How to use Spring Boot to login user via OAuth2 protocol?

Question

I use Spring Boot 2.2.4 and I would like to login into my application via OAuth2 protocol and GitHub.

Here is my source code of most important configuration files and classes:

The application.properties file

spring.security.oauth2.client.registration.github.client-id=[my client id]
spring.security.oauth2.client.registration.github.client-secret=[my client secret]
spring.security.oauth2.client.registration.github.redirect-uri=http://[host ip]:8080/login_success

Spring Security config class

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Override
    public void configure(HttpSecurity http) throws Exception {
        http
                .authorizeRequests()
                .antMatchers("/test")
                .authenticated()
                .anyRequest().permitAll()
        .and()
        .oauth2Login();
    }
}

Sample controller class

@RestController
public class SampleController {
    @GetMapping("/")
    public String home() {
        return "Home";
    }

    @GetMapping("/login_success")
    public String loginSuccessMethod() {
        return "Login success";
    }

    @GetMapping("/user")
    public OAuth2User user(@AuthenticationPrincipal OAuth2User principal) {
        return principal;
    }

    @GetMapping("/test")
    public String testMethod() {
        return "Test method";
    }
}

Problem description:

1. When I had tried to visit the /test page then I was redirected to the /login page. It is expected behavior.

2. When I had clicked the GitHub link then I was redirected to login form on github.com. It is expected behavior.

3. When I had typed my user name and password and clicked "sign in" button then I was redirected to /login_success page. It is expected behavior.

4. When I had tried to visit the /test page again then I was redirected to the /login page. So the session was not created. Why?

5. When I had tried to visit the /user page then the user method of my controller returned null. Why?

Answer 1

Problem solved. I have typed wrong redirect uri value on GitHub and application.properties file. The correct value is http://[host ip]:8080/login/oauth2/code/github