README.md

@purrfect-tools/event-store

Projections

Reference: https://developers.eventstore.com/http-api/v24.2/projections

@purrfect-tools/event-store allows you to handle your projections on two ways

Manual load

EventStoreModule exposes the EventStoreProjectionService that allows you to use the loadProjection method to manually load your projections. This method will update the projection if it was already created by another means.

OnApplicationBootstrap load

You can decorate your services with the @Projection() decorator and implement the EventStoreProjection interface. EventStoreModule will take care of your services and load them as projections.

The @Projection() decorator has multiple usages:

@Injectable()
@Projection() 
class MyService implements EventStoreProjection {
    getQuery {
        return '<MY_PROJECTION>';
    }
}

Being used like this, the @Projection() decorator will take the default configuration and will be named with a sanitized version of your class name: my_service

@Injectable()
@Projection('my_custom_named_projection')
class MyService implements EventStoreProjection {
    getQuery {
        return '<MY_PROJECTION>';
    }
}

Being used like this, the @Projection() decorator will take the default configuration and will be named with a custom name: my_custom_named_projection

@Injectable()
@Projection({
    name: 'my_name',
    configuration: {
        ...
    }
})
class MyService implements EventStoreProjection {
    getQuery {
        return '<MY_PROJECTION>';
    }
}

Being used like this, the @Projection() decorator will take a descriptor as parameter that allows you to define the configuration and the projection name. The name key is optional.

Subscriptions

Catch-up Subscriptions

Reference: https://developers.eventstore.com/clients/grpc/subscriptions

@purrfect-tools/event-store allows you to handle your catch-up subscriptions on two ways

Manual load

EventStoreModule exposes the EventStoreCatchUpSubscriptionService that allows you to use the loadCatchUpSubscriptionToAll method to manually load your catch-up subscription when it must subscribe the $all stream or loadCatchUpSubscriptionToStream when you want to use a named stream.

OnApplicationBootstrap load

You can decorate your services with the @CatchUpSubscription() decorator and implement the EventStoreCatchUpSubscription interface. EventStoreModule will take care of your services and load them as catch-up subscriptions.

The @CatchUpSubscription() decorator has multiple usages:

@Injectable()
@CatchUpSubscription() 
class MyService implements EventStoreCatchUpSubscription {
    handleEvent(resolvedEvent: ResolvedEvent) {
        // ...
    }
}

Being used like this, the @CatchUpSubscription() decorator will take the default configuration and will be subscribed to the $all stream.

@Injectable()
@CatchUpSubscription('my_stream')
class MyService implements EventStoreCatchUpSubscription {
    handleEvent(resolvedEvent: ResolvedEvent) {
        // ...
    }
}

Being used like this, the @CatchUpSubscription() decorator will take the default configuration and will be subscribed to the my_stream stream.

@Injectable()
@CatchUpSubscription({
    configuration: {
        ...
    }
})
class MyService implements EventStoreCatchUpSubscription {
    handleEvent(resolvedEvent: ResolvedEvent) {
        // ...
    }
}

Being used like this, the @CatchUpSubscription() decorator will take a descriptor as parameter that allows you to define the configuration and will be subscribed to the $all stream.

@Injectable()
@CatchUpSubscription({
    stream: 'my_stream',
    configuration: {
        ...
    }
})
class MyService implements EventStoreCatchUpSubscription {
    handleEvent(resolvedEvent: ResolvedEvent) {
        // ...
    }
}

Being used like this, the @CatchUpSubscription() decorator will take a descriptor as parameter that allows you to define the configuration and will be subscribed to the my_stream stream.

Any error thrown by the handler will be ignored and won't interrupt the event flow. Remember to handle the errors being throw by your subscriber.

Persistent Subscriptions

Reference: https://developers.eventstore.com/clients/grpc/persistent-subscriptions

@purrfect-tools/event-store allows you to handle your persistent subscriptions on two ways

Manual load

EventStoreModule exposes the EventStorePersistentSubscriptionService that allows you to use the loadProjection method to manually load your projections. This method will update the projection if it was already created by another means.

OnApplicationBootstrap load

// TODO: Works similar to CatchUp Subscriptions

// TODO: The error logic must be defined. Error logic won't interrupt the stream. Default error logic will be nack + park.