feat(api): create slice SendEmailMessage -> EmailMessageWasSent (#261) (#340)

* Configure application email account.
* Sending email messages with NodeMailer.

Author: PawelSzambelan

packages/api/.env.example

@@ -14,3 +14,10 @@ PROCESS_ST_CHECKLIST_URL="https://app.process.st/workflows/CodersCamp-Test-Check
 EVENT_REPOSITORY="prisma"
 SUBSCRIPTION_QUEUE_MAX_RETRY_COUNT=10
 SUBSCRIPTION_QUEUE_WAITING_TIME_ON_RETRY_MS=100
+
+EMAIL_SENDER_TYPE="just-log"
+APP_EMAIL_ADDRESS_FROM="rejestracja@coderscamp.edu.pl"
+NODEMAILER_PORT=
+NODEMAILER_HOST=""
+NODEMAILER_USER=""
+NODEMAILER_PASSWORD=""

packages/api/.env.test

@@ -12,3 +12,6 @@ COOKIE_SECRET="786Tgiu3564Rti8oh89YG6re6"
 
 PROCESS_ST_CHECKLIST_URL="https://app.process.st/workflows/CodersCamp-Test-Checklist-kTrxJoZgP-9IabhRbohIrw/run-link"
 EVENT_REPOSITORY="prisma"
+
+EMAIL_SENDER_TYPE="just-log"
+APP_EMAIL_ADDRESS_FROM="test-email-address@coderscamp.edu.pl"

packages/api/package.json

@@ -39,6 +39,7 @@
     "express": "4.17.1",
     "leaked-handles": "5.2.0",
     "lodash": "4.17.21",
+    "nodemailer": "6.6.3",
     "passport": "0.4.1",
     "passport-github2": "0.1.12",
     "passport-jwt": "4.0.0",

packages/api/src/module/shared/commands/send-email-message.application-command.ts

@@ -0,0 +1,5 @@
+import { AbstractApplicationCommand } from '@/module/application-command-events';
+
+import { SendEmailMessage } from './send-email-message.domain-command';
+
+export class SendEmailMessageApplicationCommand extends AbstractApplicationCommand<SendEmailMessage> {}

packages/api/src/module/shared/commands/send-email-message.domain-command.ts

@@ -0,0 +1,12 @@
+import { EmailMessageId } from '@/shared/domain.types';
+
+export type SendEmailMessage = {
+  type: 'SendEmailMessage';
+  data: {
+    emailMessageId: EmailMessageId;
+    to: string;
+    subject: string;
+    text: string;
+    html: string;
+  };
+};

packages/api/src/module/shared/events/email-message-was-sent.domain-event.ts

@@ -0,0 +1,13 @@
+import { EmailMessageId } from '@/shared/domain.types';
+
+export type EmailMessageWasSent = {
+  type: 'EmailMessageWasSent';
+  data: {
+    emailMessageId: EmailMessageId;
+    from: string;
+    to: string;
+    subject: string;
+    text: string;
+    html: string;
+  };
+};

packages/api/src/module/write/email-sender/application/email-sender.ts

@@ -0,0 +1,7 @@
+export const EMAIL_SENDER = Symbol('EMAIL_SENDER');
+
+export type EmailMessage = { from: string; to: string; subject: string; text: string; html: string };
+
+export interface EmailSender {
+  sendAnEmail(message: EmailMessage): Promise<void>;
+}

packages/api/src/module/write/email-sender/application/send-email-message.command-handler.ts

@@ -0,0 +1,41 @@
+import { Inject } from '@nestjs/common';
+import { CommandHandler, ICommandHandler } from '@nestjs/cqrs';
+
+import { SendEmailMessageApplicationCommand } from '@/commands/send-email-message.application-command';
+import { env } from '@/shared/env';
+import { EMAIL_SENDER, EmailSender } from '@/write/email-sender/application/email-sender';
+import { EmailMessageDomainEvent } from '@/write/email-sender/domain/events';
+import { sendEmailMessage } from '@/write/email-sender/domain/sendEmailMessage';
+import { APPLICATION_SERVICE, ApplicationService } from '@/write/shared/application/application-service';
+import { EventStreamName } from '@/write/shared/application/event-stream-name.value-object';
+
+@CommandHandler(SendEmailMessageApplicationCommand)
+export class SendEmailMessageCommandHandler implements ICommandHandler<SendEmailMessageApplicationCommand> {
+  constructor(
+    @Inject(APPLICATION_SERVICE)
+    private readonly applicationService: ApplicationService,
+
+    @Inject(EMAIL_SENDER)
+    private readonly emailSender: EmailSender,
+  ) {}
+
+  async execute(command: SendEmailMessageApplicationCommand): Promise<void> {
+    const appEmailAddress = env.APP_EMAIL_ADDRESS_FROM;
+    const { emailMessageId, to, subject, text, html } = command.data;
+    const eventStream = EventStreamName.from('EmailMessage', `EmailMessage_${emailMessageId}`);
+
+    await this.emailSender.sendAnEmail({
+      from: appEmailAddress,
+      to,
+      subject,
+      text,
+      html,
+    });
+
+    await this.applicationService.execute<EmailMessageDomainEvent>(
+      eventStream,
+      { causationId: command.id, correlationId: command.metadata.correlationId },
+      (pastEvents) => sendEmailMessage(pastEvents, command, appEmailAddress),
+    );
+  }
+}

packages/api/src/module/write/email-sender/domain/events.ts

@@ -0,0 +1,3 @@
+import { EmailMessageWasSent } from '@/events/email-message-was-sent.domain-event';
+
+export type EmailMessageDomainEvent = EmailMessageWasSent;

packages/api/src/module/write/email-sender/domain/sendEmailMessage.spec.ts

@@ -0,0 +1,34 @@
+import { SendEmailMessage } from '@/commands/send-email-message.domain-command';
+import { EmailMessageDomainEvent } from '@/write/email-sender/domain/events';
+import { sendEmailMessage } from '@/write/email-sender/domain/sendEmailMessage';
+
+describe('sending email message', () => {
+  it('create event EmailMessageWasSent when sendEmailMessage is invoked', () => {
+    // Given
+    const pastEvents: EmailMessageDomainEvent[] = [];
+
+    const emailData = {
+      emailMessageId: '577e13dd-20ad-4d95-bdd9-d544c73ce358',
+      to: 'test@test.com',
+      subject: 'Test email',
+      text: 'Welcome on board!',
+      html: 'Welcome on board! HTML',
+    };
+    const appEmail = 'coderscamp@gmail.com';
+
+    // When
+    const command: SendEmailMessage = {
+      type: 'SendEmailMessage',
+      data: emailData,
+    };
+    const events = sendEmailMessage(pastEvents, command, appEmail);
+
+    // Then
+    expect(events).toStrictEqual([
+      {
+        type: 'EmailMessageWasSent',
+        data: { ...emailData, from: appEmail },
+      },
+    ]);
+  });
+});