Refactor filter application into own model

This also avoids storing an object in the overviews query rewriter
for the bbox filter (a plain data structure is used instead).

lib/cartodb/backends/dataview.js

@@ -140,7 +140,17 @@ DataviewBackend.prototype.getDataview = function (mapConfigProvider, user, param
             if (params.bbox) {
                 var bboxFilter = new BBoxFilter({column: 'the_geom', srid: 4326}, {bbox: params.bbox});
                 query = bboxFilter.sql(query);
-                queryRewriteData = _.extend(queryRewriteData, { bbox_filter: bboxFilter });
+                var bbox_filter_definition = {
+                    type: 'bbox',
+                    options: {
+                        column: 'the_geom',
+                        srid: 4326,
+                    },
+                    params: {
+                        bbox: params.bbox
+                    }
+                };
+                queryRewriteData = _.extend(queryRewriteData, { bbox_filter: bbox_filter_definition });
             }
 
             var dataviewFactory = DataviewFactoryWithOverviews.getFactory(

lib/cartodb/models/filter/camshaft.js

@@ -0,0 +1,13 @@
+// this is meant as a hack for development
+// TODO: reproduce here the filter application of Camshaft
+var queryBuilder = require('camshaft/lib/filter/query-builder');
+
+function CamshaftFilters(filters) {
+    this.filters = filters;
+}
+
+CamshaftFilters.prototype.sql = function(rawSql) {
+    return queryBuilder.getSQL(rawSql, filters);
+};
+
+module.exports = CamshaftFilters;

lib/cartodb/utils/overviews_query_rewriter.js

@@ -1,15 +1,17 @@
 var _ = require('underscore');
 var TableNameParser = require('./table_name_parser');
 
-// this is meant as a hack for development
-var queryBuilder = require('camshaft/lib/filter/query-builder');
+var BBoxFilter = require('../models/filter/bbox');
+var CamshaftFilter = require('../models/filter/camshaft');
+
 function apply_filters_to_query(query, filters, bbox_filter) {
-    // TODO: implement filter application here
     if ( filters && !_.isEmpty(filters)) {
-        query = queryBuilder.getSql(query, filters);
+        var camshaftFilter = new CamshaftFilter(filters)
+        query = camshaftFilter.sql(query);
     }
     if ( bbox_filter ) {
-        query = bbox_filter.sql(query);
+        var bboxFilter = new BBoxFilter(bbox_filter.options, bbox_filter.params);
+        query = bboxFilter.sql(query);
     }
     return query;
 }