AbstractJacksonEncoder ignores FILTER_PROVIDER_HINT when encoding Flux<T> #35575
Description
WebFlux 7.0.0-M9: AbstractJacksonEncoder considers the FILTER_PROVIDER_HINT only when going through encodeValue():
however when encoding a
Flux<T> to a non-streaming media type, the hint is ignored. The filter hint should probably be checked here:
Context: I was using MappingJacksonValue extensively to programmatically add Jackson filters to my responses and am replacing it now with using hints, where I noticed that they are not used for Flux<T> body types.
Side note: Some guidance on how to actually provide hints would be helpful. The only proper, user-facing API I found was the ServerResponse builder for functional endpoints. But I haven't found anything on how to provide hints for encoding client requests (WebClient) or responses returned from @RequestMapping controller methods.
My current solution is to replace the default JacksonJsonEncoder with a custom one:
class MyCustomEncoder extends JacksonJsonEncoder { MyCustomEncoder(JsonMapper jsonMapper) { super(jsonMapper); } @Override public Flux<DataBuffer> encode(Publisher<?> inputStream, DataBufferFactory bufferFactory, ResolvableType elementType, MimeType mimeType, Map<String, Object> hints) { return Flux.deferContextual(reactorContext -> { FilterProvider myFilter = ...; // Create configured FilterProvider from reactorContext Map<String, Object> hintsToUse = Hints.merge(hints, JacksonCodecSupport.FILTER_PROVIDER_HINT, myFilter); return super.encode(inputStream, bufferFactory, elementType, mimeType, hintsToUse); }); } @Override public DataBuffer encodeValue(Object value, DataBufferFactory bufferFactory, ResolvableType valueType, MimeType mimeType, Map<String, Object> hints) { ContextView reactorContext = Context.empty(); if (hints != null) { // thank you for putting the context in here 🙏 reactorContext = (ContextView) hints.get(ContextView.class.getName(), Context.empty()); } FilterProvider myFilter = ...; // Create configured FilterProvider from reactorContext Map<String, Object> hintsToUse = Hints.merge(hints, JacksonCodecSupport.FILTER_PROVIDER_HINT, myFilter); return super.encodeValue(value, bufferFactory, valueType, mimeType, hintsToUse); } }