absync

absync is a highly opinionated framework to synchronize data pools in MEAN applications.

It consists of:

• a type modeling tool set that builds on top of mongoose
• a transactional layer that builds on top of socket.io
• a caching service for Angular

One of the key concepts of absync is that model properties can be decorated with permission requirements that affect the data during transaction, which allows you to hide or change properties when the model is transferred between the server and the client (and vice versa).

Usage

1. Construct domain model and decorate it.

   var mongoose = require( "mongoose-q" )();
   var Person = require( "./person.js" );
   var Schema = mongoose.Schema;
   var uuid = require( "node-uuid" );
   var TypeDecorator = require( "absync" ).TypeDecorator;
   var typeFactory = require( "absync" ).typeFactory;
   var TypeInfo = require( "absync" ).TypeInfo;
   
   var typeDescription = {
   	__v   : { type : Number, select : false },
   	guid  : { type : String, default : uuid.v4 },
   	owner : { type : Schema.Types.ObjectId, ref : "Person" },
   	added : { type : Date, default : Date.now }
   };
   
   new TypeDecorator( typeDescription )
   	.decorate( "__v", TypeInfo.USERCLASS_USER, TypeInfo.HIDDEN )
   	.decorate( "guid", TypeInfo.USERCLASS_USER, TypeInfo.READ_ONLY )
   	.decorate( "added", TypeInfo.USERCLASS_USER, TypeInfo.HIDDEN )
   ;
   
   var type = typeFactory.assemble( "Device", "devices", typeDescription );
   
   // Extend schema
   type.schema.pre( "remove", function( next ) {
   	// …
   } );
   

   absync support model inheritance, through mongoose-schema-extend:

   var extendedTypeDescription = {
   	identifierForVendor : { type : String },
   	deviceToken         : { type : String }
   };
   
   new TypeDecorator( extendedTypeDescription )
   	.decorate( "identifierForVendor", TypeInfo.USERCLASS_USER, [ TypeInfo.HIDDEN, TypeInfo.READ_ONLY ] )
   	.decorate( "deviceToken", TypeInfo.USERCLASS_USER, [ TypeInfo.CONCEALED, TypeInfo.READ_ONLY ] )
   ;
   
   var extended = typeFactory.extend( "IosDevice", "Device", extendedTypeDescription );
   

2. When data changes, use typehelper to sanitize inputs and conductor to synchronize updates with clients:

   module.exports.updateDevice = function( request, response ) {
   	var device = request.body.device;
   	var id = request.params.id;
   	return Device.model.findByIdQ( id )
   		.then( function( existingDevice ) {
   			// Update the model with the sent data and persist it to the database.
   			var updatedDeviceData = Device.typehelper.omitReadOnly( device, Device.typeinfo.USERCLASS_USER );
   			_.extend( existingDevice, updatedDeviceData );
   
   			// Persist the device record.
   			return existingDevice.saveQ()
   				.then( function( updatedDevice, numberAffected ) {
   					// Send HTTP response
   					conductor.respondToUser( updatedDevice, Device, response );
   					// Push websocket update
   					conductor.sendToUsers( updatedDevice, Device );
   				} );
   		} );
   };
   

3. Construct caching services in Angular to hold the data:

   var deviceService = absync.CacheServiceFactory( "device", "device", "/api/devices", "/api/device", Device.fromJson );
   deviceService.assemble();
   

   Device.fromJson is supposed to be a function that transforms incoming entities before they are put into the cache.

   Services emit entityNew and entityUpdated events. The data is contained in their entityCache member.