Allow session adapter to be required directly (still supporting `adap…

…ter` being a string naming the adapter to be required).

lib/hooks/session/index.js

@@ -199,10 +199,22 @@ module.exports = function(app) {
           // or catch and return error:
           else {
 
-            var SessionAdapter;
+            var SessionAdapter, CustomStore;
             try {
+              // If `sails.config.session.adapter` is a string, attempt to require the
+              // modulde identified by the string.
+              if (_.isString(app.config.session.adapter)) {
+                SessionAdapter = require(path.resolve(app.config.appPath, 'node_modules', app.config.session.adapter));
+              }
+              // Otherwise if it's an object (including a function!), set SessionAdapter to that value.
+              else if (_.isObject(app.config.session.adapter)) {
+                SessionAdapter = app.config.session.adapter;
+              }
+              // Otherwise bail, because sails.config.session.adapter is invalid.
+              else {
+                return cb(new Error('If configured, `sails.config.session.adapter` should be a reference to an Express session adapter!  Instead got `' + util.inspect(app.config.session.adapter)));
+              }
               // Attempt to initialize the adapter using the express-session module
-              SessionAdapter = require(path.resolve(app.config.appPath, 'node_modules', sessionConfig.adapter));
               try {
                 var CustomStore = SessionAdapter(require('express-session'));
                 sessionConfig.store = new CustomStore(sessionConfig);