How do you integrate Spring Security with Thymeleaf?

Table of Contents

Introduction

Integrating Spring Security with Thymeleaf enables you to create secure, dynamic web applications that manage user authentication and authorization directly within the Thymeleaf templates. By combining Spring Security’s robust security features with Thymeleaf’s flexible templating engine, you can easily display content based on user roles and access rights, protect pages, and customize user interfaces based on security contexts.

In this guide, we will walk through the process of integrating Spring Security with Thymeleaf, providing examples of how to use Thymeleaf security attributes and tags to control access to different parts of your application’s user interface.

Steps to Integrate Spring Security with Thymeleaf

1. Set Up Spring Security Dependencies

To get started, you need to add Spring Security and Thymeleaf dependencies to your Spring Boot project.

Add Dependencies to pom.xml (for Maven)

Add Dependencies to build.gradle (for Gradle)

These dependencies will automatically configure Spring Security and Thymeleaf support in your Spring Boot application.

2. Enable Security Configuration in Spring Boot

Spring Boot’s spring-boot-starter-security provides basic security features out of the box. However, you can configure and customize it by creating a security configuration class.

Here’s an example of a simple Spring Security configuration class:

• **antMatchers("/admin/**").hasRole("ADMIN")**: This line restricts access to /admin/** URLs to users with the ADMIN role.
• **formLogin()**: Configures Spring Security to use form-based authentication with a custom login page (/login).

3. Create a Login Page with Thymeleaf

Next, you can create a Thymeleaf template for the login page. Here’s an example of a simple login form using Spring Security’s built-in authentication system.

login.html (Thymeleaf Template)

• **th:action="@{/login}"**: This will submit the login form to the /login endpoint.
• **th:if="${param.error}"**: This condition shows an error message if the login attempt fails.

4. Add Security Expressions in Thymeleaf Templates

You can use Thymeleaf Security Dialect to include security-specific functionality in your templates. These functions allow you to conditionally render parts of the page based on the current user's authentication or role.

Example 1: Display Content Based on Roles

Use sec:authorize to conditionally display elements based on the user's roles:

• **sec:authorize="hasRole('ADMIN')"**: This will display content only to users with the ADMIN role.
• **sec:authorize="isAuthenticated()"**: This will show content to authenticated users.
• **sec:authorize="!isAuthenticated()"**: This shows content to unauthenticated users.

Example 2: Display Login/Logout Links

You can use the sec:authentication tag to display login or logout links based on whether the user is authenticated:

• **sec:authorize="isAuthenticated()"**: Displays the logout link to authenticated users.
• **sec:authorize="!isAuthenticated()"**: Displays the login link to unauthenticated users.

5. Secure Other Pages and Resources

You can also secure other parts of your web application by applying Spring Security annotations to your controller methods and Thymeleaf templates.

Example: Controller with Security Annotations

• **@Secured("ROLE_ADMIN")**: Ensures that only users with the ROLE_ADMIN authority can access the adminDashboard method.

6. Handle Access Denied and Unauthorized Requests

You can also configure a custom Access Denied Page by specifying it in the Spring Security configuration:

Then, create a simple access-denied.html Thymeleaf template:

Conclusion

Integrating Spring Security with Thymeleaf enables you to secure your web application both at the backend (via Spring Security) and at the frontend (via Thymeleaf templates). By using Spring Security's annotations and Thymeleaf's security attributes, you can easily manage authentication, authorization, and access control at the user interface level. This approach allows you to create highly secure applications where the display and functionality of content depend on the user's roles, permissions, and authentication status.