allow persistence.factory in options to be string

lib/persistence/index.js

@@ -33,3 +33,12 @@ module.exports.Memory = require("./memory");
 module.exports.LevelUp = require("./levelup");
 module.exports.Redis = require("./redis");
 module.exports.Mongo = require("./mongo");
+
+var factories = {};
+Object.keys(module.exports).forEach(function(type) {
+  factories[type.toLowerCase()] = module.exports[type];
+});
+
+module.exports.getFactory = function(name) {
+  return factories[name.toLowerCase()];
+};

lib/server.js

@@ -39,6 +39,7 @@ var Stats = require("./stats");
 var uuid = require("node-uuid");
 var st = require("st");
 var url = require("url");
+var persistence = require('./persistence');
 var defaults = {
   port: 1883,
   host: null,
@@ -120,12 +121,21 @@ function Server(opts, callback) {
 
   this.opts = extend(true, {}, defaults, opts);
 
-  if (this.opts.persistence && this.opts.persistence.factory) {
-    this.opts.persistence.factory(this.opts.persistence).wire(this);
-  }
-
   callback = callback || function() {};
 
+  var persistenceFactory = this.opts.persistence && this.opts.persistence.factory;
+  if (persistenceFactory) {
+    if (typeof persistenceFactory === 'string') {
+      var factoryName = persistenceFactory;
+      persistenceFactory = persistence.getFactory(factoryName);
+      if (!persistenceFactory) {
+        return callback(new Error('No persistence factory found for ' + factoryName ));
+      }
+    }
+
+    persistenceFactory(this.opts.persistence).wire(this);
+  }
+
   this._dedupId = 0;
   this.clients = {};
   this.closed = false;

test/server.js

@@ -736,4 +736,53 @@ describe("mosca.Server - MQTT backend", function() {
       }
     ], done);
   });
+
+  it("should build the correct persistence with string", function(done) {
+    var newSettings = moscaSettings();
+
+    newSettings.persistence = {
+      factory: 'redis',
+      port: 6379,
+      host: 'localhost'
+    };
+
+    var server = new mosca.Server(newSettings);
+
+    async.series([
+
+      function(cb) {
+        server.on("ready", cb);
+      },
+
+      function(cb) {
+        expect(server.persistence.constructor).to.match(/RedisPersistence/);
+        cb();
+      },
+
+      function(cb) {
+        server.close(cb);
+      }
+    ], done);
+  });
+
+  it("should fail if persistence string is not correct", function(done) {
+    var newSettings = moscaSettings();
+
+    newSettings.persistence = {
+      factory: 'no_such_persistence',
+      port: 6379,
+      host: 'localhost'
+    };
+
+    var server = new mosca.Server(newSettings, function(err) {
+      if(err instanceof Error) {
+        done();
+      } else {
+        expect().fail('new mosca.Server should fail');
+      }
+    });
+
+  });
+
+
 });