How to Implement Spring Security With OAuth2

Spring Security provides comprehensive security services for J2EE-based enterprise software applications. It is powerful, flexible, and pluggable. It is not like a Proxy server, firewall, OS level Security, Intrusion Detection System, or JVM Security.

OAuth is an open-authorization protocol that allows accessing resources of the resource owner by enabling the client applications on HTTP services, such as Gmail, GitHub, etc.

The OAuth 2.0 framework enables a third-party application to obtain limited access to an HTTP service, either on behalf of a resource owner by orchestrating an approval interaction between resource owner and HTTP service or by allowing the third-party application to obtain access on its own behalf.

OAuth2 Roles: There are four roles that can be applied on OAuth2:

1. Resource Owner: The owner of the resource — this is pretty self-explanatory.
2. Resource Server: This serves resources that are protected by the OAuth2 token.
3. Client: The application accessing the resource server.
4. Authorization Server:  This is the server issuing access tokens to the client after successfully authenticating the resource owner and obtaining authorization.

OAuth2 Tokens: Tokens are implementation specific random strings, generated by the authorization server.

• Access Token: Sent with each request, usually valid for about an hour only.
• Refresh Token: It is used to get a 00new access token, not sent with each request, usually lives longer than access token.

Let's Implement the Project for Spring Security With OAuth2:

First, create a maven project here, in Eclipse IDE, which will look like :

Resource Server

package com.security.oauth.security;

import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.oauth2.config.annotation.web.configuration.EnableResourceServer;
import org.springframework.security.oauth2.config.annotation.web.configuration.ResourceServerConfigurerAdapter;
import org.springframework.security.oauth2.config.annotation.web.configurers.ResourceServerSecurityConfigurer;
import org.springframework.security.oauth2.provider.error.OAuth2AccessDeniedHandler;

@Configuration
@EnableResourceServer 
/*@EnableResourceServer enables a Spring Security filter that authenticates requests using an incoming OAuth2 token.*/
public class ResourceServerConfiguration extends ResourceServerConfigurerAdapter {
/*class ResourceServerConfigurerAdapter implements ResourceServerConfigurer providing methods to adjust the access rules and paths that are protected by OAuth2 security.*/
private static final String RESOURCE_ID = "my_rest_api";

@Override
public void configure(ResourceServerSecurityConfigurer resources) {
resources.resourceId(RESOURCE_ID).stateless(false);
}

@Override
public void configure(HttpSecurity http) throws Exception {
http.
anonymous().disable()
.requestMatchers().antMatchers("/user/**")
.and().authorizeRequests()
.antMatchers("/user/**").access("hasRole('ADMIN')")
.and().exceptionHandling().accessDeniedHandler(new OAuth2AccessDeniedHandler());
}

}

Authorization Server

package com.security.oauth.security;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.authentication.AuthenticationManager;
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.config.annotation.web.configurers.AuthorizationServerEndpointsConfigurer;
import org.springframework.security.oauth2.config.annotation.web.configurers.AuthorizationServerSecurityConfigurer;
import org.springframework.security.oauth2.provider.approval.UserApprovalHandler;
import org.springframework.security.oauth2.provider.token.TokenStore;

@Configuration
@EnableAuthorizationServer
/*@EnableAuthorizationServer enables an Authorization Server (i.e. an AuthorizationEndpoint and a TokenEndpoint) in the current application context.*/
public class AuthorizationServerConfiguration extends AuthorizationServerConfigurerAdapter {
/*class AuthorizationServerConfigurerAdapter implements AuthorizationServerConfigurer which provides all the necessary methods to configure an Authorization server.*/
private static String REALM="MY_OAUTH_REALM";

@Autowired
private TokenStore tokenStore;

@Autowired
private UserApprovalHandler userApprovalHandler;

@Autowired
@Qualifier("authenticationManagerBean")
private AuthenticationManager authenticationManager;

@Override
public void configure(ClientDetailsServiceConfigurer clients) throws Exception {

clients.inMemory()
        .withClient("my-trusted-client")
            .authorizedGrantTypes("password", "authorization_code", "refresh_token", "implicit")
            .authorities("ROLE_CLIENT", "ROLE_TRUSTED_CLIENT")
            .scopes("read", "write", "trust")
            .secret("secret")
            .accessTokenValiditySeconds(120).//Access token is only valid for 2 minutes.
            refreshTokenValiditySeconds(600);//Refresh token is only valid for 10 minutes.
}

@Override
public void configure(AuthorizationServerEndpointsConfigurer endpoints) throws Exception {
endpoints.tokenStore(tokenStore).userApprovalHandler(userApprovalHandler)
.authenticationManager(authenticationManager);
}

@Override
public void configure(AuthorizationServerSecurityConfigurer oauthServer) throws Exception {
oauthServer.realm(REALM+"/client");
}

}

Security Configuration

package com.security.oauth.security;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.crypto.password.NoOpPasswordEncoder;
import org.springframework.security.oauth2.provider.ClientDetailsService;
import org.springframework.security.oauth2.provider.approval.ApprovalStore;
import org.springframework.security.oauth2.provider.approval.TokenApprovalStore;
import org.springframework.security.oauth2.provider.approval.TokenStoreUserApprovalHandler;
import org.springframework.security.oauth2.provider.request.DefaultOAuth2RequestFactory;
import org.springframework.security.oauth2.provider.token.TokenStore;
import org.springframework.security.oauth2.provider.token.store.InMemoryTokenStore;

@Configuration
@EnableWebSecurity
public class OAuth2SecurityConfiguration extends WebSecurityConfigurerAdapter {

@Autowired
private ClientDetailsService clientDetailsService;

@Autowired
    public void globalUserDetails(AuthenticationManagerBuilder auth) throws Exception {
        auth.inMemoryAuthentication()
        .withUser("bill").password("abc123").roles("ADMIN").and()
        .withUser("bob").password("abc123").roles("USER");
    }


    @Override
    protected void configure(HttpSecurity http) throws Exception {
http
.csrf().disable()
.anonymous().disable()
  .authorizeRequests()
  .antMatchers("/oauth/token").permitAll();
    }

    @Override
    @Bean
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }


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

@Bean
@Autowired
public TokenStoreUserApprovalHandler userApprovalHandler(TokenStore tokenStore){
TokenStoreUserApprovalHandler handler = new TokenStoreUserApprovalHandler();
handler.setTokenStore(tokenStore);
handler.setRequestFactory(new DefaultOAuth2RequestFactory(clientDetailsService));
handler.setClientDetailsService(clientDetailsService);
return handler;
}

@Bean
@Autowired
public ApprovalStore approvalStore(TokenStore tokenStore) throws Exception {
TokenApprovalStore store = new TokenApprovalStore();
store.setTokenStore(tokenStore);
return store;
}

}

Method Security Configuration

package com.security.oauth.security;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.access.expression.method.MethodSecurityExpressionHandler;
import org.springframework.security.config.annotation.method.configuration.EnableGlobalMethodSecurity;
import org.springframework.security.config.annotation.method.configuration.GlobalMethodSecurityConfiguration;
import org.springframework.security.oauth2.provider.expression.OAuth2MethodSecurityExpressionHandler;

@Configuration
@EnableGlobalMethodSecurity(prePostEnabled = true, proxyTargetClass = true)
public class MethodSecurityConfig extends GlobalMethodSecurityConfiguration {
    @SuppressWarnings("unused")
@Autowired
    private OAuth2SecurityConfiguration securityConfig;

    @Override
    protected MethodSecurityExpressionHandler createExpressionHandler() {
        return new OAuth2MethodSecurityExpressionHandler();
    }
}

Controller

package com.security.oauth.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.util.UriComponentsBuilder;

import com.security.oauth.model.User;
import com.security.oauth.service.UserService;

@RestController
public class OAuth2RestController {

    @Autowired
    UserService userService;  //Service which will do all data retrieval/manipulation work


    //-------------------Retrieve All Users--------------------------------------------------------

    @RequestMapping(value = "/user/", method = RequestMethod.GET)
    public ResponseEntity<List<User>> listAllUsers() {
        List<User> users = userService.findAllUsers();
        if(users.isEmpty()){
            return new ResponseEntity<List<User>>(users, HttpStatus.NO_CONTENT);//You many decide to return HttpStatus.NOT_FOUND
        }
        return new ResponseEntity<List<User>>(users, HttpStatus.OK);
    }


    //-------------------Retrieve Single User--------------------------------------------------------

    @RequestMapping(value = "/user/{id}", method = RequestMethod.GET, produces = {MediaType.APPLICATION_JSON_VALUE,MediaType.APPLICATION_XML_VALUE})
    public ResponseEntity<User> getUser(@PathVariable("id") long id) {
        System.out.println("Fetching User with id " + id);
        User user = userService.findById(id);
        if (user == null) {
            System.out.println("User with id " + id + " not found");
            return new ResponseEntity<User>(HttpStatus.NOT_FOUND);
        }
        return new ResponseEntity<User>(user, HttpStatus.OK);
    }



    //-------------------Create a User--------------------------------------------------------

    @RequestMapping(value = "/user/", method = RequestMethod.POST)
    public ResponseEntity<Void> createUser(@RequestBody User user, UriComponentsBuilder ucBuilder) {
        System.out.println("Creating User " + user.getName());

        if (userService.isUserExist(user)) {
            System.out.println("A User with name " + user.getName() + " already exist");
            return new ResponseEntity<Void>(HttpStatus.CONFLICT);
        }

        userService.saveUser(user);

        HttpHeaders headers = new HttpHeaders();
        headers.setLocation(ucBuilder.path("/user/{id}").buildAndExpand(user.getId()).toUri());
        return new ResponseEntity<Void>(headers, HttpStatus.CREATED);
    }


    //------------------- Update a User --------------------------------------------------------

    @RequestMapping(value = "/user/{id}", method = RequestMethod.PUT)
    public ResponseEntity<User> updateUser(@PathVariable("id") long id, @RequestBody User user) {
        System.out.println("Updating User " + id);

        User currentUser = userService.findById(id);

        if (currentUser==null) {
            System.out.println("User with id " + id + " not found");
            return new ResponseEntity<User>(HttpStatus.NOT_FOUND);
        }

        currentUser.setName(user.getName());
        currentUser.setAge(user.getAge());
        currentUser.setSalary(user.getSalary());

        userService.updateUser(currentUser);
        return new ResponseEntity<User>(currentUser, HttpStatus.OK);
    }

    //------------------- Delete a User --------------------------------------------------------

    @RequestMapping(value = "/user/{id}", method = RequestMethod.DELETE)
    public ResponseEntity<User> deleteUser(@PathVariable("id") long id) {
        System.out.println("Fetching & Deleting User with id " + id);

        User user = userService.findById(id);
        if (user == null) {
            System.out.println("Unable to delete. User with id " + id + " not found");
            return new ResponseEntity<User>(HttpStatus.NOT_FOUND);
        }

        userService.deleteUserById(id);
        return new ResponseEntity<User>(HttpStatus.NO_CONTENT);
    }


    //------------------- Delete All Users --------------------------------------------------------

    @RequestMapping(value = "/user/", method = RequestMethod.DELETE)
    public ResponseEntity<User> deleteAllUsers() {
        System.out.println("Deleting All Users");

        userService.deleteAllUsers();
        return new ResponseEntity<User>(HttpStatus.NO_CONTENT);
    }

}

Running the Application

• You can either run the application by hitting the REST API by Postman.
• You can also run this application by SpringRestClient class present in src/test/java, which is internally hitting the REST API by RestTemplateclass.