ng-recaptcha

What is ng-recaptcha?

The ng-recaptcha package is an Angular library that provides a simple way to integrate Google's reCAPTCHA into Angular applications. It supports both reCAPTCHA v2 and v3, allowing developers to add CAPTCHA verification to forms and other interactive elements to enhance security.

What are ng-recaptcha's main functionalities?

Basic reCAPTCHA v2 Integration

This feature allows you to integrate the basic reCAPTCHA v2 into your Angular application. The component listens for the resolved event to handle the CAPTCHA response.

import { Component } from '@angular/core';

@Component({
  selector: 'app-recaptcha',
  template: '<re-captcha (resolved)="resolved($event)" siteKey="your-site-key"></re-captcha>'
})
export class RecaptchaComponent {
  resolved(captchaResponse: string) {
    console.log(`Resolved captcha with response: ${captchaResponse}`);
  }
}

reCAPTCHA v3 Integration

This feature demonstrates how to use reCAPTCHA v3, which does not require user interaction. Instead, it generates a token based on user behavior, which can be used for verification.

import { Component } from '@angular/core';
import { ReCaptchaV3Service } from 'ng-recaptcha';

@Component({
  selector: 'app-recaptcha-v3',
  template: '<button (click)="executeAction()">Execute reCAPTCHA v3</button>'
})
export class RecaptchaV3Component {
  constructor(private recaptchaV3Service: ReCaptchaV3Service) {}

  executeAction() {
    this.recaptchaV3Service.execute('importantAction').subscribe((token) => {
      console.log(`Token received: ${token}`);
    });
  }
}

Invisible reCAPTCHA

This feature shows how to implement invisible reCAPTCHA, which is triggered programmatically rather than by user interaction. This is useful for forms where you want to minimize user friction.

import { Component } from '@angular/core';

@Component({
  selector: 'app-invisible-recaptcha',
  template: '<re-captcha (resolved)="resolved($event)" siteKey="your-site-key" size="invisible"></re-captcha><button (click)="executeCaptcha()">Submit</button>'
})
export class InvisibleRecaptchaComponent {
  resolved(captchaResponse: string) {
    console.log(`Resolved captcha with response: ${captchaResponse}`);
  }

  executeCaptcha() {
    // Trigger the invisible reCAPTCHA
  }
}

Other packages similar to ng-recaptcha

ngx-captcha

ngx-captcha is another Angular library for integrating Google's reCAPTCHA. It supports both reCAPTCHA v2 and v3, similar to ng-recaptcha. However, ngx-captcha offers more customization options and additional features like language support and multiple CAPTCHA instances on a single page.

angular-google-recaptcha

angular-google-recaptcha is a lightweight Angular package for adding Google's reCAPTCHA to your application. It is simpler and less feature-rich compared to ng-recaptcha, making it suitable for projects that require basic CAPTCHA functionality without additional complexity.

README

Angular component for Google reCAPTCHA

ng-recaptcha

A simple, configurable, easy-to-start component for handling reCAPTCHA.

Installation

The easiest way is to install trough npm:

npm i ng-recaptcha --save

Usage (see in action)

To start with, you need to import the RecaptchaModule (more on that later):

// app.module.ts
import { RecaptchaModule } from 'ng-recaptcha';
import { BrowserModule }  from '@angular/platform-browser';
import { MyApp } from './app.component.ts';

@NgModule({
  bootstrap: [MyApp],
  declarations: [MyApp],
  imports: [
    BrowserModule,
    RecaptchaModule.forRoot(), // Keep in mind the "forRoot"-magic nuances!
  ],
})
export class MyAppModule { }

Once you have done that, the rest is simple:

// app.component.ts
import { Component } from '@angular/core';

@Component({
    selector: 'my-app',
    template: `<recaptcha (resolved)="resolved($event)" siteKey="YOUR_SITE_KEY"></recaptcha>`,
}) export class MyApp {
    resolved(captchaResponse: string) {
        console.log(`Resolved captcha with response ${captchaResponse}:`);
    }
}

// boot.ts
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { MyAppModule } from './app.module.ts';

platformBrowserDynamic().bootstrapModule(MyAppModule);

Modules: "Forms"-ready and "No-forms"

There are two modules available for you:

import { RecaptchaModule } from 'ng-recaptcha';
import { RecaptchaFormsModule } from 'ng-recaptcha/forms';

If you want your <recaptcha> element to work correctly with [(ngModel)] directive, you need to import the RecaptchaFormsModule into your application module (pretty much like with Angular own '@angular/forms' module).

If you do not rely on Angular forms in your project, you should use the "no-forms" module version, as it does not require the @angular/forms package to be bundled with your code.

Options

The component supports this options:

• siteKey
• theme
• type
• size
• tabIndex

They are all pretty well described in the reCAPTCHA docs, so I won't duplicate it here.

Events

• resolved(response: string). Occurs when the captcha resolution value changed. When user resolves captcha, use response parameter to send to the server for verification. This parameter is equivalent to calling grecaptcha.getResponse.

  If the captcha has expired prior to submitting its value to the server, the component will reset the captcha, and trigger the resolved event with response === null.

Methods

• reset. Performs a manual captcha reset. This method might be useful if your form validation failed, and you need the user to re-enter the captcha.

Specifying a different language (see in action)

<recaptcha> supports various languages. By default recaptcha will guess the user's language itself (which is beyond the scope of this lib). But you can override this behavior and provide a specific language to use. The language setting is global, though, and cannot be set on a per-captcha basis. It can be provided like this:

import { RECAPTCHA_LANGUAGE } from 'ng-recaptcha';

@NgModule({
  providers: [
    {
      provide: RECAPTCHA_LANGUAGE,
      useValue: 'fr', // use French language
    },
  ],
}) export class MyModule { }

You can find the list of supported languages in reCAPTCHA docs.

Loading the reCAPTCHA API by yourself (see in action)

By default, the component assumes that the reCAPTCHA API loading will be handled by the RecaptchaLoaderService. However, you can override that by providing your instance of this service to the Angular DI.

The below code snippet is an example of how such a provider can be implemented.

TL;DR: there should be an Observable that eventually resolves to a grecaptcha-compatible object (e.g. grecaptcha itself).

<script src="https://www.google.com/recaptcha/api.js?render=explicit&amp;onload=onloadCallback"></script>

<script>
    // bootstrap the application once the reCAPTCHA api has loaded
    function onloadCallback() {
        System.import('app').catch(function(err) { console.error(err); });
    }
</script>

import { RecaptchaLoaderService } from 'ng-recaptcha';

@Injectable()
export class PreloadedRecaptchaAPIService {
  public ready: Observable<ReCaptchaV2.ReCaptcha>;

  constructor() {
    let readySubject = new BehaviorSubject<ReCaptchaV2.ReCaptcha>(grecaptcha);
    this.ready = readySubject.asObservable();
  }
}

@NgModule({
  providers: [
    {
      provide: RecaptchaLoaderService,
      useValue: new PreloadedRecaptchaAPIService(),
    },
  ],
}) export class MyModule { }

Usage with required in forms (see in action)

It's very easy to put recaptcha in an Angular form and have it required - just add the required attribute to the <recaptcha> element. Do not forget to import RecaptchaFormsModule from 'ng-recaptcha/forms'!

@Component({
  selector: 'my-form',
  template: `
  <form>
    <recaptcha
      [(ngModel)]="formModel.captcha"
      name="captcha"
      required
      siteKey="YOUR_SITE_KEY"
    ></recaptcha>
  </form>`,
}) export class MyForm {
  formModel = new MyFormModel();
}