[afs] Don't render in preview jobs

These servers can be sloooooooow, and unpredictable.
The previous preview job may have been fast to render,
but the next may take minutes or worse to download...

Author: nyalldawson

src/providers/arcgisrest/qgsafsprovider.cpp

@@ -315,6 +315,13 @@ QgsAbstractVectorLayerLabeling *QgsAfsProvider::createLabeling( const QVariantMa
   return QgsArcGisRestUtils::parseEsriLabeling( mLabelingDataList );
 }
 
+bool QgsAfsProvider::renderInPreview( const QgsDataProvider::PreviewContext & )
+{
+  // these servers can be sloooooooow, and unpredictable. The previous preview job may have been fast to render,
+  // but the next may take minutes or worse to download...
+  return false;
+}
+
 #ifdef HAVE_GUI
 
 //! Provider for AFS layers source select

src/providers/arcgisrest/qgsafsprovider.h

@@ -72,6 +72,7 @@ class QgsAfsProvider : public QgsVectorDataProvider
     void reloadData() override;
     QgsFeatureRenderer *createRenderer( const QVariantMap &configuration = QVariantMap() ) const override;
     QgsAbstractVectorLayerLabeling *createLabeling( const QVariantMap &configuration = QVariantMap() ) const override;
+    bool renderInPreview( const QgsDataProvider::PreviewContext &context ) override;
 
   private:
     bool mValid = false;