Spring Boot OAuth2 with Github - spring-boot

Question

I am implementing OAuth2 architecture with GitHub as authorization server to log into my dummy web application. Everything works perfectly fine. I got problem when I log in using my GitHub credentials I want the redirected page to show some message for user for example Welcome XYZ, but I could not get username who is logged in currently but a number is shown instead. I used principal object as well as Authentication object. Please would any body tell how do I achieve it?
Here is code for OAuth2 GitHub Configuration.
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.config.oauth2.client.CommonOAuth2Provider;
import org.springframework.security.oauth2.client.registration.ClientRegistration;
import org.springframework.security.oauth2.client.registration.ClientRegistrationRepository;
import org.springframework.security.oauth2.client.registration.InMemoryClientRegistrationRepository;
#Configuration
public class WebSecurityConfigurerAdapterImp extends WebSecurityConfigurerAdapter {
#Override
protected void configure(HttpSecurity http) throws Exception {
http.oauth2Login((c)->
{
c.clientRegistrationRepository(this.clientRegistrationRepository());
}
);
http.authorizeRequests().anyRequest().authenticated();
}
private ClientRegistrationRepository clientRegistrationRepository()
{
ClientRegistration c=this.clientRegistration();
return new InMemoryClientRegistrationRepository(c);
}
private ClientRegistration clientRegistration()
{
return CommonOAuth2Provider.GITHUB.getBuilder("github").clientId("72bc31d8b0304575442c").clientSecret("XYZSECRET").build();
}
}
Code for main_controller to which user will be redirected after logging in.
package com.controllers;
import java.security.Principal;
import org.springframework.security.core.Authentication;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseBody;
#Controller
public class Main_Controller {
#GetMapping("/")
#ResponseBody
public String HomePage(Authentication p)
{
System.out.println("Hellow "+p.getName());
return "Hello People.";
}
}

Answer 1

By default if you use "CommonOAuth2Provider.GITHUB" then principal name is map to "id" of your github user. So, you need to map principal name attribute to "login"