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How to Create and Read QR Code in Node.js

Introduction

In this post, you will learn how to Create a QR code in Node. 

Project Structure

This is image title

Setup the Folder

First, we have to create a folder for our project.

  • Open the command prompt /terminal and type mkdir command followed by the folder name.

    # mkdir qrcodee

  • Now change to that folder using cd followed by the folder name.

    # cd qrcodee

Setup Node in Folder

To setup node in the folder, we have to type the following command from the command prompt/terminal.

# npm init -y

This will create a package.json file in the folder which means that Node has been set up in our folder. The file will look like this.

{    
  "name": "qrcodee",  
  "version": "1.0.0",    
  "description": "",    
  "main": "index.js",    
  "scripts": {    
    "test": "echo \"Error: no test specified\" && exit 1"    
  },    
  "keywords": [],    
  "author": "",    
  "license": "ISC"    
}

Install Packages

To build our application, we need to install packages. For installing the packages, we have to use the below command followed by the package name.

# npm install body-parser ejs express mongoose QRcode

After the packages are installed, the package.json will look like this.

{    
  "name": "qrcodee",    
  "version": "1.0.0",    
  "description": "",    
  "main": "index.js",    
  "scripts": {    
    "test": "echo \"Error: no test specified\" && exit 1"  
  },    
  "keywords": [],    
  "author": "",    
  "license": "ISC",    
  "dependencies": {    
    "body-parser": "^1.19.0",    
    "ejs": "^3.0.1",    
    "express": "^4.17.1",    
    "mongoose": "^5.8.11",    
    "qrcode": "^1.4.4"    
  }    
}

Add New Folders

Now add 2 new folders in our project folder:

  • models
  • views

Models Folder

Add a file to it and name it user.js.

user.js

var mongoose    =   require('mongoose');    

var userSchema  =   new mongoose.Schema({    
    name:{    
        type:String    
    },    
    phno:{    
        type:Number    
    }    
});    

module.exports = mongoose.model('user',userSchema);
  • mongoose.schema() - this is used to create the collection(table) schema.
  • mongoose.model() - here we will provide the name to our schema by which we can access it and can do data manipulation in it.

Views Folder

Add a new file to it and name it home.ejs

home.ejs

<html lang="en">    
<head>    
    <meta charset="UTF-8">    
    <meta name="viewport" content="width=device-width, initial-scale=1.0">    
    <meta http-equiv="X-UA-Compatible" content="ie=edge">    
    <title>Qrcode</title>    
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">    
</head>    
<body>    
    <div class="nav justify-content-center">    
    <div class="card border-primary mb-3" style="max-width: 18rem;margin-top: 20px;">    
        <div class="card-header">User Details</div>    
        <div class="card-body text-primary">    
            <form action="/" method="post">    
                <input type="text" name="name" placeholder="enter the name" class="form-control"><br>    
                <input type="text" name="phno" placeholder="enter the phone number" class="form-control"><br>    
               <div class="text-center"> <input type="submit" value="get qrcode" class="btn"> </div>     
             </form>    
        </div>    
      </div>    
    </div>    
    <%if(data){%>     
        <div class="text-center">    
         <h5>Scan QRCode</h5>    
        <img src="<%=data%>" alt="" style="width:100px; height:100px;">    
         </div>    
    <%}%>      
</body>    
</html>

Set The Start Point

In the project folder add a new file and name it app.js.This is the starting point of our application

app.js

var express     =   require('express');    
var mongoose    =   require('mongoose');    
var userModel   =   require('./models/user');    
var bodyParser  =   require('body-parser');    
var QRCode      =   require('qrcode');    

//connect to db    
mongoose.connect('mongodb://localhost:27017/qrdemo',{useNewUrlParser:true})    
.then(()=>console.log('connected to db'))    
.catch((err)=>console.log(err))    

//init app    
var app = express();    

//set the template engine    
app.set('view engine','ejs');    

//fetch data from the reuqest    
app.use(bodyParser.urlencoded({extended:false}));    

//default page load    
app.get('/',(req,res)=>{    
       userModel.find((err,data)=>{    
          if(err){    
              console.log(err);    
          }else{    
              if(data!=''){    
                  var temp =[];    
                  for(var i=0;i< data.length;i++){    
                      var name = {    
                          data:data[i].name    
                      }    
                      temp.push(name);    
                      var phno = {    
                          data:data[i].phno    
                      }    
                      temp.push(phno);    
                  }   
                  // Returns a Data URI containing a representation of the QR Code image.  
                  QRCode.toDataURL(temp,{errorCorrectionLevel:'H'},function (err, url) {    
                    console.log(url)    
                    res.render('home',{data:url})    
                  });    
              }else{    
                  res.render('home',{data:''});    
              }    
          }    
       });    
});    

app.post('/',(req,res)=>{    
        var userr = new userModel({    
            name:req.body.name,    
            phno:req.body.phno    
        });    
        userr.save((err,data)=>{    
             if(err){    
                 console.log(err);    
             }else{    
                 res.redirect('/');    
             }    
        });    
});    

//assign port    
var port  = process.env.PORT || 3000;    
app.listen(port,()=>console.log('server run at '+port));

Now open the package.json file and in the script, add "start":"node app.js"

The package.json file will look like this:

{    
  "name": "qrcodee",    
  "version": "1.0.0",    
  "description": "",    
  "main": "index.js",    
  "scripts": {    
    "test": "echo \"Error: no test specified\" && exit 1",    
    "start": "node app.js"    
  },    
  "keywords": [],    
  "author": "",    
  "license": "ISC",    
  "dependencies": {    
    "body-parser": "^1.19.0",    
    "ejs": "^3.0.1",    
    "express": "^4.17.1",    
    "mongoose": "^5.8.11",    
    "qrcode": "^1.4.4"    
  }    
}

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