client-context.adoc

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, for example, via flatMap, or executed after, for example, 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", ...));