Refactored email service for modernity and clarity

Server/index.js

@@ -1,26 +1,24 @@
 const express = require("express");
 const helmet = require("helmet");
 const cors = require("cors");
-const authRouter = require("./routes/authRoute");
-const monitorRouter = require("./routes/monitorRoute");
-const checkRouter = require("./routes/checkRoute");
-const alertRouter = require("./routes/alertRoute");
-const { connectDbAndRunServer } = require("./configs/db");
 require("dotenv").config();
 const logger = require("./utils/logger");
 const { verifyJWT } = require("./middleware/verifyJWT");
 const { handleErrors } = require("./middleware/handleErrors");
+
+const authRouter = require("./routes/authRoute");
+const monitorRouter = require("./routes/monitorRoute");
+const checkRouter = require("./routes/checkRoute");
+const alertRouter = require("./routes/alertRoute");
+const pageSpeedCheckRouter = require("./routes/pageSpeedCheckRoute");
+
+const { connectDbAndRunServer } = require("./configs/db");
 const queueRouter = require("./routes/queueRoute");
 const JobQueue = require("./service/jobQueue");
-const pageSpeedCheckRouter = require("./routes/pageSpeedCheckRoute");
-const nodemailer = require("nodemailer");
-
-const emailService = require("./service/emailService");
+const EmailService = require("./service/emailService");
 
 // Need to wrap server setup in a function to handle async nature of JobQueue
 const startApp = async () => {
-  // const { sendEmail } = require('./utils/sendEmail')
-
   // **************************
   // Here is where we can swap out DBs easily.  Spin up a mongoDB instance and try it out.
   // Simply comment out the FakeDB and uncomment the MongoDB or vice versa.
@@ -42,12 +40,6 @@ const startApp = async () => {
     ? DB_TYPE[process.env.DB_TYPE]()
     : require("./db/FakeDb");
 
-  /**
-   * NOTES
-   * Email Service will be added
-   * Logger Service will be added (Winston or similar)
-   */
-
   const app = express();
 
   // middlewares
@@ -62,11 +54,12 @@ const startApp = async () => {
   // Make DB accessible anywhere we have a Request object
   // By adding the DB to the request object, we can access it in any route
   // Thus we do not need to import it in every route file, and we can easily swap out DBs as there is only one place to change it
-  // Same applies for JobQueue
+  // Same applies for JobQueue and emailService
   // **************************
   app.use((req, res, next) => {
     req.db = db;
     req.jobQueue = jobQueue;
+    req.emailSerivce = emailSerivce;
     next();
   });
 
@@ -90,39 +83,21 @@ const startApp = async () => {
     }
   });
 
-  // Nodemailer code here
-  const transporter = nodemailer.createTransport({
-    host: process.env.EMAIL_SERVICE_HOST,
-    port: process.env.EMAIL_SERVICE_PORT,
-    auth: {
-      user: process.env.EMAIL_SERVICE_USERNAME,
-      pass: process.env.EMAIL_SERVICE_PASSWORD,
-    },
-  });
-
-  app.use("/api/v1/mail", (req, res) => {
-    console.log("Started");
-    // Replacing varibales
-    const context = { name: "Alex" };
-
-    // Define mail options
-    const mailOptions = {
-      from: "BlueWave Uptime <bluewaveuptime@gmail.com>", // sender address
-      to: "muhammadkhalilzadeh1998@gmailc.com", // list of receivers
-      subject: "Testing template emails", // Subject line
-      html: emailService.sendWelcomeEmail(context), // html body
-    };
-
-    // Send mail with defined transport object
-    transporter.sendMail(mailOptions, (error, info) => {
-      if (error) {
-        return res
-          .status(500)
-          .send({ message: "Error sending email", error: error });
-      }
-      console.log(info);
-      res.status(200).send({ message: "Email sent successfully", info: info });
-    });
+  app.use("/api/v1/mail", async (req, res) => {
+    try {
+      const id = await req.emailSerivce.buildAndSendEmail(
+        "welcomeEmailTemplate",
+        {
+          name: "Alex",
+        },
+        "ajhollid@gmail.com",
+        "Welcome"
+      );
+      res.status(200).json({ success: true, msg: "Email sent", data: id });
+    } catch (error) {
+      logger.error(error.message);
+      return res.status(500).json({ message: error.message });
+    }
   });
 
   /**
@@ -131,8 +106,10 @@ const startApp = async () => {
    */
   app.use(handleErrors);
 
+  // Create services
   await connectDbAndRunServer(app, db);
   const jobQueue = await JobQueue.createJobQueue(db);
+  const emailSerivce = new EmailService();
 
   const cleanup = async () => {
     console.log("Shutting down gracefully");

Server/service/emailService.js

@@ -1,125 +1,59 @@
 const fs = require("fs");
 const path = require("path");
+const nodemailer = require("nodemailer");
 const { compile } = require("handlebars");
 const { mjml2html } = require("mjml");
 
-// Fetching Templates
+class EmailService {
+  constructor() {
+    this.loadTemplate = (templateName) => {
+      const templatePath = path.join(
+        __dirname,
+        `../templates/${templateName}.mjml`
+      );
+      const templateContent = fs.readFileSync(templatePath, "utf8");
+      return compile(templateContent);
+    };
 
-// Welcome Email Template
-const welcomeEmailTemplatePath = path.join(
-  __dirname,
-  "../templates/welcomeEmail.mjml"
-);
-const welcomeEmailTemplateContent = fs.readFileSync(
-  welcomeEmailTemplatePath,
-  "utf8"
-);
-const welcomeEmailTemplate = compile(welcomeEmailTemplateContent);
+    // TODO  Load less used templates in their respective functions
+    this.templateLookup = {
+      welcomeEmailTemplate: this.loadTemplate("welcomeEmail"),
+      employeeActivationTemplate: this.loadTemplate("employeeActivation"),
+      noIncidentsThisWeekTemplate: this.loadTemplate("noIncidentsThisWeek"),
+      serverIsDownTemplate: this.loadTemplate("serverIsDown"),
+      serverIsUpTemplate: this.loadTemplate("serverIsUp"),
+      passwordResetTemplate: this.loadTemplate("passwordReset"),
+    };
 
-// Employee Activation Email Template
-const employeeActivationTemplatePath = path.join(
-  __dirname,
-  "../templates/employeeActivation.mjml"
-);
-const employeeActivationTemplateContent = fs.readFileSync(
-  employeeActivationTemplatePath,
-  "utf8"
-);
-const employeeActivation = compile(employeeActivationTemplateContent);
+    this.transporter = nodemailer.createTransport({
+      host: process.env.EMAIL_SERVICE_HOST,
+      port: process.env.EMAIL_SERVICE_PORT,
+      secure: true, // Use `true` for port 465, `false` for all other ports
+      auth: {
+        user: process.env.EMAIL_SERVICE_USERNAME,
+        pass: process.env.EMAIL_SERVICE_PASSWORD,
+      },
+    });
+  }
 
-// No Incident This Week Template
-const noIncidentsThisWeekTemplatePath = path.join(
-  __dirname,
-  "../templates/noIncidentsThisWeek.mjml"
-);
-const noIncidentsThisWeekTemplateContent = fs.readFileSync(
-  noIncidentsThisWeekTemplatePath,
-  "utf8"
-);
-const noIncidentsThisWeek = compile(noIncidentsThisWeekTemplateContent);
+  buildAndSendEmail = async (template, context, to, subject) => {
+    const buildHtml = (template, context) => {
+      const mjml = this.templateLookup[template](context);
+      const html = mjml2html(mjml);
+      return html;
+    };
 
-// Server is Down Template
-const serverIsDownTemplatePath = path.join(
-  __dirname,
-  "../templates/serverIsDown.mjml"
-);
-const serverIsDownTemplateContent = fs.readFileSync(
-  serverIsDownTemplatePath,
-  "utf8"
-);
-const serverIsDown = compile(serverIsDownTemplateContent);
-
-// Server is Up Template
-const serverIsUpTemplatePath = path.join(
-  __dirname,
-  "../templates/serverIsUp.mjml"
-);
-const serverIsUpTemplateContent = fs.readFileSync(
-  serverIsUpTemplatePath,
-  "utf8"
-);
-const serverIsUp = compile(serverIsUpTemplateContent);
-
-// Password Reset Template
-const passwordResetTemplatePath = path.join(
-  __dirname,
-  "../templates/passwordReset.mjml"
-);
-const passwordResetTemplateContent = fs.readFileSync(
-  passwordResetTemplatePath,
-  "utf8"
-);
-const passwordReset = compile(passwordResetTemplateContent);
-
-// *** Application specific functions ***
-
-function sendWelcomeEmail(context) {
-  const mjml = welcomeEmailTemplate(context);
-  const html = mjml2html(mjml);
-
-  return html;
+    const sendEmail = async (to, subject, html) => {
+      const info = await this.transporter.sendMail({
+        to: to,
+        subject: subject,
+        html: html,
+      });
+      return info;
+    };
+    const info = await sendEmail(to, subject, buildHtml(template, context));
+    return info.messageId;
+  };
 }
 
-function sendEmployeeActivationEmail(context) {
-  const mjml = employeeActivation(context);
-  const html = mjml2html(mjml);
-
-  return html;
-}
-
-function sendNoIncidentsThisWeekEmail(context) {
-  const mjml = noIncidentsThisWeek(context);
-  const html = mjml2html(mjml);
-
-  return html;
-}
-
-function sendServerIsDownEmail(context) {
-  const mjml = serverIsDown(context);
-  const html = mjml2html(mjml);
-
-  return html;
-}
-
-function sendServerIsUpEmail(context) {
-  const mjml = serverIsUp(context);
-  const html = mjml2html(mjml);
-
-  return html;
-}
-
-function sendPasswordResetEmail(context) {
-  const mjml = passwordReset(context);
-  const html = mjml2html(mjml);
-
-  return html;
-}
-
-module.exports = {
-  sendWelcomeEmail,
-  sendEmployeeActivationEmail,
-  sendNoIncidentsThisWeekEmail,
-  sendServerIsDownEmail,
-  sendServerIsUpEmail,
-  sendPasswordResetEmail,
-};
+module.exports = EmailService;