New map config provider to allow injecting limits in context

lib/cartodb/controllers/layergroup.js

@@ -3,8 +3,7 @@ var step = require('step');
 
 var cors = require('../middleware/cors');
 
-var windshaft = require('windshaft');
-var MapStoreMapConfigProvider = windshaft.model.provider.MapStoreMapConfig;
+var MapStoreMapConfigProvider = require('../models/mapconfig/map_store_provider');
 
 /**
  * @param app

lib/cartodb/models/mapconfig/map_store_provider.js

@@ -0,0 +1,56 @@
+var _ = require('underscore');
+var dot = require('dot');
+
+/**
+ * @param {MapStore} mapStore
+ * @param {Object} params
+ * @constructor
+ * @type {MapStoreMapConfigProvider}
+ */
+function MapStoreMapConfigProvider(mapStore, params) {
+    this.mapStore = mapStore;
+    this.params = params;
+    this.token = params.token;
+    this.cacheBuster = params.cache_buster || 0;
+}
+
+module.exports = MapStoreMapConfigProvider;
+
+MapStoreMapConfigProvider.prototype.getMapConfig = function(callback) {
+    var self = this;
+    this.mapStore.load(this.token, function(err, mapConfig) {
+        return callback(err, mapConfig, self.params, {});
+    });
+};
+
+MapStoreMapConfigProvider.prototype.getKey = function() {
+    return this.createKey(false);
+};
+
+MapStoreMapConfigProvider.prototype.getCacheBuster = function() {
+    return this.cacheBuster;
+};
+
+MapStoreMapConfigProvider.prototype.filter = function(key) {
+    var regex = new RegExp('^' + this.createKey(true) + '.*');
+    return key && key.match(regex);
+};
+
+// Configure bases for cache keys suitable for string interpolation
+var baseKey   = '{{=it.dbname}}:{{=it.token}}';
+var rendererKey = baseKey + ':{{=it.dbuser}}:{{=it.format}}:{{=it.layer}}:{{=it.scale_factor}}';
+
+var baseKeyTpl = dot.template(baseKey);
+var rendererKeyTpl = dot.template(rendererKey);
+
+MapStoreMapConfigProvider.prototype.createKey = function(base) {
+    var tplValues = _.defaults({}, this.params, {
+        dbname: '',
+        token: '',
+        dbuser: '',
+        format: '',
+        layer: '',
+        scale_factor: 1
+    });
+    return (base) ? baseKeyTpl(tplValues) : rendererKeyTpl(tplValues);
+};

lib/cartodb/models/mapconfig/named_map_provider.js

@@ -6,6 +6,10 @@ var step = require('step');
 var MapConfig = require('windshaft').model.MapConfig;
 var templateName = require('../../backends/template_maps').templateName;
 
+/**
+ * @constructor
+ * @type {NamedMapMapConfigProvider}
+ */
 function NamedMapMapConfigProvider(templateMaps, pgConnection, owner, templateId, config, authToken, params) {
     this.templateMaps = templateMaps;
     this.pgConnection = pgConnection;
@@ -131,7 +135,7 @@ NamedMapMapConfigProvider.prototype.getTemplate = function(callback) {
 };
 
 NamedMapMapConfigProvider.prototype.getKey = function() {
-    return this.createKey();
+    return this.createKey(false);
 };
 
 NamedMapMapConfigProvider.prototype.getCacheBuster = function() {