Context
Attributes provide a convenient way to pass information to the filter
chain but they only influence the current request. If you want to pass information that
propagates to additional requests that are nested, e.g. via flatMap
, or executed after,
e.g. via concatMap
, then you’ll need to use the Reactor Context
.
The Reactor Context
needs to be populated at the end of a reactive chain in order to
apply to all operations. For example:
-
Java
WebClient client = WebClient.builder()
.filter((request, next) ->
Mono.deferContextual(contextView -> {
String value = contextView.get("foo");
// ...
}))
.build();
client.get().uri("https://example.org/")
.retrieve()
.bodyToMono(String.class)
.flatMap(body -> {
// perform nested request (context propagates automatically)...
})
.contextWrite(context -> context.put("foo", ...));