Liquid Projections

What is this?

Liquid Projections is designed as a library (and not a framework) that should help you write maintainable projection code in an event sourcing architecture. After evaluating several years of working with an event sourced architecture, I decided I needed a fresh start. This project has been designed based on the following principles:

• Designed as a library which doesn't hide the magic behind abstractions and tries to avoid the need to sub-class anything.
• Projections must be autonomous so whether a projector stores its projections in-memory, in RavenDB or in a RDBMS is a local concern.
• Similarly, whether it restarts from scratch every time or stores progress information in-between is a decision each projection can make.
• Is distributed as separate NuGet packages so that you don't need to take dependencies on stuff you don't need.
• async all the way

What does it offer?

Liquid Projections offers several components that are designed to be used independently.

• An EventMapBuilder to fluently build an EventMap that defines how events should be handled during projection.
• A thin abstraction named IEventStore to represent an event store. Currently only NEventStore is supported as well as a in-memory event store for testing purposes.
• Projector classes for RavenDB, NHibernate as well as an agnostic Projector that you can use within your projectors.
• Support for look-ups by allowing you to nest projectors.
• A Dispatcher that can be used to connect an IEventStore implementation with a projector.
• A ProjectionException that provides everything you would like to know to understand why a projection fails.

How to get started?

For now, please review the unit tests.