Refactor FindCourseCounter to use query bus

Co-authored-by: Rubén Salado <rsaladocid@users.noreply.github.com>
Co-authored-by: aliondev <antonioleon@audiense.com>

Author: 3 people

src/Contexts/Mooc/CoursesCounter/application/Find/CoursesCounterFinder.ts

@@ -1,6 +1,6 @@
 import { CoursesCounterRepository } from '../../domain/CoursesCounterRepository';
 import { CoursesCounterNotExist } from '../../domain/CoursesCounterNotExist';
-import { CoursesCounterResponse } from './CoursesCounterResponse';
+import { FindCoursesCounterResponse } from './FindCoursesCounterResponse';
 
 export class CoursesCounterFinder {
   constructor(private repository: CoursesCounterRepository) {}
@@ -11,6 +11,6 @@ export class CoursesCounterFinder {
       throw new CoursesCounterNotExist();
     }
 
-    return new CoursesCounterResponse(counter.total.value);
+    return new FindCoursesCounterResponse(counter.total.value);
   }
 }

src/Contexts/Mooc/CoursesCounter/application/Find/FindCoursesCounterQuery.ts

@@ -0,0 +1,3 @@
+import { Query } from "../../../../Shared/domain/Query";
+
+export class FindCoursesCounterQuery implements Query {}

src/Contexts/Mooc/CoursesCounter/application/Find/FindCoursesCounterQueryHandler.ts

@@ -0,0 +1,17 @@
+import { QueryHandler } from "../../../../Shared/domain/QueryHandler";
+import { FindCoursesCounterQuery } from "./FindCoursesCounterQuery";
+import { FindCoursesCounterResponse } from "./FindCoursesCounterResponse";
+import { Query } from "../../../../Shared/domain/Query";
+import { CoursesCounterFinder } from "./CoursesCounterFinder";
+
+export class FindCoursesCounterQueryHandler implements QueryHandler<FindCoursesCounterQuery, FindCoursesCounterResponse> {
+    constructor(private finder: CoursesCounterFinder) {}
+
+    subscribedTo(): Query {
+        return FindCoursesCounterQuery;
+    }
+    handle(_query: FindCoursesCounterQuery): Promise<FindCoursesCounterResponse> {
+        return this.finder.run();
+    }
+
+}

src/Contexts/Mooc/CoursesCounter/application/Find/CoursesCounterResponse.ts renamed to src/Contexts/Mooc/CoursesCounter/application/Find/FindCoursesCounterResponse.ts

@@ -1,4 +1,4 @@
-export class CoursesCounterResponse {
+export class FindCoursesCounterResponse {
   readonly total: number;
 
   constructor(total: number) {

src/apps/mooc_backend/config/dependency-injection/CoursesCounter/application.yaml

@@ -1,5 +1,4 @@
 services:
-
   Mooc.coursesCounter.CoursesCounterRepository:
     class: ../../../../../Contexts/Mooc/CoursesCounter/infrastructure/persistence/mongo/MongoCoursesCounterRepository
     arguments: ["@Mooc.shared.ConnectionManager"]
@@ -21,4 +20,10 @@ services:
     class: ../../../../../Contexts/Mooc/CoursesCounter/application/Find/CoursesCounterFinder
     arguments: ["@Mooc.coursesCounter.CoursesCounterRepository"]
 
+  
+  Mooc.coursesCounter.FindCoursesCounterQueryHandler:
+    class: ../../../../../Contexts/Mooc/CoursesCounter/application/Find/FindCoursesCounterQueryHandler
+    arguments: ["@Mooc.coursesCounter.CoursesCounterFinder"]
+    tags:
+      - { name: 'queryHandler' }
 

src/apps/mooc_backend/config/dependency-injection/Shared/application.yaml

@@ -28,3 +28,11 @@ services:
   Mooc.shared.EventBus.DomainEventJsonDeserializer:
     class: ../../../../../Contexts/Shared/infrastructure/EventBus/DomainEventJsonDeserializer
     arguments: ['@Mooc.shared.EventBus.DomainEventMapping']
+
+  Mooc.shared.QueryHandlersInformation:
+    class: ../../../../../Contexts/Shared/infrastructure/QueryBus/QueryHandlersInformation
+    arguments: ['!tagged queryHandler']
+
+  Mooc.shared.QueryBus:
+    class: ../../../../../Contexts/Shared/infrastructure/QueryBus/InMemoryQueryBus
+    arguments: ['@Mooc.shared.QueryHandlersInformation']

src/apps/mooc_backend/config/dependency-injection/apps/application.yaml

@@ -10,4 +10,4 @@ services:
 
   Apps.mooc.controllers.CoursesCounterGetController:
     class: ../../../controllers/CoursesCounterGetController
-    arguments: ["@Mooc.coursesCounter.CoursesCounterFinder"]
+    arguments: ["@Mooc.shared.QueryBus"]

src/apps/mooc_backend/controllers/CoursesCounterGetController.ts

@@ -1,18 +1,19 @@
 import { Controller } from './Controller';
 import { Request, Response } from 'express';
-import { CoursesCounterFinder } from '../../../Contexts/Mooc/CoursesCounter/application/Find/CoursesCounterFinder';
 import httpStatus = require('http-status');
 import { CoursesCounterNotExist } from '../../../Contexts/Mooc/CoursesCounter/domain/CoursesCounterNotExist';
+import { FindCoursesCounterQuery } from '../../../Contexts/Mooc/CoursesCounter/application/Find/FindCoursesCounterQuery';
+import { QueryBus } from '../../../Contexts/Shared/domain/QueryBus';
+import { FindCoursesCounterResponse } from '../../../Contexts/Mooc/CoursesCounter/application/Find/FindCoursesCounterResponse';
 
 export class CoursesCounterGetController implements Controller {
-  constructor(private coursesCounterFinder: CoursesCounterFinder) {}
+  constructor(private queryBus: QueryBus) {}
   async run(req: Request, res: Response): Promise<void> {
     try {
-      const query = new FindCourseCounterQuery();
-      const count = await this.queryBus.query(query);
+      const query = new FindCoursesCounterQuery();
+      const count = await this.queryBus.ask<FindCoursesCounterResponse>(query);
 
-      const counter = await this.coursesCounterFinder.run();
-      res.status(httpStatus.OK).send(counter);
+      res.status(httpStatus.OK).send(count);
     } catch (e) {
       if (e instanceof CoursesCounterNotExist) {
         res.status(httpStatus.NOT_FOUND).send();

tests/Contexts/Mooc/CoursesCounter/__mocks__/CoursesCounterRepositoryMock.ts

@@ -1,7 +1,6 @@
 import { CoursesCounterRepository } from '../../../../../src/Contexts/Mooc/CoursesCounter/domain/CoursesCounterRepository';
 import { CoursesCounter } from '../../../../../src/Contexts/Mooc/CoursesCounter/domain/CoursesCounter';
 import { Nullable } from '../../../../../src/Contexts/Shared/domain/Nullable';
-import { CourseId } from '../../../../../src/Contexts/Mooc/Shared/domain/Courses/CourseId';
 
 export class CoursesCounterRepositoryMock implements CoursesCounterRepository {
   private mockSave = jest.fn();

tests/Contexts/Mooc/CoursesCounter/application/Find/CoursesCounterFinder.test.ts renamed to tests/Contexts/Mooc/CoursesCounter/application/Find/FindCourseCounterQueryHandler.test.ts

@@ -3,28 +3,37 @@ import { CoursesCounterMother } from '../../domain/CoursesCounterMother';
 import { CoursesCounterRepositoryMock } from '../../__mocks__/CoursesCounterRepositoryMock';
 import { CoursesCounterResponseMother } from '../../domain/CoursesCounterResponseMother';
 import { CoursesCounterNotExist } from '../../../../../../src/Contexts/Mooc/CoursesCounter/domain/CoursesCounterNotExist';
+import { FindCoursesCounterQueryHandler } from '../../../../../../src/Contexts/Mooc/CoursesCounter/application/Find/FindCoursesCounterQueryHandler';
+import { FindCoursesCounterQuery } from '../../../../../../src/Contexts/Mooc/CoursesCounter/application/Find/FindCoursesCounterQuery';
 
-describe('CoursesCounter Finder', () => {
-  let finder: CoursesCounterFinder;
+describe('FindCourseCounter QueryHandler', () => {
   let repository: CoursesCounterRepositoryMock;
 
   beforeEach(() => {
     repository = new CoursesCounterRepositoryMock();
-    finder = new CoursesCounterFinder(repository);
   });
 
+
   it('should find an existing courses counter', async () => {
     const counter = CoursesCounterMother.random();
-    const expected = CoursesCounterResponseMother.create(counter.total);
     repository.returnOnSearch(counter);
 
-    const actual = await finder.run();
-
+    const handler = new FindCoursesCounterQueryHandler(new CoursesCounterFinder(repository));
+    
+    const query = new FindCoursesCounterQuery();
+    const response = await handler.handle(query);
+    
     repository.assertSearch();
-    expect(expected).toEqual(actual);
+
+    const expected = CoursesCounterResponseMother.create(counter.total);
+    expect(expected).toEqual(response);
   });
 
   it('should throw an exception when courses counter does not exists', async () => {
-    await expect(finder.run()).rejects.toBeInstanceOf(CoursesCounterNotExist);
+    const handler = new FindCoursesCounterQueryHandler(new CoursesCounterFinder(repository));
+
+    const query = new FindCoursesCounterQuery();
+
+    await expect(handler.handle(query)).rejects.toBeInstanceOf(CoursesCounterNotExist);
   });
 });