Merge pull request #788 from CartoDB/786-number-categories-param

Add a "category" query param to define the number of categories to be ranked for aggregation dataviews

lib/cartodb/backends/dataview.js

@@ -24,7 +24,7 @@ module.exports = DataviewBackend;
 
 DataviewBackend.prototype.getDataview = function (mapConfigProvider, user, params, callback) {
 
-    var dataviewName = params.dataviewName;  
+    var dataviewName = params.dataviewName;
     step(
         function getMapConfig() {
             mapConfigProvider.getMapConfig(this);
@@ -94,7 +94,7 @@ function getQueryRewriteData(mapConfig, dataviewDefinition, params) {
 }
 
 function getOverrideParams(params, ownFilter) {
-    var overrideParams = _.reduce(_.pick(params, 'start', 'end', 'bins', 'offset'),
+    var overrideParams = _.reduce(_.pick(params, 'start', 'end', 'bins', 'offset', 'categories'),
         function castNumbers(overrides, val, k) {
             if (!Number.isFinite(+val)) {
                 throw new Error('Invalid number format for parameter \'' + k + '\'');

lib/cartodb/controllers/layergroup.js

@@ -109,7 +109,8 @@ LayergroupController.prototype.register = function(app) {
         'bins', // number
         'aggregation', //string
         'offset', // number
-        'q' // widgets search
+        'q', // widgets search
+        'categories', // number
     ];
 
     app.get(

lib/cartodb/models/dataview/aggregation.js

@@ -245,6 +245,10 @@ module.exports = class Aggregation extends BaseDataview {
             return null;
         }
 
+        const limit = Number.isFinite(override.categories) && override.categories > 0 ?
+            override.categories :
+            CATEGORIES_LIMIT;
+
         const aggregationSql = aggregationDataviewQueryTpl({
             override: override,
             query: this.query,
@@ -256,7 +260,7 @@ module.exports = class Aggregation extends BaseDataview {
                 aggregationColumn: this.aggregationColumn || 1
             }),
             isFloatColumn: this._isFloatColumn,
-            limit: CATEGORIES_LIMIT
+            limit
         });
 
         debug(aggregationSql);