Investigate simplifying gateway/microservice oauth2 config.

[mshima]

Overview of the feature request

We currently implement some custom filters which probably can be replaced by spring-cloud features.
Like replacing our custom token relay filter with token relay filter

Motivation for or Use Case

Related issues or PR

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[mraible]

FWIW, we already use TokenRelay for Spring Cloud Gateway.

[mshima]

Ok https://github.com/jhipster/generator-jhipster/blob/main/generators/server/templates/src/main/java/package/client/TokenRelayRequestInterceptor.java.ejs is something else then.

https://github.com/jhipster/generator-jhipster/blob/main/generators/server/templates/src/main/java/package/client/AuthorizedUserFeignClient.java.ejs, https://github.com/jhipster/generator-jhipster/blob/main/generators/server/templates/src/main/java/package/client/OAuth2_UserFeignClientInterceptor.java.ejs and https://github.com/jhipster/generator-jhipster/blob/main/generators/server/templates/src/main/java/package/client/OAuth2UserClientFeignConfiguration.java.ejs looks unused

[mshima]

@mraible what's the reason for those feign configurations?
Can be dropped from default?

[mraible]

They're for Feign to access microservices or OAuth-protected resources. They might not be used anymore. I used something similar in this post, which uses Zuul.

[mshima]

There is only references at openapi generator.
https://github.com/jhipster/generator-jhipster/search?p=1&q=feign

I suppose we can drop feign support. Or modularize if needed.

[Tcharl]

Also noticed that client credentials flow isn't supported by our SecurityUtils class.

I used to use UserFeignInterceptor for service-to-service communication: client credentials vs authorization code flow