According to WebAsyncManager documentation,
An async scenario starts with request processing as usual in a thread (T1). Concurrent request handling can be initiated by calling startCallableProcessing or startDeferredResultProcessing, both of which produce a result in a separate thread (T2). The result is saved and the request dispatched to the container, to resume processing with the saved result in a third thread (T3). Within the dispatched thread (T3), the saved result can be accessed via getConcurrentResult() or its presence detected via hasConcurrentResult().
The Spring SecurityContext is available in T1 and T2, but not in T3. I need the SecurityContext in T3, while serializing the response (it's a peculiar requirement). I can fix this by setting
spring.security.filter.dispatcher-types=REQUEST,ERROR,ASYNC, but this causes my entire FilterChain to run twice, which I'm trying to avoid.
Is there a way to get the SecurityContext in T3 without running the FilterChain again?