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eventric

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behavior-first application development

github.com/efacilitation/eventric

efacilitation/eventric

131 lines (95 loc) • 4.23 kB
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uuidGenerator = require 'eventric/uuid_generator' class ProjectionService constructor: (@_context) -> @_logger = require('eventric').getLogger() @_handlerFunctions = {} @_projectionInstances = {} initializeInstance: (projectionInstance, params) -> if @_context._di for diName, diFn of @_context._di projectionInstance[diName] = diFn projectionId = uuidGenerator.generateUuid() aggregateId = null projectionInstance.$subscribeHandlersWithAggregateId = (_aggregateId) -> if not _aggregateId throw new Error 'Missing aggregate id' aggregateId = _aggregateId eventNames = null @_callInitializeOnProjection projectionInstance, params .then => @_parseEventNamesFromProjection projectionInstance .then (_eventNames) => eventNames = _eventNames @_applyDomainEventsFromStoreToProjection projectionInstance, eventNames, aggregateId .then => @_subscribeProjectionToDomainEvents projectionId, projectionInstance, eventNames, aggregateId .then => @_projectionInstances[projectionId] = projectionInstance .then -> projectionInstance.isInitialized = true .then -> projectionId _callInitializeOnProjection: (projection, params) -> new Promise (resolve) -> if not projection.initialize return resolve projection projection.initialize params, -> resolve projection _parseEventNamesFromProjection: (projection) -> new Promise (resolve) -> eventNames = [] for key, value of projection if (key.indexOf 'handle') is 0 and (typeof value is 'function') eventName = key.replace /^handle/, '' eventNames.push eventName resolve eventNames _applyDomainEventsFromStoreToProjection: (projection, eventNames, aggregateId) -> if aggregateId findEvents = @_context.findDomainEventsByNameAndAggregateId eventNames, aggregateId else findEvents = @_context.findDomainEventsByName eventNames findEvents .then (domainEvents) => if not domainEvents or domainEvents.length is 0 return applyDomainEventsToProjectionPromise = Promise.resolve() domainEvents.forEach (domainEvent) => applyDomainEventsToProjectionPromise = applyDomainEventsToProjectionPromise .then => @_applyDomainEventToProjection domainEvent, projection return applyDomainEventsToProjectionPromise _subscribeProjectionToDomainEvents: (projectionId, projection, eventNames, aggregateId) -> domainEventHandler = (domainEvent) => @_applyDomainEventToProjection domainEvent, projection @_handlerFunctions[projectionId] = [] subscribeProjectionToDomainEventsPromise = Promise.resolve() eventNames.forEach (eventName) => subscribeProjectionToDomainEventsPromise = subscribeProjectionToDomainEventsPromise .then => if aggregateId @_context.subscribeToDomainEventWithAggregateId eventName, aggregateId, domainEventHandler else @_context.subscribeToDomainEvent eventName, domainEventHandler .then (subscriberId) => @_handlerFunctions[projectionId].push subscriberId return subscribeProjectionToDomainEventsPromise _applyDomainEventToProjection: (domainEvent, projection) -> Promise.resolve() .then => if !projection["handle#{domainEvent.name}"] @_logger.warn "ProjectionService: handle#{domainEvent.name} not defined" return projection["handle#{domainEvent.name}"] domainEvent getInstance: (projectionId) -> @_projectionInstances[projectionId] destroyInstance: (projectionId) -> if not projectionId return Promise.reject new Error 'Missing projection id' if not @_handlerFunctions[projectionId] return Promise.reject new Error "Projection with id \"#{projectionId}\" is not initialized" unsubscribePromises = [] for subscriberId in @_handlerFunctions[projectionId] unsubscribePromises.push @_context.unsubscribeFromDomainEvent subscriberId delete @_handlerFunctions[projectionId] delete @_projectionInstances[projectionId] Promise.all unsubscribePromises module.exports = ProjectionService