Named maps controller adding cache headers

This requires a cache for affected tables as it is hitting db for
every request right now

lib/cartodb/controllers/named_maps.js

@@ -5,9 +5,10 @@ var NamedMapsCacheEntry = require('../cache/model/named_maps_entry');
 var cors = require('../middleware/cors');
 
 var NamedMapMapConfigProvider = require('../models/mapconfig/named_map_provider');
+var TablesCacheEntry = require('../cache/model/database_tables_entry');
 
 function NamedMapsController(app, pgConnection, templateMaps, tileBackend, previewBackend, surrogateKeysCache,
-                             tablesExtentApi, userLimitsApi) {
+                             tablesExtentApi, userLimitsApi, queryTablesApi) {
     this.app = app;
     this.pgConnection = pgConnection;
     this.templateMaps = templateMaps;
@@ -16,6 +17,7 @@ function NamedMapsController(app, pgConnection, templateMaps, tileBackend, previ
     this.surrogateKeysCache = surrogateKeysCache;
     this.tablesExtentApi = tablesExtentApi;
     this.userLimitsApi = userLimitsApi;
+    this.queryTablesApi = queryTablesApi;
 }
 
 module.exports = NamedMapsController;
@@ -29,9 +31,40 @@ NamedMapsController.prototype.register = function(app) {
 
 NamedMapsController.prototype.sendResponse = function(req, res, resource, headers, namedMapProvider) {
     this.surrogateKeysCache.tag(res, new NamedMapsCacheEntry(req.context.user, namedMapProvider.getTemplateName()));
-    res.setHeader('Content-Type', headers['Content-Type']);
-    res.setHeader('Cache-Control', 'public,max-age=7200,must-revalidate');
-    this.app.sendResponse(res, [resource, 200]);
+    res.header('Content-Type', headers['Content-Type']);
+    res.header('Cache-Control', 'public,max-age=7200,must-revalidate');
+
+    var self = this;
+
+    var dbName = req.params.dbname;
+    step(
+        function getAffectedTablesAndLastUpdatedTime() {
+            namedMapProvider.getAffectedTablesAndLastUpdatedTime(self.queryTablesApi, this);
+        },
+        function sendResponse(err, result) {
+            req.profiler.done('affectedTables');
+            if (err) {
+                console.log('ERROR generating cache channel: ' + err);
+            }
+            if (!result || !!result.affectedTables) {
+                // we increase cache control as we can invalidate it
+                res.header('Cache-Control', 'public,max-age=31536000');
+
+                var lastModifiedDate;
+                if (Number.isFinite(result.lastUpdatedTime)) {
+                    lastModifiedDate = new Date(result.lastUpdatedTime);
+                } else {
+                    lastModifiedDate = new Date();
+                }
+                res.header('Last-Modified', lastModifiedDate.toUTCString());
+
+                var tablesCacheEntry = new TablesCacheEntry(dbName, result.affectedTables);
+                res.header('X-Cache-Channel', tablesCacheEntry.getCacheChannel());
+                self.surrogateKeysCache.tag(res, tablesCacheEntry);
+            }
+            self.app.sendResponse(res, [resource, 200]);
+        }
+    );
 };
 
 NamedMapsController.prototype.tile = function(req, res) {

lib/cartodb/models/mapconfig/named_map_provider.js

@@ -24,6 +24,8 @@ function NamedMapMapConfigProvider(templateMaps, pgConnection, userLimitsApi, ow
     // use template after call to mapConfig
     this.template = null;
 
+    this.affectedTablesAndLastUpdate = null;
+
     // providing
     this.err = null;
     this.mapConfig = null;
@@ -198,3 +200,31 @@ NamedMapMapConfigProvider.prototype.setDBParams = function(cdbuser, params, call
 NamedMapMapConfigProvider.prototype.getTemplateName = function() {
     return this.templateName;
 };
+
+NamedMapMapConfigProvider.prototype.getAffectedTablesAndLastUpdatedTime = function(queryTablesApi, callback) {
+    var self = this;
+
+    if (this.affectedTablesAndLastUpdate !== null) {
+        return this.affectedTablesAndLastUpdate;
+    }
+
+    step(
+        function getMapConfig() {
+            self.getMapConfig(this);
+        },
+        function getSql(err, mapConfig) {
+            assert.ifError(err);
+            return mapConfig.getLayers().map(function(layer) {
+                return layer.options.sql;
+            }).join(';');
+        },
+        function getAffectedTables(err, sql) {
+            assert.ifError(err);
+            queryTablesApi.getAffectedTablesAndLastUpdatedTime(self.owner, sql, this);
+        },
+        function finish(err, result) {
+            self.affectedTablesAndLastUpdate = result;
+            return callback(err, result);
+        }
+    );
+};

lib/cartodb/server.js

@@ -221,7 +221,8 @@ module.exports = function(serverOptions) {
         previewBackend,
         surrogateKeysCache,
         tablesExtentApi,
-        userLimitsApi
+        userLimitsApi,
+        queryTablesApi
     ).register(app);
 
     new controller.NamedMapsAdmin(app, templateMaps, authApi).register(app);