From 3f2ef63976decb9e828abb23efc296288f75f2b7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Garc=C3=ADa=20Aubert?=
 <danielgarciaaubert@gmail.com>
Date: Tue, 31 Oct 2017 11:38:54 +0100
Subject: [PATCH] Extract cache channel to its own method

---
 lib/cartodb/controllers/named_maps.js | 85 +++++++++++++++------------
 1 file changed, 49 insertions(+), 36 deletions(-)

diff --git a/lib/cartodb/controllers/named_maps.js b/lib/cartodb/controllers/named_maps.js
index 55790bbf..ffea03a2 100644
--- a/lib/cartodb/controllers/named_maps.js
+++ b/lib/cartodb/controllers/named_maps.js
@@ -39,43 +39,56 @@ NamedMapsController.prototype.register = function(app) {
     );
 };
 
-NamedMapsController.prototype.sendResponse = function(req, res, body, headers, namedMapProvider) {
+NamedMapsController.prototype.sendResponse = function(req, res, body, headers) {
+    const { namedMapProvider } = res.locals;
+
     this.surrogateKeysCache.tag(res, new NamedMapsCacheEntry(res.locals.user, namedMapProvider.getTemplateName()));
     res.set('Content-Type', headers['content-type'] || headers['Content-Type'] || 'image/png');
     res.set('Cache-Control', 'public,max-age=7200,must-revalidate');
 
-    var self = this;
-
-    step(
-        function getAffectedTablesAndLastUpdatedTime() {
-            namedMapProvider.getAffectedTablesAndLastUpdatedTime(this);
-        },
-        function sendResponse(err, result) {
-            req.profiler.done('affectedTables');
-            if (err) {
-                global.logger.log('ERROR generating cache channel: ' + err);
-            }
-            if (!result || !!result.tables) {
-                // we increase cache control as we can invalidate it
-                res.set('Cache-Control', 'public,max-age=31536000');
-
-                var lastModifiedDate;
-                if (Number.isFinite(result.lastUpdatedTime)) {
-                    lastModifiedDate = new Date(result.getLastUpdatedAt());
-                } else {
-                    lastModifiedDate = new Date();
-                }
-                res.set('Last-Modified', lastModifiedDate.toUTCString());
-
-                res.set('X-Cache-Channel', result.getCacheChannel());
-                if (result.tables.length > 0) {
-                    self.surrogateKeysCache.tag(res, result);
-                }
-            }
-            res.status(200);
-            res.send(body);
+    this.setCacheChannel(req, res, (err) => {
+        if (err) {
+            global.logger.log('ERROR generating cache channel: ' + err);
         }
-    );
+
+        res.status(200);
+        res.send(body);
+    });
+};
+
+NamedMapsController.prototype.setCacheChannel = function(req, res, callback) {
+    const { namedMapProvider } = res.locals;
+
+    this.getAffectedTables(namedMapProvider, (err, result) => {
+
+        req.profiler.done('affectedTables');
+        if (err) {
+            global.logger.log('ERROR generating cache channel: ' + err);
+        }
+        if (!result || !!result.tables) {
+            // we increase cache control as we can invalidate it
+            res.set('Cache-Control', 'public,max-age=31536000');
+
+            var lastModifiedDate;
+            if (Number.isFinite(result.lastUpdatedTime)) {
+                lastModifiedDate = new Date(result.getLastUpdatedAt());
+            } else {
+                lastModifiedDate = new Date();
+            }
+            res.set('Last-Modified', lastModifiedDate.toUTCString());
+
+            res.set('X-Cache-Channel', result.getCacheChannel());
+            if (result.tables.length > 0) {
+                this.surrogateKeysCache.tag(res, result);
+            }
+        }
+
+        callback();
+    });
+};
+
+NamedMapsController.prototype.getAffectedTables = function(namedMapProvider, callback) {
+    namedMapProvider.getAffectedTablesAndLastUpdatedTime(callback);
 };
 
 NamedMapsController.prototype.tile = function(req, res, next) {
@@ -97,7 +110,7 @@ NamedMapsController.prototype.tile = function(req, res, next) {
         },
         function getTile(err, _namedMapProvider) {
             assert.ifError(err);
-            namedMapProvider = _namedMapProvider;
+            res.locals.namedMapProvider = namedMapProvider = _namedMapProvider;
             self.tileBackend.getTile(namedMapProvider, req.params, this);
         },
         function handleImage(err, tile, headers, stats) {
@@ -106,7 +119,7 @@ NamedMapsController.prototype.tile = function(req, res, next) {
                 err.label = 'NAMED_MAP_TILE';
                 next(err);
             } else {
-                self.sendResponse(req, res, tile, headers, namedMapProvider);
+                self.sendResponse(req, res, tile, headers);
             }
         }
     );
@@ -136,7 +149,7 @@ NamedMapsController.prototype.staticMap = function(req, res, next) {
         function prepareLayerVisibility(err, _namedMapProvider) {
             assert.ifError(err);
 
-            namedMapProvider = _namedMapProvider;
+            res.locals.namedMapProvider = namedMapProvider = _namedMapProvider;
 
             self.prepareLayerFilterFromPreviewLayers(cdbUser, req, res.locals, namedMapProvider, this);
         },
@@ -179,7 +192,7 @@ NamedMapsController.prototype.staticMap = function(req, res, next) {
                 err.label = 'STATIC_VIZ_MAP';
                 next(err);
             } else {
-                self.sendResponse(req, res, image, headers, namedMapProvider);
+                self.sendResponse(req, res, image, headers);
             }
         }
     );