBar: MenuBar {
       Menu {
          title: qsTr("File")
@@ -32,9 +28,22 @@ ApplicationWindow {
          }
       }
    }
+   statusBar: StatusBar {
+      Label {
+         anchors.right: parent.right
+         text: app.isConnected? qsTr("Connected") : qsTr("Disconnected")
+      }
+   }
 
    GrapheneApplication {
       id: app
+  }
+   Timer {
+      running: !app.isConnected
+      interval: 5000
+      repeat: true
+      onTriggered: app.start("ws://localhost:8090", "user", "pass")
+      triggeredOnStart: true
    }
    Settings {
       id: appSettings
@@ -47,6 +56,8 @@ ApplicationWindow {
 
    Column {
       anchors.centerIn: parent
+      enabled: app.isConnected
+
       Button {
          text: "Transfer"
          onClicked: formBox.showForm(Qt.createComponent("TransferForm.qml"), {},