Gave up my reservations about relying on Node module caching to enforce the singleton pattern. The correct way is to not use the constructor but rather a 'setup', 'init' or other method.

Signed-off-by: Alexander Mays <[email protected]>

Author: Alexander Mays

classes/BaseProvider.js

@@ -2,7 +2,9 @@ var ServiceProviderInterface = require('../interfaces/ServiceProvider');
 var util = require('util');
 
 function BaseProvider(adapter) {
-    this.adapter = adapter;
+    if (adapter) {
+        this.adapter = adapter;
+    }
 };
 
 util.inherits(BaseProvider, ServiceProviderInterface);
@@ -17,5 +19,6 @@ function setAdapter(adapter) {
 
 BaseProvider.prototype.getAdapter = getAdapter;
 BaseProvider.prototype.setAdapter = setAdapter;
+BaseProvider.prototype.BaseProvider = BaseProvider;
 
-module.exports = BaseProvider;
+exports = module.exports = new BaseProvider();

classes/CacheProvider.js

@@ -1,19 +1,12 @@
-var BaseProvider = require('./BaseProvider');
+var BaseProvider = require('./BaseProvider').BaseProvider;
 var util = require('util');
 
-// Singleton for the entire server.
-// TODO: Refactor away from singleton paradigm
-var instance = null;
-
 function CacheProvider(adapter) {
-    if (instance) {
-        return instance;
-    }
-
-    instance = this;
-    this.adapter = adapter;
+    CacheProvider.super_.call(this)
 };
 
 util.inherits(CacheProvider, BaseProvider);
 
-module.exports = CacheProvider;
+CacheProvider.prototype.CacheProvider = CacheProvider;
+
+exports = module.exports = new CacheProvider();

interfaces/ServiceProvider.js

@@ -9,4 +9,4 @@ ServiceProviderInterface.prototype.setAdapter = function() {
     throw new Error('A service provider must implement setAdapter!');
 }
 
-module.exports = ServiceProviderInterface;
+exports = module.exports = ServiceProviderInterface;

src/Auth.js

@@ -41,8 +41,7 @@ function nobody(config) {
 
 // Returns a promise that resolves to an Auth object
 var getAuthForSessionToken = function(config, sessionToken) {
-  var cacheProvider = new (require('./classes/CacheProvider'));
-  var cache = cacheProvider.getAdapter();
+  var cache = require('./classes/CacheProvider').getAdapter();
 
   var cachedUser = cache.get(sessionToken);
   if (cachedUser) {

src/Config.js

@@ -2,8 +2,7 @@
 // configured.
 // mount is the URL for the root of the API; includes http, domain, etc.
 function Config(applicationId, mount) {
-  var cacheProvider = new (require('./classes/CacheProvider'));
-  var cache = cacheProvider.getAdapter();
+  var cache = require('./classes/CacheProvider').getAdapter();
   var DatabaseAdapter = require('./DatabaseAdapter');
 
   var cacheInfo = cache.get(applicationId);

src/DatabaseAdapter.js

@@ -34,8 +34,7 @@ function setAppDatabaseURI(appId, uri) {
 }
 
 function getDatabaseConnection(appId) {
-  var cacheProvider = new (require('./classes/CacheProvider'));
-  var cache = cacheProvider.getAdapter();
+  var cache = require('./classes/CacheProvider').getAdapter();
   if (dbConnections[appId]) {
     return dbConnections[appId];
   }

src/index.js

@@ -195,7 +195,8 @@ function setupCache(config) {
   config.adapter = config.adapter || DefaultCacheAdapter;
 
   var adapter = this.resolveAdapter(config.adapter, config.options);
-  this.cacheProvider = new CacheProvider(adapter);
+  CacheProvider.setAdapter(adapter);
+  this.cacheProvider = CacheProvider;
 }
 
 ParseServer.prototype.setupCache = setupCache;

src/middlewares.js

@@ -10,8 +10,7 @@ var Config = require('./Config');
 // req.config - the Config for this app
 // req.auth - the Auth for this request
 function handleParseHeaders(req, res, next) {
-  var cacheProvider = new (require('./classes/CacheProvider'));
-  var cache = cacheProvider.getAdapter();
+  var cache = require('./classes/CacheProvider').getAdapter();
   var mountPathLength = req.originalUrl.length - req.url.length;
   var mountPath = req.originalUrl.slice(0, mountPathLength);
   var mount = req.protocol + '://' + req.get('host') + mountPath;

src/rest.js

@@ -35,8 +35,7 @@ function del(config, auth, className, objectId) {
   enforceRoleSecurity('delete', className, auth);
 
   var inflatedObject;
-  var cacheProvider = new (require('./classes/CacheProvider'));
-  var cache = cacheProvider.getAdapter();
+  var cache = require('./classes/CacheProvider').getAdapter();
 
   return Promise.resolve().then(() => {
     if (triggers.getTrigger(className, 'beforeDelete') ||

src/testing-routes.js

@@ -8,8 +8,7 @@ var router = express.Router();
 
 // creates a unique app in the cache, with a collection prefix
 function createApp(req, res) {
-  var cacheProvider = new (require('./classes/CacheProvider'));
-  var cache = cacheProvider.getAdapter();
+  var cache = require('./classes/CacheProvider').getAdapter();
   var appId = rack();
   cache.put(appId,  {
     'collectionPrefix': appId + '_',