Spring Security with LDAP Authentication

// LdapController.java

package org.geeksforgeeks.ldap;

import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;

@Controller
public class LdapController {

    @Autowired
    LdapService ldapService;
    
    @GetMapping("/")
    @ResponseBody // This is used to override the default behaviour of @Controller Annotation to return HTML pages.
    public String homePage() {
        return "Welcome to home page!"; // This text will be only visible to authenticated users.
    }

    @GetMapping("/add-user")
    public String addUser() {
        return "addUser.html"; // Custom form page to take inputs from users and create them.
    }
  
    // We will be receiving data from the HTML page and create a user object to generate LDAP user using LdapService.
    @PostMapping(path="/add-user", consumes="application/x-www-form-urlencoded") 
    public String generateUser(@RequestParam Map<String, String> body) {
        UserDTO userDTO = new UserDTO(body.get("email"), body.get("commonName"), body.get("surname"), body.get("password"));
        ldapService.createUser(userDTO);
        return "redirect:/add-user";
    }    
}

//LdapService.java

package org.geeksforgeeks.ldap;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.ldap.core.LdapTemplate;
import org.springframework.stereotype.Service;

@Service
public class LdapService {

    @Autowired
    private LdapTemplate ldapTemplate;
    
  	// Create a entry in the LDAP server
    public void createUser(UserDTO userDTO){
        ldapTemplate.bind("userid="+userDTO.getEmail()+",ou=users,ou=system", null, userDTO.toAttributes());
    }
}

// UserDTO.java

package org.geeksforgeeks.ldap;

import javax.naming.directory.Attributes;
import javax.naming.directory.BasicAttributes;

// Data Transfer Object for LDAP user
public class UserDTO{

    UserDTO(String email, String commonName, String surname, String password){
        this.commonName = commonName;
        this.email = email;
        this.surname = surname;
        this.password = password;
    }

    public String getEmail() {
        return this.email;
    }
    public String getCommonName() {
        return this.commonName;
    }
    public String getSurname() {
        return this.surname;
    }
    public String getPassword() {
        return this.password;
    }
    
    private String email;
    private String commonName;
    private String surname;
    private String password;

    public Attributes toAttributes(){
        Attributes attributes = new BasicAttributes();
        attributes.put("objectClass","inetOrgPerson");
        attributes.put("cn",commonName);
        attributes.put("sn",surname);
        attributes.put("userPassword",password);
        return attributes;
    }
}

//SecurityConfig.java

package org.geeksforgeeks.ldap;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.ldap.core.LdapTemplate;
import org.springframework.ldap.core.support.BaseLdapPathContextSource;
import org.springframework.ldap.core.support.LdapContextSource;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.config.Customizer;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.ldap.LdapBindAuthenticationManagerFactory;
import org.springframework.security.config.annotation.web.configurers.AbstractHttpConfigurer;
import org.springframework.security.web.SecurityFilterChain;

@Configuration
@EnableWebSecurity
public class SecurityConfig{

    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
      http
        .authorizeHttpRequests((authorize) -> authorize
          .anyRequest().fullyAuthenticated() // All requests to all endpoints need authentication
        )
        .formLogin(Customizer.withDefaults())
        .csrf(AbstractHttpConfigurer::disable); // Disable CSRF protection
  
      return http.build();
    }

    @Bean
    public LdapContextSource contextSource() {
        LdapContextSource ldapContextSource = new LdapContextSource();
        ldapContextSource.setUrl("ldap://localhost:10389"); // URL of our LDAP server
        ldapContextSource.setUserDn("uid=admin,ou=system"); // Distinguishable Node of Admin
        ldapContextSource.setPassword("secret"); // Password of Admin
        return ldapContextSource;
    }

    @Bean
    public LdapTemplate ldapTemplate() {
        return new LdapTemplate(contextSource()); // Template used for creating new users
    }

    @Bean
    AuthenticationManager authenticationManager(BaseLdapPathContextSource source){
        LdapBindAuthenticationManagerFactory factory = new LdapBindAuthenticationManagerFactory(source);
        factory.setUserDnPatterns("userid={0},ou=users,ou=system"); // Location of our user directory
        return factory.createAuthenticationManager();
    }
}