cqrs-eventdenormalizer

Introduction

Node-cqrs-eventdenormalizer is a node.js module that implements the cqrs pattern. It can be very useful as eventdenormalizer component if you work with (d)ddd, cqrs, domain, host, etc.

Installation

$ npm install cqrs-eventdenormalizer

Usage

Initialization

var eventDenormalizer = require('cqrs-eventdenormalizer').eventDenormalizer;

eventDenormalizer.on('event', function(evt) {
    // send to clients
});
eventDenormalizer.initialize({
    viewBuildersPath: __dirname + '/viewBuilders',
    extendersPath: __dirname + '/eventExtenders',
    ignoreRevision: false,
    disableQueuing: false
}, function(err) {

});

eventDenormalizer.denormalize({ id: 'msgId', event: 'dummyChanged', payload: { id: '23445' } }, function(err) {

});

// if revision checks are enabled
eventDenormalizer.on('eventMissing', function(id, aggregateRevision, eventRevision, evt) {
    // request the appropriate missing events from domain...
});

// to replay
eventDenormalizer.replay([] /* array of ordered events */, function(err) {});

Define ViewBuilders...

var base = require('cqrs-eventdenormalizer').viewBuilderBase;

module.exports = base.extend({

    events: [
        'dummied',
        {
            event: 'dummyCreated',
            method: 'create',
            viewModelId: 'payload.id'
        },
        {
            event: 'dummyChanged',
            method: 'update',
            payload: 'payload'
        },
        {
            event: 'dummyDeleted',
            method: 'delete'
        },
        'dummySpezi',
        'somethingFlushed'
    ],

  collectionName: 'dummies',

  dummied: function(data, vm, evt) {
  },

  dummySpezi: function(data, vm, evt) {
    vm.otherValue = 'value';
  },

  somethingFlushed: function(data, vm, evt) {
  }

});

Settings for a scalable solution

{
    viewBuildersPath: __dirname + '/viewBuilders',
    extendersPath: __dirname + '/eventExtenders',
    eventQueue: { type: 'inMemory', collectionName: 'events' },
    repository: {
        type: 'mongoDb',
        dbName: 'mydb',
        timeout: 60 * 1000
    },
    revisionGuardStore: {
        type: 'mongoDb',
        dbName: 'mydb',
        collectionName: 'revisionguard',
        timeout: 60 * 1000//,
        //revisionStart: 1
    },
    ignoreRevision: false,
    disableQueuing: false,
    revisionGuardQueueTimeout: 3000,
    revisionGuardQueueTimeoutMaxLoops: 3
}

See tests for detailed information...

Release Notes

v0.3.2

• introduced optional revisionStart (default = 1)

v0.3.1

• optimized guard for first event for a new denormalized aggregate id

v0.3.0 (BREAKING CHANGES!!!)

• introduction of revisionGuard
• contextEventDenormalizer is now eventDenormalizer
• eventMissing notification (for atomic replay)
• eventDenormalizer.replay to replay (from scratch)
• eventDenormalizerBase is now viewBuilderBase
• viewBuilderBase new signature (see documentation or tests)

v0.2.6

• use new concurrency feature of viewmodel

v0.2.4

• added disableQueuing and ignoreRevision flag

License

Copyright (c) 2014 Adriano Raiano

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.