Fix visibility of missing/lost printers

qml/pages/FirstPage.qml

@@ -73,11 +73,24 @@ Page {
             delegate: ListItem {
                 id: delegate
                 contentItem.height: visible ? Math.max(column.implicitHeight, Theme.itemSizeLarge+2*Theme.paddingMedium) : 0
-                visible: printer.attrs["printer-name"] ? true : false
 
-                property string name: printer.attrs["printer-name"].value
+                visible: false
+
+                property string name: printer.attrs["printer-name"] ? printer.attrs["printer-name"].value : qsTr("Unknown")
                 property bool canPrint: Utils.can_print(printer, selectedFile)
 
+                Connections {
+                    target: printer
+                    onAttrsChanged: {
+                        if(Object.keys(printer.attrs).length === 0) {
+                            delegate.visible = false
+                        }
+                        else {
+                            delegate.visible = true
+                        }
+                    }
+                }
+
                 onClicked: {
                     if(!canPrint)
                         return;

src/ippprinter.cpp

@@ -65,20 +65,20 @@ void IppPrinter::onUrlChanged()
 void IppPrinter::getPrinterAttributesFinished(QNetworkReply *reply)
 {
     qDebug() << reply->error() << reply->errorString() << reply->attribute(QNetworkRequest::RedirectionTargetAttribute).toString();
+    _attrs = QJsonObject();
     if(reply->error()  == QNetworkReply::NoError)
     {
         try {
             IppMsg resp(reply);
             qDebug() << resp.getStatus() << resp.getOpAttrs() << resp.getPrinterAttrs();
             _attrs = resp.getPrinterAttrs();
-            emit attrsChanged();
         }
         catch(std::exception e)
         {
             qDebug() << e.what();
         }
     }
-
+    emit attrsChanged();
 }
 
 void IppPrinter::printRequestFinished(QNetworkReply *reply)

translations/harbour-seaprint-de.ts

@@ -108,6 +108,10 @@
         <source>Remove printer</source>
         <translation type="unfinished"></translation>
     </message>
+    <message>
+        <source>Unknown</source>
+        <translation type="unfinished"></translation>
+    </message>
 </context>
 <context>
     <name>JobsPage</name>

translations/harbour-seaprint.ts

@@ -108,6 +108,10 @@
         <source>Remove printer</source>
         <translation type="unfinished"></translation>
     </message>
+    <message>
+        <source>Unknown</source>
+        <translation type="unfinished"></translation>
+    </message>
 </context>
 <context>
     <name>JobsPage</name>