SecurityFilterChain configuration in Spring Boot - Mini Project: Build & Apply

SecurityFilterChain configuration

📖 Scenario: You are building a simple Spring Boot web application that needs basic security setup.You want to configure which URLs require authentication and which do not.

🎯 Goal: Create a SecurityFilterChain bean that configures HTTP security to allow public access to the home page and require authentication for all other requests.

📋 What You'll Learn

Create a SecurityFilterChain bean method named securityFilterChain

Use HttpSecurity to configure security

Allow all requests to / without authentication

Require authentication for any other request

Enable form login for authentication

💡 Why This Matters

🌍 Real World

Web applications often need to control which pages users can see without logging in and which require login. This setup is a common starting point.

💼 Career

Understanding SecurityFilterChain configuration is essential for backend developers working with Spring Boot to secure web applications.

1

Create SecurityFilterChain bean method

Create a method named securityFilterChain that returns SecurityFilterChain and accepts a parameter HttpSecurity http. Annotate this method with @Bean.

Spring Boot

import org.springframework.context.annotation.Bean;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.web.SecurityFilterChain;

public class SecurityConfig {
    // Create securityFilterChain method here
}

Hint

Define a method with @Bean annotation that returns SecurityFilterChain and takes HttpSecurity http as parameter.

2

Configure public access to home page

Inside the securityFilterChain method, configure http to allow all requests to "/" without authentication using authorizeHttpRequests and requestMatchers.

Spring Boot

import org.springframework.context.annotation.Bean;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.web.SecurityFilterChain;

public class SecurityConfig {
    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        // Allow public access to "/"
        // Your code here
        return null;
    }
}

Hint

Use http.authorizeHttpRequests(auth -> auth.requestMatchers("/").permitAll()) to allow public access to the home page.

3

Require authentication for other requests and enable form login

Extend the http configuration to require authentication for any request other than "/" by adding anyRequest().authenticated(). Also enable form login by calling formLogin().

Spring Boot

import org.springframework.context.annotation.Bean;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.web.SecurityFilterChain;

public class SecurityConfig {
    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        // Require authentication for other requests and enable form login
        // Your code here
        return null;
    }
}

Hint

Chain .anyRequest().authenticated() and .formLogin() after permitting "/".

4

Return the built SecurityFilterChain

Complete the securityFilterChain method by returning the built SecurityFilterChain from http.build().

Spring Boot

import org.springframework.context.annotation.Bean;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.web.SecurityFilterChain;

public class SecurityConfig {
    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        http.authorizeHttpRequests(auth -> auth
            .requestMatchers("/").permitAll()
            .anyRequest().authenticated()
        ).formLogin();
        // Return the built SecurityFilterChain
        // Your code here
    }
}

Hint

Use return http.build(); to return the configured SecurityFilterChain.

Practice

1. What is the primary purpose of a SecurityFilterChain in Spring Boot?

easy

A. To handle file uploads

B. To define security rules for web requests and control access

C. To manage application logging levels

D. To configure database connections

Solution

1. Step 1: Understand the role of SecurityFilterChain

   The SecurityFilterChain is used in Spring Security to define how HTTP requests are secured, including which URLs require authentication and what roles can access them.

2. Step 2: Compare with other options

   Database connections, logging, and file uploads are unrelated to SecurityFilterChain's purpose.

3. Final Answer:

   To define security rules for web requests and control access -> Option B

4. Quick Check:

   SecurityFilterChain controls web security = D [OK]

Hint: SecurityFilterChain controls web request security rules [OK]

Common Mistakes:

• Confusing SecurityFilterChain with database or logging config
• Thinking it manages file uploads
• Assuming it handles application-wide settings

2. Which of the following is the correct way to declare a SecurityFilterChain bean in Spring Boot?

easy

A. @Component public void filterChain(HttpSecurity http) { http.build(); }

B. public SecurityFilterChain filterChain() { return new SecurityFilterChain(); }

C. @Bean public void filterChain() { return http.build(); }

D. @Bean public SecurityFilterChain filterChain(HttpSecurity http) throws Exception { return http.build(); }

Solution

1. Step 1: Identify correct bean declaration syntax

   In Spring Boot, a SecurityFilterChain bean must be annotated with @Bean, accept HttpSecurity as a parameter, and return the built chain with http.build().

2. Step 2: Check each option

   @Bean public SecurityFilterChain filterChain(HttpSecurity http) throws Exception { return http.build(); } correctly uses @Bean, returns SecurityFilterChain, and calls http.build(). Options B and D have wrong return types or missing annotations. @Component public void filterChain(HttpSecurity http) { http.build(); } uses @Component and void return, which is incorrect.

3. Final Answer:

   @Bean public SecurityFilterChain filterChain(HttpSecurity http) throws Exception { return http.build(); } -> Option D

4. Quick Check:

   Correct bean method signature = C [OK]

Hint: Bean method must return SecurityFilterChain and use @Bean [OK]

Common Mistakes:

• Forgetting @Bean annotation
• Using void return type
• Not passing HttpSecurity parameter

3. Given this SecurityFilterChain configuration snippet, what will happen when a user accesses /admin URL?

@Bean
public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
  http.authorizeHttpRequests(auth -> auth
    .requestMatchers("/admin").hasRole("ADMIN")
    .anyRequest().authenticated()
  ).formLogin();
  return http.build();
}

medium

A. All URLs are open without authentication

B. Anyone can access /admin without login

C. Only users with role ADMIN can access /admin; others must log in

D. Access to /admin is denied to everyone

Solution

1. Step 1: Analyze the authorization rules

   The config states that requests to "/admin" require the user to have role "ADMIN". All other requests require authentication but no specific role.

2. Step 2: Understand formLogin and access control

   Form login is enabled, so users must log in. Only users with ADMIN role can access /admin; others will be blocked or redirected to login.

3. Final Answer:

   Only users with role ADMIN can access /admin; others must log in -> Option C

4. Quick Check:

   /admin requires ADMIN role = A [OK]

Hint: Check requestMatchers roles and formLogin presence [OK]

Common Mistakes:

• Assuming /admin is open to all
• Ignoring role restrictions
• Thinking formLogin disables security

4. Identify the error in this SecurityFilterChain configuration:

@Bean
public SecurityFilterChain filterChain(HttpSecurity http) {
  http.authorizeHttpRequests(auth -> auth
    .requestMatchers("/user").authenticated()
    .anyRequest().permitAll()
  );
  return http.build();
}

medium

A. Missing throws Exception in method signature

B. Calling http.build() without returning it

C. No error, configuration is correct

D. Using permitAll() before authenticated() causes error

Solution

1. Step 1: Check method signature for exceptions

   The http.build() method can throw a checked exception, so the method should declare throws Exception.

2. Step 2: Verify return statement and method correctness

   The method returns http.build() correctly. The order of authenticated() and permitAll() is valid. So the only issue is missing exception declaration.

3. Final Answer:

   Missing throws Exception in method signature -> Option A

4. Quick Check:

   http.build() may throw Exception = B [OK]

Hint: Add throws Exception when calling http.build() [OK]

Common Mistakes:

• Omitting throws Exception causes compile error
• Misunderstanding order of permitAll and authenticated
• Forgetting to return http.build()

5. You want to configure a SecurityFilterChain that allows anonymous access to /public/**, requires authentication for /user/**, and restricts /admin/** to users with role ADMIN, and denies access to all other requests. Which configuration snippet correctly implements this?

hard

A. @Bean
public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
http.authorizeHttpRequests(auth -> auth
.requestMatchers("/public/**").permitAll()
.requestMatchers("/user/**").authenticated()
.requestMatchers("/admin/**").hasRole("ADMIN")
.anyRequest().denyAll()
).formLogin();
return http.build();
}

B. @Bean
public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
http.authorizeHttpRequests(auth -> auth
.requestMatchers("/admin/**").hasRole("ADMIN")
.requestMatchers("/user/**").authenticated()
.requestMatchers("/public/**").permitAll()
.anyRequest().authenticated()
).formLogin();
return http.build();
}

C. @Bean
public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
http.authorizeHttpRequests(auth -> auth
.requestMatchers("/public/**").authenticated()
.requestMatchers("/user/**").permitAll()
.requestMatchers("/admin/**").hasRole("ADMIN")
.anyRequest().denyAll()
).formLogin();
return http.build();
}

D. @Bean
public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
http.authorizeHttpRequests(auth -> auth
.requestMatchers("/public/**").permitAll()
.requestMatchers("/user/**").permitAll()
.requestMatchers("/admin/**").authenticated()
.anyRequest().denyAll()
).formLogin();
return http.build();
}

Solution

1. Step 1: Match access rules to URL patterns

   The requirement is: /public/** open to all (permitAll), /user/** requires authentication, /admin/** requires ADMIN role, and all others denied.

2. Step 2: Check each option's order and rules

   @Bean public SecurityFilterChain filterChain(HttpSecurity http) throws Exception { http.authorizeHttpRequests(auth -> auth .requestMatchers("/public/**").permitAll() .requestMatchers("/user/**").authenticated() .requestMatchers("/admin/**").hasRole("ADMIN") .anyRequest().denyAll() ).formLogin(); return http.build(); } matches the requirements exactly. @Bean public SecurityFilterChain filterChain(HttpSecurity http) throws Exception { http.authorizeHttpRequests(auth -> auth .requestMatchers("/admin/**").hasRole("ADMIN") .requestMatchers("/user/**").authenticated() .requestMatchers("/public/**").permitAll() .anyRequest().authenticated() ).formLogin(); return http.build(); } allows anyRequest authenticated (not denyAll). @Bean public SecurityFilterChain filterChain(HttpSecurity http) throws Exception { http.authorizeHttpRequests(auth -> auth .requestMatchers("/public/**").authenticated() .requestMatchers("/user/**").permitAll() .requestMatchers("/admin/**").hasRole("ADMIN") .anyRequest().denyAll() ).formLogin(); return http.build(); } swaps permitAll and authenticated for /public and /user incorrectly. @Bean public SecurityFilterChain filterChain(HttpSecurity http) throws Exception { http.authorizeHttpRequests(auth -> auth .requestMatchers("/public/**").permitAll() .requestMatchers("/user/**").permitAll() .requestMatchers("/admin/**").authenticated() .anyRequest().denyAll() ).formLogin(); return http.build(); } permits /user/** to all and only authenticates /admin/**, which is wrong.

3. Final Answer:

   @Bean public SecurityFilterChain filterChain(HttpSecurity http) throws Exception { http.authorizeHttpRequests(auth -> auth .requestMatchers("/public/**").permitAll() .requestMatchers("/user/**").authenticated() .requestMatchers("/admin/**").hasRole("ADMIN") .anyRequest().denyAll() ).formLogin(); return http.build(); } -> Option A

4. Quick Check:

   Correct URL access rules = A [OK]

Hint: Match URL patterns to correct access methods in order [OK]

Common Mistakes:

• Mixing permitAll and authenticated for URLs
• Forgetting to restrict admin URLs by role
• Using anyRequest().authenticated() instead of denyAll()