[Server][Feature][needs-docs] Update WMTS service to use cache manager for tiles

Author: rldhont

src/server/services/wmts/qgswmtsgettile.cpp

@@ -27,16 +27,57 @@ namespace QgsWmts
                      QgsServerResponse &response )
   {
     Q_UNUSED( version );
-
     QgsServerRequest::Parameters params = request.parameters();
 
     // WMS query
     QUrlQuery query = translateWmtsParamToWmsQueryItem( QStringLiteral( "GetMap" ), params, project, serverIface );
 
+    // Get cached image
+    QStringList cacheKeyList;
+    bool cache = true;
+
+    QgsAccessControl *accessControl = serverIface->accessControls();
+    if ( accessControl )
+      cache = accessControl->fillCacheKey( cacheKeyList );
+
+    QString cacheKey = cacheKeyList.join( QStringLiteral( "-" ) );
+    QgsServerCacheManager *cacheManager = serverIface->cacheManager();
+    if ( cacheManager && cache )
+    {
+      QString contentType = params.value( QStringLiteral( "FORMAT" ) );
+      QString saveFormat;
+      std::unique_ptr<QImage> image;
+      if ( contentType == "image/jpeg" )
+      {
+        saveFormat = "JPEG";
+        image = qgis::make_unique<QImage>( 256, 256, QImage::Format_RGB32 );
+      }
+      else
+      {
+        saveFormat = "PNG";
+        image = qgis::make_unique<QImage>( 256, 256, QImage::Format_ARGB32_Premultiplied );
+      }
+
+      QByteArray content = cacheManager->getCachedImage( project, request, cacheKey );
+      if ( !content.isEmpty() && image->loadFromData( content ) )
+      {
+        response.setHeader( "Content-Type", contentType );
+        image->save( response.io(), qPrintable( saveFormat ) );
+        return;
+      }
+    }
+
+
     QgsServerParameters wmsParams( query );
     QgsServerRequest wmsRequest( "?" + query.query( QUrl::FullyDecoded ) );
     QgsService *service = serverIface->serviceRegistry()->getService( wmsParams.service(), wmsParams.version() );
     service->executeRequest( wmsRequest, response, project );
+    if ( cache && cacheManager )
+    {
+      QByteArray content = response.data();
+      if ( !content.isEmpty() )
+        cacheManager->setCachedImage( &content, project, request, cacheKey );
+    }
   }
 
 } // namespace QgsWmts