Calculated fields

packages/framework-common-helpers/src/instances.ts

@@ -1,5 +1,5 @@
 /* eslint-disable @typescript-eslint/no-explicit-any */
-import { Class } from '@boostercloud/framework-types'
+import { Class, ReadModelInterface } from '@boostercloud/framework-types'
 
 /**
  * Creates an instance of the given class from the given raw object.
@@ -43,3 +43,89 @@
 export function createInstances<T>(instanceClass: Class<T>, rawObjects: Array<Record<string, any>>): T[] {
   return rawObjects.map((rawObject) => createInstance(instanceClass, rawObject))
 }
+
+/**
+ * Creates an instance of the read model class with the calculated properties included
+ * @param instanceClass The read model class
+ * @param raw The raw read model data
+ * @param propertiesToInclude The properties to include in the response
+ * @private
+ */
+export async function createInstanceWithCalculatedProperties<T extends ReadModelInterface>(
+  instanceClass: { new (...args: any[]): T },
+  raw: Partial<T>,
+  propertiesToInclude: string[]
+): Promise<{ [key: string]: any }> {
+  const instance = new instanceClass()
+  Object.assign(instance, raw)
+  const result: { [key: string]: any } = {}
+
+  const propertiesMap = buildPropertiesMap(propertiesToInclude)
+
+  await processProperties(instance, result, propertiesMap)
+
+  return result
+}
+
+/**
+ * Builds a map of properties to include in the response
+ * @param properties The properties to include in the response
+ * @private
+ */
+function buildPropertiesMap(properties: string[]): any {
+  const map: any = {}
+  properties.forEach((property) => {
+    const parts = property.split('.')
+    let current = map
+    parts.forEach((part) => {
+      const isArray = part.endsWith('[]')
+      const key = isArray ? part.slice(0, -2) : part
+      if (!current[key]) {
+        current[key] = isArray ? { __isArray: true, __children: {} } : {}
+      }
+      current = isArray ? current[key].__children : current[key]
+    })
+  })
+  return map
+}
+
+/**
+ * Processes the properties of the source object and adds them to the result object
+ * @param source The source object
+ * @param result The result object
+ * @param propertiesMap The map of properties to include in the response
+ * @private
+ */
+async function processProperties(source: any, result: any, propertiesMap: any): Promise<void> {
+  for (const key of Object.keys(propertiesMap)) {
+    if (key === '__isArray' || key === '__children') continue
+
+    if (source[key] !== undefined) {
+      if (propertiesMap[key].__isArray) {
+        result[key] = []
+        for (const item of source[key]) {
+          const newItem: any = {}
+          await processProperties(item, newItem, propertiesMap[key].__children)
+          if (Object.keys(newItem).length > 0) {
+            result[key].push(newItem)
+          }
+        }
+      } else if (typeof propertiesMap[key] === 'object' && Object.keys(propertiesMap[key]).length > 0) {
+        const value = source[key]
+        const resolvedValue = isPromise(value) ? await value : value
+        result[key] = {}
+        await processProperties(resolvedValue, result[key], propertiesMap[key])
+        if (Object.keys(result[key]).length === 0) {
+          delete result[key]
+        }
+      } else {
+        const value = source[key]
+        result[key] = isPromise(value) ? await value : value
+      }
+    }
+  }
+}
+
+function isPromise(obj: any): obj is Promise<any> {
+  return !!obj && (typeof obj === 'object' || typeof obj === 'function') && typeof obj.then === 'function'
+}

packages/framework-core/src/booster-read-models-reader.ts

@@ -1,25 +1,32 @@
 /* eslint-disable @typescript-eslint/no-explicit-any */
 import {
-  TraceActionTypes,
   AnyClass,
   BoosterConfig,
   FilterFor,
   GraphQLOperation,
   InvalidParameterError,
   NotFoundError,
+  ProjectionFor,
   ReadModelInterface,
   ReadModelListResult,
+  ReadModelMetadata,
   ReadModelRequestEnvelope,
   ReadOnlyNonEmptyArray,
   SortFor,
   SubscriptionEnvelope,
-  ProjectionFor,
+  TraceActionTypes,
 } from '@boostercloud/framework-types'
-import { createInstance, createInstances, getLogger } from '@boostercloud/framework-common-helpers'
+import {
+  createInstance,
+  createInstances,
+  createInstanceWithCalculatedProperties,
+  getLogger,
+} from '@boostercloud/framework-common-helpers'
 import { Booster } from './booster'
 import { applyReadModelRequestBeforeFunctions } from './services/filter-helpers'
 import { ReadModelSchemaMigrator } from './read-model-schema-migrator'
 import { Trace } from './instrumentation'
+import { PropertyMetadata } from '@boostercloud/metadata-booster'
 
 export class BoosterReadModelsReader {
   public constructor(readonly config: BoosterConfig) {}
@@ -88,6 +95,23 @@ export class BoosterReadModelsReader {
     select?: ProjectionFor<TReadModel>
   ): Promise<Array<TReadModel> | ReadModelListResult<TReadModel>> {
     const readModelName = readModelClass.name
+
+    let selectWithDependencies: ProjectionFor<TReadModel> | undefined = undefined
+    const calculatedFieldsDependencies = this.getCalculatedFieldsDependencies(readModelClass)
+
+    if (select && Object.keys(calculatedFieldsDependencies).length > 0) {
+      const extendedSelect = new Set<string>(select)
+
+      select.forEach((field: any) => {
+        const topLevelField = field.split('.')[0].replace('[]', '')
+        if (calculatedFieldsDependencies[topLevelField]) {
+          calculatedFieldsDependencies[topLevelField].map((dependency) => extendedSelect.add(dependency))
+        }
+      })
+
+      selectWithDependencies = Array.from(extendedSelect) as ProjectionFor<TReadModel>
+    }
+
     const searchResult = await this.config.provider.readModels.search<TReadModel>(
       this.config,
       readModelName,
@@ -96,13 +120,13 @@ export class BoosterReadModelsReader {
       limit,
       afterCursor,
       paginatedVersion ?? false,
-      select
+      selectWithDependencies ?? select
     )
 
+    const readModels = this.createReadModelInstances(searchResult, readModelClass)
     if (select) {
-      return searchResult
+      return this.createReadModelInstancesWithCalculatedProperties(searchResult, readModelClass, select ?? [])
     }
-    const readModels = this.createReadModelInstances(searchResult, readModelClass)
     return this.migrateReadModels(readModels, readModelName)
   }
 
@@ -133,6 +157,34 @@ export class BoosterReadModelsReader {
     }
   }
 
+  /**
+   * Creates instances of the read model class with the calculated properties included
+   * @param searchResult The search result
+   * @param readModelClass The read model class
+   * @param propertiesToInclude The properties to include in the response
+   * @private
+   */
+  private async createReadModelInstancesWithCalculatedProperties<TReadModel extends ReadModelInterface>(
+    searchResult: Array<TReadModel> | ReadModelListResult<TReadModel>,
+    readModelClass: AnyClass,
+    propertiesToInclude: string[]
+  ): Promise<Array<TReadModel> | ReadModelListResult<TReadModel>> {
+    const processInstance = async (raw: Partial<TReadModel>): Promise<TReadModel> => {
+      const instance = await createInstanceWithCalculatedProperties(readModelClass, raw, propertiesToInclude)
+      return instance as TReadModel
+    }
+
+    if (Array.isArray(searchResult)) {
+      return await Promise.all(searchResult.map(processInstance))
+    } else {
+      const processedItems = await Promise.all(searchResult.items.map(processInstance))
+      return {
+        ...searchResult,
+        items: processedItems,
+      }
+    }
+  }
+
   public async subscribe(
     connectionID: string,
     readModelRequest: ReadModelRequestEnvelope<ReadModelInterface>,
@@ -216,4 +268,20 @@ export class BoosterReadModelsReader {
     }
     return this.config.provider.readModels.subscribe(this.config, subscription)
   }
+
+  /**
+   * Returns the dependencies of the calculated fields of a read model
+   * @param readModelClass The read model class
+   * @private
+   */
+  private getCalculatedFieldsDependencies(readModelClass: AnyClass): Record<string, Array<string>> {
+    const readModelMetadata: ReadModelMetadata = this.config.readModels[readModelClass.name]
+
+    const dependenciesMap: Record<string, Array<string>> = {}
+    readModelMetadata?.properties.map((property: PropertyMetadata): void => {
+      dependenciesMap[property.name] = property.dependencies
+    })
+
+    return dependenciesMap
+  }
 }

packages/framework-core/src/decorators/read-model.ts

@@ -24,12 +24,35 @@ export function ReadModel(
       }
 
       const authorizer = BoosterAuthorizer.build(attributes) as ReadModelAuthorizer
+      const classMetadata = getClassMetadata(readModelClass)
+      const dynamicDependencies = Reflect.getMetadata('dynamic:dependencies', readModelClass) || {}
+
+      // Combine properties with dynamic dependencies
+      const properties = classMetadata.fields.map((field: any) => {
+        return {
+          ...field,
+          dependencies: dynamicDependencies[field.name] || [],
+        }
+      })
+
       config.readModels[readModelClass.name] = {
         class: readModelClass,
-        properties: getClassMetadata(readModelClass).fields,
+        properties,
         authorizer,
         before: attributes.before ?? [],
       }
     })
   }
 }
+
+/**
+ * Decorator to mark a property as a calculated field with dependencies.
+ * @param dependencies - An array of strings indicating the dependencies.
+ */
+export function CalculatedField(dependencies: string[]): PropertyDecorator {
+  return (target: object, propertyKey: string | symbol): void => {
+    const existingDependencies = Reflect.getMetadata('dynamic:dependencies', target.constructor) || {}
+    existingDependencies[propertyKey] = dependencies
+    Reflect.defineMetadata('dynamic:dependencies', existingDependencies, target.constructor)
+  }
+}

packages/framework-core/test/booster-read-models-reader.test.ts

@@ -457,6 +457,7 @@ describe('BoosterReadModelReader', () => {
             filters,
             currentUser,
             select: ['id'],
+            skipInstance: false,
           } as any
 
           const expectedReadModels = [new TestReadModel(), new TestReadModel()]
@@ -491,6 +492,7 @@ describe('BoosterReadModelReader', () => {
             filters,
             currentUser,
             select: ['id'],
+            skipInstance: false,
           } as any
 
           const expectedResult = [new TestReadModel(), new TestReadModel()]