Quick Response code crash course using Angular 12

User authentications play a vital role when it comes to securing your application. In addition to the existing authentication methods, Angular 12 comes with another simple yet powerful tool, the quick response code. <!--more--> In this tutorial, we will learn how to create a quick response code that can be used to authenticate users or perform different tasks in an Angular SPA.

Table of contents #

• Table of contents
• Prerequisites
• Objectives
• Setting up the angular project
• Quick response codes in angular
• Integrating the quick response code
• Setting up the quick response code for an angular app
• Configure the QR code scanner for authentication
• Containerize the QR code scanner application
• Conclusion

Prerequisites #

To follow this tutorial, you will need to have:

• Basic knowledge of JavaScript or TypeScript.
• Basic knowledge of Angular 2+. In this tutorial, we will be using Angular 12.
• An IDE is locally installed. We'll be using the WebStorm IDE for this course.
• Angular CLI installed. You can also build the Angular file structure from the ground up.

Objectives #

By the end of this tutorial, you will be able to:

• Create a quick response code that can be used to authenticate users in an Angular SPA.
• Set up the quick response code to work with the Angular CLI.
• Build an Angular project from scratch.
• Deploy the application to a production environment.
• Containerize the application using docker.

Setting up the angular project #

In this tutorial, we will be using the Angular CLI to build an Angular project from scratch.

To create an Angular project, you will need to run the following command:

ng new quick-response-code-crash-course

The above command will create a new Angular project called quick-response-code-crash-course within the current directory.

Next, navigate into the project root and run the following command:

ng serve

The above command starts your Angular application on the default port 4200. However, you can change the port by running the following command:

ng serve port <port>

Open your browser and navigate to http://localhost:4200. You will notice that your application is loading.

Now that we've set up the Angular project, we can start working on the quick response code.

In the next section, we will look at how QR codes work and install the necessary packages.

Quick response codes in angular #

As discussed previously, quick response codes are a simple way to authenticate users on an Angular SPA.

They are barcodes that can be read by a digital device(camera). This information is then stored on the device and can be used to authenticate users.

QR codes have a significant advantage over other authentication methods. They are easy to read and scan hence an efficient way of interacting with the application.

To use a scanner in your Angular application, you will need to install the following packages:

• NPM
• Angular QR Code

It's also worth noting that several packages are available on NPM. However, some of them may not be compatible with your Angular version.

Now let's proceed and install the required packages for scanning as follows:

cd quick-response-code-crash-course
npm i angular2-qrcode

In the above command, we first navigate into our project root and install the angular2-qrcode package.

You should be able to see the package in the package.json file as shown below:

...
"@angular/router": "~7.2.0",
"angular2-qrcode": "^2.0.3",
"core-js": "^2.5.4",
...

At the time of this writing, the latest version of Angular QR Code is 2.0.3. This may be different from your version.

Now that we have installed the packages, we can start using the quick response code.

Let's start by registering this package to our application. Add the following to your app.module.ts file:

//... add other missing imports
// the following import is required for the QR code scanner
import { QRCodeModule } from 'angular2-qrcode';
@NgModule({
  declarations: [
    //... add declarations
  ],
  imports: [
    //... add the BrowserModule,AppRoutingModule and other modules
    QRCodeModule
  ],
  providers: [
      //... add the providers
  ],
  bootstrap: [
      //...add the bootstrap components
  ]
})
export class AppModule { }

Integrating the quick response code #

Now that we have the quick response code installed and registered, we can start using it in our application.

Let's start by creating a new component, QrCodeScannerComponent, that will be used to scan the QR code by running the following command:

ng  g c components/qr-code-scanner

The above command generates a new component called qr-code-scanner in the components directory as follows:

CREATE src/app/components/qr-code-scanner/qr-code-scanner.component.css (0 bytes)
CREATE src/app/components/qr-code-scanner/qr-code-scanner.component.html (34 bytes)
CREATE src/app/components/qr-code-scanner/qr-code-scanner.component.spec.ts (679 bytes)
CREATE src/app/components/qr-code-scanner/qr-code-scanner.component.ts (303 bytes)
UPDATE src/app/app.module.ts (583 bytes)

Next, we need to add the following code to the app.component.html file:

<!--BEGIN the qr code -->
<app-qr-code-scanner></app-qr-code-scanner>
<!--END the qr code -->

We have added the app-qr-code-scanner component to the app.component.html file. These are special QR scanner directives made available by the angular2-qrcode package.

The QR code scanner will be displayed with these directives whenever this component is triggered.

This directive has a couple of attributes that can be used to customize the QR scanner. For example, you can set the width and height of the scanner as follows:

<qr-code [width]="300" [height]="300"></qr-code>

We can customize it further by setting its value to a string. For instance, you can set the value of the QR code as follows:

<!--Add this to qr-code-scanner.component.html-->
<!--BEGIN the qr code -->
<qr-code [value]="'www.section.io'"></qr-code>
<!--END the qr code -->

You notice that we use the <qr-code></qr-code> tag to display the QR code in the above code.

The [value] attribute is used to set the value of the QR code. In this case, we have set the value to www.section.io.

To test the QR code scanner, we can run the following command if you haven't started your Angular application yet:

cd quick-response-code-crash-course
ng serve

Next, visit the http://localhost:4200 URL in your browser.

When you execute the above code, you will notice that a QR code is displayed, as shown in the screenshot below:

Setting up the quick response code for an angular app #

In the previous section, we created a new component called QrCodeScannerComponent that we used to display the QR code scanner.

This section will learn how to customize the QR code scanner to meet our needs, such as user authentication.

The <qr-code> above has the value attribute, which we can use to set the value of the QR code.

Let's proceed and create a public data property called qrCodeValue in the qr-code-scanner.component.ts file as shown below:

// import the component from the core module
import { Component, OnInit } from '@angular/core';

@Component({
  selector: 'app-qr-code-scanner',
  templateUrl: './qr-code-scanner.component.html',
  styleUrls: ['./qr-code-scanner.component.css']
})
export class QrCodeScannerComponent implements OnInit {
  //add the property to hold the qr values
  qrCodeValue = null;
  constructor() { }

  ngOnInit() {
    // on page load, start the scanner
    this.setQRData();
  }

  /**
   * Add a method to generate a QR code
   */
  setQRData() {
    const items = [{
      'First Name': 'John',
      'Last Name': 'Doe',
      'Author At': 'www.section.io',
      'email': 'johndoe@test.io',
      'Top Article': 'Angular Scanner',
      'Years Of Experience': '3 years',
    }];
    this.qrCodeValue = JSON.stringify(items);
  }
}

In the above script, we first import the required dependencies. We then create a public data property called qrCodeValue and set its value to null.

We then add the ngOnInit() to initialize our component with the QR data. Finally, we call the setQRData() method to set the QR code value.

In this method, we create an array called items and add a dummy to it.

Now that we have the data, we need to add the following code to the qr-code-scanner.component.html file:

<qr-code
  [value]="qrCodeValue"
  background="#9DD0FF"
  foreground="#0084FF"
  size="400"
>
</qr-code>

We set the [value] property to the qrCodeValue property in the above code. This is the value defined in the controller that will be displayed in the QR code.

Configure the QR code scanner for authentication #

Now that we have the QR code scanner working, we need to configure it to work for authentication.

QR authentication is on the rise, becoming more and more popular. This is attributed to the fact that QR codes offer a balance of security and convenience.

To use QR in Angular, create a user object that will hold the user information.

Following the previous example, store this value in the qrCodeValue property.

Next, use your smartphone to scan the QR code and see if you can authenticate the user.

To scan the QR codes, you can use the Google Authenticator app or any other QR code scanner app. You may also need a backend server to validate and store the user information upon successful scan.

Containerize the QR code scanner application #

Create a Dockerfile file in the quick-response-code-crash-course root directory and add the following:

FROM node:lts-alpine
RUN npm install -g http-server
WORKDIR /QR
COPY package.json ./
RUN npm install
COPY . .
# Generate the Build of the angular application
RUN npm run build

EXPOSE 4200
CMD [ "http-server", "dist" ]

In the above Dockerfile, we use the official node image as the base image, install the http-server package, and copy the package.json and . directory to the root directory.

Next, we run the npm install command to install the dependencies.

Finally, we run the npm run build command to build the application and then expose the port 4200 to the host machine.

Conclusion #

This article has covered how to install and configure the quick response code.

We have also covered how to use the quick response code in our application.

We have seen how we can generate these QR codes for user authentication. You can improve your skills by implementing the QR code backend for an end-to-end test.

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Peer Review Contributions by: Miller Juma