Add return types description

Author: verils

framework-docs/modules/ROOT/pages/web/webflux/controller/ann-methods/return-types.adoc

@@ -89,9 +89,7 @@ Reactor provides a dedicated operator for that, `Flux#collectList()`.
   downloads or proxying data.
 
 | `Resource`
-| Return a single resource that is written to the response using `ResourceHttpMessageWriter`.
-
-  Notice, this writer overrides your response's `Content-Type` header, make sure you're intending to do so.
+| Return a single resource that is written to the response using xref:web/webflux/reactive-spring.adoc#webflux-codecs-resource[ResourceHttpMessageWriter].
 
 | Other return values
 | If a return value remains unresolved in any other way, it is treated as a model

framework-docs/modules/ROOT/pages/web/webflux/reactive-spring.adoc

@@ -611,6 +611,12 @@ and from higher level objects, or unless they choose to create custom codecs. Fo
 cases please review the information in xref:core/databuffer-codec.adoc[Data Buffers and Codecs],
 especially the section on xref:core/databuffer-codec.adoc#databuffers-using[Using DataBuffer].
 
+[[webflux-codecs-resource]]
+=== `Resource`
+
+`Resource` is a general abstraction for file-like resources in Spring. WebFlux applications can use the `ResourceHttpMessageReader` and `ResourceHttpMessageWriter` to read and write `Resource` instances to and from HTTP requests and responses.
+
+Notice, the `ResourceHttpMessageWriter` automatically detects the media type by the filename of the `Resource` and uses it to override your response's `Content-Type` header. If the detection fails, `application/octet-stream` is used as a fallback. Don't return `Resource` type if you want to control the media type of the response.
 
 [[webflux-logging]]
 == Logging

framework-docs/modules/ROOT/pages/web/webmvc/message-converters.adoc

@@ -83,4 +83,9 @@ content type. This requires the `com.google.protobuf:protobuf-java` dependency.
 | An `HttpMessageConverter` implementation that can read and write JSON documents to and from Protobuf messages.
 This requires the `com.google.protobuf:protobuf-java-util` dependency.
 
+| `ResourceHttpMessageConverter`
+| An `HttpMessageConverter` implementation that can read and write `org.springframework.core.io.Resource` instances from the HTTP request and response.
+
+Notice, the `ResourceHttpMessageWriter` automatically detects the media type by the filename of the `Resource` and uses it to override your response's `Content-Type` header. If the detection fails, `application/octet-stream` is used as a fallback. Don't return `Resource` type if you want to control the media type of the response.
+
 |===

framework-docs/modules/ROOT/pages/web/webmvc/mvc-controller/ann-methods/return-types.adoc

@@ -96,10 +96,7 @@ supported for all return values.
   xref:web/webmvc/mvc-ann-async.adoc#mvc-ann-async-reactive-types[Reactive Types].
 
 | `Resource`
-| Return a single resource that is written to the response using
-  `ResourceHttpMessageConverter` implementations.
-
-  Notice, this writer overrides your response's `Content-Type` header, make sure you're intending to do so.
+| Return a single resource that is written to the response using `ResourceHttpMessageConverter` implementations.
 
 | Other return values
 | If a return value remains unresolved in any other way, it is treated as a model