Spring Boot 2, oAuth2 get access token minimal configuration example

basic spring boot working application to show how to setup spring boot to get oAuth2 access_token (url: /oauth/token) with minimal configuration. (basic project and directory structure generated using https://start.spring.io/)

source code@: https://github.com/buddhiprab/springboot-oauth2-token-example

pom.xml, with spring-security-oauth2 dependancy (in this example i’m using spring-security-oauth2 version 2.3.6.RELEASE, spring-security-oauth2 version 2.4 has some deprecations)

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.buddhi</groupId>
   <artifactId>springboot-oauth2-token-example</artifactId>
   <version>1.0-SNAPSHOT</version>
   <packaging>jar</packaging>
   <description>Demo project for Spring Boot oAuth2 get token</description>

   <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>2.1.8.RELEASE</version>
   </parent>

   <properties>
      <java.version>1.8</java.version>
   </properties>

   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-web</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework.security.oauth</groupId>
         <artifactId>spring-security-oauth2</artifactId>
         <version>2.3.6.RELEASE</version>
      </dependency>
   </dependencies>

   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
         </plugin>
      </plugins>
   </build>

</project>

spring boot application class with @EnableAuthorizationServer

package com.buddhi.oauth2;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.security.oauth2.config.annotation.web.configuration.EnableAuthorizationServer;

@SpringBootApplication
@EnableAuthorizationServer
public class Oauth2Application {

   public static void main(String[] args) {
      SpringApplication.run(Oauth2Application.class, args);
   }

}

extend the AuthorizationServerConfigurerAdapter and specify 2 clients

used InMemoryTokenStore as TokenStore

package com.buddhi.oauth2;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.security.oauth2.config.annotation.configurers.ClientDetailsServiceConfigurer;
import org.springframework.security.oauth2.config.annotation.web.configuration.AuthorizationServerConfigurerAdapter;
import org.springframework.security.oauth2.config.annotation.web.configuration.EnableAuthorizationServer;
import org.springframework.security.oauth2.provider.token.TokenStore;
import org.springframework.security.oauth2.provider.token.store.InMemoryTokenStore;

@Configuration
public class AuthorizationServerConfig extends AuthorizationServerConfigurerAdapter {

    @Override
    public void configure(ClientDetailsServiceConfigurer clients) throws Exception {
        clients
                .inMemory()
            .withClient("client_a")
            .secret(passwordEncoder().encode("password_a"))
            .authorities("ROLE_A")
            .scopes("all")
            .authorizedGrantTypes("client_credentials")
            .and()
            .withClient("client_b")
            .secret(passwordEncoder().encode("password_b"))
            .authorities("ROLE_B")
            .scopes("all")
            .authorizedGrantTypes("client_credentials");
   }

   @Bean
   public TokenStore tokenStore() {
      return new InMemoryTokenStore();
    }

   @Bean
   public PasswordEncoder passwordEncoder(){
      return new BCryptPasswordEncoder(4);
    }
}

Postman request

POST /oauth/token?grant_type=client_credentials HTTP/1.1
Host: localhost:8100
Authorization: Basic YTph

response

{
“access_token”: “9a734f52–76e3–46cc-8b3c-43b101de7609”,
“token_type”: “bearer”,
“expires_in”: 43199,
“scope”: “all”
}

for Spring Boot OAuth 2.0 separating Authorization Service and Resource Service

see: https://medium.com/@buddhiprabhath/spring-boot-oauth-2-0-separating-authorization-service-and-resource-service-1641ebced1f0