REST API Authentication with Spring Security and MongoDB

Introduction

Why does our API need authentication?

How it works

Authentication: Basic YWRtaW46cEA1NXcwUmQ=

How Spring Manages Security

What do we need

• A new collection in our MongoDB instance called "users"
• A new document in the users collection with the following fields (any other fields are optional, but these are necessary): username, password (hashed using the BCrypt algorithm, more on that later)
• Sources from the previous post

BCrypt for password hashing

Why should we hash passwords?

Adding a user to MongoDB

db.users.insert({
  “username” : “admin”,
  “password” : “$2a$10$AjHGc4x3Nez/p4ZpvFDWeO6FGxee/cVqj5KHHnHfuLnIOzC5ag4fm”
});

Adding a user model and repository

Model

package com.example.gtommee.rest_tutorial.models;

import org.bson.types.ObjectId;
import org.springframework.data.annotation.Id;

public class Users {
  @Id
  public ObjectId _id;

  public String username;
  public String password;

  public Users() {}

  public Users(ObjectId _id, String username, String password) 
{
    this._id = _id;
    this.username = username;
    this.password = password;
  }

  public void set_id(ObjectId _id) { this._id = _id; }

  public String get_id() { return this._id.toHexString(); }

  public void setPassword(String password) { this.password = password; }

  public String getPassword() { return password; }

  public void setUsername(String username) { this.username = username; }

  public String getUsername() { return username; }
}

Repository

package com.example.gtommee.rest_tutorial.repositories;

import com.example.gtommee.rest_tutorial.models.Users;
import org.springframework.data.mongodb.repository.MongoRepository;

public interface UsersRepository extends MongoRepository<Users, String> {
  Users findByUsername(String username);
}

Adding Security Dependencies

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-security</artifactId>
</dependency>

Create Authentication Service

MongoUserDetailsService.java

package com.example.gtommee.rest_tutorial.services;

import com.example.gtommee.rest_tutorial.models.Users;
import com.example.gtommee.rest_tutorial.repositories.UsersRepository;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.stereotype.Component;

import java.util.Arrays;
import java.util.List;

@Component
public class MongoUserDetailsService implements UserDetailsService{
  @Autowired
  private UsersRepository repository;

  @Override
  public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
    Users user = repository.findByUsername(username);

    if(user == null) {
      throw new UsernameNotFoundException(“User not found”);
    }

    List<SimpleGrantedAuthority> authorities = Arrays.asList(new SimpleGrantedAuthority(“user”));

    return new User(user.getUsername(), user.getPassword(), authorities);
  }
}

Create Security Configuration

SecurityConfiguration.java

package com.example.gtommee.rest_tutorial.config;

import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;

@Configuration
@EnableConfigurationProperties
public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
 @Autowired
 MongoUserDetailsService userDetailsService;
}

Authentication step

@Override
protected void configure(HttpSecurity http) throws Exception {
 http
   .csrf().disable()
   .authorizeRequests().anyRequest().authenticated()
   .and().httpBasic()
   .and().sessionManagement().disable();
}

• csrf().disable(): Disables CSRF Protection because it is not needed for the API
• authorizeRequests().anyRequest().authenticated(): Declares that all requests to any endpoint must be authorized, otherwise they must be rejected.
• and().httpBasic(): Springso that it expects basic HTTP authentication (discussed above).
• .and().sessionManagement().disable(): tells Spring not to store session information for users, as this is not necessary for the API

Adding a Bcrypt Encoder

@Bean
public PasswordEncoder passwordEncoder() {
   return new BCryptPasswordEncoder();
}

Specify Authentication Manager

@Override
public void configure(AuthenticationManagerBuilder builder) 
throws Exception {
  builder.userDetailsService(userDetailsService);
}

Final SecurityConfiguration.java file

import com.example.gtommee.rest_tutorial.services.MongoUserDetailsService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;

@Configuration
@EnableConfigurationProperties
public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
 @Autowired
 MongoUserDetailsService userDetailsService;

 @Override
 protected void configure(HttpSecurity http) throws Exception {
   http
     .csrf().disable()
     .authorizeRequests().anyRequest().authenticated()
     .and().httpBasic()
     .and().sessionManagement().disable();
 }

 @Bean
 public PasswordEncoder passwordEncoder() {
   return new BCryptPasswordEncoder();
 }

 @Override
 public void configure(AuthenticationManagerBuilder builder) 
throws Exception {
   builder.userDetailsService(userDetailsService);
 }
}

Authentication check

401 Unauthorized

[
 {
   “_id”: “5aeccb0a18365ba07414356c”,
   “name”: “Spot”,
   “species”: “dog”,
   “breed”: “pitbull”
 },
 {
   “_id”: “5aeccb0a18365ba07414356d”,
   “name”: “Daisy”,
   “species”: “cat”,
   “breed”: “calico”
 },
 {
   “_id”: “5aeccb0a18365ba07414356e”,
   “name”: “Bella”,
   “species”: “dog”,
   “breed”: “australian shepard”
 }
]

Conclusion