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Learn Nodemailer Module in Node.js

In this tutorial, we will learn how to send email in Node.js using the nodemailer npm package.For the email provider, we are going to use Sendinblue. Prerequisites Node.js (>v6.0.0 for nodemailer module) Code Editor (For Ex. VS Code, Atom) An account in SendinblueStart by creating a free account in Sendinblue. A Sendinblue free account offers 300 mails/day. Its setup is easy and straightforward. An introduction to Nodemailer Nodemailer, an open source project started in 2010, is annpm module for Node.js applications to send emails. Today, nodemailer is a de facto to send an email in Node.js. Highlights of Nodemailer It is a single module with zero dependencies  It supports HTML Content  Allows you to easily add attachments to messages Supports SMTP as default transport method; other supported transport methods are SES, Sendmail, Stream. OAuth2 authenticationGetting Started For this tutorial, I am using Nodejs v12.16.1 and VS Code as the Code Editor. Create a new directory nodemailer-example.  Open the terminal or cmd inside the directory and run  $ npminit --yes It will initialize a new npm package. Install dependencies Following different npm packages, we are going to use in this project. nodemailer – To send the mail express – To create APIs cors – To resolve the cross originresource sharing body-parser – To extract the body from the API request dotenv – To access the environment variables $ npm install --save nodemailer express cors body-parser dotenv This command will install all the dependencies. Now, we can start the coding. Project Structure Open the nodemailer-example in the code editor and create the following folders and files in it; not to worry, I will be explaining all the files and commands involved.  nodemailer-example    |- routes      |- mail-api.js    |- src      |- send-mail.js    |- template      |- mail.html    |- .env    |- index.js Sendinmail Setup Login to your Sendinmail account. From the top-left menu, select SMTP & API. Select the SMTP tab. Click on Create a new SMTP key. Copy the key at some safe place.  You can deactivate the SMTP key anytime. Now, open the .env file and create 2 key-value pair. USER=YOUREMAILADDRESS  PASS=xxxxxxx-xxxxxxxxxxxx-xxxxxxxxxxxxxxxxxxxxxx USER: The email address using which you created the sendinmail account. PASS:SMTP Key By using .env file we are not exposing the credentials to the web.  Using environment variables in the project is an industrial standard.  Source Code Open the send-mail.js in the editor. Copy and paste the below code in it."use strict";  require("dotenv").config();  constnodemailer = require("nodemailer");  /**   * sendEmail   * @param{Object}mailObj - Email information   * @param{String}from- Email address of the sender   * @param{Array}to- Array of recipients email address   * @param{String}subject - Subject of the email   * @param{String}text - Email body   */  constsendEmail = async (mailObj) => {  const{ from, to, subject, text } = mailObj;  try {  // Create a transporter  lettransporter = nodemailer.createTransport({  host:"smtp-relay.sendinblue.com",  port:587,  auth: {  user:process.env.USER,  pass:process.env.PASS,        },      });  // send mail with defined transport object  letinfo = awaittransporter.sendMail({  from:from, // sender address  to:to, // list of receivers  subject:subject, // subject line  text:text, // plain text body      });  console.log(`Message sent: ${info.messageId}`);  return`Message sent: ${info.messageId}`;    } catch (error) {  console.error(error);  thrownewError(  `Something went wrong in the sendmail method. Error: ${error.message}`      );    }  };  module.exports = sendEmail; Code Walk Through In the beginning, we are importing dotenv to get the environment variables from the .env file and nodemailer to send the email. The sendEmailfunction accepts an object. This object has from, to, subject, text fields. Please note that, from and USER must be same. The nodemailer.createTransportreturns a mail object. The transporter variable is storing the mail object.  let transporter = nodemailer.createTransport({       host: "smtp-relay.sendinblue.com",       port: 587,       auth: {         user: process.env.USER,         pass: process.env.PASS,       },     });Open SMTP tab in your sendinmail account and cross check the host and port.In the auth object, we are passing the user and password from the environment variable.Send the mail using sendMail method.// send mail with defined transport object     let info = await transporter.sendMail({       from: from, // sender address       to: to, // list of receivers       subject: subject, // Subject line       text: text, // plain text body     });It returns a Promise of Send Message Info. In the end, it is returning the message id.  Express Route The sendEmail method is ready.  Let’s create an express route for it. This is the API endpoint using which we can access the sendEmail function. Open the mail-api.js in the code editor and paste the below code. constexpress = require("express");  constrouter = express.Router();  constsendMailMethod = require("../src/send-mail");  // Post request to send an email  router.post("/sendmail", async (req, res) => {  try {  constresult = awaitsendMailMethod(req.body);  // send the response  res.json({  status:true,  payload:result          });      } catch (error) {  console.error(error.message);  res.json({  status:false,  payload:"Something went wrong in Sendmail Route."          })      }  }) module.exports = router; The express framework provides a Router method to create different HTTP methods. Here, we have created a POST method to send the mail.  Instead of extracting the req.body parameters, we passed it as it is. The benefit of this approach is that if there is a change in argument or position, then we would not have to change it in all the places.  In the end, we are exporting the router. Now, this can be used in the server side. Express Server Now, it’s time to create a server and expose the routes on it. Open the index.js and paste the below code in it. "use strict";  constexpress = require("express");  constbodyParser = require("body-parser");  constcors = require("cors");  constapp = express();  constmailAPI = require("./routes/mail-api.js");  // Express body parser  app.use(cors());  app.use(bodyParser.json());  app.use(  bodyParser.urlencoded({  limit:"50mb",  extended:false,  parameterLimit:50000    })  );  // use the routes specified in route folder  app.use("/api/v1", mailAPI);  constport = process.env.PORT || 4444;  //listen to the server  app.listen(port, function () {  console.log(`listening to the port ${port} .....`);  }); The route is available on /api/v1/sendmail. Run the server. $ node index.js  listening to the port 4444 ..... Send an Email using API There are couple of methods to test the API. Using the Postmanor using the Curl command. Using Postman Install Postman on your machine if it is not installed. Create a POST request. URL: http://localhost:4444/api/v1/sendmail Content Type: JSON – Body tab > select JSON from dropdown Request Body:  {  "from": "hello@schadokar.dev",  "to": ["shubham@schadokar.dev"],  "subject": "Mail from Nodemailer",  "text": "Sending an email using nodemailer package."  } Hit Send. Make sure the server is running. On Success, the response returns the message id. Now, check your mailbox. If you are unable to find the mail in your Inbox, check the promotional mail folder. Using Curl CommandOpen the terminal or cmd.In the below curl command, change the parameters and enter.curl -X POST http://localhost:4444/api/v1/sendmail -H "Content-Type:application/json" -d '{"from": "hello@schadokar.dev","to": ["shubham@schadokar.dev"],"subject": "Mail from Nodemailer", "text": "Sending an email using nodemailer package."}'In this example, we have sent a simple text message to the recipient.  Nodemailer also gives you an option to send the message in HTML format. Mail template Open the mail.html in the code editor and paste the below code. <div style="text-align: center;"">  <h1 style="color: #3584c8;">Nodemailer Example</h1>   <p>   This is an example html template to demonstrate the sending email using html.   <br />
Learn Nodemailer Module in Node.js
Shubham
Shubham

Shubham Chadokar

Author

I am a Software Engineer who loves to write articles and tutorials on the latest technologies. I write majorly on Nodejs and Golang. 

Posts by Shubham Chadokar

Learn Nodemailer Module in Node.js

In this tutorial, we will learn how to send email in Node.js using the nodemailer npm package.For the email provider, we are going to use Sendinblue. Prerequisites Node.js (>v6.0.0 for nodemailer module) Code Editor (For Ex. VS Code, Atom) An account in SendinblueStart by creating a free account in Sendinblue. A Sendinblue free account offers 300 mails/day. Its setup is easy and straightforward. An introduction to Nodemailer Nodemailer, an open source project started in 2010, is annpm module for Node.js applications to send emails. Today, nodemailer is a de facto to send an email in Node.js. Highlights of Nodemailer It is a single module with zero dependencies  It supports HTML Content  Allows you to easily add attachments to messages Supports SMTP as default transport method; other supported transport methods are SES, Sendmail, Stream. OAuth2 authenticationGetting Started For this tutorial, I am using Nodejs v12.16.1 and VS Code as the Code Editor. Create a new directory nodemailer-example.  Open the terminal or cmd inside the directory and run  $ npminit --yes It will initialize a new npm package. Install dependencies Following different npm packages, we are going to use in this project. nodemailer – To send the mail express – To create APIs cors – To resolve the cross originresource sharing body-parser – To extract the body from the API request dotenv – To access the environment variables $ npm install --save nodemailer express cors body-parser dotenv This command will install all the dependencies. Now, we can start the coding. Project Structure Open the nodemailer-example in the code editor and create the following folders and files in it; not to worry, I will be explaining all the files and commands involved.  nodemailer-example    |- routes      |- mail-api.js    |- src      |- send-mail.js    |- template      |- mail.html    |- .env    |- index.js Sendinmail Setup Login to your Sendinmail account. From the top-left menu, select SMTP & API. Select the SMTP tab. Click on Create a new SMTP key. Copy the key at some safe place.  You can deactivate the SMTP key anytime. Now, open the .env file and create 2 key-value pair. USER=YOUREMAILADDRESS  PASS=xxxxxxx-xxxxxxxxxxxx-xxxxxxxxxxxxxxxxxxxxxx USER: The email address using which you created the sendinmail account. PASS:SMTP Key By using .env file we are not exposing the credentials to the web.  Using environment variables in the project is an industrial standard.  Source Code Open the send-mail.js in the editor. Copy and paste the below code in it."use strict";  require("dotenv").config();  constnodemailer = require("nodemailer");  /**   * sendEmail   * @param{Object}mailObj - Email information   * @param{String}from- Email address of the sender   * @param{Array}to- Array of recipients email address   * @param{String}subject - Subject of the email   * @param{String}text - Email body   */  constsendEmail = async (mailObj) => {  const{ from, to, subject, text } = mailObj;  try {  // Create a transporter  lettransporter = nodemailer.createTransport({  host:"smtp-relay.sendinblue.com",  port:587,  auth: {  user:process.env.USER,  pass:process.env.PASS,        },      });  // send mail with defined transport object  letinfo = awaittransporter.sendMail({  from:from, // sender address  to:to, // list of receivers  subject:subject, // subject line  text:text, // plain text body      });  console.log(`Message sent: ${info.messageId}`);  return`Message sent: ${info.messageId}`;    } catch (error) {  console.error(error);  thrownewError(  `Something went wrong in the sendmail method. Error: ${error.message}`      );    }  };  module.exports = sendEmail; Code Walk Through In the beginning, we are importing dotenv to get the environment variables from the .env file and nodemailer to send the email. The sendEmailfunction accepts an object. This object has from, to, subject, text fields. Please note that, from and USER must be same. The nodemailer.createTransportreturns a mail object. The transporter variable is storing the mail object.  let transporter = nodemailer.createTransport({       host: "smtp-relay.sendinblue.com",       port: 587,       auth: {         user: process.env.USER,         pass: process.env.PASS,       },     });Open SMTP tab in your sendinmail account and cross check the host and port.In the auth object, we are passing the user and password from the environment variable.Send the mail using sendMail method.// send mail with defined transport object     let info = await transporter.sendMail({       from: from, // sender address       to: to, // list of receivers       subject: subject, // Subject line       text: text, // plain text body     });It returns a Promise of Send Message Info. In the end, it is returning the message id.  Express Route The sendEmail method is ready.  Let’s create an express route for it. This is the API endpoint using which we can access the sendEmail function. Open the mail-api.js in the code editor and paste the below code. constexpress = require("express");  constrouter = express.Router();  constsendMailMethod = require("../src/send-mail");  // Post request to send an email  router.post("/sendmail", async (req, res) => {  try {  constresult = awaitsendMailMethod(req.body);  // send the response  res.json({  status:true,  payload:result          });      } catch (error) {  console.error(error.message);  res.json({  status:false,  payload:"Something went wrong in Sendmail Route."          })      }  }) module.exports = router; The express framework provides a Router method to create different HTTP methods. Here, we have created a POST method to send the mail.  Instead of extracting the req.body parameters, we passed it as it is. The benefit of this approach is that if there is a change in argument or position, then we would not have to change it in all the places.  In the end, we are exporting the router. Now, this can be used in the server side. Express Server Now, it’s time to create a server and expose the routes on it. Open the index.js and paste the below code in it. "use strict";  constexpress = require("express");  constbodyParser = require("body-parser");  constcors = require("cors");  constapp = express();  constmailAPI = require("./routes/mail-api.js");  // Express body parser  app.use(cors());  app.use(bodyParser.json());  app.use(  bodyParser.urlencoded({  limit:"50mb",  extended:false,  parameterLimit:50000    })  );  // use the routes specified in route folder  app.use("/api/v1", mailAPI);  constport = process.env.PORT || 4444;  //listen to the server  app.listen(port, function () {  console.log(`listening to the port ${port} .....`);  }); The route is available on /api/v1/sendmail. Run the server. $ node index.js  listening to the port 4444 ..... Send an Email using API There are couple of methods to test the API. Using the Postmanor using the Curl command. Using Postman Install Postman on your machine if it is not installed. Create a POST request. URL: http://localhost:4444/api/v1/sendmail Content Type: JSON – Body tab > select JSON from dropdown Request Body:  {  "from": "hello@schadokar.dev",  "to": ["shubham@schadokar.dev"],  "subject": "Mail from Nodemailer",  "text": "Sending an email using nodemailer package."  } Hit Send. Make sure the server is running. On Success, the response returns the message id. Now, check your mailbox. If you are unable to find the mail in your Inbox, check the promotional mail folder. Using Curl CommandOpen the terminal or cmd.In the below curl command, change the parameters and enter.curl -X POST http://localhost:4444/api/v1/sendmail -H "Content-Type:application/json" -d '{"from": "hello@schadokar.dev","to": ["shubham@schadokar.dev"],"subject": "Mail from Nodemailer", "text": "Sending an email using nodemailer package."}'In this example, we have sent a simple text message to the recipient.  Nodemailer also gives you an option to send the message in HTML format. Mail template Open the mail.html in the code editor and paste the below code. 
6827
Learn Nodemailer Module in Node.js

In this tutorial, we will learn how to send email ... Read More

How to read files with Node.js?

In this tutorial, we will explore different ways we can read files in Node.js.  In software development, reading files is a regular part of the job. However, this simple process very often becomes complicated and tedious. Fortunately, that's not the case in Node.js. Node.js provides a built-infile system(fs) module, to carry out file operations. Before we start, let us make sure we have the basic prerequisites. You will need to ensure you have: Node.js  Code Editor (Ex. VS Code, Atom) For this tutorial, my environment setup includes: Node.js - v12.16.1 Code Editor - VS Code fs module fs module is a built-in module in the Node.js. You do notnecessarily need to install it.  The fs module supports both Synchronous and Asynchronous function calls. Getting started I am assuming you have installed the NodeJS. Create a new directory node-fs.  Create 2 files inside the node-fs, data.txt and index.js. Paste the dummy data in the data.txt.Lorem ipsum dolor sit amet, consecteturadipiscingelit, sed do eiusmodtemporincididuntutlabore et dolore magna aliqua. Open this directory in the code editor. From the index.js, we will read the test.txt.  Read file Synchronously using readFileSync The readFileSync is a synchronous method to read a file. Syntax fs.readFileSync(path[, options]) pathfilepath options encoding string or buffer Default null flag string DefaultrOpen index.js in the Code Editor. Paste the below code.// import the fs module const fs = require("fs"); // read file synchronously const readData = fs.readFileSync("./data.txt"); console.log(readData);Open the terminal or cmd in the node-fs directory and run the below command.$ node index.js It has returned the content in the buffer format. The readFileSync by default returns the content in the Buffer format.To get the content in normal string format, we need to pass the utf8 encoding as a parameter.Change the code.// import the fs module const fs = require("fs"); // read file synchronously const readData = fs.readFileSync("./data.txt", "utf8"); console.log(readData);run it.$ node index.jsLorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.Read file Asynchronously using readFileAsynchronous methods are great when you don’t want to wait for a process to complete.  fs module provides an asynchronous method to read a file. It returns a callback.Syntaxfs.readFileSync(path[, options], callback)pathfilepathoptionsencoding string or buffer Default nullflag string Defaultrcallback functionerr Errordata string | BufferSyntax is similar tothe synchronous method except it returns a callback function.// import the fs module const fs = require("fs"); // read file asynchronously fs.readFile("./data.txt", "utf8", (err, data) => {     if (!err) {         console.log(data);     } else {         console.error("Something went wrong while reading the file.");     } });Run the code.$ node index.jsLorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.Read file using Stream Reading file using fs.readFileis an ideal way if the file size is less. If the size is huge, the read will consume the complete Memory and you may find your system hanging. In such scenarios, Stream is the best option. This breaks the file into small chunks of data and sends a piece at a time. In this way, the system can continue with other tasks without allocating the complete memory to it.   Let us code and understand. Node.js provides a createReadStreammethod to stream the file. createReadStreamreturns a fs.ReadStreamobject. The readStream events like data, end, or error. To read the file, we have to listen to these events.  The data event will return the content of the file in chunks.  The end event will notify that, there is no data left in the file to read. The error event returns an error. // import the fs module constfs = require("fs");  // read file using stream const streamRead = async () => {  return new Promise((resolve, reject) => {  try {  // create a read stream const streamRead = fs.createReadStream("./data.txt", {  encoding:"utf8",        });  // listen to data event streamRead.on("data", (data) => {  console.log(data);        });  // listen to end event streamRead.on("end", () => {  resolve("File read complete");        });  // listen to error event streamRead.on("error", (error) => {  throw Error(  "Something went wrong while streaming the file.",  error.message         );        });      } catch (error) {  reject(error);      }    });  };  streamRead().then((res, err) => {  if(!err) console.log(res);  else console.error(err);  }); Run the code.$ node index.jsLorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. File read completeExperiment time! For the purpose of the experiment, I created a file of 20MB to check the performance of readFileSync, readFileand createReadStream.  The average memory consumption of VS Code is 600-700MB in my machine. This is a screenshot before running any of the commands. readFileSync Check the screenshot. This operation took 373MB and it went on to upto ~450MB. readFile (Asynchronous)Check the screenshot. This operation took 506MB and it went on to upto ~600MB.createReadStream Check the screenshot. This operation took 287MB and it reached upto ~300MB.  Conclusion Node.js provides multiple methods to read a file. It completely depends on the file size and the requirement, which method to choose. From our performance tests, streaming turns out to be the most efficient method to use.  The performance may vary from machine to machine and file size. One must note that what we have demonstrated is just for the sake of a demo, so this must not be taken to be the final words. There are other npm packages available for file system, for example,fs-extra.  Hope this tutorial has helped. Taking a formal training course in Node.js would be a great way to fast-track your career.  Happy coding!Tired of fixing bugs? Find easy solutions to your programming queries with our live, interactive workshops. Explore now.
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How to read files with Node.js?

In this tutorial, we will explore different ways w... Read More