« Job Scheduling in Node.js

Introduction

Here will learn how to create a job in node JS using node-cron. Job scheduling allows you to schedule arbitrary code (methods/functions) to execute at a fixed date/time, at recurring intervals, or once after a specified interval.

Prerequisites

1. Need a Node.js installed on your local machine.
2. Have a basic knowledge of Node.js.
3. Have a basic knowledge of the Express framework.
4. Be familiar with sending emails through nodemailer.

Step- 1. Creating a Node.js Application

Create a directory and give it a name node-job-schedule(You can also give name as per your choice). Then open the directory you have created using your favorite code editor. Now open the terminal and type:

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1npm init -y

Add the express framework, node-cron module, and node-mailer module by typing on terminal:

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1npm install express node-cron nodemailer

Step-2. Creating The Server

Create the server that we will use for scheduling tasks. Create an index.js file in our directory(node-job-schedule).

Import the express module and initialize it:

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1const express = require('express');
2const app = express();

Now set the server to listen to port 3001. (You can set port number as you wish)

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1app.listen(3001, () => {
2    console.log('Server started at port 3001');
3});

Step -3. Creating The Email Function

Let’s create the function that will send emails. First, import the node-mailer module:

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1const mailer = require('nodemailer');

Then create a transporter through nodemailer’s createTransport method.

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1const transporter = mailer.createTransport({
2    host: 'smtp.gmail.com',
3    port: 587,
4    auth: {
5        user: 'kumaranishdubey2022@gmail.com',
6        pass: '****************',
7    },
8});

Use this link for pass

https://stackoverflow.com/questions/45478293/username-and-password-not-accepted-when-using-nodemailer

Now create a function and give it a name of your choice, I have used a name sendEmail. In the function, we will use the transporter’s sendMail method to send the email.

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1function sendEmail(message) {
2    transporter
3        .sendMail({
4            from: '"Anish" <kumaranishdubey2023@gmail.com>',
5            to: '"Anish" <kumaranishdubey2022@gmail.com>',
6            subject: 'Scheduled Job Email',
7            text: message,
8        })
9        .then((_) => {
10            console.log('Email sent on ' + new Date());
11        })
12        .catch((error) => {
13            console.log(error);
14        });
15}

Step -4. Scheduling a Task

Import the node-cron module:

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1const cron = require('node-cron');

In this step, we are going to use the schedule method we created above to schedule the sendEmail function. We will schedule the function to run after every 10 minutes.

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1const cron = require('node-cron');
2// cron run at every 10 min
3cron.schedule('*/1 * * * *', function () {
4    sendEmail('Hey User, this email was sent to you automatically');
5});

Step -5. Run the Server and Check.

Now open your terminal in the project root folder, run the following command:

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1node index.js

Result:

Server started at port 3001

Email sent on Thu Nov 03 2022 21:27:04 GMT+0530 (India Standard Time)

Email sent on Thu Nov 03 2022 21:28:03 GMT+0530 (India Standard Time)

For full working code please visit

https://github.com/anishakd4/node-job-schedule