2015
https://stackoverflow.com/questions/29797721/oauth2-security-expressions-on-method-level

ExpressionHandler
    https://stackoverflow.com/questions/33638850/how-to-protect-spring-security-oauth-resources-using-preauthorize-based-on-scop
    https://docs.spring.io/spring-security/oauth/apidocs/org/springframework/security/oauth2/provider/expression/OAuth2SecurityExpressionMethods.html
        hasScope
        hasScopeMatching
        hasScopeAnyMatching
        clientHasRole
        clientHasAnyRole
        isOAuth
        isUser
        isClient


import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.security.oauth2.client.DefaultOAuth2ClientContext;
import org.springframework.security.oauth2.client.token.grant.client.ClientCredentialsResourceDetails;
import org.springframework.cloud.security.oauth2.client.feign.OAuth2FeignRequestInterceptor;
import feign.RequestInterceptor;

@Configuration
public class OAuth2ClientConfig {
    @Bean
    @ConfigurationProperties("security.oauth2.localas.client")
    public ClientCredentialsResourceDetails localAuthServerResourceDetails() {
        return new ClientCredentialsResourceDetails();
    }
    @Bean
    public OAuth2RestTemplate localAuthServerRestTemplate() {
        return new OAuth2RestTemplate(localAuthServerResourceDetails());
    }
    @Bean
    public RequestInterceptor oauth2FeignRequestInterceptor() {
        return new OAuth2FeignRequestInterceptor(new DefaultOAuth2ClientContext(), localAuthServerResourceDetails());
    }
}