Command handler to create course

Co-authored-by: Rubén Salado <rsaladocid@users.noreply.github.com>
Co-authored-by: Iván Portillo <ivanportillo@me.com>

Author: 3 people

src/Contexts/Mooc/Courses/application/CourseCreator.ts

@@ -6,6 +6,12 @@ import { CourseName } from '../domain/CourseName';
 import { CourseDuration } from '../domain/CourseDuration';
 import { EventBus } from '../../../Shared/domain/EventBus';
 
+type Params = {
+  courseId: CourseId;
+  courseName: CourseName;
+  courseDuration: CourseDuration;
+};
+
 export class CourseCreator {
   private repository: CourseRepository;
   private eventBus: EventBus;
@@ -15,11 +21,11 @@ export class CourseCreator {
     this.eventBus = eventBus;
   }
 
-  async run(request: CreateCourseRequest): Promise<void> {
+  async run({ courseId, courseName, courseDuration }: Params): Promise<void> {
     const course = Course.create(
-      new CourseId(request.id),
-      new CourseName(request.name),
-      new CourseDuration(request.duration)
+      courseId,
+      courseName,
+      courseDuration
     );
 
     await this.repository.save(course);

src/Contexts/Mooc/Courses/application/CreateCourseCommand.ts

@@ -0,0 +1,20 @@
+import { Command } from '../../../Shared/domain/Command';
+
+type Params = {
+    id: string;
+    name: string;
+    duration: string;
+};
+
+export class CreateCourseCommand extends Command {
+    id: string;
+    name: string;
+    duration: string;
+
+    constructor({ id, name, duration }: Params) {
+        super();
+        this.id = id;
+        this.name = name;
+        this.duration = duration;
+    }
+}

src/Contexts/Mooc/Courses/application/CreateCourseCommandHandler.ts

@@ -0,0 +1,22 @@
+import { CreateCourseCommand } from './CreateCourseCommand';
+import { CommandHandler } from '../../../Shared/domain/CommandHandler';
+import { CourseCreator } from './CourseCreator';
+import { Command } from '../../../Shared/domain/Command';
+import { CourseId } from '../../Shared/domain/Courses/CourseId';
+import { CourseName } from '../domain/CourseName';
+import { CourseDuration } from '../domain/CourseDuration';
+
+export class CreateCourseCommandHandler implements CommandHandler<CreateCourseCommand> {
+    constructor(private courseCreator: CourseCreator) {}
+
+    subscribedTo(): Command {
+        return CreateCourseCommand;
+    }
+
+    async handle(command: CreateCourseCommand): Promise<void> {
+        const courseId = new CourseId(command.id);
+        const courseName = new CourseName(command.name);
+        const courseDuration = new CourseDuration(command.duration);
+        await this.courseCreator.run({ courseId, courseName, courseDuration });
+    }
+}

src/Contexts/Shared/domain/CommandBus.ts

@@ -1,5 +1,5 @@
 import { Command } from './Command';
 
 export interface CommandBus {
-  dispatch(command: Command): void;
+  dispatch(command: Command): Promise<void>;
 }

src/Contexts/Shared/domain/CommandHandler.ts

@@ -1,6 +1,6 @@
 import { Command } from './Command';
 
 export interface CommandHandler<T extends Command> {
-  subscribedTo(): T;
-  handle(command: T): void;
+  subscribedTo(): Command;
+  handle(command: T): Promise<void>;
 }

src/Contexts/Shared/infrastructure/CommandBus/InMemoryCommandBus.ts

@@ -5,9 +5,9 @@ import { CommandHandlersInformation } from './CommandHandlersInformation';
 export class InMemoryCommandBus implements CommandBus {
   constructor(private commandHandlersInformation: CommandHandlersInformation) {}
 
-  dispatch(command: Command): void {
+  async dispatch(command: Command): Promise<void> {
     const handler = this.commandHandlersInformation.search(command);
 
-    handler.handle(command);
+    await handler.handle(command);
   }
 }

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

@@ -7,3 +7,9 @@ services:
   Mooc.courses.CourseCreator:
     class: ../../../../../Contexts/Mooc/Courses/application/CourseCreator
     arguments: ['@Mooc.courses.CourseRepository', '@Mooc.shared.EventBus']
+
+  Mooc.courses.CreateCourseCommandHandler:
+    class: ../../../../../Contexts/Mooc/Courses/application/CreateCourseCommandHandler
+    arguments: ['@Mooc.courses.CourseCreator']
+    tags:
+      - { name: 'commandHandler' }

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

@@ -13,6 +13,14 @@ services:
     class: ../../../../../Contexts/Shared/infrastructure/EventBus/InMemoryAsyncEventBus
     arguments: []
 
+  Mooc.shared.CommandHandlersInformation:
+    class: ../../../../../Contexts/Shared/infrastructure/CommandBus/CommandHandlersInformation
+    arguments: ['!tagged commandHandler']
+
+  Mooc.shared.CommandBus:
+    class: ../../../../../Contexts/Shared/infrastructure/CommandBus/InMemoryCommandBus
+    arguments: ['@Mooc.shared.CommandHandlersInformation']
+
   Mooc.shared.EventBus.DomainEventMapping:
     class: ../../../../../Contexts/Shared/infrastructure/EventBus/DomainEventMapping
     arguments: ['!tagged domainEventSubscriber']

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

@@ -2,7 +2,7 @@ services:
 
   Apps.mooc.controllers.CoursePutController:
     class: ../../../controllers/CoursePutController
-    arguments: ["@Mooc.courses.CourseCreator"]
+    arguments: ["@Mooc.shared.CommandBus"]
 
   Apps.mooc.controllers.StatusGetController:
     class: ../../../controllers/StatusGetController

src/apps/mooc_backend/controllers/CoursePutController.ts

@@ -1,19 +1,21 @@
 import { Request, Response } from 'express';
-import { CourseCreator } from '../../../Contexts/Mooc/Courses/application/CourseCreator';
 import httpStatus from 'http-status';
 import { Controller } from './Controller';
 import { CourseAlreadyExists } from '../../../Contexts/Mooc/Courses/domain/CourseAlreadyExists';
+import { CommandBus } from '../../../Contexts/Shared/domain/CommandBus';
+import { CreateCourseCommand } from '../../../Contexts/Mooc/Courses/application/CreateCourseCommand';
 
 export class CoursePutController implements Controller {
-  constructor(private courseCreator: CourseCreator) {}
+  constructor(private commandBus: CommandBus) {}
 
   async run(req: Request, res: Response) {
     const id: string = req.params.id;
     const name: string = req.body.name;
     const duration: string = req.body.duration;
+    const createCourseCommand = new CreateCourseCommand({ id, name, duration });
 
     try {
-      await this.courseCreator.run({ id, name, duration });
+      await this.commandBus.dispatch(createCourseCommand);
     } catch (error) {
       if (error instanceof CourseAlreadyExists) {
         res.status(httpStatus.BAD_REQUEST).send(error.message);