Skip duplicate JWT parse in AccessControlResource when SecurityContext is already populated

[Yicong-Huang]

Task Summary

In access-control-service/src/main/scala/org/apache/texera/service/resource/AccessControlResource.scala, when SecurityContext.getUserPrincipal is already a SessionUser populated by JwtAuthFilter, reuse it instead of calling JwtParser.parseToken on the Authorization header value again. Fall back to the existing query/body token extraction only when SecurityContext is unauthenticated.

Task Type

• Refactor / Cleanup