harvest 1.1.2

Event store for Dart with multiple backends for easly creating event sourced applications on both the browser and VM.

Harvest

Event store for Dart with multiple backends for easly creating event sourced applications on both the browser and VM.

Introduction

Event sourcing is the concept of saving and retriving domain objects by the events that occured on them rather than by their current state (CRUD). To understand this concept consider the following bank deposit list

1. Create account
2. Deposit 10$
3. Withdraw 2$

In a CRUD application you would have a BankAccount object with an amount property with the value 8. In a event sourced application you have a BankAccount object and 3 events for it

1. AccountCreated
2. AmountDeposited
3. AmountWithdrawn

Why is this a trick ?.

For certain types of applications this eventlog can be benificial in it self (like auditing in financial systems) but it can also be a valuable design for complex web since it makes each use case explicit and makes debugging easy (you can replay the event log to recreate any system state. Finally it also makes implementing online/offline syncronization managable, since the offline application can just queue up any events that occures and replay them on the backend once it comes back online.

For more information, see the provided example application.

Supported Storage Engines

Currently DartStore implements the following event stores.

• Memory engine: suitable for testing purposes
• IndexDB: suitable for web applications (work in progress)
• Cordova: suitable for mobile applications (work in progress)

Links

• https://github.com/joliver/EventStore