Now that mapConfigProvider is linked to 'res.locals' do not pass the whole 'res.locals' to map-config-provider to avoid converting circular structure to JSON

lib/cartodb/controllers/layergroup.js

@@ -83,13 +83,15 @@ LayergroupController.prototype.register = function(app) {
         this.attributes(this.attributesBackend)
     );
 
+    const forcedFormat = 'png';
+
     app.get(
         app.base_url_mapconfig + '/static/center/:token/:z/:lat/:lng/:width/:height.:format',
         cors(),
         userMiddleware,
         allowQueryParams(['layer']),
         this.prepareContext,
-        this.getMapStoreMapConfigProvider(this.mapStore, this.userLimitsApi),
+        this.getMapStoreMapConfigProvider(this.mapStore, this.userLimitsApi, forcedFormat),
         this.center(this.previewBackend)
     );
 
@@ -99,7 +101,7 @@ LayergroupController.prototype.register = function(app) {
         userMiddleware,
         allowQueryParams(['layer']),
         this.prepareContext,
-        this.getMapStoreMapConfigProvider(this.mapStore, this.userLimitsApi),
+        this.getMapStoreMapConfigProvider(this.mapStore, this.userLimitsApi, forcedFormat),
         this.bbox(this.previewBackend)
     );
 
@@ -188,11 +190,27 @@ LayergroupController.prototype.analysisNodeStatus = function (analysisStatusBack
     }.bind(this);
 };
 
-LayergroupController.prototype.getMapStoreMapConfigProvider = function (mapStore, userLimitsApi) {
+function getRequestParams(locals) {
+    const params = Object.assign({}, locals);
+
+    delete params.mapConfigProvider;
+    delete params.allowedQueryParams;
+
+    return params;
+}
+
+LayergroupController.prototype.getMapStoreMapConfigProvider = function (mapStore, userLimitsApi, forcedFormat = null) {
     return function getMapStoreMapConfigProviderMiddleware (req, res, next) {
         const { user } = res.locals;
 
-        res.locals.mapConfigProvider = new MapStoreMapConfigProvider(mapStore, user, userLimitsApi, res.locals);
+        const params = getRequestParams(res.locals);
+
+        if (forcedFormat) {
+            params.format = forcedFormat;
+            params.layer = params.layer || 'all';
+        }
+
+        res.locals.mapConfigProvider = new MapStoreMapConfigProvider(mapStore, user, userLimitsApi, params);
 
         next();
     };
@@ -338,12 +356,6 @@ LayergroupController.prototype.center = function (previewBackend) {
         };
 
         const format = req.params.format === 'jpg' ? 'jpeg' : 'png';
-
-        // We force always the tile to be generated using PNG because
-        // is the only format we support by now
-        res.locals.format = 'png';
-        res.locals.layer = res.locals.layer || 'all';
-
         const { mapConfigProvider } = res.locals;
 
         previewBackend.getImage(mapConfigProvider, format, width, height, zoom, center,(err, image, headers, stats) => {
@@ -371,14 +383,7 @@ LayergroupController.prototype.bbox = function (previewBackend) {
             east: +req.params.east,
             south: +req.params.south
         };
-
         const format = req.params.format === 'jpg' ? 'jpeg' : 'png';
-
-        // We force always the tile to be generated using PNG because
-        // is the only format we support by now
-        res.locals.format = 'png';
-        res.locals.layer = res.locals.layer || 'all';
-
         const { mapConfigProvider } = res.locals;
 
         previewBackend.getImage(mapConfigProvider, format, width, height, bounds, (err, image, headers, stats) => {