Skip to main content

Token Refresh Interceptor

Overview​

The TokenRefreshInterceptor is an Angular HTTP interceptor that handles the automatic refresh of authentication tokens. It ensures that API requests are made with valid tokens, and if a token is expired, it attempts to refresh it before proceeding with the request. This interceptor is essential for maintaining seamless user sessions and ensuring secure API communication.

Why Use TokenRefreshInterceptor​

  • Automatic Token Refresh: Automatically refreshes expired tokens, reducing the need for manual token management.
  • Seamless User Experience: Ensures that users remain authenticated without interruptions.
  • Security: Maintains secure communication by ensuring that all API requests are made with valid tokens.

Installation​

To use the TokenRefreshInterceptor, you need to have the following dependencies installed in your Angular project:

  • @angular/common
  • @angular/core
  • rxjs

Usage​

Step 1: Import the Interceptor​

First, import the TokenRefreshInterceptor in your Angular module.

import { HTTP_INTERCEPTORS } from '@angular/common/http';
import { TokenRefreshInterceptor } from './token-refresh.interceptor';

@NgModule({
  providers: [
    {
      provide: HTTP_INTERCEPTORS,
      useClass: TokenRefreshInterceptor,
      multi: true,
    },
  ],
})
export class AppModule {}

Step 2: Configure OAuthService and TokenHandlerService​

Ensure that OAuthService and TokenHandlerService are properly configured in your application. These services are responsible for handling token storage and refresh logic.

Step 3: Implement the Interceptor​

The TokenRefreshInterceptor is already implemented to handle token refresh logic. Here is the complete implementation for reference:

Step 4: Handle Token Refresh Logic​

Ensure that the OAuthService and TokenHandlerService are correctly handling the token refresh logic. The TokenRefreshInterceptor relies on these services to refresh tokens and manage token events.

Example​

Here is an example of how to use the TokenRefreshInterceptor in an Angular application:

Configure OAuthService​

Ensure that your OAuthService is set up to handle token refresh.

Add Interceptor to Module​

Add the TokenRefreshInterceptor to your Angular module as shown in Step 1.

Make API Requests​

Make API requests as usual. The TokenRefreshInterceptor will automatically handle token refresh when necessary.

import { HttpClient } from '@angular/common/http';
import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  template: `<h1>Token Refresh Example</h1>`,
})
export class AppComponent {
  constructor(private http: HttpClient) {
    this.http.get('/api/protected-resource').subscribe((response) => {
      console.log(response);
    });
  }
}

In this example, the TokenRefreshInterceptor will ensure that the request to /api/protected-resource is made with a valid token, refreshing it if necessary.

Conclusion​

The TokenRefreshInterceptor is a powerful tool for managing token refresh in Angular applications. By automatically handling token refresh, it ensures a seamless and secure user experience. Follow the steps outlined in this documentation to integrate the interceptor into your application.