Spring Security with Google OAuth2 Authentication

July 8, 2025 ยท View on GitHub

This application uses Spring Security with Google OAuth2 for authentication.

Set the embabel.security.enabled property to true in your application.properties file to enable security features.

Follow these steps to set up Google OAuth2:

Setting Up Google OAuth2

  1. Go to the Google Cloud Console
  2. Create a new project or select an existing one
  3. Navigate to "APIs & Services" > "Credentials"
  4. Click "Create Credentials" and select "OAuth client ID"
  5. Select "Web application" as the application type
  6. Add a name for your OAuth client
  7. Add authorized redirect URIs:
  • http://localhost:8080/login/oauth2/code/google (for local development)
  • Add your production URLs if deploying to production
  1. Click "Create"
  2. Google will provide a Client ID and Client Secret

Configuring the Application

  1. Open src/main/resources/application.properties
  2. Replace the placeholder values with your actual Google OAuth2 credentials:
spring.security.oauth2.client.registration.google.client-id=YOUR_GOOGLE_CLIENT_ID
spring.security.oauth2.client.registration.google.client-secret=YOUR_GOOGLE_CLIENT_SECRET

Security Configuration

The security configuration is defined in SecurityConfig.kt. The current setup:

  • Requires authentication for all pages except static resources and the login page
  • Uses Google OAuth2 for authentication
  • Provides a login page at /login
  • Redirects to the home page after successful login
  • Allows logout with redirect to the login page

User Information

After authentication, user details from Google are available:

  • User profile at /user shows detailed information
  • User name displayed in the navigation bar
  • Access to OAuth2 user attributes in Thymeleaf templates

Custom OAuth2 User Service

The application uses a custom OAuth2 user service (CustomOAuth2UserService.kt) to:

  • Load user details from Google
  • Extract user information (email, name)
  • Assign default role (ROLE_USER)
  • Return a properly configured OAuth2User

Thymeleaf Security Integration

The application uses Thymeleaf's Spring Security integration to show/hide content based on authentication status:

  • Use sec:authorize="isAuthenticated()" to show content only to authenticated users
  • Use sec:authentication="name" to display the authenticated user's name

Example:


<div sec:authorize="isAuthenticated()">
    Welcome, <span sec:authentication="name">User</span>!
</div>

For Production Deployment

For production deployments, consider:

  1. Enabling CSRF protection
  2. Implementing proper user persistence in a database
  3. Adding more granular authorization rules
  4. Configuring secure session management