Allow define projection fields in read model queries

common/changes/@boostercloud/framework-core/allow_define_projection_fields_in_read_model_queries_2023-10-25-12-18.json

@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@boostercloud/framework-core",
+      "comment": "Allow define projection fields in read model queries",
+      "type": "minor"
+    }
+  ],
+  "packageName": "@boostercloud/framework-core"
+}

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

@@ -13,6 +13,7 @@ import {
   ReadOnlyNonEmptyArray,
   SortFor,
   SubscriptionEnvelope,
+  ProjectionFor,
 } from '@boostercloud/framework-types'
 import { createInstance, createInstances, getLogger } from '@boostercloud/framework-common-helpers'
 import { Booster } from './booster'
@@ -71,7 +72,8 @@ export class BoosterReadModelsReader {
       readModelTransformedRequest.sortBy,
       readModelTransformedRequest.limit,
       readModelTransformedRequest.afterCursor,
-      readModelTransformedRequest.paginatedVersion
+      readModelTransformedRequest.paginatedVersion,
+      readModelTransformedRequest.select
     )
   }
 
@@ -82,7 +84,8 @@ export class BoosterReadModelsReader {
     sort?: SortFor<unknown>,
     limit?: number,
     afterCursor?: any,
-    paginatedVersion?: boolean
+    paginatedVersion?: boolean,
+    select?: ProjectionFor<TReadModel>
   ): Promise<Array<TReadModel> | ReadModelListResult<TReadModel>> {
     const readModelName = readModelClass.name
     const searchResult = await this.config.provider.readModels.search<TReadModel>(
@@ -92,9 +95,13 @@ export class BoosterReadModelsReader {
       sort ?? {},
       limit,
       afterCursor,
-      paginatedVersion ?? false
+      paginatedVersion ?? false,
+      select
     )
 
+    if (select) {
+      return searchResult
+    }
     const readModels = this.createReadModelInstances(searchResult, readModelClass)
     return this.migrateReadModels(readModels, readModelName)
   }

packages/framework-core/src/decorators/schema-migration.ts

@@ -4,6 +4,9 @@ import 'reflect-metadata'
 
 const migrationMethodsMetadataKey = 'booster:migrationsMethods'
 
+/**
+ * **NOTE:** Using this decorator for read model migrations is deprecated. Prefer using `@DataMigration` instead.
+ */
 export function SchemaMigration(conceptClass: AnyClass): (schemaMigrationClass: AnyClass) => void {
   return (schemaMigrationClass) => {
     Booster.configureCurrentEnv((config) => {

packages/framework-core/src/read-model-schema-migrator.ts

@@ -11,6 +11,9 @@ import { Trace } from './instrumentation'
 export class ReadModelSchemaMigrator {
   public constructor(private config: BoosterConfig) {}
 
+  /**
+   * **NOTE:** Read model schema migration is deprecated. Prefer data migration.
+   */
   @Trace(TraceActionTypes.READ_MODEL_SCHEMA_MIGRATOR_MIGRATE)
   public async migrate<TMigratableReadModel extends ReadModelInterface>(
     readModel: TMigratableReadModel,

packages/framework-core/src/services/graphql/graphql-generator.ts

@@ -6,6 +6,7 @@ import {
   EventSearchParameters,
   EventSearchRequest,
   EventSearchResponse,
+  ProjectionFor,
   QueryEnvelope,
   ReadModelByIdRequestArgs,
   ReadModelInterface,
@@ -15,7 +16,18 @@ import {
   TimeKey,
 } from '@boostercloud/framework-types'
 import { getLogger } from '@boostercloud/framework-common-helpers'
-import { GraphQLFieldResolver, GraphQLInputObjectType, GraphQLSchema } from 'graphql'
+import {
+  FieldNode,
+  getNamedType,
+  GraphQLFieldResolver,
+  GraphQLInputObjectType,
+  GraphQLList,
+  GraphQLNonNull,
+  GraphQLObjectType,
+  GraphQLResolveInfo,
+  GraphQLSchema,
+  isObjectType,
+} from 'graphql'
 import { pluralize } from 'inflected'
 import { BoosterCommandDispatcher } from '../../booster-command-dispatcher'
 import { BoosterEventsReader } from '../../booster-events-reader'
@@ -26,6 +38,8 @@ import { GraphQLQueryGenerator } from './graphql-query-generator'
 import { GraphQLSubscriptionGenerator } from './graphql-subcriptions-generator'
 import { GraphQLTypeInformer } from './graphql-type-informer'
 import { BoosterQueryDispatcher } from '../../booster-query-dispatcher'
+import { SelectionSetNode } from 'graphql/language/ast'
+import { GraphQLInputType, GraphQLNamedInputType } from 'graphql/type/definition'
 
 export class GraphQLGenerator {
   private static commandsDispatcher: BoosterCommandDispatcher
@@ -90,10 +104,19 @@ export class GraphQLGenerator {
   ): GraphQLFieldResolver<unknown, GraphQLResolverContext, ReadModelRequestArgs<ReadModelInterface>> {
     return (parent, args, context, info) => {
       let isPaginated = false
+      const fields: ProjectionFor<unknown> = this.getFields(info) as ProjectionFor<unknown>
+      let select: ProjectionFor<unknown> | undefined = fields.length > 0 ? fields : undefined
       if (info?.fieldName === `List${pluralize(readModelClass.name)}`) {
         isPaginated = true
+        if (select) {
+          select = select
+            .map((field: string) => {
+              return field.split('.').slice(1).join('.')
+            })
+            .filter((str: string) => str.trim().length > 0) as ProjectionFor<unknown>
+        }
       }
-      const readModelEnvelope = toReadModelRequestEnvelope(readModelClass, args, context, isPaginated)
+      const readModelEnvelope = toReadModelRequestEnvelope(readModelClass, args, context, isPaginated, select)
       return this.readModelsReader.search(readModelEnvelope)
     }
   }
@@ -198,13 +221,111 @@ export class GraphQLGenerator {
       sortBy: {},
     }
   }
+
+  /**
+   * Extracts the fields from a GraphQLResolveInfo object. This object is part of a GraphQL request and the goal is to
+   * identify the fields in the request. For example, for the following GraphQL query request:
+   *
+   * ```graphql
+   * query {
+   *   CartReadModel {
+   *     id
+   *     cartItems {
+   *       id
+   *       quantity
+   *     }
+   *   }
+   * }
+   * ```
+   *
+   * it will return the following list of fields: `['id', 'cartItems[].id', 'cartItems[].quantity']`
+   *
+   * @param {GraphQLResolveInfo} info - The GraphQLResolveInfo object.
+   * @returns {string[]} - The extracted fields.
+   * @private
+   */
+  private static getFields(info: GraphQLResolveInfo): string[] {
+    let fields: string[] = []
+
+    /**
+     * Checks if a type is a list.
+     * @param {any} type - The type to check.
+     * @returns {boolean} - True if the type is a list, false otherwise.
+     */
+    const isList = (type: any): boolean => {
+      if (type instanceof GraphQLNonNull) {
+        return type.ofType instanceof GraphQLList
+      }
+      return type instanceof GraphQLList
+    }
+
+    /**
+     * Extracts fields from a selection set.
+     * @param {SelectionSetNode} selectionSet - The selection set.
+     * @param {string[]} path - The current path.
+     * @param {GraphQLObjectType | any} parentType - The parent type.
+     * @returns {string[]} - The extracted fields.
+     */
+    const extractFields = (
+      selectionSet: SelectionSetNode,
+      path: string[] = [],
+      parentType: GraphQLObjectType | any
+    ): string[] => {
+      let subFields: string[] = []
+      if (selectionSet && selectionSet.selections) {
+        selectionSet.selections.forEach((selection: any) => {
+          const fieldName = selection.name.value
+          const field = parentType.getFields()[fieldName]
+
+          if (!field) {
+            return
+          }
+
+          const fieldType: GraphQLNamedInputType = getNamedType(field.type as GraphQLNamedInputType)
+          const currentPath = [...path, fieldName]
+
+          if (isList(field.type)) {
+            const elementType = getNamedType(field.type.ofType)
+            if (isObjectType(elementType)) {
+              currentPath[currentPath.length - 1] += '[]'
+            }
+          }
+
+          if (!selection.selectionSet) {
+            subFields.push(currentPath.join('.'))
+          } else {
+            const nextParentType = isObjectType(fieldType) ? fieldType : parentType
+            subFields = subFields.concat(extractFields(selection.selectionSet, currentPath, nextParentType))
+          }
+        })
+      }
+      return subFields
+    }
+
+    info.fieldNodes.forEach((fieldNode: FieldNode) => {
+      const firstField: string = fieldNode.name.value
+      // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+      // @ts-ignore
+      const firstFieldType = info.schema.getQueryType().getFields()[firstField].type
+      const rootType: GraphQLObjectType = getNamedType(
+        firstFieldType as GraphQLInputType
+      ) as unknown as GraphQLObjectType
+
+      if (fieldNode.selectionSet) {
+        fields = fields.concat(extractFields(fieldNode.selectionSet, [], rootType))
+      }
+    })
+
+    return fields
+  }
 }
 
 function toReadModelRequestEnvelope(
   readModelClass: Class<ReadModelInterface>,
   args: ReadModelRequestArgs<ReadModelInterface>,
   context: GraphQLResolverContext,
-  paginatedVersion = false
+  paginatedVersion = false,
+  select?: ProjectionFor<unknown> | undefined
 ): ReadModelRequestEnvelope<ReadModelInterface> {
   return {
     requestID: context.requestID,
@@ -217,6 +338,7 @@ function toReadModelRequestEnvelope(
     afterCursor: args.afterCursor,
     paginatedVersion,
     version: 1, // TODO: How to pass the version through GraphQL?
+    select,
   }
 }
 

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

@@ -385,7 +385,8 @@ describe('BoosterReadModelReader', () => {
           {},
           undefined,
           undefined,
-          false
+          false,
+          undefined
         )
         expect(result).to.be.deep.equal(expectedReadModels)
       })
@@ -408,7 +409,8 @@ describe('BoosterReadModelReader', () => {
           {},
           undefined,
           undefined,
-          false
+          false,
+          undefined
         )
         expect(result).to.be.deep.equal(expectedReadModels)
         expect(migratorStub).to.have.been.calledTwice
@@ -438,12 +440,84 @@ describe('BoosterReadModelReader', () => {
           {},
           undefined,
           undefined,
-          true
+          true,
+          undefined
         )
         expect(result).to.be.deep.equal(searchResult)
         expect(migratorStub).to.have.been.calledTwice
       })
 
+      context('when there are projections fields', () => {
+        it('calls the provider search function with the right parameters', async () => {
+          const readModelWithProjectionRequestEnvelope: ReadModelRequestEnvelope<TestReadModel> = {
+            class: TestReadModel,
+            className: TestReadModel.name,
+            requestID: random.uuid(),
+            version: 1,
+            filters,
+            currentUser,
+            select: ['id'],
+          } as any
+
+          const expectedReadModels = [new TestReadModel(), new TestReadModel()]
+          const providerSearcherFunctionFake = fake.returns(expectedReadModels)
+          replace(config.provider.readModels, 'search', providerSearcherFunctionFake)
+
+          replace(Booster, 'config', config) // Needed because the function `Booster.readModel` references `this.config` from `searchFunction`
+
+          migratorStub.callsFake(async (readModel, readModelName) => readModel)
+
+          const result = await readModelReader.search(readModelWithProjectionRequestEnvelope)
+
+          expect(providerSearcherFunctionFake).to.have.been.calledOnceWithExactly(
+            match.any,
+            TestReadModel.name,
+            filters,
+            {},
+            undefined,
+            undefined,
+            false,
+            ['id']
+          )
+          expect(result).to.be.deep.equal(expectedReadModels)
+        })
+
+        it('do not  call migrates if select is set', async () => {
+          const readModelWithProjectionRequestEnvelope: ReadModelRequestEnvelope<TestReadModel> = {
+            class: TestReadModel,
+            className: TestReadModel.name,
+            requestID: random.uuid(),
+            version: 1,
+            filters,
+            currentUser,
+            select: ['id'],
+          } as any
+
+          const expectedResult = [new TestReadModel(), new TestReadModel()]
+          const providerSearcherFunctionFake = fake.returns(expectedResult)
+          replace(config.provider.readModels, 'search', providerSearcherFunctionFake)
+
+          replace(Booster, 'config', config) // Needed because the function `Booster.readModel` references `this.config` from `searchFunction`
+
+          migratorStub.callsFake(async (readModel, readModelName) => readModel)
+
+          const result = await readModelReader.search(readModelWithProjectionRequestEnvelope)
+
+          expect(providerSearcherFunctionFake).to.have.been.calledOnceWithExactly(
+            match.any,
+            TestReadModel.name,
+            filters,
+            {},
+            undefined,
+            undefined,
+            false,
+            ['id']
+          )
+          expect(result).to.be.deep.equal(expectedResult)
+          expect(migratorStub).to.have.not.been.called
+        })
+      })
+
       context('when there is only one before hook function', () => {
         const fakeBeforeFn = fake(beforeFn)
 

packages/framework-core/test/booster.test.ts

@@ -84,7 +84,8 @@ describe('the `Booster` class', () => {
         {},
         undefined,
         undefined,
-        false
+        false,
+        undefined
       )
     })
     it('has an instance method', async () => {