Refactor/fix potential problems

lib/cartodb/controllers/map.js

@@ -155,12 +155,18 @@ MapController.prototype.create = function(req, res, prepareConfigFn) {
         function addOverviewsInformation(err, requestMapConfig, datasource) {
           assert.ifError(err);
           var next = this;
-          self.overviewsAdapter.getMapConfig(req.context.user, requestMapConfig, function(err, mapconfig) {
-                if (err) {
-                    return next(err);
-                }
-                return next(null, mapconfig, datasource);
-          });
+          self.overviewsAdapter.getLayers(req.context.user, requestMapConfig.layers,
+              function(err, layers) {
+                  if (err) {
+                      return next(err);
+                  }
+
+                  if (layers) {
+                      requestMapConfig.layers = layers;
+                  }
+                  return next(null, requestMapConfig, datasource);
+              }
+          );
         },
         function createLayergroup(err, requestMapConfig, datasource) {
             assert.ifError(err);

lib/cartodb/models/mapconfig_overviews_adapter.js

@@ -1,4 +1,5 @@
 var queue = require('queue-async');
+var _ = require('underscore');
 
 function MapConfigNamedLayersAdapter(overviewsApi) {
     this.overviewsApi = overviewsApi;
@@ -6,32 +7,40 @@ function MapConfigNamedLayersAdapter(overviewsApi) {
 
 module.exports = MapConfigNamedLayersAdapter;
 
-MapConfigNamedLayersAdapter.prototype.getMapConfig = function(username, mapconfig, callback) {
+MapConfigNamedLayersAdapter.prototype.getLayers = function(username, layers, callback) {
 
-    // TODO: we're modifying mapconfig in place and then returning it... not very nice
+  if (!layers) {
+      return callback(null);
+  }
 
-    var layers = mapconfig.getlayers();
+  var augmentLayersQueue = queue(layers.length);
 
-    var parallelism = 2;
-    var q = queue(parallelism);
+  function augmentLayer(layer, done) {
+      this.overviewsApi.getOverviewsMetadata(username, layer.options.sql, function(err, metadata){
+           if ( !_.isEmpty(metadata) ) {
+               layer = _.extend({}, layer, { overviews: metadata });
+           }
+           done(null, layer);
+      });
+  }
 
-    for ( var i=0; i < layers.length; ++i ) {
-        q.defer(function(layer, done){
-            this.overviewsApi.getOverviewsMetadata(username, layer.options.sql, function(err, metadata){
-                 // TODO: is it legit to modify layer like this?
-                 layer.options.overviews = metadata;
-                 done(null);
-            });
-        }, layers[i]);
+  function layersAugmentQueueFinish(err, layers) {
+    if (err) {
+        return callback(err);
     }
 
-    q.awaitAll(function(err){
-      if (err) {
-          return callback(err);
-      } else {
-          return callback(null, mapconfig);
-      }
-    });
+    if (!layers || layers.length === 0) {
+        return callback(new Error('Missing layers array from layergroup config'));
+    }
+
+    return callback(null, layers);
+  }
+
+  layers.forEach(function(layer) {
+      augmentLayersQueue.defer(augmentLayer, layer);
+  });
+  augmentLayersQueue.awaitAll(layersAugmentQueueFinish);
+
 };
 
 // TODO: document in https://github.com/CartoDB/Windshaft/blob/master/doc/MapConfig-1.5.0.md